Tube Amp Archive

I've been recently doing some research on these two master-volume mods, and apparently, they seem to be the exact same schematics, differing just in the pot/parallel resistor values, which results in different tapper and behavior of the input resistance. I've been using LarMar in my AC30 build, impl...

Roe, the Hammond choke you talk about, is it the four-hole "193L"? Would it fit the chassis? Found it here:
http://www.hammondmfg.com/193.htm

BTW, I guess I used 1n4007's in front of the GZ. Do you expect difference from your uf4007's?

The full DP conversion is descibed here: http://www.mikeryde.com/%5CDP_Amp%5CBMAC30_upgrade_to_DP_Spec.pdf I was wondering whether my MM 20h, 100mA choke would work. I currently have 64uF mains filtering and I believe 40uF at screens, no standby switch. I've added two diodes before the GZ, as Ceriat...

Good discussion on coupling cap values is here:

http://vintageamps.com/plexiboard/viewt ... t=tweaking

Hi, I am building an ac30 Weber Clone without the tremolo circuit. The schematic is here https://taweber.powweb.com/store/6v30_schem.jpg. All you need to do is cut the connection between c9 and VR4 pot and just ground the c9. Then drop the rest of the circuit. Of course you drop the c40 and r36 in t...

The problem seems to be solved!

Looks like all was about shielding. More in this thread: http://vintageamps.com/plexiboard/viewt ... 10#p980210

A good ac30 is pretty unstable. My ac picks up Japanese radio transmissions from 1941. Uhh.. This is without a guitar? that won't do. Check it with a guitar. You'd NEVER run treble and no cut. NEVER. On dark guitars I cut about 50% or more with 70% treble or so. Controls near the middle, volume wid...

Hi, having my guitar unplugged from the amp with full gain on the top boost channel, cut control fully left (= no cut), turning the treble control right (= more treble), the amp starts to oscillate at about 14:00. It's a very high-pitch sound. As I increase the treble even more, I get a sort of tuni...