I am copying a guitar amp and have some questions.
It's an EL84 push-pull amp - about 18 watts, with a circuit very similar to a Matchless Spitfire.
The tone stack is a little unusual. It's similar to the Fender stack (for the 18 Watt Lite II) but not really.
It works, but you have to turn the knob to about 8 and then at 9 the volume falls off quickly. I've attached a photo.
I'm also considering adding a triode/pentode switch to lower it to 5 watts, which would be nice for bedroom use.
Does this sound good?
I'm asking because I don't see one on the 18 Watt or Matchless.
Another change would be a master volume.
There's only one stage of gain, so there's two choices:
A pot between the output of the phase splitter
(I've seen this in the Vox AC30 circuit)
A dual pot on each side of the phase splitter.
There's also a 1/2 of an 12AX7, which I could add as a boost stage.
I don't really see a need, however, since the amp screams (although it is a bit loud).
Schematics for the 18 Watt Lite II can be found here
http://www.silvatone.bravepages.com/
Thanks!!
PS - If you're interested in helping me fine tune it, I'll send you a schematic by email or private message. Let me know.
It's an EL84 push-pull amp - about 18 watts, with a circuit very similar to a Matchless Spitfire.
The tone stack is a little unusual. It's similar to the Fender stack (for the 18 Watt Lite II) but not really.
It works, but you have to turn the knob to about 8 and then at 9 the volume falls off quickly. I've attached a photo.
I'm also considering adding a triode/pentode switch to lower it to 5 watts, which would be nice for bedroom use.
Does this sound good?
I'm asking because I don't see one on the 18 Watt or Matchless.
Another change would be a master volume.
There's only one stage of gain, so there's two choices:
A pot between the output of the phase splitter
(I've seen this in the Vox AC30 circuit)
A dual pot on each side of the phase splitter.
There's also a 1/2 of an 12AX7, which I could add as a boost stage.
I don't really see a need, however, since the amp screams (although it is a bit loud).
Schematics for the 18 Watt Lite II can be found here
http://www.silvatone.bravepages.com/
Thanks!!
PS - If you're interested in helping me fine tune it, I'll send you a schematic by email or private message. Let me know.
Attachments
Are you using the correct taper pots?
5W is still too loud for the bedroom, 0.5W would be more like it;
Check out how the master vol is done in this schematic:
http://ampage.org/schematics/spitfire.gif
Cheers,
Pete McK
5W is still too loud for the bedroom, 0.5W would be more like it;
Check out how the master vol is done in this schematic:
http://ampage.org/schematics/spitfire.gif
Cheers,
Pete McK
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