Another cool article on tube simulation by Viktor Kempf

[johngreene]

Hey, what happened to this thread?  Any more info.  I couldn't get a real clean translation no matter what I did.  Always had some parts of it getting messed up. 

Well, thought I'd bump it and see if anyone had a good translation of it.

Jim

Doesn't look too different from a Peavy.
http://www.pat2pdf.org/patents/pat5619578.pdf

*edit* I see now he mentions the peavy patents in the bottom of the article.

--john

[mac]

To Marcelo Tripodi:
I wanted to ask you why you put those diodes instead of source resistors? Interesting...
Should we talk between us in Spanish?

Instead of setting the source voltage with a 1k or so, and bypassing it with a big cap, the diodes set the source voltage at some level over the gate, and their small on resistance give a fair amount of gain. I killed two birds with one shot.
Send me a PM since this is out of this topic.

mac

[Isaiah]

Looks pretty cool.

[dschwartz]

wow...i´m really impressed but we should discuss more the idea.

I simulated the circuit with livewire..with one stage, the output waveform  was very similar to the tube emulation shape, but i cascaded 4  stages and the clipping was simmetrical, no difference with normal use of fets, by tweaking the gain pot, the shape varied from pure senoidal (like the input waveform) to compressed tops, at some ponts the tube emulation shape, and at max gain, hard clipped at both sides.

The fet setup proposed is VERY sensitive with the values of source resistors. The excel file at the article is suposed to help with that,m i guess.. but i dont understand russian so i tried random values.. ended up with 3k and 4k ohm combination seemed to work fine..

there are some more questions though...will different fets (like gainier j201) need different source resistors to do the trick? can CMOS linear amps make the same effect?

I´d love to have an oscilloscope and check live the choice of resistors and fet biasing....

[mac]

There is still the fact that fets and tubes have a different internal behaviour, 2 and 1.5 power law. Maybe using Dimitri Danyuk trick and the input diode, a fetzer valve with the input diode.

mac

[StephenGiles]

To Marcelo Tripodi:

I wanted to ask you why you put those diodes instead of source resistors? Interesting...

Should we talk between us in Spanish?

No me digas!!

[dschwartz]

sí te digo!!!!

[slideman82]

Aaaaaaaaaaah bueno, estan todos graciosos? Viva la joda!

[mac]

Someone said that Peavy ¿transtube? uses this trick. Any one like those emulation amps?

Aaaaaaaaaaah bueno, estan todos graciosos? Viva la joda!

algiuen dijo joda? donde q me prendo!

mac

[dschwartz]

hmm...i read peavey's patent (posted in this topic) and is pretty much the same thing..

Anyway i have a 90's bandit 112, and it´s distortion KICKS ASS!!! it´s the supersat circuit..I´m not sure if the patent showed is the transtube or supersat idea..

Transtube tech has different reviews, some love it, some hate it...i dont think it´s the best sound aoround, but it´s a step forward from typical SS distortions..

[mac]

I have to try a bandit. I need an inspiring SS to practice at home.

Some article about OT and tube power amp emulation?

mac

[dschwartz]

those early 90´s bandits are really good for practicing and rehersal, the clean channel is LOUD and very sparkly, i just love it..the supersat channel is very versatile and sounds really good, but at very high volumes it tends to loose some definition, but i think that´s for a not-so-good speaker..

I also use an all tube peavey, the triumph PAG120..nice amp, but (don´t hate me) i rather use the bandit, is more reliable and has more lowend kick (that this 6L6GC powered 120W amp) the tube clean channel sounds dead to me..but the distortions are the best!!! but again..too heavy, too delicate, too much of a hassle..

[slideman82]

those early 90´s bandits are really good for practicing and rehersal, the clean channel is LOUD and very sparkly, i just love it..the supersat channel is very versatile and sounds really good, but at very high volumes it tends to loose some definition, but i think that´s for a not-so-good speaker..

I also use an all tube peavey, the triumph PAG120..nice amp, but (don´t hate me) i rather use the bandit, is more reliable and has more lowend kick (that this 6L6GC powered 120W amp) the tube clean channel sounds dead to me..but the distortions are the best!!! but again..too heavy, too delicate, too much of a hassle..

Solid state amp for practicing... Te mando por mail algunas ideas, igual a vos no creo que te falten!!!!

De MDP a La Plata hay 400 km, y aca siempre hay joda!!!!! No se donde, pero hay!

[dschwartz]

pero yo soy de Santiago de chile