[Vintage-Audio] Present audio tube manufacturers and substitutions.
Philip Atchley
[email protected]
Tue Jun 18 13:38:00 2002
Hello
While browsing I found the following information on tubes at the following
url. I thought it might be of interest here. But do check out the url as
there is a lot of good info there. It lost all formatting in
cutting/pasting to this message.
http://geofex.com/tubeampfaq/taffram.htm
Appendix B. Tube Makers Producing Today (Eric Barbour news posting)
(The following is the text of a note posted to the alt.guitar news group by
Eric Barbour <[email protected] is also badly out of date, and will
be upgraded by Eric soon.)
Different makers of tubes use different designs. There are six makers of
common audio tubes right now:
Shuguang, China--good 12AX7s, so-so power tubes
Tesla, Czech--ok EL34s, preamp tubes variable
Reflector, Russia (sold under Sovtek brand)--good 5881, EL84, so-so 12AX7
(they came out with EL34s recently---I am testing them)
Kaluga, Russia (only a few types--sold under Sovtek, Audio Glassic) good
5881s, not sure what else they make today
Svetlana, Russia--has a 6550 now, good---will introduce an EL34 soon
EI, Yugoslavia (in Serbia)--fair 12AX7s, fair EL34s, future supplies are
questionable because Serbian products are under economic sanction; thanks to
that Bosnia business!
That's ALL there are right now. That's it. Any NEW tube you buy is from one
of the above.
For your guitar amp, I would recommend the "Sovtek" 5881, it's a really
nice, rugged and smooth-sounding tube. It was a military type used in servo
amps in jet aircraft, so it has to be good. If you have a Marshall or other
EL34 amp, the Sovtek 6CA7 imitation (recently released) is probably most
rugged. If you want more distortion and a more bluesy sound, you want the
skinny EL34s. The Svetlana EL34 will be a skinny type, it should be very
good.
AND.....
Tube Characteristics and substitutions
Some quick and dirty subs and some tube data such as recommended bias
current and appx voltages. These subs are all taken from the Tube
Substitution Handbook sold by Antique Electronics Supply. or provided from
the net.
A (short) catalog of tubes you are likely to see in a guitar amp:
12AX7[A, WA] and substitutes - preamp and driver tubes
12AT7, 12AU7 and subs, preamp and driver tubes
12AY7 - driver tubes
6EU7 - dual triode used in some older amps for preamp tube
6L6 types - power output tubes, up to 50 watts/pair, a mainstay of Fender
EL34 - Euro power pentodes, up to 50 watts/pair, many Marshalls
6V6 - smaller, lower power cousin of the 6L6, 10-14 watts per pair; used in
smaller Fenders
EL84 - fits a 9 pin socket like a 12AX7 but twice as tall; miniature power
pentode, good for 12-18 watts per pair; used in smaller Vox amps, and a quad
of these drives the Vox AC-30 for 30 watts.
Substitutions:
* means appropriate for parallel filament circuits
# means may not work in all circuits
Preamp and driver tube substitutions:
12AX7 (high gain dual triodes with pinout 9A)
12AD7* 12DT7 7729
12AU7# 5751* B339
12AU7A# 5751WA* B759
12AX7 6057 CV4004
12AX7A 6681 E83CC
12AX7WA 6L13 ECC803
12BZ7* 7025 ECC83
12DF7 7025A M8137
12DM7* 7494
12AU7 (moderately high gain dual triodes with pinout 9A)
12AU7[A,AW,] 6189 7730
12AX7* and subs 6670 ECC186
5814[A,AW]* 6680 ECC802
5963 7316 ECC82
6067 7489 M8136
12AT7 (medium gain dual triodes with pinout 9A)
12AT7[many suffixes] 7492 E81CC
6201 7728 ECC801
6679 A2900 M8162
ECC81 B152 QA2406
12AZ7[A]* B309 QB309
6060 B739
6671 CV4024
12AY7 (low gain dual triodes with pinout 9A)
12AY7(and suffixes) 6072
2082
Power tube substitutions:
6BQ5/EL84 (miniature pentode with pinout 9CV)
6267 7189 EF86
6BQ5 7189A EL84
6BQ5WA 7320 N709
6P15 E84L Z729
6L6 (beam power tube with pinout 7AC)
6L6(many suffixes) 7581(A)
5881 WT6
5932 EL37
EL34/6CA7 (power pentode with pinout 8ET)
EL34 12E13
6CA7 KT77
7D11 KT88
6550 (power pentode with pinout 7S)
6550[A] 7027A#
7D11 KT88
12E13
Cautionary Tubes - these are very hard to find
7591/7591A - legend has it that these otherwise excellent tubes were all
bought up by an oriental buyer who toured the USA paying cash for all of
them he could find, then disappearing. You are likely to only find used ones
or the odd pair in some out of the way place. Dealers will in general not
have them. I have personally seen trays full of NOS 7591A's for sale in the
Akihabra electronics district in Tokyo, lending some credence to the rumor.
These were used a lot in old Ampegs. They are very small and high gain for
their physical size, so there may not be a lot of room in a chassis for a
larger replacement. The 5881 will work in some circuits, but has
significantly lower transconductance.
Rumor Update: The rumor mill on the net says that the Russians will soon be
making 7591's soon. Cross your fingers...
7199 - combination pentode/triode used as a one-tube voltage amp/phase
inverter/driver for a pair of output tubes in some Ampeg amplifiers Note:
These were once popular, but are now getting rarer and more expensive. There
are a number of other pentode/triodes that can be substituted, but the
pinouts are different and this will require require rewiring the socket for
the tube. Examples are the 6AN8 and the 6U8. There is a Russian tube that is
labeled 7199 which may work, although this is new.
7027/7027A - this is a high power tube similar to a 6550. The supply of
these is very poor.
7189/7189A - a higher power/voltage version of the 6BQ5/EL84. Hard to find.
A stock 6BQ5/EL84 may work if the power and voltage conditions in the amp
are not right out at the limits of the tube design.
73 de Phil KO6BB
REAL Radio is heard on Boatanchor Receivers.
REAL Music is played through 'Valve' Guitar amps!
[email protected]
Merced, Central California