I have a Fender reissue model guitar amp in for service. It has 2
Fender 12AX7's that are microphonic. These are Chinese manufacture. I
have replaced them with 5814's which is some sort of 12AU7 type just
to get the amp working. There is no more microphonic problem, however
the amplifier sensitivity is now somewhat lower so perhaps that may
have a bearing on this. I realise that I have no 12AX7's in the shop
at all and would like to buy several, two for this amplifier and two
or three for stock. I was looking at NOS and JAN types online and
would like to go with either but I suffered real sticker shock when I
noticed the prices. I don't have much faith in the Russian or Chinese
tubes so I was hoping that someone could offer some advice as to a
source for good preamp tubes either new or tested used, and ones that
I don't have to worry about microphonics. Thanks, Lenny.

wrote in message
...
I have a Fender reissue model guitar amp in for service. It has 2
Fender 12AX7's that are microphonic. These are Chinese manufacture. I
have replaced them with 5814's which is some sort of 12AU7 type just
to get the amp working. There is no more microphonic problem, however
the amplifier sensitivity is now somewhat lower so perhaps that may
have a bearing on this. I realise that I have no 12AX7's in the shop
at all and would like to buy several, two for this amplifier and two
or three for stock. I was looking at NOS and JAN types online and
would like to go with either but I suffered real sticker shock when I
noticed the prices. I don't have much faith in the Russian or Chinese
tubes so I was hoping that someone could offer some advice as to a
source for good preamp tubes either new or tested used, and ones that
I don't have to worry about microphonics. Thanks, Lenny.
I've had some complete junk Chinese tubes, e.g. power output pentodes that
burned the cathode resistors on the first use due to internal shorts. I've
had good luck with Russian tubes however, the Svetlana ones seem to be very
good but you must make sure they're the St.Petersburg manufactured ones and
not the Sovtek ones; see the bottom of this page for more information:
http://www.amp-fix.com/biasing%5B1%5D.htm
Martin
--
martindot herewhybrowat herentlworlddot herecom

wrote:
I have a Fender reissue model guitar amp in for service. It has 2
Fender 12AX7's that are microphonic. These are Chinese manufacture. I
have replaced them with 5814's which is some sort of 12AU7 type just
to get the amp working. There is no more microphonic problem, however
the amplifier sensitivity is now somewhat lower so perhaps that may
have a bearing on this. I realise that I have no 12AX7's in the shop
at all and would like to buy several, two for this amplifier and two
or three for stock. I was looking at NOS and JAN types online and
would like to go with either but I suffered real sticker shock when I
noticed the prices. I don't have much faith in the Russian or Chinese
tubes so I was hoping that someone could offer some advice as to a
source for good preamp tubes either new or tested used, and ones that
I don't have to worry about microphonics. Thanks, Lenny.

Dave,

I've had good success with the JJ/Tesla tubes (from Slovakia as I
recall) They usually run around $10-15 each. One vendor that has them
is Antique Electronic Supply (www.tubesandmore.com). They have various
grades of the things. I'm speaking form a standpoint of reliability.
We could have an endless discussion (and tread) about the sound quality
of various tubes which I'd rather avoid.

Regards,
Tim Schwartz
Bristol Electronics

wrote in message
...
I have a Fender reissue model guitar amp in for service. It has 2
Fender 12AX7's that are microphonic. These are Chinese manufacture. I
have replaced them with 5814's which is some sort of 12AU7 type just
to get the amp working. There is no more microphonic problem, however
the amplifier sensitivity is now somewhat lower so perhaps that may
have a bearing on this. I realise that I have no 12AX7's in the shop
at all and would like to buy several, two for this amplifier and two
or three for stock. I was looking at NOS and JAN types online and
would like to go with either but I suffered real sticker shock when I
noticed the prices. I don't have much faith in the Russian or Chinese
tubes so I was hoping that someone could offer some advice as to a
source for good preamp tubes either new or tested used, and ones that
I don't have to worry about microphonics. Thanks, Lenny.

The shop that I do a lot of work for uses many Russian tubes, and I have, in
general, not found them to be a problem either reliability, spec or
microphony wise. Brands that he stocks are, for instance, Ruby and Electro
Harmonix. Do you have a music shop in your area ? They all stock replacement
tubes over here, so I guess they would there too. Genuine Fender supplied
tubes are not all that expensive, and likewise, Marshalls. However, preamp
tubes such as 12AX7 do tend to come in quality levels. For instance, some of
the 12AX7s that this particular shop stocks, are specced as "Premium Grade"
and retail for 21 GBP (around $33) each, although obviously not that much to
buy trade ...

Arfa

On Nov 16, 8:42*pm, "Arfa Daily" wrote:
wrote in message

...

I have a Fender reissue model guitar amp in for service. It has 2
Fender 12AX7's that are microphonic. These are Chinese manufacture. I
have replaced them with 5814's which is some sort of 12AU7 type just
to get the amp working. There is no more microphonic problem, however
the amplifier sensitivity is now somewhat lower so perhaps that may
have a bearing on this. I realise that I have no 12AX7's in the shop
at all and would like to buy several, two for this amplifier and two
or three for stock. I was looking at NOS and JAN types online and
would like to go with either but I suffered real sticker shock when I
noticed the prices. I don't have much faith in the Russian or Chinese
tubes so I was hoping that someone could offer some advice as to a
source for good preamp tubes either new or tested used, and ones that
I don't have to worry about microphonics. Thanks, Lenny.

The shop that I do a lot of work for uses many Russian tubes, and I have, in
general, not found them to be a problem either reliability, spec or
microphony wise. Brands that he stocks are, for instance, Ruby and Electro
Harmonix. Do you have a music shop in your area ? They all stock replacement
tubes over here, so I guess they would there too. Genuine Fender supplied
tubes are not all that expensive, and likewise, Marshalls. However, preamp
tubes such as 12AX7 do tend to come in quality levels. For instance, some of
the 12AX7s that this particular shop stocks, are specced as "Premium Grade"
and retail for 21 GBP (around $33) each, although obviously not that much to
buy trade ...

Arfa

I've heard good things about Electro Harmonix from other people too.
Maybe I'll try some of these. Thanks, Lenny

wrote in message
...
On Nov 16, 8:42 pm, "Arfa Daily" wrote:
wrote in message

...

I have a Fender reissue model guitar amp in for service. It has 2
Fender 12AX7's that are microphonic. These are Chinese manufacture. I
have replaced them with 5814's which is some sort of 12AU7 type just
to get the amp working. There is no more microphonic problem, however
the amplifier sensitivity is now somewhat lower so perhaps that may
have a bearing on this. I realise that I have no 12AX7's in the shop
at all and would like to buy several, two for this amplifier and two
or three for stock. I was looking at NOS and JAN types online and
would like to go with either but I suffered real sticker shock when I
noticed the prices. I don't have much faith in the Russian or Chinese
tubes so I was hoping that someone could offer some advice as to a
source for good preamp tubes either new or tested used, and ones that
I don't have to worry about microphonics. Thanks, Lenny.

The shop that I do a lot of work for uses many Russian tubes, and I have,
in
general, not found them to be a problem either reliability, spec or
microphony wise. Brands that he stocks are, for instance, Ruby and Electro
Harmonix. Do you have a music shop in your area ? They all stock
replacement
tubes over here, so I guess they would there too. Genuine Fender supplied
tubes are not all that expensive, and likewise, Marshalls. However, preamp
tubes such as 12AX7 do tend to come in quality levels. For instance, some
of
the 12AX7s that this particular shop stocks, are specced as "Premium
Grade"
and retail for 21 GBP (around $33) each, although obviously not that much
to
buy trade ...

Arfa

I've heard good things about Electro Harmonix from other people too.
Maybe I'll try some of these. Thanks, Lenny


I've certainly not had a problem with them, Lenny, and my friend's shop
sells quite a lot of them as 'general' customer replacements. Matching does
seem to have been done by them with some care, on output tubes that are sold
as being a matched pair or quad.

Arfa

Arfa Daily wrote:
wrote in message
...
On Nov 16, 8:42 pm, "Arfa Daily" wrote:
wrote in message

...

I have a Fender reissue model guitar amp in for service. It has 2
Fender 12AX7's that are microphonic. These are Chinese manufacture. I
have replaced them with 5814's which is some sort of 12AU7 type just
to get the amp working. There is no more microphonic problem, however
the amplifier sensitivity is now somewhat lower so perhaps that may
have a bearing on this. I realise that I have no 12AX7's in the shop
at all and would like to buy several, two for this amplifier and two
or three for stock. I was looking at NOS and JAN types online and
would like to go with either but I suffered real sticker shock when I
noticed the prices. I don't have much faith in the Russian or Chinese
tubes so I was hoping that someone could offer some advice as to a
source for good preamp tubes either new or tested used, and ones that
I don't have to worry about microphonics. Thanks, Lenny.
The shop that I do a lot of work for uses many Russian tubes, and I have,
in
general, not found them to be a problem either reliability, spec or
microphony wise. Brands that he stocks are, for instance, Ruby and Electro
Harmonix. Do you have a music shop in your area ? They all stock
replacement
tubes over here, so I guess they would there too. Genuine Fender supplied
tubes are not all that expensive, and likewise, Marshalls. However, preamp
tubes such as 12AX7 do tend to come in quality levels. For instance, some
of
the 12AX7s that this particular shop stocks, are specced as "Premium
Grade"
and retail for 21 GBP (around $33) each, although obviously not that much
to
buy trade ...

Arfa

I've heard good things about Electro Harmonix from other people too.
Maybe I'll try some of these. Thanks, Lenny


I've certainly not had a problem with them, Lenny, and my friend's shop
sells quite a lot of them as 'general' customer replacements. Matching does
seem to have been done by them with some care, on output tubes that are sold
as being a matched pair or quad.

Arfa


Good morning all,

I'll have to disagree with at least SOME of the Electro Harmonix tubes.
I've had nothing but grief with their 7591's. Bias drifting all over
the place, and in one case trashing an output transformer.

Regards,
Tim Schwartz
Bristol Electronics

"Meat Plow" wrote in message
...
On Tue, 17 Nov 2009 01:42:02 -0000, "Arfa Daily"
wrote:


wrote in message
...
I have a Fender reissue model guitar amp in for service. It has 2
Fender 12AX7's that are microphonic. These are Chinese manufacture. I
have replaced them with 5814's which is some sort of 12AU7 type just
to get the amp working. There is no more microphonic problem, however
the amplifier sensitivity is now somewhat lower so perhaps that may
have a bearing on this. I realise that I have no 12AX7's in the shop
at all and would like to buy several, two for this amplifier and two
or three for stock. I was looking at NOS and JAN types online and
would like to go with either but I suffered real sticker shock when I
noticed the prices. I don't have much faith in the Russian or Chinese
tubes so I was hoping that someone could offer some advice as to a
source for good preamp tubes either new or tested used, and ones that
I don't have to worry about microphonics. Thanks, Lenny.

The shop that I do a lot of work for uses many Russian tubes, and I have,
in
general, not found them to be a problem either reliability, spec or
microphony wise. Brands that he stocks are, for instance, Ruby and Electro
Harmonix. Do you have a music shop in your area ? They all stock
replacement
tubes over here, so I guess they would there too. Genuine Fender supplied
tubes are not all that expensive, and likewise, Marshalls. However, preamp
tubes such as 12AX7 do tend to come in quality levels. For instance, some
of
the 12AX7s that this particular shop stocks, are specced as "Premium
Grade"
and retail for 21 GBP (around $33) each, although obviously not that much
to
buy trade ...

Arfa


I've found the new Electro Harmonix dual triodes like the AX7, 83,
etc.. to become microphonic more often than the better Ruskie tubes
from Winged C. When it has to be uber reliable and the cust wants to
spend the extra $$ we still rely on NOS from Philips. I just repaired
an Ampeg SVT 3 hybrid, FET outs, tubes in the tone holes. Electro
Harmonix the cust changed himself back in July. He wouldn't go for the
NOS tubes so we put what he wanted back in the EH.s. I told him to
keep the amp off the speaker cabinet or it would shake them loose
inside again prematurely.

Hmmm. That's odd. I can't honestly say that I've had any particular problems
with EH tubes. I have to say that most of the ones that my friend stocks in
his shop are Ruby brand, but a fair few are EH, and he's not the sort of
bloke to continue stocking a product that was giving him any trouble. Apart
from anything else, he's a muso himself, who has been in the sales / repair
/ hire business for this sort of kit, for many many years. Interestingly
though, Rubys *are* made in China ... They are available in the U.S. see

http://www.magicparts.com/main.htm

and then "Dealers".

Seems that Fender themselves are shipping with Groove Tubes now ... see

http://www.kellyindustries.com/guita...der_tubes.html

Arfa