Got this tape echo machine at work. Got tubes. Old. Tape runs and it was a fresh job for me. I see it has bias and audio mixing with it. It passes signal but does not echo. I think the tape is simply bad.

Anyway, it has no pinch roller. The tap goes about 1430 degrees around it though. That is apparently enough.

However O think this arraingement would cause faster tape deterioration due to more bending. Isn't the straightest path the best ? (for the tape itself of course)

It is kept under tension by a springed idler. There are no tape pads. It has a magnetic erase head between a fixed and spring loaded idler or tensioner. Lke a turing tape guide. The capstan is way over on the right side. There are like five heads, electronic heads not the PM erase head. I am probably going to change the tape soon and see what happens. I got some old ½" that is not in great shape. It will deteriorate quickly but I do know that it actually records. The stuff on there really looks funny. Red not brown. Of course that doesn't rally mean anything but that it is unusual a little. Thing is that it is not really opaque.

I am actually disappointed by the thing not hav ing a speed control. What, they didn't have eddy current motors in the 1940s ?

Cheapskates.

wrote:

Got this tape echo machine at work. Got tubes. Old. Tape runs and it was a fresh job for me. I see it has bias and audio mixing with it. It passes signal but does not echo. I think the tape is simply bad.

Anyway, it has no pinch roller. The tap goes about 1430 degrees around it though. That is apparently enough.

However O think this arraingement would cause faster tape deterioration due to more bending. Isn't the straightest path the best ? (for the tape itself of course)

It is kept under tension by a springed idler. There are no tape pads. It has a magnetic erase head between a fixed and spring loaded idler or tensioner. Lke a turing tape guide. The capstan is way over on the right side. There are like five heads, electronic heads not the PM erase head.


** You just MIGHT be describing Charlie Watkins' famous little horror - the "WEM Copycat" first released in 1958.

http://manningsmusicals.co.uk/wp-con...ms-007-800.jpg

A truly horrible machine that just barely worked, it's output was riddled with AC hum, tape noise (from the permanent magnet erase) and serious wow & flutter plus amplitude modualtions.

Charlie was too cheap to admit it needed a pinch roller.

Modern 1/4 inch tape normally refuses to run on a WEM Copycat as the surface friction is just too low. You could try fitting a shrink plastic sleeve over the capstan if you like.


I am actually disappointed by the thing not hav ing a speed control. What, they didn't have eddy current motors in the 1940s ?


** Some very cheap echos used simple, DC brush motors and others had two speeds - but the first machines to feature decent, BLDC variable speed motors were made by Roland of Japan. Models include the RE101, RE201, RE301 and deluxe versions were the RE501 & SRE555.

A fairly large BLDC motor branded "Pioneer" provided direct capstan drive and continuously variable speed range of about 5:1 with varying compensation applied to EQ circuits as tape speed changed to keep the response flat. There was also an NE570N compander IC to reduce tape noise to quite low levels.

The erase head was ferrite cored and the record and play heads had stainless steel face plates that simply never wore out.

Nice machines, fixable and well worth fixing even today.


..... Phil

On Wednesday, December 17, 2014 12:53:27 AM UTC-5, wrote:
I'm working on my old Ampex 4460 reel to reel machine. (work is slow), and I'd like to listen to some of my old tapes. I cleaned and lubricated it, demagnetized the heads and put a tape of some familiar music on, and I thought it seemed a bit slow. So I repeated it with other tapes and then followed with an Ampex frequency response alignment tape. The scope was calibrated to 1.0ms off the 1KHZ square wave output and then I looked at the the 1KHZ sine wave off the tape. The period was approximately 1.40ms which appears to translate to 714HZ. Truly hard to believe that it's running that slow, but I don't think that the equipment is lying.

So I next got out the Strobeotac and put it on the motor capstan. The motor is rated for 1850 RPM at 115V, and it's running rock solid at 1795. I tried loading it while watching the speed and it remains steady, so it doesn't appear to be a load problem. Could such a slight motor speed reduction cause a 25 percent reduction in the frequency of my 1KHZ test tone off the tape? It doesn't seem possible, but I don't know.

The motor has a label that reads that it uses a 3.0UF 330V capacitor. I haven't investigated this yet, but with four wires going into it I figure that the cap must be on the chassis somewhere. I wouldn't think that a cap problem though would cause my RPM's to drop 55RPM would it? Oh and I have no service manual, however I don't think that service manual would do me much good with this problem anyway.


If anyone has any thoughts on this I'd sure appreciate hearing them. Thanks, Lenny

Well I thought I'd jump back in here with an update on my progress. I ordered and installed a replacement capstan flat belt from Adams Manufacturing. After installing this belt there was no more bumping from the old misshapen belt. then, I had three pinch rollers. One is from this machine and the other two were from junkers I had in the shop. The rubber on all of them was slick but seemed pliable and I worked on two of them with sandpaper and then lacquer thinner. I finished off with rubber restorer and then cleaned them off with 99% anhydrous isopropyl. After this treatment The rollers felt a bit more "grippier" if that's the correct description but still were not what I would have liked to see. However taking a fresh look at the 1KHZ tone on the test tape with the scope immediately after installing one of the "restored" rollers showed that the machine was now running on speed. So I feel foolish to admit that it seems that I had overlooked the most basic thing, the capstan roller, as being the primary governor of speed.

So I tried a few of my old tapes to see how they sounded. Some of these tapes were 1800 ft and I noticed that they would play for a coupe of songs and then start slowing down. I had a sealed brand new roll of Scotch 206, which is a 1200 ft low noise mastering tape as it's so called. I made a fine sounding recording on this tape. Then I tried playing the 3 3/4 pre recorded Bob Dylan tape. Let me tell you when Bob Dylan is off speed there is no mistaking it. So while this was running I gently increased the take up torque with my finger and the tape seemed to sound fine as long as I kept the tension up. As soon as I relaxed it a bit the speed would waver.

So now I know that for certain I need to resolve the pinch roller issue and also I need to check the take up torque for which there is a specification in the manual. Problem is I don't have a scale for that. So I as wondering if anyone knows of a source for these type of scales, and also as I found for the capstan belt is there a generic source for replacement pinch rollers? Or as a substitute can a pinch roller be "rebuilt"?

My wife just can't understand why I've been screwing around with a 50 year old machine when she has so much other **** for me to do. But I know that you guys know and can appreciate the sense of satisfaction associated with bringing a dead body back to life. And I feel like now I'm so close. Thanks for any further advice. Lenny

"So I tried a few of my old tapes to see how they sounded. Some of these tapes were 1800 ft and I noticed that they would play for a coupe of songs and then start slowing down."

That is not a symptom of a bad pinch roller. I believe you might find heating up motor bearings, or capstan bearings, or maybe even a leaky motor cap. When pinch rollers go bad they usually do not wear or harden exactly uniformly and they screw up the tape path. It will hit the guides and actually even get damaged. This was VCRs, and the tape path in those is every bit as critical as audiophile or pro R2Rs if not moreso.

I would run it as far apart as possible and see if the RPMs go down playing, then see if they jump back up not. And then if they do, try to slow it down with your hand, maybe with a rag. I would do the same to the capstan.

I doubt you are mistaking muffled sound for slowing down. A pinch roller CAN cause that by affecting the tape path.

Ho about recording a test tape with like a 1 kHz signal on it. In fact make it a square wave. You can read the timing of it, and it will reveal the response curve. I say that because this whole thing doesn't sound right. There is an argument about pinch rollers now but that matters not. The load on the motor from ANY pinch roller (you kno you CAN use metal if you cna machine it well enough) should never pul down the motor RPMs. In fact even running Scotchtape (I mean the kind you stick to things) in it, it should break the tape, not stall or slow down. It should not happen. It should take a pair of Visegrips (tm) to stop that thing.

captainvi


Well I thought I'd jump back in here with an update on my progress. I ordered and installed a replacement capstan flat belt from Adams Manufacturing.. After installing this belt there was no more bumping from the old misshapen belt. then, I had three pinch rollers. One is from this machine and the other two were from junkers I had in the shop. The rubber on all of them was slick but seemed pliable and I worked on two of them with sandpaper and then lacquer thinner. I finished off with rubber restorer and then cleaned them off with 99% anhydrous isopropyl. After this treatment The rollers felt a bit more "grippier" if that's the correct description but still were not what I would have liked to see. However taking a fresh look at the 1KHZ tone on the test tape with the scope immediately after installing one of the "restored" rollers showed that the machine was now running on speed. So I feel foolish to admit that it seems that I had overlooked the most basic thing, the capstan roller, as being the primary governor of speed.


** Hallelujah !!



So I tried a few of my old tapes to see how they sounded. Some of these tapes were 1800 ft and I noticed that they would play for a coupe of songs and then start slowing down.

** Old tape get sticky and requires many passes through a machine to clean up, you may need to clean the heads with ISO over and over too.


I had a sealed brand new roll of Scotch 206, which is a 1200 ft low noise mastering tape as it's so called. I made a fine sounding recording on this tape. Then I tried playing the 3 3/4 pre recorded Bob Dylan tape. Let me tell you when Bob Dylan is off speed there is no mistaking it. So while this was running I gently increased the take up torque with my finger and the tape seemed to sound fine as long as I kept the tension up. As soon as I relaxed it a bit the speed would waver.

** The reel of 206 is probably sticky too - creating extra back tension that the capstan has trouble pulling through.



So now I know that for certain I need to resolve the pinch roller issue


** Sanding the surface smooth while spinning the roller in a bench drill has always worked for me.

For a R-R machine to work properly, so many things have to be just right.

Not the least of which is the tape itself.


.... Phil

jurb...@

"** You just MIGHT be describing Charlie Watkins' famous little horror - the "WEM Copycat" first released in 1958.

http://manningsmusicals.co.uk/wp-con...ms-007-800.jpg "

That is it but I think it has a differnt name on it.

** Betcha it has "Copicat" on it.



"A truly horrible machine that just barely worked, it's output was riddled with AC hum, tape noise (from the permanent magnet erase) and serious wow & flutter plus amplitude modulations. "

Well the motor is directly under the capstan.

** It's a regular turntable motor - with an added flywheel IIRC.


It seems to have some type of special tape.


** Nope - the machine was meat for regular 1/4 inch tape - not too thin either.


Other thing, the idea about the sleeve on the capstan might not be a piece of cake unless I can find it precision, no taper etc.

** Use a piece of shrink tubing - like I said.


"A fairly large BLDC motor branded "Pioneer" provided direct capstan drive and continuously variable speed range of about 5:1 with varying compensation applied to EQ circuits as tape speed changed to keep the response flat. There was also an NE570N compander IC to reduce tape noise to quite low levels. "

Yeah, try doing that with tubes.


** Would never be needed if you have proper, high frequency, AC erase and full width 1/4inch recording at 15ips.



..... Phil