Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Instruments and Amps Everything that makes music, Especially including instrument amps.

Hammond guitar amp conversion
Hammond guitar amp conversion
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 26th July 2009, 05:22 PM   #11
grahamprie is offline grahamprie  United Kingdom
diyAudio Member
Join Date: Jun 2006
Default Hammond amp mods

From the circuit I'd guess you have way too much gain - you're probably over-driving the second stage with a guitar signal and a gain of 600+. After that, there's no way back.

The reverb spring output was about 2mV and a guitar is at least 200...

I'd add a volume control where you've reduced the resistor value to 220K - it will need a series cap to block the DC on the grid of the phase-splitter stage.

At least that will let you listen to what's being over-driven in the input stages.
  Reply With Quote
Old 27th July 2009, 01:09 AM   #12
head_spaz is offline head_spaz  United States
diyAudio Member
Join Date: Mar 2004
Location: Arkansas
According to the schematic, I see no problem making a conversion for guitar.

You'll need to replace most of the resistors and caps, lose a few, add a few, but the tubes and transformers are probably ideal as is.

I would lose the feeback circuit from the output altogether.... but not UNTIL you reduce the gain of that second stage!!!

Check out AX84.com and look at their High Octane guitar amp project. I would modify your preamp stages to model the High Octane. It's a winner. High Octane Schematic

Or... you could opt for their S.E.L. model, known as the Single Ended Lead project, which has a little more crunch and grunge. (but your power tranformer is probably better suited for the H.O., since your schematic indicates 300v on the output stage.)

The H.O. and the S.E.L. are both "single ended" output models, and your's is push-pull, but your preamp stages should be all you need to modify to get her going, and you already have most of what you need.

Your hammond "pushpull output stage" looks pretty good to go as is. This should make a terrific little amp. I should be so lucky to come across junk like that!

AX84 also has some push-pull projects too if you want to compare stages. Look in the Classic Amp Projects section. You can marry just about any preamp to any ouptput stage, depending on your taste, and thurst for power.

I'd begin there... and then tweak it to suit.
Writing is good exercize for the texticles!
  Reply With Quote


Hammond guitar amp conversionHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Hammond AO29 to guitar amp? bluesman52 Instruments and Amps 7 18th September 2013 01:22 PM
Guitar amp conversion DigitalJunkie Instruments and Amps 1 7th November 2008 03:16 AM
Hammond L-100 conversion rafaelblock Tubes / Valves 0 19th February 2008 05:16 PM
Guitar Cab Conversion givethemrope Instruments and Amps 3 16th August 2006 03:03 AM
Hammond organ..to guitar amp- vince8 Instruments and Amps 11 24th October 2005 02:33 PM

New To Site? Need Help?

All times are GMT. The time now is 08:41 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio