Hoffman chassis 6V6 project
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Hoffman chassis 6V6 project
A while back I bought this Hoffman chassis from Doug when they first were introduced on his amp forum.
Decided I wanted to run 6V6 so ordered from Triodestore the 041318-48UL paper bobbin OT which was sitting on my shelf for just such a project. Primary is 6K6 and secondary 4/8/16 R for such projects as Fender Deluxe, Ampegs, and Silvertone amps.
The PT is the PT290-50 HT-6179-50 from Hoffman which is an 18w 290-0-290.
Designed and ordered the face plates (front/back) and loaded the chassis components. Fitted a blank board and still designing.
Looking for this to be a clean pedal platform small head amp.
May or may not remove rectifier tube socket and run with can type filter caps and it will be fixed bias LTP PI.
Gain, treble, middle, bass, and master volume.
Mark
Decided I wanted to run 6V6 so ordered from Triodestore the 041318-48UL paper bobbin OT which was sitting on my shelf for just such a project. Primary is 6K6 and secondary 4/8/16 R for such projects as Fender Deluxe, Ampegs, and Silvertone amps.
The PT is the PT290-50 HT-6179-50 from Hoffman which is an 18w 290-0-290.
Designed and ordered the face plates (front/back) and loaded the chassis components. Fitted a blank board and still designing.
Looking for this to be a clean pedal platform small head amp.
May or may not remove rectifier tube socket and run with can type filter caps and it will be fixed bias LTP PI.
Gain, treble, middle, bass, and master volume.
Mark
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Re: Hoffman chassis 6V6 project
If you are looking for alternate approaches, you could use a 3rd octal for 6SL7 PI and open up options. Clean goes, with reverb. Might make for a cramped box.
Best .. Ian
Best .. Ian
Re: Hoffman chassis 6V6 project
Everyone I know locally uses effect pedals for their sound so no reverb on this amp.
At 18 watts this should perform well despite the lower voltage this PT will put out. The PT can always be replaced with 325-0-325.
At 18 watts this should perform well despite the lower voltage this PT will put out. The PT can always be replaced with 325-0-325.
Re: Hoffman chassis 6V6 project
I like. This amp will be at the edge of crunchtown in a band setting. Perfect. Don't think you'll need the MV, but may be nice to have anyway. Fixed bias and SS recto are my suggestions.
I build and repair tube amps. http://amps.monkeymatic.com
Re: Hoffman chassis 6V6 project
Thanks for posting. Darn cool lil amp project
A few more "naĩve" questions
The chassis looks rather small. This will make for a compact amp
EDIT :Oops! By lookiing - too quickly - at the miniatures, I mistaken the front of the chassis with the back, and the octal sockets for noval ones...
... I was too enthousiastic, maybe. I was thinking about something else at the same time, for sure
Thanks for sharing, anyway!
EDIT :Oops! By lookiing - too quickly - at the miniatures, I mistaken the front of the chassis with the back, and the octal sockets for noval ones...
... I was too enthousiastic, maybe. I was thinking about something else at the same time, for sure
Thanks for sharing, anyway!
Last edited by ChopSauce on Tue Jun 20, 2017 4:10 pm, edited 1 time in total.
Re: Hoffman chassis 6V6 project
Using 2 preamp tubes into pair of 6V6's JJ's, solid state rectifier (removed the last octal tube socket) and installed JJ 40/20/20/20 can cap.
Recto board will go on end of chassis near PT.
Made the component board and loaded that.
I'm going to wait on faceplates to continue with wiring.
The PT 290-0-290 I think was originally chose by Hoffman to run a pair of EL84's using adapter plate for his Stout circuit but I wanted 6V6's.
Might not be enough plate voltage for a really clean output should have around 325-0-325 might have to change that out.
Mark
Recto board will go on end of chassis near PT.
Made the component board and loaded that.
I'm going to wait on faceplates to continue with wiring.
The PT 290-0-290 I think was originally chose by Hoffman to run a pair of EL84's using adapter plate for his Stout circuit but I wanted 6V6's.
Might not be enough plate voltage for a really clean output should have around 325-0-325 might have to change that out.
Mark
Re: Hoffman chassis 6V6 project
Mark, thank you for all your threads and post. Super cool of you
Re: Hoffman chassis 6V6 project
Glad you enjoy I will be posting more photos as the project matures.
Taking 12 family members to Minnesota zoo, Valley Fair and Mall of America soon so not much will get done between now and end of June.
Taking 12 family members to Minnesota zoo, Valley Fair and Mall of America soon so not much will get done between now and end of June.
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Re: Hoffman chassis 6V6 project
Looks like a fun amp Mark
I have used that OT in a few 6V6 builds...a little pricey but its nice
Sounds like some fun summer activities
Have fun with the family
D
I have used that OT in a few 6V6 builds...a little pricey but its nice
Sounds like some fun summer activities
Have fun with the family
D
Re: Hoffman chassis 6V6 project
Got some time on this project.
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- JazzGuitarGimp
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Re: Hoffman chassis 6V6 project
Looks like the first octal socket mysteriously trandformed itself into a multi-section cap can.....
Lou Rossi Designs
Printed Circuit Design & Layout,
and Schematic Capture
Printed Circuit Design & Layout,
and Schematic Capture
Re: Hoffman chassis 6V6 project
Lou,
As I am working on this amp I keep changing things such as replace the tube recto with diodes and add 40/20/20/20 JJ can cap.
I might even try cathode bias and later, if needed, change over to fixed bias.
Used whatever caps and resistors I had in stock.
Mark
As I am working on this amp I keep changing things such as replace the tube recto with diodes and add 40/20/20/20 JJ can cap.
I might even try cathode bias and later, if needed, change over to fixed bias.
Used whatever caps and resistors I had in stock.
Mark
Re: Hoffman chassis 6V6 project
"FVA"! Nice faceplates.
I build and repair tube amps. http://amps.monkeymatic.com