Need help converting a tube preamp into a solid state one

[Aresta22]

Hey guys! I urged Runoffgroove guys to help me in my DIY project, convert a GP-1000 tube preamp into a solid state one (maintaing the original GP-1000 circuit as much as possible ) ,using JFETs to give it  a sound as close   as it's  tube counterpart.
Can you guys make me a schematic?
Here is the original schematic http://wormwoodprophecymetal.com/wp-content/uploads/2012/01/PC-GP1k_schem2_Rev33.jpg
1000000 thanks ,I really need to make this project...!

[J0K3RX]

Pedal or rackmount? Just use the schematic you have linked and change the tube stages to J201's or whatever and use trimmers on the drains... Probably have to change R12 and R13 to compensate for the lower voltage. That would be a good start.

I have had this preamp on my project list for a while but haven't had time lately.. I think it would be highly popular since the real tube version of this preamp is hard to find and pricey!! You can blame Alexi for that

Not overly complicated, may need a rotary switch for the mid shift..

[Aresta22]

Heyyy,thanks a lot for the nice reply ,I want it in rackmount form ! will do that and update ,any thoughts on R12 and R13 values?
The rotary switch should be no problem at all,once again thanks and yeah it is indeed very hard to find even though I have someone in my country willing to sell his for 450 euros... o:

[Ark Angel HFB]

can I ask why you want to do this?

[J0K3RX]

can I ask why you want to do this?

Why not..? Can I ask why you would not want to do this?

I guess you could build a tube version but you are looking at some $$$...

I know there are many tube purists out there, I'm not one of them If transformers, tubes etc were dirt cheap and easy to find I would be more inclined to go with them...

[Aresta22]

I want to do this project for many reasons...
1- I like the GP-1000
2- I am very curious about a SS counterpart
3-  I'll learn more and gain experience in electronics
4- I'll have a rack preamp usable in my rig...

Yeah,I agree ,if transformers and valves were cheaper I would definetly make a tube replica...
Last Summer i was planning in ordering some 6N2-P Soviet/Russian valves + tuve sockets and it wasn't that expensive,mayby I'll make one with valves in the future but for know help me with this project :p

[Kesh]

if you are interested in jfets imitating valves, check out http://www.scribd.com/doc/65330169/Triode-Emulator-by-Dimitri-Danyuk

[Aresta22]

Thanks Kesh! Will read that! Actually the author is someone form the forum isn't it?
People are really helpfull here !  

ps: I'm gonna analyse that doc you send me but i've already read something and I have one question ,is that simulator designed to immitate triode distortion or just clean amplification? thanks once again  :p
I think it is really a triode simmulator circuito that also mimmics triode distortion ,very happy to have it,thanks Kesh!

[Ronan]

To build a tube preamp is not expensive, $150 is a ballpark figure for DIY.

[Seljer]

The distortion isn't even the most important thing. Its the filtering in between the stages thats crucial. It why things like the Sansamp that directly clip opamps sound perfectly fine, you can set up diodes to clip waaaay softer than tubes and so on.

[Aresta22]

150 ? buying online?
Yeah,the PSA-1 sounds awesome!

[Seljer]

150 ? buying online?
Yeah,the PSA-1 sounds awesome!

You don't need a big expensive output transformer. For the power transformer, you can get the one used in the standalone Fender reverb units for $25 and that'll give a 300V supply and the 6.3V heater supply too (albeit not being a toroidal transformer makes it a bit tricky if you want to make a 1U rackmount unit). Spend another $25 on two 12AX7s. Then the rest is just the enclosure + all the jacks and sockets and other little things that add up.