Tube DIY Asylum

RE: Looking at PP amp designs

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Triode_Kingdom

In Reply to: RE: Looking at PP amp designs posted by Wojciech on August 02, 2014 at 11:11:59

I think your basic premise about the manufacturers is wrong. There were dozens of popular designs from American manufacturers that used cathode bias. Sound-wise, it's not clear to me that either biasing method has a consistently better track record than the other.

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Buy Chinese. Bury freedom.

Follow Ups:

RE: Looking at PP amp designs - Wojciech 15:51:26 08/02/14 (4)
Like whom? I think most popular American brands and it continues until today used and uses still fixed bias and Brits were and are using cathode bias.Is it because they are cheap or it's a convenience or just cathode bias simply sounds better overall?
I can't even recall one popular recent US PP tube amp design with cathode bias.
- RE: Looking at PP amp designs - David Smith 18:50:17 08/02/14 (3)
  Eico HF 81,86 and 87, Pilot 232, Fisher X100, Heathkit W3M, if I'm not mistaken would be some...
  - RE: Looking at PP amp designs - Triode_Kingdom 19:35:54 08/02/14 (2)
    "Eico HF 81,86 and 87, Pilot 232, Fisher X100, Heathkit W3M..."
    
    Exactly, plus many Harman Kardons (HK250, A224, A230, A250, A300, A500), Fisher 20A, SA100, 80AZ, Dynaco ST-35, Heathkit AA-151, etc. The list is almost endless.
    
    Now, if we're talking about recent designs, I honestly haven't kept up with commercial offerings over the last 20 years or so. If in fact fixed bias is being used more frequently, I'd suspect it's primarily for the higher power models. Not only does fixed bias provide more available voltage with a given HV transformer, cathode resistors become somewhat unwieldy (and wasteful) in larger amplifiers.
    
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    Buy Chinese. Bury freedom.
    - RE: Looking at PP amp designs - Wojciech 20:23:43 08/02/14 (1)
      Ok, single or a couple/few models for entire lineup and mostly marginal not so popular or cheap amps. Not a single modern amp.No Audio Research,VTL , Conrad Johnson , Manley (?),VAC, McIntosh, who else is making tube amps in this country ?..There is nothing to argue about it actually , I'm just curious why cathode bias were and is used more often or almost exclusively abroad while when I see (modern) circuit designed in US in 99 out of 100 is fixed.
      - RE: Looking at PP amp designs - Triode_Kingdom 09:11:15 08/03/14 (0)
        
        In Reply to: RE: Looking at PP amp designs posted by Wojciech on August 02, 2014 at 20:23:43
        
        Didn't realize you were referring only to current designs. There could be many reasons, and the trend might have nothing to do with considerations for sonics. Are you comparing similar topologies and power levels when you look at the European designs? Like I said before, fixed bias is typically used at higher power levels.
        
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        Buy Chinese. Bury freedom.
        
        Edits: 08/03/14

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