Welcome To the Hoffman Amplifiers Forum

September 08, 2025, 10:05:16 am
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: All in One Preamp - THOUGHTS  (Read 2636 times)

0 Members and 1 Guest are viewing this topic.

Offline Glennjeff

  • Level 2
  • **
  • Posts: 244
Hoffman Amps Forum image
All in One Preamp - THOUGHTS
« on: July 09, 2016, 06:01:10 am »
Would anyone care to comment.

In particular, would I really need to do that switch trick with the TOS / PLEXI section.

Offline John

  • Level 3
  • ***
  • Posts: 1895
Hoffman Amps Forum image
Re: All in One Preamp - THOUGHTS
« Reply #1 on: July 09, 2016, 08:46:47 pm »
I dunno about the switch trick. I try to get away with as few as possible.


Since I'm dim at this stuff, can you explain the mixer stage? At first I figured each stage would just go to your PI tube. Are you wanting to also mix each preamp nugget  if you want?
Tapping into the inner tube.

Offline Glennjeff

  • Level 2
  • **
  • Posts: 244
Hoffman Amps Forum image
Re: All in One Preamp - THOUGHTS
« Reply #2 on: July 09, 2016, 09:56:18 pm »
Hi John,

I do want to mix each nugget, plus the active tube mixer is known to generate it's own harmonic content and some people claim the active mixer stage has super special magical rainbow unicorn properties.  :laugh:

This was just the basic sketch, will need to be refined a little. There will also be a couple of overdrive sections later on.

Offline John

  • Level 3
  • ***
  • Posts: 1895
Hoffman Amps Forum image
Re: All in One Preamp - THOUGHTS
« Reply #3 on: July 10, 2016, 06:25:52 am »
Ahh yes, the unicorn properties!!  :icon_biggrin:


I was thinking more about that switch. I'd say if you're doing all this heck yeah use it. Be a good way to A/B the difference in tone, IMO.
Tapping into the inner tube.

Offline HotBluePlates

  • Global Moderator
  • Level 5
  • ******
  • Posts: 13127
Hoffman Amps Forum image
Re: All in One Preamp - THOUGHTS
« Reply #4 on: July 11, 2016, 02:43:03 pm »
You may want to export your .sch file to a .gif so folks without the program can view it.

Offline uki

  • Level 3
  • ***
  • Posts: 1015
  • Hot Tube Hot Sound
    • Uki's Guitar Trip
Hoffman Amps Forum image
Re: All in One Preamp - THOUGHTS
« Reply #5 on: July 11, 2016, 02:46:04 pm »
You may want to export your .sch file to a .gif so folks without the program can view it.

I got a program that can generate .sch but I can't open yours, .jpg have good quality, and .pdf is also good.
Theory is when everyone knows everything but nothing works, practice is when stuff works but nobody knows why !!!
https://soundcloud.com/ukiuki
http://tribonow.wixsite.com/tribonow

Offline Glennjeff

  • Level 2
  • **
  • Posts: 244
Hoffman Amps Forum image
Re: All in One Preamp - THOUGHTS
« Reply #6 on: July 11, 2016, 09:59:05 pm »
Apologies, thought the sch was a freeware program.

Here are the GIF's

Offline PRR

  • Level 5
  • *******
  • Posts: 17082
  • Maine USA
Hoffman Amps Forum image
Re: All in One Preamp - THOUGHTS
« Reply #7 on: July 11, 2016, 10:20:50 pm »
That form of mixer has very low maximum output level.

Suggest adding separate plate resistors and three 220K mix-resistors. Or even skipping the gain here, just mix 1 2 3 with 220K, and add make-up gain behind.

 


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