Welcome To the Hoffman Amplifiers Forum

September 07, 2025, 12:19:03 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: Single Channel DR new build arc over on one 6V6 pin 3 to 2 noisy reverb  (Read 1718 times)

0 Members and 1 Guest are viewing this topic.

Offline mresistor

  • Global Moderator
  • Level 4
  • ******
  • Posts: 3209
  • resistance is futile
As the title says during setting up bias on my new SC DR build I was measuring HV which was 456v  and as I pulled off the probe I guess I caused a path for the 456v to travel across to pin 2. Not good! and first time I have ever had this happen in my guitar amp experiences. It arced and as is always the case it seemed like it took forever to get to the off switch, which I did immediately turn off.  I don't think I did any permanent damage to the PT filament winding, as it is still putting out 6.45VAC. And I don't have any DC on the heaters. These are brand new Belton sockets. Doesn't look like any damage to the socket. I did figure out that I had my 16 ohm cab hooked up to the 8 ohm jack and I have since plugged it into the 16 ohm jack. I also dropped the HV down to 432 with a 5R4 . I did get bias adjust done and have played through the amp and it sounds pretty good. The tremolo works really well and the reverb works too well.  I'm going to have to tame it down some. However, there is alot of noise on the reverb. There is some static type noise with no input and volume turned way up, but there is a ton more noise, static and hum, when I turn up the reverb. The reverb tank is sitting out at the present time next to the chassis and I am using hifi rca cables because I haven't made the permanent cables yet as the cabinet isn't ready. 
What would cause there to be a large amount of noise and hissing/humming on the reverb? I've built two DRs from scratch and they had no problems. This is a Hoffman turret board amp.
« Last Edit: December 03, 2015, 11:32:27 am by mresistor »

Offline mresistor

  • Global Moderator
  • Level 4
  • ******
  • Posts: 3209
  • resistance is futile
Hoffman Amps Forum image
Re: Single Channel DR new build arc over on one 6V6 pin 3 to 2 noisy reverb
« Reply #1 on: December 03, 2015, 02:39:20 pm »
Well   I found the problem.  Not my day.  The reverb send wire was running very near one of the 12AX7s and I don't have any shields installed on it. Positioned wire away and all the noise went away. 
Thanks to all those that read this.  Back to working on the cab now


 


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