How hot do you Bias your Amps??

What percent Plate Dissipation do you Bias at??

  • 40%

    Votes: 1 3.2%

  • 45%

    Votes: 0 0.0%

  • 50%

    Votes: 1 3.2%

  • 55%

    Votes: 2 6.5%

  • 60%

    Votes: 8 25.8%

  • 65%

    Votes: 7 22.6%

  • 70%

    Votes: 6 19.4%

  • 75%

    Votes: 1 3.2%

  • 80%

    Votes: 0 0.0%

  • NUKE

    Votes: 5 16.1%
  • Total voters
    31
Do you know who AY's Tech is??
BTW, AY has a shit ton of cash and can afford to blow shit up every night..
Keep that in mind when you Bias for Tone..
 
Devin said:
This is what I've always done. Haven't had anything blow up on me yet :D
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Yep. If you bias too high - you'll know. It won't sound good starting with a 'warbling' sound. I've found.

I mean, I order tubes matched to a spec that I already know is what I want. I may put the meter on to check how well they are matched but I like plug and play. That is the downside of buying used tubes IMO. Unless you have the same plate voltage as what I have, your bias numbers don't mean much to me.


v - Yep. Same @Racerxrated . For the Splawn, I order tubes matched at 32-34 mA. A little hot, but with bias drift it is a perfect starting point.
 
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311splawndude said:
Yep. If you bias too high - you'll know. It won't sound good starting with a 'warbling' sound. I've found.

I mean, I order tubes matched to a spec that I already know is what I want. I may put the meter on to check how well they are matched but I like plug and play. That is the downside of buying used tubes IMO. Unless you have the same plate voltage as what I have, your bias numbers don't mean much to me.
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Yes, it will sound like shit biased too low....or too high.

But, the magic number of 30-40ma usually works with any amp I've ever owned..with 600v PTs down to 400.
 
Racerxrated said:
Yes, it will sound like shit biased too low....or too high.

But, the magic number of 30-40ma usually works with any amp I've ever owned..with 600v PTs down to 400.
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Usually the case, but some amps can be weird about that. The Gjika by default was close to 60ma with my bias meter (I never took out the chassis or messed with it). Might be because it’s class A? Not sure. And my Uber is recommended in the manual to be 22-28ma. Maybe since it’s so high gain. In some amps high 20’s sounded good to me, but yes usually somewhere 30-40 in most amps
 
My THD amps are all biased at 25. My Fryette amps are biased 55. I prefer the sound and dynamics of 25 with almost all amps. But it really comes down to the individual amp and what I am going for. Hotter bias is great if you want that always on thing. But unfortunately you loose dynamics and punch.
How it effects tone if in the normal range of 25 to 40 with most amps very much depends on the amp. Some amps there is very little difference. Other amps night and day difference. It has lot to do with how the transformer is used in the design. If you always play at bedroom volume your probably want a bit hotter.

It is interesting to see the results of the poll. Goes to show there is always a few at that are more extreme settings hot or cold.
 
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Agree with a lot said here... I'm noticing that the typical 100 watt marshall (el34)1959/2203 works and sounds great @ 30-34ma of current draw.. not to exceed 34ma.
 
I bias customer amps at around 60% at 123vac input to the amp. If the all voltage goes down, the bias will be cooler, if it goes up it will go up, either way they should be in the 50-70% range. I do listen to every amp and tweak it up or down if it’s not sounding right, but 60% is my starting point.

I did just bias my Mesa mark Iva after the recap. Amazing how cold the inner set is biased.

Outer pair is 42ma, at 480vdc plate or about 20w. Inner is 17mA for about 8w. In tweed these drop to 13.2w and 5.2W. Been running mine in class a tweed for a long time, explains why the tubes last so long.
 
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