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