homemade Valve Junior problems...

[i love everyone]

so i've been trying to build a clone of an Epiphone Valve Junior, with a few changes (Hammond transformers, 12AT7 preamp tube, additional 47uF filter cap, and a few different resistor values). until today, i'd only been able to play it in my apartment, which meant super-low volumes, and it sounded great. then today, i finally got to crank it at a friend's house. i realized that it sounded really good at really low volumes, and really good at full volume, nice and warm without too much gain, but everywhere in between, where i expected it to "crunch," it just gave this really ugly blown-out sounding clipping that got worse the harder i strummed.

i don't really know that much about troubleshooting amps, especially when they only halfway work, so if anyone has experience with these or similar amplifiers, any help would be much appreciated.

 

[LoFiBrian]

Re: homemade Valve Junior problems...

I subbed a 12AT7 into the preamp of my Epiphone Galaxie 10. I expected more crystal cleans and less mids...

What i got was pretty much what you describe from your amp with just a tad more headroom over the stock Sovtek 12AX7...

After going back to a EHX 12AX7, I get more crunch and just more of a punchy marshall crunch...

I guess a preamp tube swap could get you your desired tone...

I think a 12DW7 could be interesting...

 

[i love everyone]

Re: homemade Valve Junior problems...

interesting...yeah, i put the 12AT7 in there to get more clean headroom, but maybe changing other things in the circuit as well affected the operation of that tube...? i was actually thinking about switching to a 12AX7 because it ended up having more clean headroom than i expected/wanted, so i'll try that.