[Vintage-Audio] Re Russian Tubes

[Kevin Rank]

Hi Duane -

Here are the facts I know:

Antique Electronic Supply has NOS U.S. made 7591A tubes in stock.  Hope you're
sitting down for this part - they are $79.95 each new, and $44.90 used.

There are any number of sources for the Electro-Harmonix labelled tubes.  These are
made by Sovtek.  Triode Electronics in Chicago (www.triodeelectronics.com) has a
matched pair for $43.95 and a matched quad for $87.90.  They offer a six month
warranty on these tubes.  Their website says these are "a new tube, different from
the Sovtek 7591-XYZ."  I know you don't want speculation, but this indicates to me
that the older versions had problems.

It is very important to note that the Russian 7591A is a bigger tube than the US
made one.  The design spec for the tube as listed in the RC-30 tube manual
indicates a maximum height of 2 3/4 inches.  The Sovtek tube is a half-inch taller
at 3 1/4 inches.  It is also about an eight of an inch wider.  This could cause
problems in certain amps.  I would measure very carefully before I bought them.

On the subject of Russian tubes, I should note that I have used a pair of Sovtek
6V6 tubes in my Fender Princeton guitar amp.  This amp runs about 430 plate volts -
they all do - well over the design maximum for the 6V6.  The Sovteks have held up
for a couple of years now, and don't sound bad.  One might argue a set of NOS RCA
6V6's would sound better, but I can't seem to find a matched set for $30!

I am in the same boat as you are with regard to 7159A tubes.  I just rebuilt a
Fisher KX-200 integrated amp for a friend.  This amp uses a quad of 7159A's.  He
has a total of 8 7159A tubes in his possession.  Four are very weak and four are
marginal.  We have the four "best" tubes in the amp now, but will likely be putting
a set of the Russian tubes in it soon.  I can't see anyone spending $180 for a set
of *used* US made tubes for this amp.  A quad of NOS tubes is $320.  I'm sorry, but
this is sheer lunacy.

Kevin



"Duane Fischer, W8DBF" wrote:

>
> Hi All,
>
> I need a matched pair of 7591 for a Scott amplifier. I am told that the Russian
> version is $23 each, about a third of the USA price. However, I have also heard
> that the Russian tube quality leaves much to be desired. I am interested in
> facts, gentlemen, not speculation. Are the Russian tubes good bad or?
>
> Thanks.
>
> Duane Fischer, W8DBF
> dfischer@usol.com
>
> _______________________________________________
> Home: http://mailman.qth.net/mailman/listinfo/vintage-audio
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer@usol.com **