Welcome To the Hoffman Amplifiers Forum

September 08, 2025, 12:50:29 pm
guest image
Welcome, Guest. Please login or register.
-User Name
-Password



Hoffman Amps Forum image Author Topic: PT Hammond 291AEX is adequate for a Princeton Reverb ?  (Read 4067 times)

0 Members and 1 Guest are viewing this topic.

Offline kagliostro

  • Level 5
  • *******
  • Posts: 7740
Hoffman Amps Forum image
PT Hammond 291AEX is adequate for a Princeton Reverb ?
« on: November 27, 2013, 01:34:51 pm »
The Hammond 291AEX is sold as adequate for some Fender amps

https://www.tube-town.net/ttstore/product_info.php/info/p3346_Hammond-291AEX-Fender-Power-125P1B---022772-UPGRADE-Champ.html

Champ, Vibro Champ, Princeton, Princeton Reverb, Tweed Deluxe

the datasheet say 650V CT 81mA - 6.3V 2A - 5V 2A

http://www.hammondmfg.com/pdf/EDB291AEX.pdf

the question is about the 81mA B+

but in the net can be find indications for the use of a 100mA and also 200mA PT

May I consider the 291AEX adequate for a Princeton Reverb ?

Thanks

K

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

Offline Willabe

  • Global Moderator
  • Level 5
  • ******
  • Posts: 10524
Hoffman Amps Forum image
Re: PT Hammond 291AEX is adequate for a Princeton Reverb ?
« Reply #1 on: November 27, 2013, 03:33:07 pm »
Good question.

Doug's PT for a Princeton/Champ is listed as 70mA. His PT for a Deluxe Reverb is listed as 120mA

Mojo says their PT for BF P and Champ is 75mA,

http://www.mojotone.com/amp-parts/amp-transformers-fender-power/Tweed-Blackface-Princeton-Champ-Power-Transformer-EX

My BF PR PT is stamped 125P1B, the tube chart in the amp says AA764 for the model # and shows a GZ34 for the rectifier.

From a Gerald Webber book, Fender Transformer cross references;

Champ AA764, PT, 125P1B

Deluxe/Reverb AA763, PT, 125P23B

Harvard 6G10, PT, 125P1A

Princeton AA1164, PT, 125P1B

All the other amps that have or don't have reverb are listed like this; Deluxe/Reverb except for the Princeton.   :dontknow: 


             Brad     :icon_biggrin:

Offline jjasilli

  • Level 5
  • *******
  • Posts: 6731
  • Took the power supply test. . . got a B+
Hoffman Amps Forum image
Re: PT Hammond 291AEX is adequate for a Princeton Reverb ?
« Reply #2 on: November 27, 2013, 04:01:05 pm »
Tube data sheets are the place to look; see:  http://www.mif.pg.gda.pl/homepages/frank/sheets/135/6/6V6GTA.pdf

At max signal condition, in Class AB, 2X PP 6V6's draw 90mA.  But the amp is not always in max signal condition, and Hammond trannies are considered "over" rated in terms of power handling capacity by as much 50%.  So a 70mA PT from a quality manufacturer is considered standard for a 2X PP 6V6 amp.  The current draw of the preamp & PI tubes is too small to be considered.

Also, for guitar amps it is considered good for components to be operating "on the edge".  For hi-fi, maybe not.  A 70mA tranny is a fine choice.  The only way to know if you would prefer bigger trannies is to A/B them.

I hotrodded my Princeton (since sold) to use 6L6's, which have more current draw, and more heater draw too.  The PT git real hot so I installed a fan.  



Offline kagliostro

  • Level 5
  • *******
  • Posts: 7740
Hoffman Amps Forum image
Re: PT Hammond 291AEX is adequate for a Princeton Reverb ?
« Reply #3 on: November 28, 2013, 12:47:11 am »
Many Thanks Jjasilli

for sharing your experience, it is best of any consideration that can be done  :thumbsup:

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

 


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