What specific sonic differences have you personally observed in new production vs. NOS tubes?

Discussion in 'Amp Central Station' started by trxx, Jan 22, 2020.

  1. trxx

    trxx Tele-Holic

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    This a very subjective and murky topic. And there have been countless discussions on the internet over the years concerning new production vs. NOS tubes, where there seems to be a few main camps of thought. First camp says that NOS can be superior both in durability and in sonics. Second says that it's only really about durability. Third says that there is practically no difference. Also, it seems that some new production tubes have very different electrical characteristics than their names imply, such as JJ new production of some American style tubes.

    But even when looking at it from a perspective of a few main camps, it is still all very vague and murky. Which specific new production and NOS tubes have been directly compared? Which specific durability and sonic issues were observed between them? Without specifics, it's all pretty meaningless chatter, i.e, NOS sounds better, is a packed statement that needs unraveling to carry any real meaning.

    What has been your specific comparisons and observations between new production and NOS tubes? Did you observe more or less noise? What type of noise? Rattle, microphonics, hiss? Did you observe a different frequency response? In what way? More or less lows, low mids, upper mids, highs? A difference in breakup? In what way? A difference in 'dimension'? What does that term mean to you?
     
  2. Whatizitman

    Whatizitman Friend of Leo's

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    I've only recently acquired enough tubes to make any comparisons at all, and I'm still at pretty much blind to any meaningful differences.

    I do know that a JJ 6V6 handles the high amount of plate voltage and crazy ranges of bias on my SF Champ ok. I do know that a new EHX 12AX7 is thin and fizzy (yuck). I surmise so far that the milspec NOS 6AQ5s I put in my MMB work and sound great. The old RCA 12AX7 that was in the Champ when I got it sounds warm, but kinda weak. I think I have a JJ in it right now. The old 12AX7 that was in the MMB is still in it, and sounds as good or better than the RCA or several other JJs and EHX I tried. I had decent luck with the EHX 7591 I put in the multivox in my avatar - it was at least as good as the original. I put a JJ 5751 in V2 of my DSL20CR. It tamed it a tiny bit, but not significantly.

    That's all I got.
     
  3. schmee

    schmee Poster Extraordinaire Silver Supporter

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    GENERALLY (there are always exceptions):

    NOS pre tubes
    : noisy, hissy, crackly, microphonic. I'd say maybe 50% of the time. Sellers don't test for this. You can find a good one though, and heck, they last 40 years.
    New pre tubes: quiet, reliable

    NOS rectifiers: usually good and very reliable.
    NEW rectifiers: often iffy or bad from the get go.

    NOS power tubes: sometimes they are way out of the normal bias range. Is this bad? I don't know but they are suspect to me. (For instance, I have a set of RCA BP NOS 6V6 tubes. If my amp is biased for a set of "normal" tubes at 20-25ma, and I stick these in, their unbiased reading will be close to 90ma! I'm leary of them, even if I was to rebias changing amp components to use them.)
    Many NOS power tubes are great though.
    NEW power tubes: Often are good. Many old Sovtek 6L6's and 5881's are fine sounding really.

    I think SOME tubes you can hear a minor difference. (smooth vs sparkly comes to mind for pre tubes)

    A few types you can hear a big difference. (usually a bad difference) (I won't use a JJ pre tube. But just based on a set that were gnarly sounding years ago.)

    Many you couldn't tell in a blind test.
     
  4. trxx

    trxx Tele-Holic

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    Here is the possibly irritating part of this sort of discussion: What does 'sounds good/great' mean?
     
  5. Whatizitman

    Whatizitman Friend of Leo's

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    Barring any obvious sound issues (screeching, buzzing, cutting out, etc...), for me, good is either "doesn't make me cringe", or "sounds at least as good as I recall it sounding before the change". Great is...more pleasing version of that, I guess?

    Sorry to be of absolutely no use to this discussion. :oops:
     
  6. trxx

    trxx Tele-Holic

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    It's a difficult topic of discussion, where we guitar players generally don't have a well-defined universal vocabulary for sound characteristics. For example, the term 'warm' could mean very different things to different people. And none of us would be the wiser to what someone means specifically by that term without it being unpacked to something more specific. To me, 'warm' means that from the basis of a flat frequency response, there is a little more presence of low mids around 100hz-200hz but not heavily exaggerated to the result of being muddy, along with a little more presence in upper harmonics up into around 10khz but not so exaggerated as to sound harsh. Another person might have a very different thing in mind for that term, but I wouldn't know it unless that person spells it out. This vocabulary issue often makes me wonder how useful discussion of sound actually is.
     
  7. muscmp

    muscmp Tele-Afflicted

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    very very subjective!

    just yesterday i did some output tube rolling in my 5e3 build. i first used a tester to make sure no shorts then i picked 12 rca 6v6S. i then put two in the amp and gave it about 10mins. to warm up. i played each for about 5mins. pulled the tubes and put two more in. eventually, they were so close to my ears that i picked the two I THOUGHT sounded best. i had already tested new jj6v6s prior to the rca tubes and even tho i liked them, i found they seemed too bright whereas the rca seemed less bright. note that i had already done this test with the preamp tubes and ended up with EH 12ay7 in v1 and jj 12ax7 in v2. i didn't notice that much difference between the newer tubes and older brand name 12ax7s/7025s.

    again, very subjective.

    play music!
     
  8. RoyBGood

    RoyBGood Doctor of Teleocity

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    These are the best ones:

    tubes.jpg
     
  9. muchxs

    muchxs Doctor of Teleocity

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    You should come over here and paw through my bucket of 12AX7s.

    "Noisy, hissy, microphonic" depends on brand and production date. For example if you get into early production U.S. 12AX7s (generally long black plates) they tend to be microphonic compared to post- 1960 production and certainly compared to 12AX7As.

    Here's the thing: The 12AX7 was designed as a compact and upgraded version of the 6SL7 tube. The 6SL7 mostly supplanted the earlier metal 6SC7 although you'll see amps that use both types. Those enormous plates and relatively loose construction results in tubes that tend to be microphonic.

    And, sure enough, pre- 1960 12AX7 types tend to be microphonic.

    GE tends to be more microphonic than RCA. RCA and Raytheon are about even. I have dozens of each type to choose from.

    Vintage Telefunkens are spectacular in almost every application.

    The hidden gem: Try a 12AD7 if you can find one.


    And, speaking of generalizations,

    Technicians who service high end "tube" microphones generally agree that most new production tubes are too noisy for critical mic applications.

    I'm not going to point fingers or name names but a few tube re- sellers do indeed screen their tubes for noise and microphonics. If you're paying $100 or more each for "premium" tubes you bet they get special treatment.

    And...

    Same sellers toss the tubes they deem unsuitable for mic preamp use into the pile to be sold for use in guitar amps.

    I almost never use new production tubes. There might be a day when I can no longer scrape up NOS. that day ain't here yet.
     
  10. trxx

    trxx Tele-Holic

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    Reading through some discussions of new production vs. NOS tubes can be almost comical. Someone asks for recommendations on tubes for an amp, and inevitably, new production vs. NOS rears it's head.

    First response: JJ chicken tastes good.
    Second response: New chicken tastes like rubber. NOS Mullard chicken tastes like real chicken.
    Third response: JJ tastes like real chicken, with a hint of pigeon.
    Fourth response: My NOS Mullard chicken tastes exactly like my JJ chicken.
    Fifth response: My NOS chicken tastes yummy.
    Sixth response: My NOS chicken gave me the squirts.
    Seventh response: JJ chicken gave me stomach cramps.
    ...
     
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  11. beninma

    beninma Friend of Leo's

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    I am preparing a study.

    I bought 10,000 NOS tubes of 10 different brands and did the same for 10 newly manufactured tubes.

    I've built special rigs to simulate guitar amps running the tubes at different bias points for thousands of hours to get a statistically valid idea if the old tubes are more reliable/last longer, and I've recruited hundreds of guitarists to do double blind tone testing.

    This should get a statistically valid/scientifically valid answer to this incredibly important question once and for all.

    Oh never mind, I'm not doing any of that. It'd cost a million bucks and you probably couldn't get enough NOS tubes to make the study valid, and guitarists would not listen to science/statistics anyway, so what's the point.

    So since I didn't do any of that I'm not going to say anything on the matter.. Play what you like and don't worry about anyone else.
     
    stevemc likes this.
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