[sdiy] Tube!

[Tom Wiltshire]

On 2 Aug 2008, at 17:18, Ian Smith wrote:

>
>
>> That goofy tube only has a gain of 13. I'd say use at least a  
>> 12au7 with
>> realistic (200v+) plate supply so you'll have some headroom.
>
> Well, I was going for the 12V tube because I want it to work with  
> the voltages provided by the main power supply and not have to wire  
> up a second supply for high voltage, but I suppose if I really want  
> an old tube amp sound, I should use the high voltage stuff.
>
>> What do you plan to do with it? Use it as a buffer stage?
>>
>
> I just want something on the output that will give the synth that  
> nice tube warmth.

You should have a look at the PAIA tubehead schematics, Ian.

	http://www.paia.com/manuals/

It uses a voltage-booster circuit to generate a 45V supply from 15V,  
and then runs the tubes (12AX7s) from that. The low plate voltage is  
beneficial here. There's a great  page that explains how this  
"starved plate" tube circuit works:

http://www.paia.com/ProdArticles/tubesnd.htm

It's a great circuit.

Regards,
Tom