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-   -   simple se. can I put NO volume knob? (http://www.diyaudio.com/forums/tubelab/220288-simple-se-can-i-put-no-volume-knob.html)

murphythecat8 24th September 2012 01:23 PM

simple se. can I put NO volume knob?
 
hi,
can I use no volume pot in the simple se?

bayermar 24th September 2012 01:44 PM

Quote:

Originally Posted by murphythecat8 (Post 3176906)
hi,
can I use no volume pot in the simple se?

Yes, that should be possible. R11/21 (220k) give a reference to ground for the grid of the 12AT7. The input impedance of your amp will be a bit higher without pot, but I see that as a good thing.
If you want to have everything the same as a volume pot "on 11", you could put a resistor with the same value as the pot in parallel with your input - but I don't see why this should be necessary.

Cheers,
Martin

murphythecat8 24th September 2012 01:53 PM

I would like to know how I can bypass the volume knob.

with what I have read, thats the way: Personally I would drop the volume pot and use a line amplifier. Though I don't know why since I am working (slowly) on a Musical Machine which is integrated. Something to me just feels right about dropping the pot on this amplifier, but it is nice to get one more active component out of the signal path. If I did this I think I would look to a 12B4A (maybe choke loaded, sitting atop a CCS...maybe), or a 6SN7 actively loaded, common cathode/cathode follower, think Extended Foreplay or VTV with CCS's

can anyone comment on this?

murphythecat8 24th September 2012 01:55 PM

Quote:

Originally Posted by bayermar (Post 3176927)
Yes, that should be possible. R11/21 (220k) give a reference to ground for the grid of the 12AT7. The input impedance of your amp will be a bit higher without pot, but I see that as a good thing.
If you want to have everything the same as a volume pot "on 11", you could put a resistor with the same value as the pot in parallel with your input - but I don't see why this should be necessary.

Cheers,
Martin

okay great thanks, good to know, I'll get everything and once im ready to build the amp, ill revive this thread for guidance

thanks

bayermar 25th September 2012 02:38 PM

It really depends on the output level of your sources.
Although I have not build one myself, it looks like the Simple SE amplifier has enough gain to be fully driven by any source with line level/CD player level.
Now if all your sources have already volume controls built-in, you can just omit the volume pot. All you need is a rotary switch to select the sources.
If you have already a preamp or want to use one, because you have low-level sources (like turntable/phono) which does the switching and controls the volume, you can also just omit the volume pot.
It would also be an advantage if you switch between different amplifiers frequently, because the power amps can be simpler that way.

Cheers,
Martin


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