12AX7 ?
- Thread starter teisco
- Start date
5751s, aren't a direct replacement, though they are pin compatible, and similar in function.
In some gear they work fine but in other not so much.
Just be aware
In some gear they work fine but in other not so much.
Just be aware
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In general, so-called different 'tube sound' is as a result of spread in characteristics - even in same brand - not 'brand sound'. [For the still open-minded: Not to start on a topic that has been thoroughly exhausted, but electron tubes in themselves have no 'sound'. Electrons flow/act according to natural laws, they do not have 'emotion' and cannot influence sound in any other way than through different characteristics. Those can be measured.]
Even with NOS tubes there occasionally were unacceptable deviation/spread. Thus it does not 'characterise' a certain brand when hearing testing was done with one or two examples only. Sadly even in limited numbers like 10 I have found spreads of +/- 30% ! This can certainly alter performance to an audible extent because of deviation in design workpoint.
Many (most?) enthusiasts are not fortunate to have access to tube testers, thus it is not easy to determine how standard their tubes are. Sadly then I do not provide a solution, at most an explanation for what is really taking place.
Even with NOS tubes there occasionally were unacceptable deviation/spread. Thus it does not 'characterise' a certain brand when hearing testing was done with one or two examples only. Sadly even in limited numbers like 10 I have found spreads of +/- 30% ! This can certainly alter performance to an audible extent because of deviation in design workpoint.
Many (most?) enthusiasts are not fortunate to have access to tube testers, thus it is not easy to determine how standard their tubes are. Sadly then I do not provide a solution, at most an explanation for what is really taking place.
I'm using Telefunkens in a Luxman preamp. I pulled them from some old Fisher, Dynaco, etc gear. They might be 50 years old for all I know — and still dead-silent, with crystalline clarity and, on the subjective side, oodles of charm.
If (when) I finally have to replace them, I may just give up Music. None of the new ones I've heard even come close.
I noticed, when I was just a kid, that light bulbs always blew when you switched them on. I later learned it was the sudden surge of power that did it. So I leave my Telefunkens on, hoping to extend their lifetime.
What are your thoughts on this?
If (when) I finally have to replace them, I may just give up Music. None of the new ones I've heard even come close.
I noticed, when I was just a kid, that light bulbs always blew when you switched them on. I later learned it was the sudden surge of power that did it. So I leave my Telefunkens on, hoping to extend their lifetime.
What are your thoughts on this?
Bimasta,
Yes, this can be a particular worry. Some tubes in particular can give a most alarming surge of light at switch on. And yet in my experience (some 65+ years) I never had a tube heater fail as a result of swith-on. I have heard others having been of similar opinion. So while controlled heater warm-up sounds like a definite advantage, I am not losing sleep without it; many other more worrying matters in tube amplifiers!
Yes, this can be a particular worry. Some tubes in particular can give a most alarming surge of light at switch on. And yet in my experience (some 65+ years) I never had a tube heater fail as a result of swith-on. I have heard others having been of similar opinion. So while controlled heater warm-up sounds like a definite advantage, I am not losing sleep without it; many other more worrying matters in tube amplifiers!
Auto Analog
Justin Credible
Sovtek LPS and Tung Sol Reissues sound best in my PAS3X.
Nixxuz
Super Member
I can honestly say you are the only person I've ever heard of liking the new JJ, or Shuguan, outside of instrument amplifiers. I know both have their own "higher tier" of tubes, like the Treasures, but their plain jane tubes have never done it for me.
Poultrygeist
Lunatic Member
Telefunkens are hard to beat. I use these Fisher branded Tele's in one of my preamps. The diamond engraved on the base usually means it's the real thing.
I wouldn't. DAGS for cathode poisoning. There are tricks you can do to limit inrush on power up.
Nixxuz, I agree with you. My experience with JJ tubes is that they are best used as a means to keep dust out of tube sockets for amps in storage. Every piece of gear that I have picked up with JJ tubes has gotten substantially better with other tubes. My VTA preamp had 4 JJ 12AX7 tubes in it and was un-listenable as it came. Swapped in some good vintage tubes and it's not going anywhere.
Reputations are earned.
BillWojo
Reputations are earned.
BillWojo
Please, what are those tricks? I'd love to prolong their lives.
And if you could, please elaborate on "DAGS for cathode poisoning"...
SoCal Sam
Lunatic Member
I have a small box of Fisher Tele's. Agree, they are awesome. I feel the same way with turn on surge. I use a Monster HTS 3500 because it has a slow start switch.
I'm a big tube roller, so here I go...
Since 12ax7's can be used in so many ways, success depends on the circuit. I suggest you start trying different brands till you find your favorite.
https://www.radiomuseum.org/tubes/tube_5851.html
7025 is a low noise version of 12ax7 well suited for preamp use.
Try different tube brands. Synergy is critical and only you can decide what sounds best in your system.
Brent Jesse is a good place to find info.
http://www.audiotubes.com/12ax7.htm
Since 12ax7's can be used in so many ways, success depends on the circuit. I suggest you start trying different brands till you find your favorite.
5751 is electrically similar to 12ax7 but with only 70% of the gain. I use a Sylvania Gold Brand GB5751 at the input stage of my (cathode follower) preamp. I tried a 5751 because it sounded like the input stage was overdriving the second stage. In no other position (three 12ax7's total) does 5751 sound good.
That's a typo error. 5851 is a totally different animal. (No disrespect NJ Phoenix)
https://www.radiomuseum.org/tubes/tube_5851.html
Not a bad tube, but it depends on the circuit. Sounded harsh in all positions of my preamp. If the diamond casting is missing, it's most certainly a fake.
7025 is a low noise version of 12ax7 well suited for preamp use.
Try different tube brands. Synergy is critical and only you can decide what sounds best in your system.
Brent Jesse is a good place to find info.
http://www.audiotubes.com/12ax7.htm
Poultrygeist
Lunatic Member
Telefunkens must sound great in a variety of circuits otherwise so many folks would not hold them in such high regard.
They're great but not my favorite sounding 12ax7 and why I think it depends more on the circuit and system synergy than the manufacturer.
Very well built and rugged. It's been my impression musician's prefer Tele's because they're crystal clear, rugged and forward sounding for music production. You know what you're getting.
Music REproduction is another story.
I don't think there's "a best sounding12ax7 manufacturer" and different versions by the same manufacturer sound different too. Black plate, gray plate, smooth plate, ladder plate, round getter, D getter, the list goes on.
Tele's are great, so are Amperex and Mullard.
And RCA. And GE. And Sylvania. And Raytheon. All worthy brands that deserve evaluation.
Tubes are like guitar strings...they all have their own "sound". A tube can be silky smooth in one circuit but glare in another.
Again, just my opinion. The OP's question is valid and so is everyone's personal opinion.
I'm just saying the OP needs to decide for himself.
Many criticize them as too "bright" and "clinical". Not so in my Luxman — and the Luxman does not have the clichéd "soft and warm tube sound" that needs "tuning" with a bright tube.
I'd love to see an AK poll about the many new versions, because they're all that's available at a sane price — poll which, to satisfy Heyraz's good point, names the components the tubes were in.
Poultrygeist
Lunatic Member
Brent Jesse had a pair of NOS Telefunken 12ax7 tubes listed for $1699. Very rare tubes but there are cheaper Tele's.
Demand and supply determines price.
Demand and supply determines price.
Those might have been the e83cc ( I think that's the version) of 12ax7/ECC83 tube made by Telefunken. They're a "Holy Grail" tube and constructed differently. I think their plates are "boxed". Medical or lab grade tube.
