Welcome To the Hoffman Amplifiers Forum

September 07, 2025, 04:25:00 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Bad Cat Hot Cat 15 Schematic  (Read 13395 times)

0 Members and 1 Guest are viewing this topic.

Offline bnwitt

  • Level 4
  • *****
  • Posts: 2954
  • Crankin' out the tone.
Hoffman Amps Forum image
Bad Cat Hot Cat 15 Schematic
« on: October 22, 2014, 11:56:30 am »
Does anyone in here have a schematic and/or other details on the Bad Cat Hot Cat 15 amplifier?  I just picked up one of the Chinese made Bad Cat Cougar 15 amps that I want to gut and change to the Hot Cat 15 or the Vox Handwired AC 15.  Thanks in advance
Barry
Guides on your quest for tone.
 Oh yeah, and I'm usually just kidding so don't take me too seriously.

Offline tubenit

  • Global Moderator
  • Level 5
  • ******
  • Posts: 10274
  • Life is a daring adventure or nothing at all!
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #1 on: October 22, 2014, 12:06:50 pm »
Maybe this with only 2 EL84's ??

http://el34world.com/charts/Schematics/files/_Miscellaneous/badcat_hotcat_30.pdf

With respect, Tubenit

Offline bnwitt

  • Level 4
  • *****
  • Posts: 2954
  • Crankin' out the tone.
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #2 on: October 22, 2014, 05:58:45 pm »
Thanks Tubenit.  I do appreciate it.  I've got that one.  I'm sure the two amps are similar.  I was hoping to find the 15 schematic to make sure.  I'm assuming the 15 has EL84 power tubes though
« Last Edit: October 22, 2014, 06:02:37 pm by bnwitt »
Guides on your quest for tone.
 Oh yeah, and I'm usually just kidding so don't take me too seriously.

Offline bnwitt

  • Level 4
  • *****
  • Posts: 2954
  • Crankin' out the tone.
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #3 on: October 23, 2014, 10:16:01 am »
Is it just me or does the PI and MV in that schematic look odd?
Guides on your quest for tone.
 Oh yeah, and I'm usually just kidding so don't take me too seriously.

Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #4 on: October 23, 2014, 11:24:03 am »
Is it just me or does the PI and MV in that schematic look odd?
The PI is just a standard garden variety LTP. The MV is a bit odd. It will not vary the signal very much and won't even get close to zero volume.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline shooter

  • Level 5
  • *******
  • Posts: 11015
  • Karma Loves haters
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #5 on: October 23, 2014, 11:29:14 am »
I'll 2nd odd on the pi, the MV is one I've seen a couple times.  by other threads it appears this type is "less liked".
Went Class C for efficiency

Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #6 on: October 23, 2014, 03:44:52 pm »
I'll 2nd odd on the pi...
What's odd about it? I'm looking at the schematic posted by tubenit. Maybe I'm looking at the wrong schematic?
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline 2deaf

  • Level 3
  • ***
  • Posts: 1667
  • Now too deaf for 100 watts
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #7 on: October 23, 2014, 10:39:11 pm »
Quote
Is it just me or does the PI and MV in that schematic look odd?

The four-stage pre-amp, the 10K screen resistors, and the additional 100uf for the plates on SS rectifier all clearly indicate an amp designed for extreme overdrive.  A master volume that doesn't work fits right in.  Or maybe he meant for the 220K to go to the 100K pot and the wiper to go to "F".

Offline shooter

  • Level 5
  • *******
  • Posts: 11015
  • Karma Loves haters
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #8 on: October 24, 2014, 08:50:02 am »
You "fixed" the odd for me by stating the obvious that I missed, LTP.  I got hung up on each side of the PI being fed by 2 dif channels n missed what the PI actually was.
thanks again
Went Class C for efficiency

Offline sluckey

  • Level 5
  • *******
  • Posts: 5075
    • Sluckey Amps
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #9 on: October 24, 2014, 09:12:59 am »
Quote
...each side of the PI being fed by 2 dif channels...
That's fairly common in amps with a LTP if they don't use one input for NFB. Marshall 1974 (commonly called 18 Watt), Vox AC-15, and some AC-30s do it. And the Matchless Chieftain even uses the second input to mix reverb back into the dry signal. That second grid on the LTP is up for grabs for a lot of ideas, but it it's not going to be used for anything, it should sit at AC ground, usually via a cap to ground.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline bnwitt

  • Level 4
  • *****
  • Posts: 2954
  • Crankin' out the tone.
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #10 on: October 26, 2014, 10:09:35 am »
Steve,
Thanks for that explanation.  I did not know that. :smiley:
Guides on your quest for tone.
 Oh yeah, and I'm usually just kidding so don't take me too seriously.

Offline bnwitt

  • Level 4
  • *****
  • Posts: 2954
  • Crankin' out the tone.
Hoffman Amps Forum image
Re: Bad Cat Hot Cat 15 Schematic
« Reply #11 on: October 28, 2014, 10:33:23 am »
Ok so I guess I'm stuck with the 30 watt schematic for this amp but evidently there are some errors in that schematic.  Below is a link to a thread that has user Loudthud pointing this out:

http://music-electronics-forum.com/t19757/

Barry
Guides on your quest for tone.
 Oh yeah, and I'm usually just kidding so don't take me too seriously.

 


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