Guitar Amplifier

[blacksheep]

Hi :-)

I want to build a guitar amplifier, but i haven't found any useful schematics yet... I want it to be powerful, maybe 100 Watt if its possible, it has to be a clean pre-amp (which means: no distortion), low-noise as possible (no hiss) and a 3-band graphic equalizer (low, mid and high-controls), look at my drawing.

I'm a newbie in audio electronics, so i don't know that much about op-amps, transistors... you name it :-)

If you think you know much about it to help me creating some schematics, you are very welcome to post in this forum or to my mail-adress: peter(@)gawis.dk

[darrins]

Try these sites:

http://www.ax84.com/home.html
http://freespace.virgin.net/vyse.co/build_your_own_amp.htm
http://www.duncanamps.com/brewlink_amps.html

Good luck. :)

Darrin

[audioguru]

Hi Darrin,
Toobs and output transformers?
Yeah, I remember those.
Some transistor amps have vacuum tubes glowing just for show, since their tubes aren't connected to the amp's circuit!

[blacksheep]

Thanks for the links, but it seems like its only tube-amps, and thats not what i'm interested in... :-) hehe...

Maybe somebody have some schematics of a (very) simple preamp with TL072 or similiar opams. I think, it could help me to find out how to work with opams...

[ante]

blacksheep,

Here is all you need !

http://sound.westhost.com/projects.htm

Ante ::)

[EDY]

try this

http://www.mif.pg.gda.pl/homepages/tom/schematics.htm

Cheers ;D

[blacksheep]

Ante, I've already tried building the pre-amp - the problem is, that the sound isn't clean. I wanted a clean pre-amp :-) But maybe i could use the power-amp schematic... Thanks :-)

Really nice site, EDY, but it's still tube-amps :-[ hehe

But, thanks for helping. I would really like some beginner-guides to build pre-amps with op-amps and/or transistors. Somebody in this forum must know something about that :-)

[darrins]

Sorry about the links to tube amps. :-[ I just did got these links from a google search and didn't read all the content.

You may be able to find a good amp on eBay. Sometimes it's cheaper to buy than build. I certainly got a good deal on my oscilloscope. Not that I could build an oscilloscope. ;)

Hope you're not building one of those giant wall amps from "Back to the Future". Your neighbors might get upset.

Cheers.

Darrin

[darrins]

blacksheep,

There are a couple of amp projects on this site that use more "modern" technology. ;D

http://www.discovercircuits.com/A/a-audioamp.htm

Darrin

[audioguru]

Hi Blacksheep,
Which preamp did you build, and please explain what in its sound sounded "dirty". Hum or buzz, distortion?

[blacksheep]

I did build the pre-amp of this project:

100W Guitar Amplifier Mk II

http://sound.westhost.com/project27.htm

The problem was that almost nothing was comming out of the speaker unless i was turning up the gain-control, and then I got distortion. The Volume-control was as high as possible... then i looked on the project-site again, and changed some resistors but it didn't work very well....

I think its best if I start with a simple schematic... i think the dual opamp TL072 should be fine, but I don't know much about op-amps... so I need some help :-)

I explain: I don't need big complicated schematics of already build guitar-amps, I more need some beginner-info about building pre-amps with op-amps (or maybe transistors)

Thanks for helping me :-) - But I need more help :-( , so everybody is welcome to post some info :-)

[ante]

Blacksheep,

Maybe your input signal is to weak?

Ante ::)

[audioguru]

Blacksheep,
Did you have your speaker connected directly to the output of the preamp? Sorry, but I had to ask since it would cause your problems.
If the preamp connected to a power amp, does the power amp have a low input impedance? (I hate emitter-followers!)

[blacksheep]

The speaker was connected through a power-amp... I don't know anything about the impedance :-( but I still think it's the way that the preamp is made... you know, some guitarists likes distortion, but i want a clean pre-amp :-)

[audioguru]

Hi Blacksheep,
Did you remove the "distortion-diodes" and emitter-follower from the preamp's output, as recommended in the article?

[blacksheep]

No i didn't remove the diodes... maybe thats the problem ::)

What do you mean about an emitter-follower? I've heard about it before but i don't know what it means...

But thanks... i'll try that very soon :)

[audioguru]

Blacksheep,
The article tells what to remove under "Bass Guitar, Electric Piano".
That darned emitter-follower is the transistor. It is thrown out too.
When the diodes and transistor are removed (plus changing a few things), then your distortion will vanish.

[EDY]

I've builded this simple preamp with my friend for his guitar. It is more less just a simple active-out for guitar 'couse it is connected directly to magnet pickup. It worked like a charm. No distortion and clean sound. Best thing is it is as simple as it gets. I posted pictures below but try this link also for a little different wersion of the same pre-amp

http://www.till.com/articles/GuitarPreamp/index.html

Cheers