Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Esquirefreak on January 28, 2022, 09:03:36 am
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Good afternoon (according to swedish clocks)!
I just finished my latest build. I thought some of you guys maybe might be interested.
I was initially just gonna do a single channel version of my 6G4 clone, but I changed my mind after some consideration. You see, I wanted this amp to be a little less polite, but still have the harmonic trem that so many of us love.
First of, I'm using SS rectification to up the voltage a bit. And since I didn't need a 5v winding, I went for a brown/black face Bassman PT (Hammond 290EEX). This gave me 457vdc on the plates of the 6L6GCs when biased at 40mA.
As for the OT, I chose Hammonds version of the Bandmaster/Tremolux/Vibrolux (1760J - 4/8/16Ω).
The changes made to the trem section I just copied from my previous clone. I tuned the trem by ear and my own preferences on that build.
At initial start-up yesterday I had oscillation (about 13.64hz) when turning the bass up, but that was due to both gain stages sharing k C/R. After splitting the cathodes it is now dead quiet at idle.
This little amp lives in a Bassman head cab that I re-tolex:ed a few months ago.
So, how it sounds? Well, awesome. It has plenty of gain on tap, producing a FAT brown overdrive when pushed a little bit. Kinda like a 6G6-B with trem. I thought about putting 1k5 grid blockers on the power tubes, but I'll leave it this way for now.
Pics are coming.
Best regards,
Max Eriksson
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Well you can say anything you want, but we need photos and soundclips to be convinced 😃
I like the idea a lot. Was thinking in that direction too, but with a tweed vibrolux amp in mind...
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I tried to re-size pics and upload them yesterday, to no avail. But it just now occurred to me that maybe the format was wrong.
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More pics
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I made the faceplate myself with dry transfer lettering. I guess it came out decent.
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Very nice!
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And here's the layout
On the layout, I forgot to remove the boot strapped 1M resistor that used to mix in the normal channel before the PI.
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Wow, thanks. That means a great deal to me to hear! :)
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I made the faceplate myself with dry transfer lettering. I guess it came out decent.
I do too use the dry transfer letters, I do recommend to use some varnish on top on them so it wont fall pieces if scratched, and by that close from hands and fingers action it will suffer decay in short time.
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How the chassis looked like when it arrived. This is actually my first time buying a chassis, rather than bending one on my own.
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I made the faceplate myself with dry transfer lettering. I guess it came out decent.
I do too use the dry transfer letters, I do recommend to use some varnish on top on them so it wont fall pieces if scratched, and by that close from hands and fingers action it will suffer decay in short time.
Yeah, I've put a top/clear coat on top of it for longevity!
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Boards drilled.
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The HT feed "braid".
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The PSU cap board. Nevermind the colors compared to the original. I just wanted to use different colors to keep them apart when hooking the leads up inside the amp.
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Last one.
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...I guess it came out decent.
I was just reading an ArsTechnica review of a $150 keyboard. (I favor select <$15 KBs.) Their keycap lettering is not as good as yours.
https://arstechnica.com/gadgets/2022/01/keychron-q2-mechanical-keyboard-review-enthusiast-luxury-at-a-decent-price/
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while i do enjoy the absolute plug and play bliss of usb peripherals, i do miss the quality (if not the color) of keys that came on keyboards with ps/2 connectors attached