Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Tubes and Hybrids => Topic started by: sweetspence on March 30, 2011, 10:27:34 PM

Title: hi gain tube preamp to solid state power amp
Post by: sweetspence on March 30, 2011, 10:27:34 PM
so im gonna build one of these, http://diyaudioprojects.com/Tubes/12AX7_Preamp/ (http://diyaudioprojects.com/Tubes/12AX7_Preamp/) and my question is could i use three of these in a chain with boosters to overdrive them for more gain/distortion like a mesa or boogie lead tone, using a solid state amp from a organ

thanks
Title: Re: hi gain tube preamp to solid state power amp
Post by: J M Fahey on March 30, 2011, 11:27:44 PM
Well, not exactly *that* one.
To begin with, it's a Hi Fi design , not a guitar one
Even more important, it's wrong.
That feedback net, which in theory lowers gain and corrects distortion, won't work.
Title: Re: hi gain tube preamp to solid state power amp
Post by: sweetspence on March 30, 2011, 11:33:32 PM
could i be pointed in the right direction.
i want to try and keep each unit separate as to use them for mics and such
Title: Re: hi gain tube preamp to solid state power amp
Post by: bry melvin on March 31, 2011, 02:46:20 AM
Here's a preamp that actually WORKs well. It's Peavey used in BOTH bass and guitar rack preamps.

Would be a good starting point/
Title: Re: hi gain tube preamp to solid state power amp
Post by: J M Fahey on March 31, 2011, 05:49:49 AM
Excellent preamp.
For something somewhat simpler, the Alembic preamp :
(http://music-electronics-forum.com/attachments/5388d1242232408-alembic_f2b_preamp.gif)
It's a stereo one, but of course you can build only one channel (as shown), or both, and use them in series (what you wanted to do anyway)
Title: Re: hi gain tube preamp to solid state power amp
Post by: phatt on March 31, 2011, 09:28:08 AM
Hi sweetspence,
                     Mesa VTwin   8|
I only built the clean channel as I'm not really into mass distortion.

I used the *Silicone Chip Kit* and just rewired a 3 meg resistor between the triodes.

Of course you have to build the SS section that goes with the Vtwin but it's not so hard if you delete all the extra unwanted gizmos that hang off the output.

Wired as per the Clean ch of Vtwin the Valve section was deadly quite but you may want the Fuzz section added on.

The kit has the attraction of a cheap HT supply as well as DC heaters which is needed if you want masses of triode gain.

Sadly the kit itself was dumb because it was aimed at HiFi and did not sell many.
If those magazine geeks had half a brain they would have wired it as per a guitar circuit and they would have sold 100's more.
The RCA sockets on either end are just stupid,, they break real easy hanging out like that.

Another idea;
There is a very clever Line drive circuit in *Electronics and Beyond Nov 1990*
Not sure if it's wise to post it public but PM me and I'll try to scan it if that interests you.

BTW, That *top chap JM Fahey* reminded me long time back if you take a signal from the plate you may need a fair bit of series resistance otherwise the signal will be HiZ and full of noise.
The Vtwin negates all this via smart mix of Glass and Sand.
As does the EB line circuit cept it is all Glass.

Phil.
Title: Re: hi gain tube preamp to solid state power amp
Post by: sweetspence on March 31, 2011, 06:45:07 PM
thanks for the schematics both of you. im kinda new to this stuff and there are so many different things out there it gets kinda confusing. im a college student and am having a hard time finding part time work and had sold all my gear and as most of you know music is an expensive hobby so i figured what the heck i will make my own! lol

ps: if anyone likes to teach i would love to pick some brains here  :)
Title: Re: hi gain tube preamp to solid state power amp
Post by: joecool85 on April 01, 2011, 08:17:42 AM
Quote from: sweetspence on March 31, 2011, 06:45:07 PM
thanks for the schematics both of you. im kinda new to this stuff and there are so many different things out there it gets kinda confusing. im a college student and am having a hard time finding part time work and had sold all my gear and as most of you know music is an expensive hobby so i figured what the heck i will make my own! lol

ps: if anyone likes to teach i would love to pick some brains here  :)

Most of us like to teach and answer questions, so feel free to pick away!
Title: Re: hi gain tube preamp to solid state power amp
Post by: J M Fahey on April 01, 2011, 08:44:13 AM
Hi sweetspence.
Now that I reread your original post and a couple answers, maybe I can suggest another path (to the same end result).
I see (may be mistaken) that what you really want is to have "something" that you plug between your guitar and an organ SS power amp which provides
Quotegain/distortion like a mesa or boogie lead tone
.
You found those tube preamps, think that cascading 2 or 3 of them will have that sound.
Well, maybe, you'll also run into a nightmare of hum, hiss, oscillation, etc. , because you want to use them *way* beyond what they were meant to.
Besides that, you are just getting into this.
Please let me suggest that you search for the Marshall Guv'nor/Governor project and build it.
I think GGG (General Guitar Gadgets) has it.
Beyond the schematic itself, they provide the printed circuit board design, (you should learn to transfer it with a clothes pressing iron), the layout, and how-to-mount it in a suitable box.
It's a killer, very good sounding Marshall preamp channel disguised as a pedal, and can drive directly any power amplifier, turning it into a full guitar amp.
Lots of grind, distortion, balls, you name it, and you can have it running in a weekend.
Think about it.
Title: Re: hi gain tube preamp to solid state power amp
Post by: joecool85 on April 01, 2011, 09:40:55 AM
Here's a link to all the info on the Guv'nor.

http://www.generalguitargadgets.com/projects/17-distortion/99-guvnor

You can also buy the Gov'nor PCB if you don't feel like making it.  $14 USD.
Title: Re: hi gain tube preamp to solid state power amp
Post by: sweetspence on April 01, 2011, 08:58:05 PM
that might be smarter for my first build lol  :duh

all my parts are coming from an electric organ so i dont know how forgiving that circuit is with values?

its a 60 watt ss amp and i was gonna use the organs speaker as well its 7 ohm which ive never seen...

there are some parts that i have no idea what they are maybe sound emitting something? i will post some pics soon.

thanks again everyone
Title: Re: hi gain tube preamp to solid state power amp
Post by: sweetspence on April 01, 2011, 08:59:37 PM
what are your guys' opinions on "the real mctube"?
Title: Re: hi gain tube preamp to solid state power amp
Post by: phatt on April 03, 2011, 11:01:42 AM
Quote from: sweetspence on April 01, 2011, 08:59:37 PM
what are your guys' opinions on "the real mctube"?

More triode fizz bottle distortion,, Next please! ::)

They all tend to sound the same these days but if you are chasing the real thing build a simple Valve power stage and get some real Valve OD happening.
Just my opinion as I'm not into *mass preamp distortion* but if that is what you desire dis-regard my ramblings.
Phil.
Title: Re: hi gain tube preamp to solid state power amp
Post by: sweetspence on April 04, 2011, 01:40:22 AM
good to know haha thanks