tube preamp, crunch overdrive idea needed

[Colas LeGrippa]

Hola mis amigos ( hello my friends ) ! Hace mucho tiempo ! ( it'sbeen a while ).

Now, I live part time in Cuba playing music wth my amigos  in La Havane. I am bacjk home now( Canada for a while..)   I have 2 weeks to build a tube preamp with crunchy tone and I need your ideas for this.
I do not want no low voltage crap neither the Real  Mctube. Got 300V available, ready to feed any hot circuit for hard rock ( not metal ). What would you suggest ?

THanks. Muchas Gracias Danke Merci Grazie ?%?%((

Colas The Grip

P.S.: have you seen my wife somewhere around here ?

[DummyLoad]

dumble with a pentode for the OD. 


--pete

[tubenit]

Nice to see you drop in!

Don't know anything about this amp but with the schematic drawing .............. I think it would be pretty high gain crunch?  I haven't built it and don't remember where I got the schematic from?

with respect, Tubenit

Ah, found another one similar topology.  Maybe some ideas in there for you?

[TIMBO]

Hey Colas, I think I saw your wife at the 7/11 here in Brisbane, Australia.
This is a JTM60 clone pretty much, just a bit of a mod on the overdrive.
! No longer available

[tubenit]

dumble with a pentode for the OD

Not sure what D.L. has specifically in mind?  What pentode? Just pentode?

This is 102 preamp with a 5879 added into the OD section

With respect, Tubenit

[tubenit]

Found another one.  I have not built any of these.

[VMS]

No idea how this one sounds but I like that it has a cathode follower output:

http://el34world.com/charts/Schematics/files/kitty_hawk/kittyhawk_quatro.pdf

[terminalgs]

Got 300V available, ready to feed any hot circuit for hard rock ( not metal ). What would you suggest ?

a simple single stage triode, no tone stack, just a volume pot after it... think the first 1/2 of a champ preamp.. you can use any 12ax7/y7/u7 tube, but you'll end up needing to attenuate a ton of gain off a 12ax7, so maybe a 12ay7 or 12au7 is a better fit.  put a big resistor between the volume pot and the plate coupling cap, and use a small volume pot, like 20K-100K... tweak the big resistor to get your max output gain where you want it... (+20dBu ??+10DBu?).. you want that resistor+pot total resistance to be high since its the load the output,,  like 500K min..


if you want to use the other 1/2 of the twin-triode, duplicate the first side and have two outputs, each with its own volume control...


a couple neons controlled by external foot switches can turn on/off LDRs if you want to switch outputs on/off, or boost them., etc...

[Colas LeGrippa]

Buenos dias ! ( good morning! ), don't be afraid, I must practice the spanish I've learned down in Cuba. ( not with Fidel though )

DUMMY LOAD :  Pete, love your South Texas Amplification Website, I am impressed. Can you detail just a bit more on your « pentode out » circuit, por favor ? ( please? )

TUBENIT :  Happy to see that you recognize me después de todo el tiempo fuera de aqui ( since all the time without coming here ). Thanks for your schematics, I think your own  library is bigger than Doug's one !!!

TIMBO: What the fuck is doin' my wife in Australia ?  Feeding the kangaroos or what ?  Eres the segunda personna que yo conozco y que viene de Australia. You are the second person that I know who are Australian. The first one is a guitarist that I know here in Montreal and is called Tim also.  Thanks for your sound clip ! Muchas gracias hombre !

VMS : Encantado ! ( please to meet you!

TERMINAL GS : Buena idea compadre ! ( good idea my friend ). This is a good simple circuit and I ve built it many times. But I want something more agressive with tons of crunch.



Cheers !

Colas LeGrippa
Montreal / La Havane

[VMS]

Encantado!

So how was the tube amp situation in Cuba? I know they have all those 50's cars, but did you find any NOS tubes?

[Colas LeGrippa]

Unfortunately no. All the musicians I play with play acoustic. In  bars, there are electric bands once in a while, but have russian electric guitars and new amplifiers.
No 50's amplifiers nor guitars ( there are probably some, but well hidden... )

Colas

[terminalgs]

then maybe the matchless hotbox?

[sluckey]

There's a lot of Marshall crunch available in Hoffman's stereo preamp. Build one channel version...

[DummyLoad]

DUMMY LOAD :  Pete, love your South Texas Amplification Website, I am impressed. Can you detail just a bit more on your « pentode out » circuit, por favor ? ( please? )

thank you, but the credit for the site build goes to my partner RicharD. we have mostly gone separate ways in the business but we are still good friends. keep telling myself i need to update the site, but i just keep putting it off...  :-\

tubenit's plan is what i was thinking, only without the cathode follower and the triode gain stage in front of the pentode. should crunch well without sounding too compressed. if you want more bite, use the EF86, for more mellow crunch use the 5879. personally i'd use the EF86  because they are still being manufactured. use separate PS filters for OD stage and the clean preamps. run with 325-350V B+. add a buffer for the hi-z out: use a 12AU7 or similar.

--pete

[Colas LeGrippa]

Thanks guys, I got too many now....don't know what to choose !


Cheers !


Colas LeGrippa