Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: 12AX7 on May 04, 2026, 07:58:06 pm
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I wanted to post the whole schematic but if the only way i know how is a screenshot from the PDF and if i do tat it's too small to zoom in ans see details because it becomes pixelated when zoomed. If anyone can tell me how to get the schematic u here i'm all ears.
So heres just the part of the pre i have a question about. I noted the changes i made and it sounds much fuller and better but it still has one of the issues i wanted to alleviate. That being to lows are too dull and a tad fuzzy, and it also doesnt retain the crisp treble i usually have when i roll off the volume on my strats, and they have treble bleeds in them with no resistor, so with other amps its almost too much treble when i roll off to clean up. This just gets dark like i rolled the tone down a bit. Is there anything you see in the pre that i could do to make the lows tighter/crisper and to retain the crisp high when i roll the guitar down? (both strats have 500pf bleed caps)
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And by the way, i didn't even know this till recently but the classic 30 was revised in i think 2013 and no longer has those cheap folded 3 piece circuit boards. Thats one of the deciding factors for buying another one after haing owned the 90s original. Now it's just one main board that much higher quality and even sport better construction and many better components So the old schematic is not the same. Same circuit for the most part, but the components are numbered differently. So you can't go by the old one as far as the component names, IE: C4 is now C27. Tarnnys are supposedly hand wound now, tho not sure that matters. Quite a few other upgrades too. And well there should be, as te price is now insane for a chinese amp. I'd never pay that tho, and i got a 1 year old mint one for 1/2 of new.
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Well, i guess no one had any ideas but thats ok. I tried a bunch of things but in the end what did the trick was adding a 270pf treble bleed on the gain pot and dropping the tone stack slope resistor to marshall's 33k. Those are 2 things in most every amp i like so gave em a shot and it worked to accomplish what i was after.