Author Topic: Whats up with JJ signal tubes?  (Read 13829 times)

Offline rpf

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Re: Whats up with JJ signal tubes?
« Reply #15 on: April 09, 2014, 02:00:47 PM »
I've used JJ 12AU7s and 12AX7s in my Rogue Cronus Magnum for several months without problems. They sound better than any of the other new productions tubes that I've tried (most, including Genalex, Psvane, Tung-Sol, Mullard, Ruby Chinese, Sovtek, EH). But long term I can't comment as to their reliability.

As good as they sound they don't come close NOS.

I've revisited the JJs and Genalex after moving and making some other changes to my system. I have to say I like the Genalex better now. More resolution without the "zingy highs" (as Steve describes it).

Might have to try the Telefunken.
Mac Mini>Singxer SU-1>Lampizator Amber II>Rogue Cronus Magnum>Aural Acoustics Model B.
TWL PCs; Audio Envy ICs & SCs; Purist Digital IC; PI Audio USB Cable and Buss-Stop.
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Offline steve

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Re: Whats up with JJ signal tubes?
« Reply #16 on: April 12, 2014, 01:26:12 PM »
Hi R,

If I understand you, you mean the zingy is gone now?

I take it a tweek "down" to the highs somewhere with the system in an attempt to correct the Genalex highs?


Cheers.
« Last Edit: April 12, 2014, 01:33:54 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Acutex 320 STR Mov Iron Cart
SAS 11A Perfect Tube Preamp
SAS 25 W Ref Triode/UL Monoblocks
2 way Floor Standing Test Speakers

Offline rpf

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Re: Whats up with JJ signal tubes?
« Reply #17 on: April 12, 2014, 08:56:44 PM »
Hi Steve,

Yes, I no longer find the highs annoying, although they are perhaps still slightly prominent. At least compared to the Raytheon black plates or Amperex/Mullard I most often use.

Some of the changes to my system of late include replacing the stock resistors in my speakers with Duelunds, changing the Electra tube connectors on my speakers and Furutech banana plugs on my speaker cables to Cardas un-plated copper connectors, and changing the output coupling caps in my EE DAC Plus to VH Audio OIMP ones. The changes weren't made to compensate for the sound of the Genalex, just to improve the system. I threw the Genalex (and some other caps) back in just to hear how they sounded after the changes.

Mac Mini>Singxer SU-1>Lampizator Amber II>Rogue Cronus Magnum>Aural Acoustics Model B.
TWL PCs; Audio Envy ICs & SCs; Purist Digital IC; PI Audio USB Cable and Buss-Stop.
Sonos Connect, iFi SPDIF iPurifier, Schiit Modi Multibit, Audioengine 5+

Offline steve

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Re: Whats up with JJ signal tubes?
« Reply #18 on: April 15, 2014, 07:32:09 PM »
Thanks  for the information R.

I went ahead and did a relative tube comparison using the 11A as the reference pre and my amps. Tube changes were in the preamp.

Tubes involved were one new tube, along with some old tubes from my Tektronix O'scopes from 50s-60s, so I know there are no fakes. I measured the plate current, an indicator of Gm. All were nice specs.

The differences posted were what I would call small to moderate. Most were rather small, but the thinner top two tubes did give me the impression of near moderate difference. (Of course what does small and moderate mean.)

Soundstage was very good to excellent, just minor differences such as wider landscape.

New tubes were Genalex:

Old tubes were:
GE
Jan Sylvania
RCA (made in Japan)
Bugleboys, Holland
PQ, Holland
JJ

Genalex is a puzzle. It had nice bottom and mids, upper bass and lower mids fuller than JJs, so great flesh.
But the highs almost appeared like I had a three way speaker rather than 2 way (full range). Violins thinned out, strident, especially when installed in both the pre and amps. Just too much for me. Get that solved and a great tube.

GE was generally a little thinner across the board than the other tubes. Highs not as thin as Genalex. Not bad, but tubes below have more flesh.

PQs were a little fuller than GEs, but a little thinner than the bugleboys, Jan Sylvania, new Telefunken, JJs. Not quite as relaxed in the mids and highs. Bottom is very nicely controlled. Did sound nice though.

The RCAs and PQs were nearly identical, very difficult to differentiate them apart. A real surprise. One tube said Japan but the other I could not absolutely prove. The internals did look identical though.

Bugleboys had the most relaxed highs of any of the tubes. Almost too much. Bottom was in top form but not quite as fleshy as the Jan Sylvania, JJs.

New Telefunkens were just slightly thinner, from top to bottom than the JJs.

Jan Sylvania were a little more flesh than above tubes.
Highs relaxed while bottom nicely control. JJs bottom a little looser than Jan Syl.

JJs highs were not quite as relaxed as the Bugleboys on the highs but still very nice, bottom a little fuller, looser than Bugleboys. JJs were nicely fleshed out, very close to Genalex and Jan Sylvania.

Just my relative comparisons, using Bach Brandenburg Concertos No.3 - iii: Allegro , and a little Scheherazade.

Cheers.
« Last Edit: April 15, 2014, 07:40:53 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Acutex 320 STR Mov Iron Cart
SAS 11A Perfect Tube Preamp
SAS 25 W Ref Triode/UL Monoblocks
2 way Floor Standing Test Speakers

Offline sleepyguy24

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Re: Whats up with JJ signal tubes?
« Reply #19 on: April 22, 2014, 09:27:57 AM »
I've been trying a JJ gold pin 12AX7 tube in my Bellari headphone amp at work and it is holding its own vs. an old stock yellow label Westinghouse 12AX7. The JJ Gold Pin seems to be less sensitive to the electronic interference in my work area. Sound wise everything is good. No over emphasis on bass and highs aren't painful. Maybe JJ tubes have turned the corner now? I really like the regular 5751 tubes in my Jolida amp.