New practice guitar amp made of 3 classics amps

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microc

Active member
Joined
Nov 22, 2008
Messages
38
Hi Guys,

I've got an idea for a guitaramp, and I'm currently on the drawing board.  I’m planning of building the amp as a module system (like Randall rm100 module amp, only without the portable modules, just my favorite preamps installed).
I want a new practice amp that sounds loud without necessarily playing loud. So I thought that I would build a small power amp section based on the Fender Pro Jr (or maybe a smaller one on only 10W), and build two for a stereo configuration.
I would like to build 2 preamps: 1. Fender Blackface and 2. JCM 800. This are some classic preamps. I also would like the amp to have a preamp-in section, and effects loop. Since the preamp section will be split in three I thought I just use multiple relay to route the guitar signal to the current preamp and relay to route the preamp signals to the power amp.
The amp will be supported with 2x12 greenbacks =)
Have anybody of you done something like this before?
Any thoughts?

What I wonder most about is what to do with the signal from the preamps to the power amp. The voltage used in a marshall is significant different from a fender. Should I just make a routing section in -10dB so that an external preamp would fit right in?

best regards,
Jens

 
Hi! I'd suggest you have a look at AX84.com . They do more or less what you describe: different pre and low power amps, with different flavors that can be mixed together as you like...
If you ask, things like what you plan have been done, and try googleing a little: you will surely find examples and inspiration (on ampage homebrew gallery, for example...). For your level problem, both of these preamps are made to work with power amps that have a much higher bias voltage than the one you find in the pro jr, anyway (more than 30 volts for the JCM, probalbly more than 50 for the blackface, against 10 volts for the pro jr) . You'll have to tweak the last stages of your pres, or why not add some "master" pots at the end off each one to keep tone versatility while keeping also consistant level between them.
Laurent.
 
10 Watts in two 12" Greens is LOUD.

Classic Marshalls are mostly "based upon" Fender. The voltages, supply and signal, are not so wildly different. Marshall tended to add a stage, or shorten a cathode-cap, or increase NFB; much of this can be done with switching.

There are whole forums for guitar amps, AX84 and many others, where such thoughts are hammered every day. Might want to browse some.
 
If you're taking this route, I'd maybe try to roll it into one (as was kind of suggested). The Marshall will knock off some bottom, have more gain (stages), and may have a cold-biased stage to get the distortion crunchy. You'd maybe need to compromise the EQ.

Even 5W is bloody loud. There are suggestions elsewhere for making ECC8* class-a/b stages and other tricks for low power output. El84 class-a can be ok if you like that (bright) sound.

 
Thanks for replies!
2 x 10W is 20W and loud, but still sounding awesome! I’ve got a Marshall 6100 (30th ann 100W) and it’s loud when the volume is rated at 8-9 o’clock… not the awesome warm tube sound you want. So you think I should build an even smaller power amp block? I’m just afraid to burn the tubes with “to much” load (greenbacks)…

I thought about routing the signals with a 2 pole; 3 position rotary switch for an cool vintage feeling =).

I will check out some other forums, but since I’m all ready a member in here and the skills of the member s here are very good, I’d like to hear around.

Anywho; thank you for your time!

Have a great music weekend =)

EDIT maybe just building a Marshall 2550 (Silver) with a 10W power amp for now. It's only a mono send-return option, but the sound is solid.
 
> afraid to burn the tubes with “to much” load (greenbacks)…

That can't happen.

I used to run a 1 Watt tube amp into *two* large Altec theater speakers. Amplifier did not mind. The neighbors hated it.

A "less loud" home-use amplifier these days is less than one Watt. The smallest OT you can find, and old kitchen radio power pentodes. (Yes, you can make a nice amp with the twin-triodes, but maybe "too nice" for rock-n-roll.)

Also you may want "smaller" speakers for less loudness and to get some cone-cry with teeny power; however you can't get a "small BIG sound" with small speakers.

Nothing really replaces standing next to a full-bore Fender Twin. The ear-strain, the chest-pounding, and the long-term hearing loss.......

All you can do with a small amp is find a reasonably "full bass" sound, with mellow midrange which does not annoy too many other people.
 
good to know =)

I also wanna do a little amp with some smaller speakers, like Phil Jones' bass amps =) I think I have to quite my job or else I have to start working with amps =) LOL
 

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