Independent tube preamp + poweramp

[electrictabs]

Some time ago Ansil gave me a good idea with his project of combining a different preamp and poweramp in one…I think it is a Bogner and a Matchless but not sure…
So I’m thinking of building a nice clean power amp with a 12AX7 splitter and 2 or 4 power tubes.in a box. And then if I want to sound like Marshall I’ll build a Marshall preamp if I want sound like Boogie I’ll build a Boogie preamp etc.
The preamp and the poweramp won’t have the same power transformer and will be housed in a different box
Is this possible and worth building?

[electrictabs]

well noone having thoughts about that?
come on guyz i need your help...

[Dave Z]

Tabs, there is a whole forum on this at AX84.com, called the Tone Brewery..anyway, they have this cool bulding block approach, using a multiwire cable to hook up any preamp to the basic poweramp module.

http://ax84.com/bbs/

[smashinator]

Sure you could do that.  It sounds to me like you're essentially talking about building a rack system.  Neat!  Be sure to post pictures and a "how I did it" when you're done!  

Personally, I'd build the preamps first.  For testing, you could always run them into a Ruby/little gem.   :lol:

[Peter Snowberg]

That's a great approach. Just make sure your connectors are rated for the full voltage they'll be seeing. Molex has lots of options available at 600V.

Best of luck and I hope you can post pictures!

[JHS]

Good idea, but it will not work with distortion sounds. For clean sounds it's OK.

I had the same idea a year ago.

Try this first and than think about it again:  Marshall preamp OUT into Fender Twin Preamp IN and listen to the sound and I can tell you it's terrible.

The Marshall sound is generated by overdriven EL34 Tubes and a 4x12 closed back box. The classic Boogie sound is generated by a heavy overdriven preamp and an open 12" box.

A Bogner preamp sounds  like crap without a saturated poweramp and a 4x12 with Vintage 30, kinda like a BOSS stompbox in the effect return.

You can build something like H&K Cream Machine, Metal Master, Clean Machine. Hooked up to a poweramp with cabinet it do the job quite good but not really satisfying. (That's why H&K dropped that line)

JHS

[Ansil]

hmm well lets elaborate a little on some of the statements made above.

first of all there are desirable elements of each amp that CAN i repeat CAN be made into a preamp alone.

Will it sound like the real thing.?

Not sure,  heres the thing  building amps guitars fx whatever is about 85% knowledge experience research blood sweat and tears and a butt load of money unless you know how to get free stuff better than I.

now this is a very important fact  15% OF THIS IS VOODOO, BLACK MAGIC OR WHATEVER SUPERSTITION YOU CAN THINK OF.

dont' believe me well then you haven't built enough yet.  ask anyone here if every circuit works like it should every time.    the answer NO!!!!!!!!!!

It doesn't  its not all math its not all science  you have to take the little imperfections in everything we do as humans..  i solder different than the person next to me. i might have more or less solder better or worse solder before i begin i might have a bad batch of solder a burned out tip i might get better electron flow or worse and it could sound the same or better or worse.

Now this is not to say that their is not a certain skill level that will help ease the gap but nothing will turn out 100% every time.  hmm email zvex and tell him i sent ya  he will tell you that sometimes things should be working and they aren't and things like that dont' get sent out.

i am trying to prove a point here that there is no set formula people.

a marshall isn't all saturated EL34'S.. does it help OF COURSE is it a big factor depends you can alter other things to help it sound more "marshall" like

Do i have a marshall sitting at the shop that has a spanking fender clean tone.  YES does it baffle the S%$*  out of me..  YES.  does it have el34's and the same preamp as a regular plexi  YES.  is it a miracle of science.. NO.

short answer is this.
Higher gain amps like the bogner and mesaboogie do rely on multi tube sections saturated out and then put in blocking resistors in there to help tame the beast to keep out oscilations.

for reference.

http://www.blueguitar.org/new/schem/bogner/xtc_od.gif

this will not sound 100% like the straight up amp cuase theres plenty of factors in there but it can be made to do a very good sound that is really close but it will require some looking at.

look at most of the early marshall amps.. they gained up the crap out of the first stage slammed the second stage and the third stage was driving the eq and into the phase inverter.

look at all the high gain monsters and they will look surprising like a jcm800 there with an extra stage or so,  certain soldano's and mesaboogies and carvins' all have the 220k plate resistor 1.5k .47uf cathode resistor and a nice voltage divider afterwords. personally i have discovered this site from lovekraft.

www.tone-lizard.com
and i agree there is no reason for anthing more than 4 gain stages. unless you are going to do discrete channel switching.
you can easily change a few components in a jcm800 and make it sound like a boogie or a slo100.
shoot put in a fancy switch or do it with relays and make it foot switchable and you can move the tone circuit out of the back and into the front and it is decidingly more fender like all the time.  hmmm couldit be because the bassman circuit was "borrowed by marshall" that might be a good reason too.

so my thoughts is read the above site 100% and if you have questions email me i dont' mine there  electrictabs i will gladly help out where and when i can.

also this thread is not to pick on anyone or single anyone out.  everyones experiences here are valid. but i am trying to keep more people open minded about expirimenting with tubes and different circuits if we try something once and it doesn't work for us doesn't mean that it was a failure it means it didnt' work that time.  somewhere someone has tried it or is trying it and it may work.

and as always thanks for playing the Game.

[jim_inme]

it think its a brilliant idea. Try looking up Randall. They have an amp series that has removable and swappable preamp sections. essentailly plug and play preamps. theyre rather pricey but im keeping a eye on them.

did you ever get round to developing a project like this? id be interesed to find out how it went.