Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: submission on January 01, 2023, 10:29:00 pm
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Hello everyone ,
My first post here , Ive been coming here for years looking for help and learning how this tube amp stuff works .
I never had to post a question as all my qustions were already answered some where here on these forums .
I really just wanted to stop by and thank all the wounderfull people here and these forums for being such great help
in my journey to learn how tube amps work and how to design and building one for myself .
My amp is basickly a 2 channel amp using 6 12ax7s and 4 Kt77s , clean/crunch and overdrive .
Its design is kind of a mix of many my favorite high gain amps .... SLO , Bogner Ubershall , Mesa Dual Rect , VH4 .... etc
I compleaty designed and hand made this amp myself ( No KIts or schamatics )
Once again want to thank everyone for being here and being so helpfull to others as this forum really helped me figure this all out .
Here a quick youtube clip I made of how it came out . hope you appreciate it .
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You've built a great amp there. If anything I'd built had that clean channel, I'd die happy. But yours just starts there and leaps into SLO territory. Very, very impressive!
:bravo1:
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Thanks Lectroid
Clean channel is as simple as it gets , just 1/2 a 12ax7 to a CF for tone stack then to the PI to the KT77s
I used 2 CF for the tone stacks , one for Clean / crunch channel and one for high gain channel , I did it this way so I could wire the high gain CF hotter to get more gain with out destroying the clean channels tone .
Also the CF for the High gain is wired to be either a CF or a single ended tube to push tone stack , doing it this way gave the amp four gain staging modes Channel 1 ( clean / crunch ) Channel 2 ( Low gain / High gain ) . My video only shows the 2 book ends of the gan stages , wanted to keep the video simple as its the channels i use the most on it .
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Real grungy!
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Sounds like somebody got was he was asking for. Nice low note performance. Very effective tone control apparantly. Keep on keeping on!
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Clean channel is as simple as it gets , just 1/2 a 12ax7 to a CF for tone stack then to the PI to the KT77s
I used 2 CF for the tone stacks , one for Clean / crunch channel and one for high gain channel , I did it this way so I could wire the high gain CF hotter to get more gain with out destroying the clean channels tone .
I have never tried a cathode follower to buffer a tone stack but after hearing yours, it's now on my list to build.
So that clean sound came from just one triode preamp, one triode CF, and then into the PI? Damn!
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One other thing thats really helping that clean channel get its wide open chimmy sound its lots of voltage ......
I found from experiments that More voltage = more open / clean headroom .
Im pushing about +/- 320v to the first triode before the plate resistor and about +/- 530v to the power amp .
I forget what the exact voltage to the Tone stack CF is , I think I have it around 360/380v , thats before the plate resistor as well .