"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