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12AT7 resurrection
I think I'm going to resurrect this thread. I stumbled upon this thread while wading through some of the buried pages in the forum and thought it might be interesting to do. I used all junk-box parts and a generic Fender-type reverb transformer. I used a perfboard Nixie supply and voltage regulator to power it with 12.6V regulated for the heaters and 250V for B+. I wasn't crazy about it with a 12AX7, so I re-designed a little bit to use a 12AT7 that I had laying around. Mainly just tinkered with resistor and cap values and re-arranged a couple of things. I also added a small treble-bleed cap to the volume control to make it a little brighter and louder at lower volume settings. Since the 12AT7 is slightly lower gain, I managed to add bypass caps to the preamp and output section, so I actually get decent bedroom/recording volume. This version goes from clean to bluesy break-up/mild overdrive with crappy Squier single-coils or my G&L ASAT MFD pickups (close to P90). I like it as a practice amp and for testing pedals (works great with a Valvecaster or Bad Monkey). I don't have pictures since it's guts are still scattered on my work bench with proto board and alligator clips. Now I have to decide whether to make it a mini-head or mount it into a speaker cab for a mini-combo...
I think I'm going to resurrect this thread. I stumbled upon this thread while wading through some of the buried pages in the forum and thought it might be interesting to do. I used all junk-box parts and a generic Fender-type reverb transformer. I used a perfboard Nixie supply and voltage regulator to power it with 12.6V regulated for the heaters and 250V for B+. I wasn't crazy about it with a 12AX7, so I re-designed a little bit to use a 12AT7 that I had laying around. Mainly just tinkered with resistor and cap values and re-arranged a couple of things. I also added a small treble-bleed cap to the volume control to make it a little brighter and louder at lower volume settings. Since the 12AT7 is slightly lower gain, I managed to add bypass caps to the preamp and output section, so I actually get decent bedroom/recording volume. This version goes from clean to bluesy break-up/mild overdrive with crappy Squier single-coils or my G&L ASAT MFD pickups (close to P90). I like it as a practice amp and for testing pedals (works great with a Valvecaster or Bad Monkey). I don't have pictures since it's guts are still scattered on my work bench with proto board and alligator clips. Now I have to decide whether to make it a mini-head or mount it into a speaker cab for a mini-combo...
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