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Topic: What brand of 12AX7 is good for Sarno Black Box. |
Barry Yasika
From: Bethlehem, Pa.
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Posted 5 May 2019 8:54 pm
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The Sarno Black Box I have, had a Chinese 12AX7 tube installed. The original tube went belly up, so, because Chinese stuff can tend to be either really good or really bad I went with a Russian made Tongsul tube. (May have spelled that wrong) I don't know that I hear a marked difference either way, good or bad from the original tube when it was still working well. I'm just wondering if anyone has tried something that made a big improvement or at least a big difference in sound good or bad. The tube I bought seems to be more or less a like for like change. _________________ Emmons |
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Steven Paris
From: Los Angeles
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Dennis Detweiler
From: Solon, Iowa, US
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Posted 6 May 2019 6:39 am
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NOS RCA or a good used one. _________________ 1976 Birdseye U-12 MSA with Telonics 427 pickup, 1975 Birdseye U-12 MSA with Telonics X-12 pickup, Boss 59 Fender pedal for preamp, NDR-5 Atlantic Delay & Reverb, two Quilter 201 amps, 2- 12" Eminence EPS-12C speakers, ShoBud Pedal, 1949 Epiphone D-8. Revelation preamp into a Crown XLS 1002 power amp. |
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Jon Light
From: Saugerties, NY
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Posted 6 May 2019 7:36 am
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If it were me, I would contact Brad directly. As a contemporary, ongoing manufacturer, he would have his finger on the pulse of what he likes right now in the current crop of new tubes (an always shifting field). |
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Godfrey Arthur
From: 3rd Rock
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Posted 6 May 2019 8:21 am
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As stated previous, NOS RCA, but there are other brands and PRICES for NOS getting in the Richie Rich-o-sphere.
New tubes would be JJ brand.
Again we get another tube rolling question.
If you want to spend the time and money, start swapping (collecting) different vintage tubes to see what sparks your fancy.
NOS from 1962 Telefunken @ $228 simoleons. _________________ ShoBud The Pro 1
YES it's my REAL NAME!
Ezekiel 33:7 |
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Michael Brebes
From: Northridge CA
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Posted 9 May 2019 6:33 am
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I have found that many of the Chinese 12AX7's clip a lot earlier than most other tubes. I have had good luck with new production JJ and Electro Harmonix in this tube. To me Sovteks tend to be a bit tubby. _________________ Michael Brebes
Instrument/amp/ pickup repair
MSA D10 Classic/Rickenbacher B6/
Dickerson MOTS/Dobro D32 Hawaiian/
Goldtone Paul Beard Reso
Mesa Boogie Studio Pre/Hafler 3000
RP1/MPX100 |
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Brad Sarno
From: St. Louis, MO USA
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Posted 9 May 2019 12:10 pm
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The RULE with the Black Box is to avoid a tube with a "spiral filament". Since the 2nd stage of the Black Box is a low-impedance "cathode follower" driver circuit, that elevates the cathode-to-heater voltage to about 90 volts.
Many modern tubes us a spiral filament. In this situation the spiral heater filaments are prone to shorting out or arcing and having a reasonably spectacular failure. Doesn't always happen by any means, but it can and does sometimes.
SO - we avoid spiral filaments. Modern audiophiles and many boutique guitar amp makers agree that the latest generation of Chinese 12AX7 or 12AX7B is a good "clean" tube, and they don't have the spiral filament issue. That's my standard install.
BUT - you just can not beat a good vintage, American tube like an RCA, GE, Sylvania, Tung-Sol, JAN Philips, etc. RCA's are my favorites for pedal steel. Telefunkens are nice too, but the RCA has an especially smooth top end, clear and warm and smooth.
But if replacing a tube for a Black Box with a brand new, modern tube - I'd stick with the Chinese 12AX7 or 12AX7B. Sometimes they're also marketed under the GT-Groove Tubes brand or the Ruby brand. You can get them directly from Antique Electronics Supply in AZ.
Brad |
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Steven Paris
From: Los Angeles
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Posted 9 May 2019 1:39 pm
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Brad Sarno wrote: |
The RULE with the Black Box is to avoid a tube with a "spiral filament". Since the 2nd stage of the Black Box is a low-impedance "cathode follower" driver circuit, that elevates the cathode-to-heater voltage to about 90 volts. Many modern tubes us a spiral filament. In this situation the spiral heater filaments are prone to shorting out or arcing and having a reasonably spectacular failure. Brad |
Would the use of a DC-elevated heater supply avoid this problem? _________________ Emmons & Peavey |
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George Macdonald
From: Vancouver Island BC Canada
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Posted 9 May 2019 1:58 pm Black Box tubes
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Brad, Is the JJ ECC83-S a tube with a "spiral filament", and one to be avoided? Thanks, George |
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George Macdonald
From: Vancouver Island BC Canada
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Posted 10 May 2019 7:48 am Black Box tubes
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I just found out this morning from "The Tube Store" that the JJ Electronics ECC83-S 12AX7 tubes have the "spiral filament" that Brad suggests avoiding. They do have good reviews for other applications. |
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