Mic Kaczmarczik's TubeInformation - The Blue Guitar

Here are "more tube supply sources":
o Triode Electronics, 312-871-7459
o Elmiria Electronics 800-847-1695
o Antique Electronic Supply, oriented to radio collectors,
602-820-5411
o Antique Audio, oriented to radio collectors, 512-467-0304
o New Sensor, mostly imported tubes (here's the source of Sovtek),
call Mike Mathews, 212-980-6748. Min. order is $50.00.
o ARS Electronics, 800-422-4250
o Department of Defense surplus auctions. DRMO-Tobyhanna Army Depot,
Building 16, Tobyhanna, PA 18466 is the gummint storage facility
for communications gear and is said to have good stuff. Also,
get "How to buy...Surplus Personal Property from the Department of
Defense", free from DOD Surplus Sales, PO Box 1370, Battle Creek,
Michigan 49016.
o Surplus electronics dealers - see the Telco yellow pages
o call everybody in the yellow pages under Electronics, TV-Repair,
Communications, and any other promising category.
o Hamfests
o SM's store, Angela Instruments, 8600 Foundry St. Box 2043, Savage,
Md. 20763, 301-725-0451.
o Tube Amp Service in San Francisco,run by Tom Balon; call
415-334-5200 PST. (O'Neill)
George Kaschner notes that parts other than tubes and transformers
can be obtained easily from Mouser Electronics (800-346-6873). I have
used Mouser and they give good service and prices; $20 min order.
another good source is Digi-key for resistors, capacitors, and other
general electronic parts. They are not tube oriented, but are also
a good general parts source.
4. How can I modify my Blender Tweety Bird amp to be as loud as a
Marshall Major/AC30/Tweed Bassman/SVT/etc.? (Alternatively, how can I
make my amp twice as loud/more power/ etc.?)
You can't do this in a low power amp, at least not electronically. To
put out the power the big amps put out, you need the entire power
train to be as beefy as the big amps. This means bigger power
transformer, rectifiers, filter capacitors, output transformer, more
power tubes, bigger chassis, more ventilation to carry off the heat,
lots of things. You can't just add a couple of tubes.
> An amplifier is properly thought of as primarily a big power supply
> that has some extra junk tacked onto it to carefully let a little of
> the power out to the speakers under special, controlled circumstances.
You might be able to just pull a couple of tubes OUT of a high power
> amp to make it quieter, under some conditions. O'Connor discusses
> this in "The Ultimate Tone".
5. How can I extend my tube life?
- modify the power on switching to heat the filaments first, let them
warm up for 30 seconds, then switch on the high voltage plate supply.
- add more ventilation to the amp chassis, perhaps with a small fan.
- modify the tube operating conditions so the maximum cathode current
is not exceeded under even maximum warp drive conditions. Exceeding
max cathode current causes cumulative emission losses and early tube
death. This requires a somewhat deep understanding of the design of
tube amps to do, unfortunately.
6. How do I get...
- blues distortion? Made by overdriving preamp and power tubes a
little, enough to just start compressing the peaks of the waveforms,
and not very much high frequency content, by electronically cutting
highs or running the signal into a speaker cab that acoustically
cuts highs.
> Guitar Player magazine ran a construction article on this very
> topic, modifying a Fender Bassman to be the "Ultimate Blues
> Machine". The article ran in 1995, authored by John McIntyre.