Tube amp simulation

[rodriki1]

One day a friend of mine asked me to produce a distortion device similar to tube distortion.

It has been years of research on the internet looking for the idea of a good tube emulation.

I have heard a lot of people that simply say that its not possible to get tube sound from transistor.

But the most of them do not have knowledge to sustain what they are talking.

I agree that is not a simple task.

Maybe the "clean" tube sound is not possible to simulate.

My own experiences said that "tube amp distortion" is possible to imitate with op amp.

There are stephan moeller that simulated vox ac30,

John Murphy from CARVIN with SX100 and LXH2 with marshall and fender simulators.

Those guys are MASTERS.

The stephan moeller VOX AC30 SIMULATOR is a master project.

I live in brazil and in here is hard to get TUBES and eletronics parts.

I have just tried many strategies to get good distortion.

Until now the only project that had a comparation between the
real amp and the simulator was the vox ac30. Know it is not available any more.

I would suggest that the circuit below is a good simulation of a cranked tube amp.

(inspired by LXH2 simulations)

And i would like to hear the diference to a real tube amp.

Some ideas:

Forget 9 volt circuits.

Use 7+7 at least.

Forget simple distortion of one stage.

Tube amps always have more then one stage clipping.

All triode tubes show HARD CLIPPING on grid.

The idea is here.

For me it was really hard to get to this design, if is important to know.

Anybody has tried or experienced to simulate a tube amp like stephan ou lxh2?


The image is at


http://geocities.yahoo.com.br/rmfidelis/TubeSimulator.html

[nelson]

you should look here


http://www.runoffgroove.com

Lots of work attempting to get tube tone from jfets.

[gez]

Have you tried CMOS inverter circuits?

[rodriki1]

Thanks  for the replies

I have tried cmos inverter but the circuit is very unstable. The cmos is not a MARSHALL type of sound. I got some noise. Sound like radio frequence interference.

The runoffgroove circuits are fantastic. But fet is not triode sound.
I have tried thunderchief. The sound is good but i wish a real comparation like vox ac30.

Somebody has tried thunderchief in front of a marshall to compare??

[gez]

I have tried cmos inverter but the circuit is very unstable

Are you sure you used unbuffered chips, and tied the gates of unused devices to ground?

The cmos is not a MARSHALL type of sound. I got some noise. Sound like radio frequence interference

.

In my experience they're very quiet.  4007 chips will give you more of a Marshall vibe.  I posted a design a while ago (nut cruncher at Marcos's site) which sounds a little crunchier than 4049/4069 designs.

http://www.geocities.com/diygescorp/

[aron]

Thank you for sharing your circuit snippet. While I haven't found diode clipping to sound anything like a cranked amp, maybe this will surprise me.

[rodriki1]

Thanks for replies.

The circuit exposed here is not intended to be the miracle.

But to me it sounded exactly like GREEN DAY sound. With some changes
sounded like IRON MAIDEN. Both with marshall.

If somebody have the time to have some experience with the circuit
stay at will and send me replies.

The cmos circuit exposed before is an excelent idea to but cmos is a
hard stuff to get in here and its full of cares to implement.

I intend to have a design with "easy to find" parts.

GT2 for example is made with the cmos op amp as a "heart".
This circuit is very convincing but still not an amp sound.

Besides, i am inspired by "stephan moeller" (vox ac30) ideas.

His work was a master piece and very convincing.

The GEZ REPLY was interesting because on the site indicated there are circuits from CCDB that i have experienced  . CCDB is a brazilian guy who shared a lot of ideas of professional sound in brazil.

My intention is to have an "open design" project of a circuit at the same level as stephan moeller and john murphy. If i can even think of that.

Aron has done the best work to help for free. That is incredible.

[jmusser]

The "3 Legged" Dog on ROG with the 4049 chip does a wonderful job! I wrote up a review on it the other day. One chip, one transistor, and WOW!