Welcome To the Hoffman Amplifiers Forum

September 06, 2025, 01:06:17 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: SS rectifier in tube base  (Read 3400 times)

0 Members and 1 Guest are viewing this topic.

Offline macula56

  • Level 2
  • **
  • Posts: 346
  • welcome to the bootyranch
Hoffman Amps Forum image
SS rectifier in tube base
« on: July 08, 2011, 10:30:03 am »
I was thinking about putting one of Doug's 1000 volt - 3 amp bridge rectifiers in a tube base. anybody used these?

Offline phsyconoodler

  • SMG
  • Level 4
  • *****
  • Posts: 4679
  • honey badger don't give a ****
Hoffman Amps Forum image
Re: SS rectifier in tube base
« Reply #1 on: July 08, 2011, 10:50:34 am »
Yeah,but why? Two diodes across the rectifier tube and you have a solid state rectifier.
 Be aware of the large voltage increase.
Honey badger don't give a ****

Offline xm52

  • Level 2
  • **
  • Posts: 141
Hoffman Amps Forum image
Re: SS rectifier in tube base
« Reply #2 on: July 08, 2011, 12:43:37 pm »

I've used similar products, they work just fine in many amps.

There are modules available that not only have the diodes, but also have a resistor to simulate the voltage drop, and a thermistor to limit inrush and add a slow turn-on.

The advantage is that you can plug in either the SS module or the tube adding some flexibility to the way that the amp performs. Also you can save on filament current that the tube rectifier normally draws, making the amp run a little cooler.

Offline macula56

  • Level 2
  • **
  • Posts: 346
  • welcome to the bootyranch
Hoffman Amps Forum image
Re: SS rectifier in tube base
« Reply #3 on: July 10, 2011, 06:31:25 am »
thanks for the replies gentlemen.

Offline Rev D

  • Level 2
  • **
  • Posts: 112
Hoffman Amps Forum image
Re: SS rectifier in tube base
« Reply #4 on: July 11, 2011, 04:37:59 am »
 I use a weber copper cap in one of my el84 amps because way back when the Rec tube went south and the price of the copper cap was nearly the same so I went for it. well once when removing said copper cap the copper lid popped off. What do I see? Two of the diodes your talking about and a large ceramic resistor (which I assume dumps (resists?) a little voltage so its not quite as high as using just the diodes. I didn't write down the size of the resistor, I have a rather bad picture of the contraption somewhere. I will say I have gigged that little 18 watt amp in several different styles of build (lite 18IIb, 18watt TMB finally) and of course the copper cap has lasted for all these years (over 5). All in all it was a good investment. I know some of the Vox guys use them on the newer ac15 and ac30's I'm told because they're known to go out in those amps (as I say so I'm told). Anyway just thought I'd mention the makeup of the copper cap, if you do have voltage problems, a large resistor might just be your friend.  :icon_biggrin:

Regards,

Don

Offline kagliostro

  • Level 5
  • *******
  • Posts: 7739
Hoffman Amps Forum image
Re: SS rectifier in tube base
« Reply #5 on: July 11, 2011, 06:10:51 am »
Google "sag resistor" you'll find lot of documentation about that mod

http://www.tone-lizard.com/Mods_and_Odds.htm

Kagliostro
The world is a nice place if there is health and there are friends

Offline macula56

  • Level 2
  • **
  • Posts: 346
  • welcome to the bootyranch
Hoffman Amps Forum image
Re: SS rectifier in tube base
« Reply #6 on: July 11, 2011, 06:40:19 am »
thanks for the replies everyone. i am not looking for any sag. i just want the ease of plugging in a ss rectifier without having to build a little board in the amp. i had a ss recto in a tube base many years ago in my Super but it got broken.

Offline kagliostro

  • Level 5
  • *******
  • Posts: 7739
Hoffman Amps Forum image
Re: SS rectifier in tube base
« Reply #7 on: July 11, 2011, 06:48:56 am »
Quote
i am not looking for any sag. i just want the ease of plugging in a ss rectifier without having to build a little board in the amp.

I've understand it but it will be better if you put also the resistor instead of only the diodes, in order to reduce the B+ that will surely rise only with SS rectify instead of tube rectify

Kagliostro
The world is a nice place if there is health and there are friends

Offline macula56

  • Level 2
  • **
  • Posts: 346
  • welcome to the bootyranch
Hoffman Amps Forum image
Re: SS rectifier in tube base
« Reply #8 on: July 11, 2011, 06:54:37 am »
thanks Kagliostro. i have taken the voltage increase into account.

 


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