I've recently been resurrecting some of my old Audio cassette recorders. They are all high quality machines and work very well, but I know (particularly in the case of the Teac), which is about 40 years old, that every one of them could probably benefit from a touch up alignment.

A few months back I went searching for an alignment tape. I found used, and/or what claims to be NOS, and Chinese new, but none of these are anything that I'd be willing to put any faith in. When I last looked there was a company which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anything about either of these sources.

Other than those choices there is nothing out there that I would want to use. These alignment tapes used to be available from manufacturers like Sony and Nakamichi, and they were relatively inexpensive but unfortunately those have not been manufactured for many years.

The problem is without doing a reproduce alignment first there is no way to to properly align a machine.

I was discussing this with a friend recently and he came up with an idea. They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a cassette unit I think. The adapter had a tape "head" of sorts and it had a cable coming out of the top of the adapter that had either two RCA males or a 3..5mm stereo plug on the end. You could plug this end into the output of an IPOD or whatever and the adapter's head would induce a signal onto the cassette players head. I guess this unit must have employed the NAB characteristic curve because the ones I've heard always sounded pretty good to me.

I can probably dig up a couple of these around here, feed signals from my generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for alignment purposes? That would totally eliminate the concerns with used tape of stretching and high frequency roll off.

I would appreciate any thoughts pertaining to any of this, especially in trying to use one of these run of the mill adapters, or any other high quality version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.

So I admit it, I'm a dinosaur. And most of you guys that have been on this group for as long as I have already know that. And although I can no longer hear much above 8KHZ anymore, if you can appreciate it I just want to know that it's there. I just like to transfer my music to cassette and be able to listen to it wherever. Thanks Lenny

wrote:

I've recently been resurrecting some of my old Audio cassette recorders. They are all high quality machines and work very well, but I know (particularly in the case of the Teac), which is about 40 years old, that every one of them could probably benefit from a touch up alignment.

A few months back I went searching for an alignment tape. I found used, and/or what claims to be NOS, and Chinese new, but none of these are anything that I'd be willing to put any faith in. When I last looked there was a company which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anything about either of these sources.

Other than those choices there is nothing out there that I would want to use. These alignment tapes used to be available from manufacturers like Sony and Nakamichi, and they were relatively inexpensive but unfortunately those have not been manufactured for many years.

The problem is without doing a reproduce alignment first there is no way to to properly align a machine.

I was discussing this with a friend recently and he came up with an idea. They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a cassette unit I think. The adapter had a tape "head" of sorts and it had a cable coming out of the top of the adapter that had either two RCA males or a 3.5mm stereo plug on the end. You could plug this end into the output of an IPOD or whatever and the adapter's head would induce a signal onto the cassette players head. I guess this unit must have employed the NAB characteristic curve because the ones I've heard always sounded pretty good to me.

I can probably dig up a couple of these around here, feed signals from my generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for alignment purposes? That would totally eliminate the concerns with used tape of stretching and high frequency roll off.

I would appreciate any thoughts pertaining to any of this, especially in trying to use one of these run of the mill adapters, or any other high quality version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.

So I admit it, I'm a dinosaur. And most of you guys that have been on this group for as long as I have already know that. And although I can no longer hear much above 8KHZ anymore, if you can appreciate it I just want to know that it's there. I just like to transfer my music to cassette and be able to listen to it wherever. Thanks Lenny


I doubt that those cheap adapters are even close to being in
alignment. All they are, is a plastic shell, a tape head and a cord.
They work by magnetically coupling the signal between the heads, and
that doesn't require precision.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

On 17/03/2014 15:00, wrote:
I've recently been resurrecting some of my old Audio cassette recorders. They are all high quality machines and work very well, but I know (particularly in the case of the Teac), which is about 40 years old, that every one of them could probably benefit from a touch up alignment.

A few months back I went searching for an alignment tape. I found used, and/or what claims to be NOS, and Chinese new, but none of these are anything that I'd be willing to put any faith in. When I last looked there was a company which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anything about either of these sources.

Other than those choices there is nothing out there that I would want to use. These alignment tapes used to be available from manufacturers like Sony and Nakamichi, and they were relatively inexpensive but unfortunately those have not been manufactured for many years.

The problem is without doing a reproduce alignment first there is no way to to properly align a machine.

I was discussing this with a friend recently and he came up with an idea. They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a cassette unit I think. The adapter had a tape "head" of sorts and it had a cable coming out of the top of the adapter that had either two RCA males or a 3..5mm stereo plug on the end. You could plug this end into the output of an IPOD or whatever and the adapter's head would induce a signal onto the cassette players head. I guess this unit must have employed the NAB characteristic curve because the ones I've heard always sounded pretty good to me.

I can probably dig up a couple of these around here, feed signals from my generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for alignment purposes? That would totally eliminate the concerns with used tape of stretching and high frequency roll off.

I would appreciate any thoughts pertaining to any of this, especially in trying to use one of these run of the mill adapters, or any other high quality version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.

So I admit it, I'm a dinosaur. And most of you guys that have been on this group for as long as I have already know that. And although I can no longer hear much above 8KHZ anymore, if you can appreciate it I just want to know that it's there. I just like to transfer my music to cassette and be able to listen to it wherever. Thanks Lenny


But those adaptor gizmos do not have to consider alignment, in the sense
of the lateral position of a piece of tape between guide pins or its
azimuth, just vaguely one coil over one head and the other over the
other head.
As far as tape speed is concerned, I've moved over to correlation of the
spindle diameter (x.y9mm diameter where x and y are integres) to capstan
rotation speed, for pretty discerning listners, ie one classic music
buff and another a railway sounds archiver

Here's a thought...

Do you have any commercially recorded cassettes? If so, use them check the
head alignment with an XY (Lissajous) display on your scope. If they're close
to each other, you can reasonably assume their alignment is absolute, or very
close to it.

On Monday, March 17, 2014 11:00:55 AM UTC-4, wrote:
I've recently been resurrecting some of my old Audio cassette recorders. They are all high quality machines and work very well, but I know (particularly in the case of the Teac), which is about 40 years old, that every one of them could probably benefit from a touch up alignment.



A few months back I went searching for an alignment tape. I found used, and/or what claims to be NOS, and Chinese new, but none of these are anything that I'd be willing to put any faith in. When I last looked there was a company which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anything about either of these sources.



Other than those choices there is nothing out there that I would want to use. These alignment tapes used to be available from manufacturers like Sony and Nakamichi, and they were relatively inexpensive but unfortunately those have not been manufactured for many years.



The problem is without doing a reproduce alignment first there is no way to to properly align a machine.



I was discussing this with a friend recently and he came up with an idea. They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a cassette unit I think. The adapter had a tape "head" of sorts and it had a cable coming out of the top of the adapter that had either two RCA males or a 3.5mm stereo plug on the end. You could plug this end into the output of an IPOD or whatever and the adapter's head would induce a signal onto the cassette players head. I guess this unit must have employed the NAB characteristic curve because the ones I've heard always sounded pretty good to me.



I can probably dig up a couple of these around here, feed signals from my generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for alignment purposes? That would totally eliminate the concerns with used tape of stretching and high frequency roll off.



I would appreciate any thoughts pertaining to any of this, especially in trying to use one of these run of the mill adapters, or any other high quality version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.



So I admit it, I'm a dinosaur. And most of you guys that have been on this group for as long as I have already know that. And although I can no longer hear much above 8KHZ anymore, if you can appreciate it I just want to know that it's there. I just like to transfer my music to cassette and be able to listen to it wherever. Thanks Lenny

Azimuth is not the issue. As you mentioned William I can use a commercially made tape and the scope to peak it for that. What I can't do is assure that every frequency that is being impressed into the head is being processed, amplified, and frequency compensated by the reproduce amplifier as to produce a flat signal output. For that the machine's head must see a finite level, either from a standard alignment tape or possibly this hair brained adapter idea of mine.

Once the reproduce amplifier is flat, the record amplifier can be adjusted using the reproduce amplifier as the standard. Lenny

Hold on here, just what is the issue ? there is an amplifier, it applies a frequency response curve. That is that. Do you think the EQ network is faulty or what ?

wrote:

I've recently been resurrecting some of my old Audio cassette recorders.
They are all high quality machines and work very well, but I know
(particularly in the case of the Teac), which is about 40 years old, that
every one of them could probably benefit from a touch up alignment.

A few months back I went searching for an alignment tape. I found used,
and/or what claims to be NOS, and Chinese new, but none of these are
anything that I'd be willing to put any faith in. When I last looked there
was a company which still makes these and there is also apparently
something "hand made" by some individual on what he claims to be
"professional equipment". However the cost for both of these is
exorbitant. And I don't know anything about either of these sources.

Other than those choices there is nothing out there that I would want to
use. These alignment tapes used to be available from manufacturers like
Sony and Nakamichi, and they were relatively inexpensive but unfortunately
those have not been manufactured for many years.

The problem is without doing a reproduce alignment first there is no way
to to properly align a machine.
[...]

There is a further problem that the original recordings may not have
been correctly aligned, or the tapes have become distorted so that they
no longer track through the playback machine correctly. You may find
you have to replay a sample section of each tape to adjust the azimuth
for that particular tape, then rewind it and begin the transfer process.

The alignment process is often a lot easier if you add the two channels
to give mono, or if you can display them on an X-Y oscilloscope.

If you really want a proper alignment tape, you could ask Ted Kendall if
he can still supply them:

http://www.tedkendall.com/



--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

wrote in message
...
I've recently been resurrecting some of my old Audio cassette recorders.
They are all high quality machines and work very well, but I know
(particularly in the case of the Teac), which is about 40 years old, that
every one of them could probably benefit from a touch up alignment.

A few months back I went searching for an alignment tape. I found used,
and/or what claims to be NOS, and Chinese new, but none of these are
anything that I'd be willing to put any faith in. When I last looked there
was a company which still makes these and there is also apparently something
"hand made" by some individual on what he claims to be "professional
equipment". However the cost for both of these is exorbitant. And I don't
know anything about either of these sources.

Other than those choices there is nothing out there that I would want to
use. These alignment tapes used to be available from manufacturers like Sony
and Nakamichi, and they were relatively inexpensive but unfortunately those
have not been manufactured for many years.

The problem is without doing a reproduce alignment first there is no way to
to properly align a machine.

I was discussing this with a friend recently and he came up with an idea.
They make, or used to make anyway these adapters in the shape of an audio
cassette tape. They were mostly used in vehicles who's radios only had a
cassette unit I think. The adapter had a tape "head" of sorts and it had a
cable coming out of the top of the adapter that had either two RCA males or
a 3.5mm stereo plug on the end. You could plug this end into the output of
an IPOD or whatever and the adapter's head would induce a signal onto the
cassette players head. I guess this unit must have employed the NAB
characteristic curve because the ones I've heard always sounded pretty good
to me.

I can probably dig up a couple of these around here, feed signals from my
generator into it but I know that these adapters were never very expensive
so I have to question the wisdom of attempting this. So I was wondering if
perhaps a high quality version of anything like this was ever made for
alignment purposes? That would totally eliminate the concerns with used tape
of stretching and high frequency roll off.

I would appreciate any thoughts pertaining to any of this, especially in
trying to use one of these run of the mill adapters, or any other high
quality version, if such a thing is or was ever available, for my purpose.
Most of my 70's music is on either records or cassettes, (and reel to reel
for that matter, but that's another story), and my service van has a 1990
Delco radio that has seen service in 5 vans already and it has a cassette
player in it as well.

So I admit it, I'm a dinosaur. And most of you guys that have been on this
group for as long as I have already know that. And although I can no longer
hear much above 8KHZ anymore, if you can appreciate it I just want to know
that it's there. I just like to transfer my music to cassette and be able to
listen to it wherever. Thanks Lenny

As has been pointed out, one of those adaptors will not help in the physical
alignment of the head. But, that method will help you to check the EQ of the
playback preamplifier. Basically all you need is a single turn loop of wire
in the proximity of the head, or put the loop inside of a cassettes shell.
Put a resistor between the loop and your generator, like 600 ohm , 50 ohm,
whatever your generator needs for a termination. The current through the
loop will be constant at all audio frequencies provided the generator is
flat too. Then you plot the frequency response at the output of the deck.
The response you get is a 6db per octave rolloff starting at nearly DC. Then
at 1326 hz there should be a 3db boost added to the 6db rolloff. This is a
120usec EQ. There are also EQ's for 70usec and perhaps 90usec, don't recall
the specs for all tape types. There is also a 3180 usec or 1590 usec boost
in the low end. So the overall frequency response is the sum of all three
EQ's. It is tedious way to do it but the curves are standardized EQ's for
NAB. Google for Flux Loop. Or look around on the Ampex Mailing list. You
might find the curves. When all is said and done, you still have the issue
of tape to head contact, and azimuth at high frequencies, and fringing at
low frequencies. A flux loop doesn't help out with that part of the
alignment. And it won't help you set the correct playback operating
level.Dolby chips need to be hit with the correct operating level otherwise
the dolby processing will screw with the EQ too. It might be fun to do, but
in the long run, a flux loop will not align a tape deck.

I used to buy BASF alignment tapes at about $100 a shot. They were the only
ones that were consistant for cassette. And they didn't last long. I beleive
you can still find tapes from MRL (magnetic reference laboratories) or check
with JRF, John French. Any tape that is worth using will cost alot. The sony
and teac tapes were mass produced garbage.

bg

wrote in message ...

Hold on here, just what is the issue? there is an amplifier,
it applies a frequency response curve. That is that. Do you
think the EQ network is faulty or what?

Good point. Once the playback EQ has been set, it doesn't need adjustment. In
fact, most tape decks //don't// have adjustable playback EQ! The curve is
standardized.

So the OP doesn't really have a problem. Even if there //is// a pot in the
playback EQ, there should be no reason to touch it.

On 03/17/2014 02:53 PM, William Sommerwerck wrote:
wrote in message
...

Hold on here, just what is the issue? there is an amplifier,
it applies a frequency response curve. That is that. Do you
think the EQ network is faulty or what?

Good point. Once the playback EQ has been set, it doesn't need
adjustment. In fact, most tape decks //don't// have adjustable playback
EQ! The curve is standardized.

So the OP doesn't really have a problem. Even if there //is// a pot in
the playback EQ, there should be no reason to touch it.



Dolby B dynamically adjusts the curve slightly. Are you trying to
calibrate with a compander running at the same time? When all else fails
use your ears, after listening to your favorite source material on the
same speakers. At 1+7/8 ips it's a miracle they work at all.

"dave" wrote in message
m...
On 03/17/2014 02:53 PM, William Sommerwerck wrote:
wrote in message
...

Once the playback EQ has been set, it doesn't need adjustment.
In fact, most tape decks //don't// have adjustable playback
EQ! The curve is standardized.

Dolby B dynamically adjusts the curve slightly. Are you trying to
calibrate with a compander running at the same time? When all
else fails use your ears, after listening to your favorite source
material on the same speakers. At 1+7/8 ips it's a miracle they
work at all.

Let's back up. Dolby B does not modify playback EQ. This is fixed.

The OP wanted to trim the playback EQ. But on most decks, this is impossible.
* So that brings the discussion to its logical conclusion.

If you're simply /measuring/ the playback response, then of course the noise
reduction should be shut off.

* When I bought an Otari MX 5050 many years ago, I noticed that the playback
response, using an MRL tape, was off. Looking at the schematic, I discovered
that the playback EQ had the wrong resistor value. I changed it to the
theoretically correct value -- and the response flattened out to what it
should have been. Naturally, the people at Otari told me I didn't know what
the hell I was talking about.

On 03/18/2014 07:29 AM, William Sommerwerck wrote:
"dave" wrote in message
m...
On 03/17/2014 02:53 PM, William Sommerwerck wrote:
wrote in message
...

Once the playback EQ has been set, it doesn't need adjustment.
In fact, most tape decks //don't// have adjustable playback
EQ! The curve is standardized.

Dolby B dynamically adjusts the curve slightly. Are you trying to
calibrate with a compander running at the same time? When all
else fails use your ears, after listening to your favorite source
material on the same speakers. At 1+7/8 ips it's a miracle they
work at all.

Let's back up. Dolby B does not modify playback EQ. This is fixed.

The OP wanted to trim the playback EQ. But on most decks, this is
impossible. * So that brings the discussion to its logical conclusion.

If you're simply /measuring/ the playback response, then of course the
noise reduction should be shut off.

* When I bought an Otari MX 5050 many years ago, I noticed that the
playback response, using an MRL tape, was off. Looking at the schematic,
I discovered that the playback EQ had the wrong resistor value. I
changed it to the theoretically correct value -- and the response
flattened out to what it should have been. Naturally, the people at
Otari told me I didn't know what the hell I was talking about.

I replaced all our Ampex 300s, 350s and Crowns with MX?5050B2s (One 1/2
inch 4 track I think). NTIA grant. Public radio.

"dave" wrote in message
...

I replaced all our Ampex 300s, 350s, and Crowns with MX 5050 B2s
(one 1/2" 4 track I think). NTIA grant. Public radio.

Did you ever check playback response with a standard tape? If so, what did you
find?

On Monday, March 17, 2014 11:00:55 AM UTC-4, wrote:
I've recently been resurrecting some of my old Audio cassette recorders. They are all high quality machines and work very well, but I know (particularly in the case of the Teac), which is about 40 years old, that every one of them could probably benefit from a touch up alignment.



A few months back I went searching for an alignment tape. I found used, and/or what claims to be NOS, and Chinese new, but none of these are anything that I'd be willing to put any faith in. When I last looked there was a company which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anything about either of these sources.



Other than those choices there is nothing out there that I would want to use. These alignment tapes used to be available from manufacturers like Sony and Nakamichi, and they were relatively inexpensive but unfortunately those have not been manufactured for many years.



The problem is without doing a reproduce alignment first there is no way to to properly align a machine.



I was discussing this with a friend recently and he came up with an idea. They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a cassette unit I think. The adapter had a tape "head" of sorts and it had a cable coming out of the top of the adapter that had either two RCA males or a 3.5mm stereo plug on the end. You could plug this end into the output of an IPOD or whatever and the adapter's head would induce a signal onto the cassette players head. I guess this unit must have employed the NAB characteristic curve because the ones I've heard always sounded pretty good to me.



I can probably dig up a couple of these around here, feed signals from my generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for alignment purposes? That would totally eliminate the concerns with used tape of stretching and high frequency roll off.



I would appreciate any thoughts pertaining to any of this, especially in trying to use one of these run of the mill adapters, or any other high quality version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.



So I admit it, I'm a dinosaur. And most of you guys that have been on this group for as long as I have already know that. And although I can no longer hear much above 8KHZ anymore, if you can appreciate it I just want to know that it's there. I just like to transfer my music to cassette and be able to listen to it wherever. Thanks Lenny

During the early 70's I worked on professional multi track Ampex and Scully machines. They were loaded with adjustment pots in both the record and playback amplifiers. The adjustments are there to compensate for differences in heads and to address the problem of component aging. I don't want to assume that frequency response is OK. I want to see it.

On Mon, 17 Mar 2014 11:33:23 -0400, "Michael A. Terrell"
wrote:


wrote:

I've recently been resurrecting some of my old Audio cassette recorders. They are all high quality machines and work very well, but I know (particularly in the case of the Teac), which is about 40 years old, that every one of them could probably benefit from a touch up alignment.

A few months back I went searching for an alignment tape. I found used, and/or what claims to be NOS, and Chinese new, but none of these are anything that I'd be willing to put any faith in. When I last looked there was a company which still makes these and there is also apparently something "hand made" by some individual on what he claims to be "professional equipment". However the cost for both of these is exorbitant. And I don't know anything about either of these sources.

Other than those choices there is nothing out there that I would want to use. These alignment tapes used to be available from manufacturers like Sony and Nakamichi, and they were relatively inexpensive but unfortunately those have not been manufactured for many years.

The problem is without doing a reproduce alignment first there is no way to to properly align a machine.

I was discussing this with a friend recently and he came up with an idea. They make, or used to make anyway these adapters in the shape of an audio cassette tape. They were mostly used in vehicles who's radios only had a cassette unit I think. The adapter had a tape "head" of sorts and it had a cable coming out of the top of the adapter that had either two RCA males or a 3.5mm stereo plug on the end. You could plug this end into the output of an IPOD or whatever and the adapter's head would induce a signal onto the cassette players head. I guess this unit must have employed the NAB characteristic curve because the ones I've heard always sounded pretty good to me.

I can probably dig up a couple of these around here, feed signals from my generator into it but I know that these adapters were never very expensive so I have to question the wisdom of attempting this. So I was wondering if perhaps a high quality version of anything like this was ever made for alignment purposes? That would totally eliminate the concerns with used tape of stretching and high frequency roll off.

I would appreciate any thoughts pertaining to any of this, especially in trying to use one of these run of the mill adapters, or any other high quality version, if such a thing is or was ever available, for my purpose. Most of my 70's music is on either records or cassettes, (and reel to reel for that matter, but that's another story), and my service van has a 1990 Delco radio that has seen service in 5 vans already and it has a cassette player in it as well.

So I admit it, I'm a dinosaur. And most of you guys that have been on this group for as long as I have already know that. And although I can no longer hear much above 8KHZ anymore, if you can appreciate it I just want to know that it's there. I just like to transfer my music to cassette and be able to listen to it wherever. Thanks Lenny


I doubt that those cheap adapters are even close to being in
alignment. All they are, is a plastic shell, a tape head and a cord.
They work by magnetically coupling the signal between the heads, and
that doesn't require precision.

I must agree. I see many ways to design the precision out of the adapter.

?-)

On 03/18/2014 08:16 AM, William Sommerwerck wrote:
"dave" wrote in message
...

I replaced all our Ampex 300s, 350s, and Crowns with MX 5050 B2s
(one 1/2" 4 track I think). NTIA grant. Public radio.

Did you ever check playback response with a standard tape? If so, what
did you find?

Nothing terribly unusual. A lot depends on the tape used. We tried to
use 406 (stolen from NPR) or 456 exclusively. We were pretty careful
with tape as we had more pancakes than flanged reels, and occasionally
had to dub a priceless master. After Crowns and Ampex 350 series, I
noticed nothing terribly weird about the decks.

"dave" wrote in message
m...
On 03/18/2014 08:16 AM, William Sommerwerck wrote:
"dave" wrote in message
...

I replaced all our Ampex 300s, 350s, and Crowns with MX 5050 B2s
(one 1/2" 4 track I think). NTIA grant. Public radio.

Did you ever check playback response with a standard tape?
If so, what did you find?

Nothing terribly unusual. A lot depends on the tape used. We tried to use
406 (stolen from NPR) or 456 exclusively.

By "a standard tape", I meant a reference calibration tape, such as one from
MRL.

On 03/19/2014 06:29 AM, William Sommerwerck wrote:
"dave" wrote in message
m...
On 03/18/2014 08:16 AM, William Sommerwerck wrote:
"dave" wrote in message
...

I replaced all our Ampex 300s, 350s, and Crowns with MX 5050 B2s
(one 1/2" 4 track I think). NTIA grant. Public radio.

Did you ever check playback response with a standard tape?
If so, what did you find?

Nothing terribly unusual. A lot depends on the tape used. We tried to
use 406 (stolen from NPR) or 456 exclusively.

By "a standard tape", I meant a reference calibration tape, such as one
from MRL.

What standard? We frequently exceeded 250 nW/m or whatever. For a while
MRL had no alignment tape for higher saturation operation. If the
compensation was off as delivered we wouldn't have dwelled on it, we
would have fixed it. My problems were more of mechanical in nature. You
can get those things for nothing nowadays.

On 03/19/2014 06:29 AM, William Sommerwerck wrote:

By "a standard tape", I meant a reference calibration tape, such as one
from MRL.

What standard? We frequently exceeded 250 nW/m or whatever.
For a while MRL had no alignment tape for higher saturation
operation.

I'm talking about playback frequency response, which as what the OP was
actually interested in.

It doesn't matter what the reference fluxivity is. You can set playback
/level/ wherever you want it.

" I don't want to assume that frequency response is OK. I want to see it."

First of all, I tried to post a couple of times and for some reason it wouldn't go through. It's not Google either becasue I already eliminated them as a problem. I must live in one of "those" areas". Figures.

Anyway, before I was not aware of exactly what you were after, I assumed it was azimuth like most people. Now I see what you are trying to do. In fact upon further examination I take it you also want to record ? Wow.

The problem is getting a reference, you ain't gonna. Even if you get ahold of an old reference tape it is likely to be out, stretched, oxide falliong off or something. As such, thre closest refernce must be determined.

Hopefully you have something that'll generate a 1Khz square wave. I would record that and see how it comes out. In fact I wouild lower the frequency some until it comes out pretty much square. Try it at about -3Db, because unless the deck has Dolby HX it is going to roll off more highs at higher levels.

Then you play it back.

I am going to be right back and reply to myuself becaus all this typind for noting is for the birds.

OK, it is working now.

Once you record a square wave successfully, and it comes back square, play it in different decks to make sure they put out a mostly square wave. Do all of this with the Dolby turned off, or with HX only. If oyu have a deck withHX and theothers without, use the HX one to record always, even oi the head is more worn it will make a better recording. Of course I recommend dubbing everything that is non-replaceable, but that is your perogative.

The first thing I would recommend is to post the model numbers of all these things. We might be able to get the service manuals online from like HIFIengine or HIFImanuals. These will allow us to identify the parts that will age, like electrolytics and tantalum caps. the small poly ones and all that will either uisually be shorted, open or something, and it will be noticable and most likely in one channel.

Assuming tape head wear is not really bad, the channels should be equal. when the heads start losing it, usually the left goes first being the edge track. Hopefull your decks have (working) pad pushers and use regulated tape tension to maintain head to tape contact.

I would record the square waves and see which ones record the best and which ones play back the best. Are any of these things three head ? Evne in the high end units, not all are. And hopefully they are not autoreverse.

There are mainly only so many alignments to do and not all exist on all machines. You have playback EQ, this may be separate for 70 and 120 uS, depends. that's something we want to know. When it comes to record there may be another for metal tape if equipped.

Then comes Dolby calibration. Dolby calibrated at the factory is almost never right because they use the absolutely best type of tape for their unit of course, to get the best specs. If you plan on dubbing the material out to another format like CD or FLAC on the computer, you might want to calibrate the Dolby for the source tape used. The only other good way to ake the noise reduction work right is to have an outboard Dolby decoder, though if the deck has output level controls that PRECEDE the Dolby decoder, you're in luck and don''t have to go through all that.

This is why we need the prints for these things. There are different ways to proceed, depending on not only which adjustments are provided, but also the exact architechture of the machine.

We coid just wing it, but you indicated you want to be sure and not guess. To do that we need to establish a reference and to do that we need to know what COULD be wrong electronically.

As such I highly recommend we get the prints, in fact if you have them you could scan them and upload them to one of those cloud things like dropbox por photobucket. In fact if they are clear scans they might be better than what is available out there. I have seen some terrible ones.

When you get into recording though, tha tis a whole new ballgame. Underbias will cause a loss of a certain range of frequncies, probably around 2Khz to 5Khz or so. Overbias will lose the real high end, even worse. both conditions cause odd order distortion. Too much bias will cause compression of the peaks wheras too little bias will cause expansion of the peaks.. Either is a nonlinearity and results in high harmonic distortion. This can only be removed with big buck digital sound equipment which I doubt any of us has.

Really, give me the model numbers. We can go from there after you run some square wave tests. If these decks have continuously variable bias, you might just be able to make a good enough test tape. The square wave will tell you the general response quite accurately, and don't be disappointed if it shows what looks like ringing. that is characteristic of the system.

what causes that is that the response is not flat, and I mean not like anythning else that is unflat. It is not simply a rolloff usually. When they say +-3dB, it could mean +2Db at 2,100Hz, -2.5Db at 3,000Hz, 0Db at 5,000Hzz, +2,8Db at 8,000Hz, -2Db at 9,300Hz, and so forth. They ALL do that. (of course that's not really worse than most speakers)

If they don't you have some DAMN GOOD decks there.

The square wave tels all, except distortion. For that we will have to find a way to mix two frequencies, just like they to run an intermodulation distortion test. When it comes to tape recording, the cause for both THD and IM distortion are the same so the results are the same.

The reason a square wave test should work at least halfway decently is that it is extermely unlikely that faults could be in both the record and play and null out and resut in a good recording. the odds are astronomical against. So that is one of the facts we use to try to determine some sort of reference.

We can do this, remember those signs that say :

:We the unwilling,
Led by the unknowing,
Have been doing so much,
With so little,
For so long,
We are now qualified to do anything with nothing" ?

That's me. I can align the record section of a VCR without freq. counters or any of that stuff. I'll reveal how on request, I remember a bunch of those early Funais came in with the controls all whacked out by the customer. I was the one to get them done without ordering a **** ton of equipment.

This is no different. In the meantime if we ruin into any real difficulty I think I might be able to pump some info or maybe even something resembling a test tape on one of the purely audio forums.

I knda like doing **** like this, ust because you "can't" haha.

On 03/19/2014 01:05 PM, William Sommerwerck wrote:
On 03/19/2014 06:29 AM, William Sommerwerck wrote:

By "a standard tape", I meant a reference calibration tape, such as one
from MRL.

What standard? We frequently exceeded 250 nW/m or whatever.
For a while MRL had no alignment tape for higher saturation
operation.

I'm talking about playback frequency response, which as what the OP was
actually interested in.

It doesn't matter what the reference fluxivity is. You can set playback
/level/ wherever you want it.

What reference fluxivity should I use?

The "reference fluxivity" section of a Calibration Tape is normally used
to set the reproducer gain on a tape recorder with a vu meter so that
the output level reads 0 dB. The reference fluxivity you should use
depends on:
your program level meter (whether a standard vu meter, a standard peak
program meter, or something non-standard);
the kind of blank tape you'll be using;
whether you'll be using a noise reduction system (e.g., Dolby, dBX); and
whether you desire "tape compression."

For some specific recommendations, see the literature from the
manufacturer of the tape you'll be using, and also see MRL's Choosing
and Using MRL Calibration Tapes...., Sec. 1.2.6 and Table 2 (pages 4
and 5).

Common usages are 200 nanowebers per meter [nWb/m] for older and
consumer-type tapes; 250 nWb/m for general studio usage; and 500 nWb/m
with the highest output mastering tapes when "tape compression" is desired.
If you have a Calibration Tape that is not at the reference fluxivity
that you want, but is otherwise correct, you can easily use it to set
your reproducer for a different reference fluxivity by the method shown
in Choosing and Using..., Sec. 2.3.1 "Shifting the Reference Fluxivity".

Which test signals should I use?

Multifrequency Calibration Tapes

These tapes are the "old traditional alignment tapes" sold by Ampex and
others since 1948. They have 18 or 20 shorter tones -- 1 kHz level set,
8- and 16-kHz azimuth set and preliminary frequency response, and 13
frequencies from 32 Hz to 20 kHz. for frequency response. The 13
frequency response tones measure the response over the entire audio
spectrum, and are necessary for diagnosis and repair of reproducers with
poor frequency response. They are also needed to set up a reproducer
when the equalization is not already known to be adjusted close to
optimum. An example would be calibrating a newly-purchased machine for
the first time. Though more expensive, multifrequency tapes are the most
generally useful.
Once a reproducer is set up with a Multifrequency Calibration Tape,
routine checks at 1 kHz and 10 kHz are usually adequate, and those tapes
are shorter, and therefore both less expensive to purchase, and quicker
to use.

On 03/19/2014 01:05 PM, William Sommerwerck wrote:
On 03/19/2014 06:29 AM, William Sommerwerck wrote:

By "a standard tape", I meant a reference calibration tape, such as one
from MRL.

What standard? We frequently exceeded 250 nW/m or whatever.
For a while MRL had no alignment tape for higher saturation
operation.

I'm talking about playback frequency response, which as what the OP was
actually interested in.

It doesn't matter what the reference fluxivity is. You can set playback
/level/ wherever you want it.

The OP was talking about a standard calibration tape for Philips Cassette.

Step 2: What kind of tape are you recording on? There's three common
"operating levels" (see below for definitions) of recording tape our MRL
tapes will cover: +3 dB, +6 dB, and +9 dB. Ampex/Q 406, 407, 408, 480,
and 478 are +3dB and use 250 nWb/m calibration tapes. RMGI Emtec SM911,
LPR35, & Ampex/Q 456 and 457 are +6 dB and use 355 nWb/m calibration
tapes. Also, the very high output tapes like RMGI Emtec SM900, Ampex/Q
GP9 are +9 dB tapes and can also use the 355 nWb/m tapes by setting the
operating level on playback to a -3 VU on the meters. Why not have a +9
or a 520 nWb/m calibration tape? Most users of tape use either RMGI
Emtec SM911, RMGI Emtec SM900, AMPEX/Q 456 or AMPEX/Q GP9 (and soon the
ATR Magnetics tapes). The 350 nWb/m tapes will cover both with a -3VU
output adjustment for the +9 tapes.
Step 3: How many adjustments to your deck are you going to do?
Usually, the main adjustments are the "operating level" and the azimuth
adjustment to the heads. The next in line adjustment would be the low
frequency equalization. Beyond that, MRL offers calibration tapes that
offer complete octaves of frequencies over the whole spectrum of hearing.

Operating Levels: (See also "What Tape Should I Use?" in our archives
section
Open reel recorders record at different "operating" levels depending on
the deck's design and the tape you are recording on. The "maximum"
operating level means this is the setting that will read "0 VU" on your
meters with respect to .776 V or NAB 0 VU. AMPEX/Q 407 is a +3 dB tape
for instance which means that when your deck is calibrated for a +3 dB
tape that "0" on your VU meters is actually +3 dB with reference to the
NAB "0".

What do you gain with elevated levels? By being able to record "louder"
or "hotter" on the tape the residual noise level on the tape drops with
respect to where your recording levels are set. To explain this, think
of it this way. If your recordings are recorded hotter you will have to
turn down your sound system's volume control compared to a recording not
recorded at a hotter level. By turning down the volume control you will
get the same music sound volume but the noise floor is reduced.

The noise floor becomes very critical in multi track situations where
all the tracks of music and residual tape hiss are mixed together. In
this situation, the noise floor becomes much more of a critical issue
than simply copying a two track master tape, for instance.

Most consumer decks are set to a specific operating level. There were no
+9 dB tapes around at the time, and these decks mostly can not take
advantage of the increased recording volume. But you can gain even more
headroom with these tapes. RMGI Emtec SM900 saturates at roughly +18.5
dB over a +9 dB operating level. If your deck is set to a +3 dB
operating level like many consumer decks are, you'll gain an additional
6dB headroom by not recording as hot.

Just because a tape has a +9 dB or +6 dB operating level doesn't mean
you have to record at that level. It's a recommended setting, not a
must. When buying a calibration tape, buy one according to your deck's
settings. You might be able to boost your settings by +3 dB but +6 dB
would be a stretch unless you have a studio quality recorder.

"dave" wrote in message
...

What reference fluxivity should I use?

I believe it's 200nW/m for cassette, 250nW/m for open-reel. I once aligned a
ReVox consumer deck for Scotch ultra-high-output tape, and set it at least 6dB
higher. Otherwise, the meter would have banging at peak output.

The level for cassette is not really negotiable, because it's supposed to
represent Dolby level.

The OP wanted to know the tape's /playback/ response. Recording test tones
isn't going to tell you how flat the /playback/ response is. For that, you
need a high-quality reference tape.

One of the problems with cassette reference tapes (as opposed to open-reel) is
that the wavelengths are so short, the tape's HF output will slowly decline,
as the tape self-erases. If you want an accurate measurement, you're going to
need a recently manufactured tape from a reliable supplier (such as MRL).
These are not cheap.

If you have a Nakamichi, there's another problem. Nakamichi's playback heads
supposedly had lower losses and correspondingly greater HF output. Rather than
adjusting the standard playback curve to compensate, Nakamichi took advantage
of the higher output and used less recording pre-emphasis, to increase HF
headroom.

The OP is worrying about something that isn't of great importance. If the
heads are in good condition, then the response should be pretty much what is
was when the deck was manufactured. And you're not going to have much
component-value drift in a solid-state recorder.

"William Sommerwerck" wrote in message ...

The level for cassette is not really negotiable, because
it's supposed to represent Dolby level.

Whoops! True, but... There were cassette decks in which Dolby level -- on the
meter -- was 2 or 3dB above 0VU.

On 03/21/2014 07:06 AM, William Sommerwerck wrote:
"William Sommerwerck" wrote in message ...

The level for cassette is not really negotiable, because
it's supposed to represent Dolby level.

Whoops! True, but... There were cassette decks in which Dolby level --
on the meter -- was 2 or 3dB above 0VU.



dolby Type B or C. Standard or metal oxide. Metal was more Nanowebers

On 03/21/2014 07:33 AM, dave wrote:
On 03/21/2014 07:06 AM, William Sommerwerck wrote:
"William Sommerwerck" wrote in message
...

The level for cassette is not really negotiable, because
it's supposed to represent Dolby level.

Whoops! True, but... There were cassette decks in which Dolby level --
on the meter -- was 2 or 3dB above 0VU.



dolby Type B or C. Standard or metal oxide. Metal was more Nanowebers

HX was when I started using VHS HiFi for archives.

"dave" wrote in message
...

Dolby Type B or C. Standard or metal oxide. Metal was more Nanowebers

The reference level remains the same, regardless.

"dave" wrote in message
...

HX was when I started using VHS HiFi for archives.

HX was not a noise-reduction system (though it was controlled by the Dolby B
level-sense circuitry).

Dolby HX decreases the bias dynamically during times with alot of (mainly) high frequency content. This helped avoid tape saturation and allowed recording at significantly higher levels, or at normal levels with significantly less distortion.

the first units I noticed it on were Harmon Kardons I think which actually had a switch to disable it, and you could record at +6Db or so and see a big difference oin the playback level, though of course you had to switch the switch while recording. the results were VERY noticable and later HX equipped units omitted the switch because nobody would wnat to turn it off.

On Fri, 21 Mar 2014 06:08:28 -0700, "William Sommerwerck"
wrote:

"dave" wrote in message
...

What reference fluxivity should I use?

I believe it's 200nW/m for cassette, 250nW/m for open-reel. I once aligned a
ReVox consumer deck for Scotch ultra-high-output tape, and set it at least 6dB
higher. Otherwise, the meter would have banging at peak output.

The level for cassette is not really negotiable, because it's supposed to
represent Dolby level.

I has been fun reading this thread. My personal issue is where to get an
open reel (1/4 inch wide tape, 7-inch max reel size) setup and calibration
tape for my old Ampex AX-300 semi-pro tape deck.

?-)

" has been fun reading this thread. My personal issue is where to get an
open reel (1/4 inch wide tape, 7-inch max reel size) setup and calibration
tape for my old Ampex AX-300 semi-pro tape deck. "

They have them all over the place on the planet Meezar 5. Twelve bucks.

T

See they have a different time constant there.

On 03/21/2014 07:56 AM, William Sommerwerck wrote:
"dave" wrote in message
...

Dolby Type B or C. Standard or metal oxide. Metal was more Nanowebers

The reference level remains the same, regardless.



B has a reference level, Does C? Or is C more like DBX? I know there was
a switch for Metal Oxide.

On 03/21/2014 07:57 AM, William Sommerwerck wrote:
"dave" wrote in message
...

HX was when I started using VHS HiFi for archives.

HX was not a noise-reduction system (though it was controlled by the
Dolby B level-sense circuitry).



Variable bias. It's all coming back to me. Useless knowledge from
another dimension..

On 03/21/2014 10:10 PM, josephkk wrote:
On Fri, 21 Mar 2014 06:08:28 -0700, "William Sommerwerck"
wrote:

"dave" wrote in message
...

What reference fluxivity should I use?

I believe it's 200nW/m for cassette, 250nW/m for open-reel. I once aligned a
ReVox consumer deck for Scotch ultra-high-output tape, and set it at least 6dB
higher. Otherwise, the meter would have banging at peak output.

The level for cassette is not really negotiable, because it's supposed to
represent Dolby level.

I has been fun reading this thread. My personal issue is where to get an
open reel (1/4 inch wide tape, 7-inch max reel size) setup and calibration
tape for my old Ampex AX-300 semi-pro tape deck.

?-)


MRL seems to be offered by several vendors. They can cost in the
hundreds. Do you have all the fish scales required for mechanical
alignment? We used the 10 kHz tone on the beginning of NPR tapes for
azimuth reference. Are you using stock electronics on the 300?

"dave" wrote in message
m...

B has a reference level. Does C? Or is C more like dbx?

All Dolby NR systems are level-sensitive. dbx is not.

OK, now who ever used Dolby A ?

That's right, since there is a B is implies there was an A. There was, it was used on a porfessional level. It was also level sensitive of course.

har bragt dette til os:
OK, now who ever used Dolby A ?

That's right, since there is a B is implies there was an A. There was, it was
used on a porfessional level. It was also level sensitive of course.

Not necessarily.

dBaseII was dominating the database market at one time.
There never were a dBaseI.
Also, the company was called Ashton-Tate, but while there were a Tate,
there never were an Ashton.

But anyway, Dolby A was/is? used professionally, eg. in recording
studios.

Leif

--
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