[MiRaCL]

Hello

I've read how to adjust the bias on the Millett Hybrid.
I've set it to 12V ,but it's fluctating between 11.80v & 12.40v +/-
Is there anyway to sett this to be stable?

I've left the amp on for about 48hours now,adjusting the bias every 6 hours, all yesterday,when i used the amp for music listening,the bias was at 12.06v on both tubes, now it's down to 11.89v when the amp is idle.

Is this correct or is there something wrong with my amp?

 

[bperboy]

I'm pretty sure that these are minor fluctuations, and they vary with room temperature. After 24 - 48 hours of adjustment, I'd leave it alone, because it is as stable as it'll get. I think.

 

[[AK]Zip]

Quote:

Originally Posted by bperboy I'm pretty sure that these are minor fluctuations, and they vary with room temperature. After 24 - 48 hours of adjustment, I'd leave it alone, because it is as stable as it'll get. I think.

That is correct. They will go up and down a little depending on room temp.

-Alex-

 

[nikongod]

i have found my millet to be stable with all of my tubes, under 1 condition.

the volume knob must be in EXACTLY the same postition when you check the bias in the standard milet configuration. i have also found that weather or not there is music playing has an effect.

if you want to see soemthing fun, set the bias to as close to 12V with the knob all the way left. then turn up the volume.

 

[vixr]

Keep in mind the trimmer pot wasn't built to perform constant adjustments. Get it as close as you can, then leave it alone. As a side note... I think when these tubes were popular in automobile radios, most cars had magnetos instead of alternators... no voltage regulator... The faster the engine turned, the more voltage the magneto produced... The tubes can handle a pretty big voltage variance, or they never would have lasted long in a car radio... I remember my grandfathers old ford truck, the headlights would get brighter if he revved the engine...

 

[nikongod]

i think you mean generators rather than alternators.
its a BIG diference, made possible by the invention of cheap high current diodes.

a magneto is part of the ignition system.

 

[sbelyo]

Run the bias at 15V. Pete's original magazine article showed the sweetspot is between 15 and 16 volts