Vox AC30: Back panel settings

[rjdupe]

Hi all,

This is probably a question for Charlie or for anyone that might have some advice.

I run my AC 30 (6 months old) with 'back panel settings:
Output bias 82 Warm (as I don't need the power for practice and this setting is meant to preserve valve life.)

What should I set the smoothing to: 22 uf for vintage, where the instructions say the sound will be loose and open but with more hum ;or 44uf Modern which they say is like a modern hand wired AC 30.
Some advice would be appreciated.

Best regards,

Robert

[Charlie Hall]

Hi Robert,

The 82 (ohms) setting is the cathode resistor value, used in the earliest AC30s (it was 80 ohms in those days, 82 is the nearest modern value). Keep it set there at all times. I am actually surprised you had valve problems with using this setting as it runs cooler than the other setting (I referred to later AC30s running too hot, that's because of the later resistor value). Even so, Watford Valves cooler running valve sets should still be used in my opinion.

Use the 22uF setting for the nearest to the traditional Vox sound, originals were actually 16uF. It might hum a little more but the sound will have more vintage flavour. Either of these settings makes no difference to the reliability of the amp.

Regards,
Charlie

[rjdupe]

Thanks Charlie.
I will switch to the 22uf Vintage setting for the smoothing. One quick question. I assume the only point in having the 'hot' output bias is to give more power. If I use the 82 warm setting I assume the quality of sound will be the same. Vox claim 22 watts on the warm setting and about 33 watts on the hot setting. 22 watts is far more than I need anyhow!

All the best,

Robert

[Charlie Hall]

Hi Robert,
I think the sound will not be much different either way, unless playing at higher volume levels. The settings I suggested will run the amp close to how Dick Denney originally designed the AC30.
Regards,
Charlie