5AR4/GZ34 Tube Source Wanted and subsequent suggestions.

[Multi-Volti Devices]

I agree mostly.

However, you can get Chinese (Sino) or Russian (Sovtek) tubes for $7.90
and $6.90 respectively. Quality and tube envelope height are things you
may want to get opinions on from others. Try the newsgroup
rec.audio.tubes, or maybe it's rec.tubes.audio ??? for opinions.
New Sensor Corp has the above prices (800-633-5477), but I have heard
they PREFER selling to corporate accounts, just because it's less
hassle. We audio & ham customers can be very demanding & discriminating
to say the least. If you call them and matter-of-factly order without
chewing their ear with questions & warranty hassles, etc. they may not
flinch. A friend bought from them recently but he thought their initial
reluctance was a little weird.

My only warning about subbing tubes with SS diodes is to be aware that
the tube has a higher impedance and drops substantially more voltage.
Using solid state diodes can result in higher plate voltage, which could
exceed the ratings of your tubes or capacitors if the design was
originally close to maximum ratings. Also, tube rectifiers slowly warm
up and apply the voltage a little more slowly. The SS diodes will apply
hv quicker than the filaments heat up. This may not be a problem in many
if not most circuits, but just be aware of it, if it is an issue for
you.

Bob & Bettina Groh wrote:

> > >Subject: 5AR4/GZ34 Tube WantedTo:  Denny, WB7EGG/6
> From:  Bob Groh, WA2CKY
>
> I, personally, do not try to replace vacuum tube rectifiers directly
> but
> simply replace them with silicon power rectifier diodes.  Work much
> better, cost much, much less and reduce power supply drain (i.e. no
> filament power and less forward conduction loss).  I use 1N4005 or
> 1N4007 diodes - they are (respectively) 600 V, 1A and 1000 V, 1A.  I
> keep a bunch of them in the parts drawers for just such use.  Very
> readily available and, as mentioned, cheap (like 4 cents each for the
> 1N4007).  You can either put them directly across the tube socket pin
> under the chassis or, if you want to get exotic, pry out the glass
> envelope on the old, deflunct rectifier, wire the diodes inside the
> base
> and then epoxy the glass back on.  Other than the lack of filament
> glow,
> you're back in business.  But just a lot better.  73 and good luck.