Welcome To the Hoffman Amplifiers Forum

September 06, 2025, 02:29:17 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: My First High Gain Tube Amp  (Read 3927 times)

0 Members and 1 Guest are viewing this topic.

Offline submission

  • Level 1
  • *
  • Posts: 3
  • I love Tube amps
Hoffman Amps Forum image
My First High Gain Tube Amp
« on: January 01, 2023, 10:29:00 pm »
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 .


Offline Lectroid

  • Level 3
  • ***
  • Posts: 632
  • Progress is made by lazy people
Hoffman Amps Forum image
Re: My First High Gain Tube Amp
« Reply #1 on: January 02, 2023, 01:14:32 pm »
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:

Subvert the Dominant Paradigm!
Free Beer Tomorrow!

Offline submission

  • Level 1
  • *
  • Posts: 3
  • I love Tube amps
Hoffman Amps Forum image
Re: My First High Gain Tube Amp
« Reply #2 on: January 02, 2023, 06:17:46 pm »
 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 .

Offline tubeswell

  • Level 4
  • *****
  • Posts: 4201
  • He who dies with the most tubes... wins
Hoffman Amps Forum image
Re: My First High Gain Tube Amp
« Reply #3 on: January 02, 2023, 09:56:41 pm »
Real grungy!
A bus stops at a bus station. A train stops at a train station. On my desk, I have a work station.

Offline Williamblake

  • Level 2
  • **
  • Posts: 482
  • I just picked values that I've seen in other circu
Hoffman Amps Forum image
Re: My First High Gain Tube Amp
« Reply #4 on: January 03, 2023, 09:18:12 am »
Sounds like somebody got was he was asking for. Nice low note performance. Very effective tone control apparantly. Keep on keeping on!

Offline Lectroid

  • Level 3
  • ***
  • Posts: 632
  • Progress is made by lazy people
Hoffman Amps Forum image
Re: My First High Gain Tube Amp
« Reply #5 on: January 03, 2023, 03:15:44 pm »
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!

Subvert the Dominant Paradigm!
Free Beer Tomorrow!

Offline submission

  • Level 1
  • *
  • Posts: 3
  • I love Tube amps
Hoffman Amps Forum image
Re: My First High Gain Tube Amp
« Reply #6 on: January 03, 2023, 07:14:15 pm »
  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 .

 


Choose a link from the
Hoffman Amplifiers parts catalog
Mobile Device
Catalog Link
Yard Sale
Discontinued
Misc. Hardware
What's New Board Building
 Parts
Amp trim
Handles
Lamps
Diodes
Hoffman Turret
 Boards
Channel
Switching
Resistors Fender Eyelet
 Boards
Screws/Nuts
Washers
Jacks/Plugs
Connectors
Misc Eyelet
Boards
Tools
Capacitors Custom Boards
Tubes
Valves
Pots
Knobs
Fuses/Cords Chassis
Tube
Sockets
Switches Wire
Cable


Handy Links
Tube Amp Library
Tube Amp
Schematics library
Design a custom Eyelet or
Turret Board
DIY Layout Creator
File analyzer program
DIY Layout Creator
File library
Transformer Wiring
Diagrams
Hoffmanamps
Facebook page
Hoffman Amplifiers
Discount Program


password