Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: cap217 on March 26, 2024, 05:20:09 pm
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I have been a fan of the wreck/ac30 amps for a long time. I dove into the circuits over 10 years ago but after owning all of the different variants (besides a real trainwreck) I still have questions. Im not an expert at amps and circuits but I do understand a lot.
I think the best feeling amp to play is an UG30. I am always trying to figure out why that is. Is it because the reverb in the front has an effect on the amp? The UG30 is softer, more sag, more forgiving (all words that may or may not make sense). You can not have your best playing and still sound good. Where the Z Wreck is very unforgiving and direct. You better be warmed up and ready to go. But why?
The circuit is pretty much identical besides components used. Reverb. And filtering. The surprising thing to me is that the Bruno uses all 47uf caps where the wreck uses 40/40 and then all 8uf. Both use 22uf bypass caps and 1.5k resistors but the bruno uses 3.2k on the 2nd bypass.
So why does the bruno have more feel to it vs the wreck? Id like to dive in and discuss.
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If you have schematics for each you'll get a lot more insight from the forum.
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There isnt a schematic for the bruno. I have the cwreck layout which is close to the dr z wreck. The difference in the bruno is carbon comp resistors and Bruno uses all 47uf caps where the wreck uses 40/40 and then all 8uf (The ceriatone has different filtering). Both use 22uf bypass caps and 1.5k resistors but the bruno uses 3.2k on the 2nd bypass.
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My hypothesis is that amps with stiff HT supplies tend to have a stiff response at high power output, whereas saggy HT supplies tend to result in a softer, more compressed / forgiving responding amp.
To compare / contrast similar amps, these rarely discussed characteristics are rather significant -
end to end resistance of the mains transformer HT winding = ?
Choke resistance = ?
They're a key aspect of the spec but are rarely documented on a schematic.
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My hypothesis is that amps with stiff HT supplies tend to have a stiff response at high power output, whereas saggy HT supplies tend to result in a softer, more compressed / forgiving responding amp.
To compare / contrast similar amps, these rarely discussed characteristics are rather significant -
end to end resistance of the mains transformer HT winding = ?
Choke resistance = ?
They're a key aspect of the spec but are rarely documented on a schematic.
Im not sure how to get specs on the chokes used. I know for most of brad paisleys brunos, he used mercury transfomers and chokes but his stock stuff wasnt mercury.