Tube amplifiers: distortion & coloration or transparency & realism?

Discussion in 'Audio Hardware' started by raferx, Jul 19, 2014.

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  1. Lonson

    Lonson I'm in the kitchen with the Tombstone Blues

    My Decware amps and preamps have been amazingly reliable, I haven't used solid state for many years so not really able to compare, but the Decware build quality and parts quailty have led to over a decade of worry free listening.
     
    raferx likes this.
  2. chervokas

    chervokas Senior Member

    Yeah, new or old, reliability is no more of an inherent problem with tubes than with solid state. My '66 Fender Bandmaster does fine taking a beating with load ins and load outs in hot rooms, almost 50 years later facing conditions environmental and electrical that are way more challenging than anything a hifi amp faces in the home. It's all about the specific design, the quality of the parts and of construction, how well the amp dissipates heat. I don't really love tube sockets mounted to PCs for example -- the PCs flex when you change tubes, they're subject to high heats. But PCs can be problems with any sort of amp if you're talking repair. Sure, tubes, particularly output tubes, are going to need to be changed from time to time. Electrolytic caps are probably going to have to be changed ever decade or so (which is also true for solid state), and new production tubes definitely are not as reliable or long-lived as old production tube were -- so the tubes themselves tend to be more of a reliability challenge than the electronics. But I don't thing there's any meaningful reliability differences between tube gear and solid state gear on average.
     
  3. Lonson

    Lonson I'm in the kitchen with the Tombstone Blues

    I agree about boards. . . glad I only have one Decware product with a board (ZP3) and it does not have the tube sockets mounted on it!

    Good point about the abuse instrument amplification takes and how the well-built amps can take what's dished out!
     
    beowulf likes this.
  4. ROLO46

    ROLO46 Forum Resident

    The Aphex Aural Exciter was developed in the 70s when multitrack analogue was at its height and tracks were being bounced to death
    The exciter synthesises harmonics to tired tracks
    It was originally a rental device @$30 per minute finished track time
    Now its a plug in from BBE ,Joe Meek etc
    If you want more controlled begnign distortion this is it.
     
  5. Scott Wheeler

    Scott Wheeler Forum Resident

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    Will it do the same thing as my ARC SP 10/D 115? Will I get the same sound with the Aphex and some budget SS amplification? I'm thinking I wont. I'm thinking I will not getting anything close to the same effect.
     
  6. ROLO46

    ROLO46 Forum Resident

    Depends on your skills and moderation of application
    It was good enough for Jackson Browne and Linda Ronstadt.
     
  7. Scott Wheeler

    Scott Wheeler Forum Resident

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    So you are saying with the right skills and moderation of application this can actually give me the same sound as my tube amplification and I guess the same sound as any other tube gear. Correct? That is what you are saying?


    They used them in their home systems in place of tube gear?
     
  8. ROLO46

    ROLO46 Forum Resident

    No their producer/engineer used them in studios
    However today,you can do this at home...
    To synthesis signal harmonics
     
  9. Scott Wheeler

    Scott Wheeler Forum Resident

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    Well, truth be told I know all about the Aphex. I was just messing with you. But only because your suggestion that the aphex would be a good substitute for tube gear is pretty much like saying mustard is a good substitute for sugar. I have heard a demo of a recording with and without the Aphex and playback of the Aphex alone. Not what I want in my system. Not the same effect as my ARC gear.

    By the way Linda Rondstant had quite the high end system back in the day. Not sure what she has now. But I am pretty sure she had tube gear and no Aphex in the system. :cool:
     
    Robin L, T'mershi Duween and Lonson like this.
  10. Not sure if you are still playing around. This may be Captain Obvious for many here. But just to be clear; The Aphex harmonic generating device was used on the recording end, not play back. Simple Dreams has it on the master tape AFAIK. No one used an Aphex in a home stereo in those times.
     
  11. Scott Wheeler

    Scott Wheeler Forum Resident

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    yeah I was still poking some fun. But I suppose it could have been used in home playback as could any pro signal processor if one were so inclined to do so. I was not joking about Linda Rondstant having a nice high end system. That was quite true. She had WATT/Puppy speakers. I *think* she may have also had tube gear in her system but I don't know for sure.
     
    morinix likes this.
  12. Burt

    Burt Forum Resident

    Location:
    Kirkwood, MO
    Actually ARC equipment is generally considered and generally is pretty clean and neutral. I like the sound of ARC, I don't like working on them, I've seen spectacular fails on their power amps and some of their pre's eat 6DJ8s like popcorn.

    No one I know of uses actual Aphex equipment but the principle of deliberate signal tweezing is certainly out there.
     
  13. Scott Wheeler

    Scott Wheeler Forum Resident

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    ARC has been around since the 70s and has produced a wide range of gear with many different sonic signatures. I speak only for the gear I have owned and still own.
     
  14. Burt

    Burt Forum Resident

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    Kirkwood, MO
    No but once they were an outright sale item you saw them in live performance venues. A couple of TV preachers used them on their pulpit mics in fact.
     
    morinix likes this.
  15. sublemon

    sublemon Forum Resident

    This statement is certainly not true. At least in terms of global negative feedback there are certainly SS designs with no feedback. Also, plenty of tube amps have global negative feedback as well. Though I guess it easier to implement a tube design without global feedback, but I'm not an expert.
     
  16. jupiterboy

    jupiterboy Forum Residue

    Location:
    Buffalo, NY
    Good to know. I had recently read something that stated otherwise.
     
  17. sublemon

    sublemon Forum Resident

    the aphex aural exiter and say the BBE sonic maximizer are the kind of studio devices that can make something sound exciting at first, but maybe fatiguing. You have to use them sparingly, kind of like how a compressor too much will make a track pop but then can get annoying or artificial sounding (though sometimes can be an intentional sound).
     
  18. chervokas

    chervokas Senior Member

    Yeah, Utra-Linear and distributed load tube amps are all about the negative feedback. Even most of the beloved old amps -- not just the obviously Ultra-linear ones like the Dynacos, but the McIntoshes use some global negative feedback scheme, amps like the Marantz 8, etc. I suspect that in push-pull AB tube amps of greater than say 15 watts output global negative feedback is probably more common than not, no?
     
  19. vinylkid58

    vinylkid58 Forum Resident

    Location:
    Victoria, B.C.
    Circuit topology dictates what style of feedback you're going to implement, not the output power for the most part. Lots of <15 watt amps out there with global feedback (or Shade style), some single ended.

    jeff
     
  20. chervokas

    chervokas Senior Member

    Oh yeah, no doubt plenty of lower watt amps with global negative feedback. I'm just saying you don't come across a lot of push-pull AB tube hifi amps that are generating more power than that that aren't using global NFB, but you might run into lower wattage triode amps with no global NFB.
     
  21. norman_frappe

    norman_frappe Forum Resident

    That is true although negative feedback helps improve almost every measurable performance factor in an amp so I think it's wise to use it. You can overuse it to negative affect so it's a balancing act The problem with tubes amps is the transformer will limit how much negative feedback you can reasonably use in the design. Too much and the output impedance will be too high.
     
  22. Burt

    Burt Forum Resident

    Location:
    Kirkwood, MO
    There are commerical high end (Nelson Pass, others) and DIY (Susan Parker, others) designs of solid state no global feedback power amplifiers but they are not commercially popular or found in any mass market, home or PA/MI/etc product. Solid state, transformerless designs both make feedback much easier and are more dependent on it. Transformers are the bane of feedback application in that you can't put feedback directly across more than one without extreme measures to deal with phase shift.

    No one built no-feedback tube amps besides those in table radios or Champ size guitar amps after the late 30s, until the single ended triode guys came out. Most Western Electric designs, for the record did use feedback, only not across the output transformer. The Brook triode amps of the fifties which were the closest thing to modern ideas of "sound over measurements" used feedback across the output transformer.
     
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  23. DaveC113

    DaveC113 Forum Resident

    Location:
    Front Range CO
    Worth saying three times Burt! ;)

    I certainly prefer amps that do not use feedback at all. Improving measured performance doesn't mean much if it doesn't actually sound good.
     
    beowulf likes this.
  24. Mike in OR

    Mike in OR Through Middle-earth...onto Heart of The Sunrise

    Location:
    Portland, Oregon
    This is not entirely true.
     
  25. Burt

    Burt Forum Resident

    Location:
    Kirkwood, MO
    Which part of that?

    I can't speak to every WE design but most of them have feedback from the final to a previous stage, sometimes to the screen or suppressor grid of a preceding pentode.
     
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