Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on January 31, 2026, 04:27:54 am

Title: IS there a reason to build another AMP
Post by: TIMBO on January 31, 2026, 04:27:54 am

HELL YEAH !!!!!
After seeing this post https://www.aggh.net/discussion/index.php?topic=55279.0
And having a cab and chassis under construction, a circuit chosen from a well known amp builder
https://www.bing.com/videos/riverview/relatedvideo?q=jim+kelly+facs&mid=A2CE73DACDB09905C4F8A2CE73DACDB09905C4F8&FORM=VIRE
I believe this circuit is proven
(https://i.imgur.com/0m6yTDb.jpg)
And I've deleted the second channel as it is the same circuit for both channels, foot switchable between channels so you can have the second channel cranked for an overdriven effect
The reverb has been deleted for the moment
So a deep dive into my junk box and a couple of these were found
  (https://i.imgur.com/ZDNX6Xp.jpg)
I found something similar on ebay in a 30 turret strip
(https://i.imgur.com/tFqWMDI.jpg)
The step drill did a nice job of the holes
(https://i.imgur.com/dJhMZyw.jpg)
(https://i.imgur.com/XTpan4t.jpg)
Even the socket holes line up
(https://i.imgur.com/pCTGg94.jpg)
A quick doddle to see how it would layout

Title: Re: IS there a reason to build another AMP
Post by: tubeswell on January 31, 2026, 11:09:35 am

There’ll always be a reason

Title: Re: IS there a reason to build another AMP
Post by: bmccowan on January 31, 2026, 12:41:25 pm

Yup - for me, if I stop for awhile I really miss it. And that's all the reason I need.
Schematic looks interesting - a bit of gain in that one, eh?

Title: Re: IS there a reason to build another AMP
Post by: Banjan73 on January 31, 2026, 03:17:28 pm

For me:
Theres always a reason. I don't mind building amps thats already have been built. But then, tubeamps is not actually the newest invention. So, maybe some of my builds have been build somewhere in the world.
My approach is to make something that sounds nice, off course. But with perhaps with a twitch.
And it needs to be useful for something. Many famous amps are, for me, not the "thing" I want to use. So I maybe will build them, as a base, and then modify them to my own preferances...

Title: Re: IS there a reason to build another AMP
Post by: Banjan73 on January 31, 2026, 03:23:21 pm

Hmm.
Just had a look on that schematics.
I'm looking at this on my cell phone, and its a very bad picture. Anyway, one question:
Those diodes to grid on gaintage 2 is new for me. Whats the purpose there?

Title: Re: IS there a reason to build another AMP
Post by: TIMBO on January 31, 2026, 04:07:42 pm

Apologies for the crap schematic photo, my printer ran out of ink and they want $65 for a cartridge
The diodes are 1N914's, I'm not tech enough to explain their purpose. :help: 

Title: Re: IS there a reason to build another AMP
Post by: Rontone on February 01, 2026, 07:29:07 am

Quote from: TIMBO on January 31, 2026, 04:07:42 pm

my printer ran out of ink and they want $65 for a cartridge

check eBay, there should be some good self refill kits with syringes for a lot cheaper, do it outside though, it can get messy real quick!

Title: Re: IS there a reason to build another AMP
Post by: dogburn on February 01, 2026, 09:31:31 am

I was wondering about the diodes, too - they are also on V2. They are above my level of understanding as well.

Edit to add: Would they be clipping diodes?

Title: Re: IS there a reason to build another AMP
Post by: TIMBO on February 22, 2026, 04:20:20 am

Hey guys,
A bit progress in the wiring dept.
(https://i.imgur.com/CRRPdsn.jpg)
(https://i.imgur.com/sbbFEhF.jpg)