Hoffman chassis 6V6 project

Fender Amp Discussion

Moderators: pompeiisneaks, Colossal

User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Hoffman chassis 6V6 project

Post by M Fowler »

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
IMG_0963.JPG
IMG_0964.JPG
IMG_0965.JPG
IMG_0966.JPG
IMG_0967.JPG
You do not have the required permissions to view the files attached to this post.
User avatar
didit
Posts: 976
Joined: Thu Sep 25, 2008 3:37 pm
Location: Canada

Re: Hoffman chassis 6V6 project

Post by didit »

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
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Hoffman chassis 6V6 project

Post by M Fowler »

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.
User avatar
xtian
Posts: 6990
Joined: Mon Apr 19, 2010 8:15 pm
Location: NorCal
Contact:

Re: Hoffman chassis 6V6 project

Post by xtian »

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
68strat
Posts: 32
Joined: Fri Sep 19, 2008 6:48 am

Re: Hoffman chassis 6V6 project

Post by 68strat »

Thanks for posting. Darn cool lil amp project
ChopSauce
Posts: 1038
Joined: Wed Mar 15, 2017 12:08 pm
Location: So Paris, France

A few more "naĩve" questions

Post by ChopSauce »

The chassis looks rather small. This will make for a compact amp 8)

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...

:roll:

... I was too enthousiastic, maybe. I was thinking about something else at the same time, for sure :wink:

Thanks for sharing, anyway!
Last edited by ChopSauce on Tue Jun 20, 2017 4:10 pm, edited 1 time in total.
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Hoffman chassis 6V6 project

Post by M Fowler »

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
68strat
Posts: 32
Joined: Fri Sep 19, 2008 6:48 am

Re: Hoffman chassis 6V6 project

Post by 68strat »

Mark, thank you for all your threads and post. Super cool of you
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Hoffman chassis 6V6 project

Post by M Fowler »

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.
dcribbs1412
Posts: 1377
Joined: Wed Jun 11, 2008 6:56 pm
Location: Arizona Desert

Re: Hoffman chassis 6V6 project

Post by dcribbs1412 »

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
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Hoffman chassis 6V6 project

Post by M Fowler »

Got some time on this project.
20031877_10209021517846709_3684266415161778619_n.jpg
19884373_10209021514486625_6084628516811196815_n.jpg
19905312_10209021533887110_1865259204340462261_n.jpg
6v6 project amp 01.jpg
You do not have the required permissions to view the files attached to this post.
User avatar
JazzGuitarGimp
Posts: 2355
Joined: Mon Jul 23, 2012 4:54 pm
Location: Northern CA

Re: Hoffman chassis 6V6 project

Post by JazzGuitarGimp »

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
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Hoffman chassis 6V6 project

Post by M Fowler »

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
User avatar
xtian
Posts: 6990
Joined: Mon Apr 19, 2010 8:15 pm
Location: NorCal
Contact:

Re: Hoffman chassis 6V6 project

Post by xtian »

"FVA"! Nice faceplates.
I build and repair tube amps. http://amps.monkeymatic.com
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Hoffman chassis 6V6 project

Post by M Fowler »

xtian wrote: Wed Jul 12, 2017 2:55 pm "FVA"! Nice faceplates.
Thanks, anodized aluminum from Front Panel Express which now have printing option instead of milling the panels.

Mark
Post Reply