Soo... I want to build a tube amp. I am going to build a firefly since it is small, relatively easy to build and quiet (for a tube amp). I was wondering if I could "marry" this EQ with this schematic. If so how / diagrams would be much appreciated!

By bobdahaxor at 2008-07-28

By bobdahaxor at 2008-07-28

That and is there any way to make a headphone jack for it?
Last edited by ESP_Shreder at Jul 28, 2008,
I'm not an expert but there will be more attenuation than usual going off of a 12AX7 common cathode stage than what you see on the output graph in Duncan's amp sim if that's what you're using. I think the source impedance should be 38k in your case.

The highs will be attenuated more with a higher source impedance. Running through the simulator I would suggest making R3, the bass pot, lower (200-500k), and R5 higher (1-2M). You might want to play around with the cap values a bit too to improve bass response.
First off you posted a layout not a schematic. I would need a schematic to tell you...

You would most likely need to add a single triode gain make up stage, AKA you need another tube buddy. Tone stacks usually go after the first or second triode.

UG gets a lot of these "How do I add a EQ?" topics.... You know there is probably a reason why a EQ is not in place.
so... that second 12AX7 is for the gain then right? What about replacing the gain with the EQ?
There is a schematic. Sorry for being a bit uneducated. I really just would like some help. I am new to amp building and just want some information. I would go to ax84 or some place like that, but they have not accepted my account yet.

By bobdahaxor at 2008-07-28
Last edited by ESP_Shreder at Jul 28, 2008,