Tube boost + overdrive running off a 9 volt battery

[armstrom]

I have built a clean 25W stereo power amp based on a tripath chip and I'm trying to decide on a preamp for it. I would like something warm, clean and tube-like that can be made to just break up a bit with high gain. I'm wondering if one of the many variations discussed in this (LONG!) thread would fit the bill. I'm trying to cram everything in to a small enclosure so the 6111 tubes really appeal to me. I would mount two in 8-pin DIP sockets on a single board with dual-gang pots to produce a stereo preamp.  So.. given my requirement of a range of clean sounds to just breaking up "dirty" overdrive (a bluesy sound) does this seem feasable? I'm not sure if this circuit would produce enough gain to properly drive my power amp though.

Any thoughts?
Edit:
To give a better idea of what kind of tone I'm looking for my current "best choice" for a preamp is a Professor Tweed from ROG but a hybrid sounds much more appealing to me.
Also, if it helps to answer my question, the power amp I built has an input impedance of 22kOhms (but I can bump that up to 58K if I need more gain from the power amp) and is meant to be driven by a 1V RMS line level signal but can handle up to ~4V on the inputs before frying the chip.

[puretube]

Don`t over-heat this 12AU7!

[frequencycentral]

Yes! My Valvecaster works! Just hooked it up - now I need to work on the enclosure. 

Now if I could just get my Subcaster to work......!

Tube-Town Pepper Shredder next I think! http://www.tube-town.net/diy/lov/lov02-peppershredder.html

[Renegadrian]

quote author=frequencycentral
Yes! My Valvecaster works! Just hooked it up - now I need to work on the enclosure. 
GREAT! HAPPY TO READ THAT...ENJOY!!!

Now if I could just get my Subcaster to work......!
UH, DUNNO ABOUT THE SUBCASTER...CAN'T HELP...

Tube-Town Pepper Shredder next I think! http://www.tube-town.net/diy/lov/lov02-peppershredder.html
YES, SOMEONE POSTED A WHILE AGO...WOULD BE GREAT IF YOU OR SOMEONE ELSE COULD DRAW A P2P-PERF-VERO LAYOUT OUT OF THAT SCHEMATIC...

[frequencycentral]

Thanks Renegadrian!

I built my Valvecaster on the tube socket - really easy. I don't think a perfboard is needed. I will build the Pepper Shredder the same way, its pretty much like two Valvecasters with a few mods.

I'll post some pictures tomorrow if I find time. I drilled the enclosure today - just need to fit it all in tomorrow.

Today I had fun:

LPB1 (DIY) > Valvecaster > Harley Benton GA5 (VJ clone) - Now that just rock!

then:

Valvecaster > Ruby > thru the GA5 speaker.

I'm defo going to build a combo with a Valvecaster, Ruby and 12" speaker - powered from a 9v battery!!

In fact I may even fit a Ruby in my Valvecaster enclosure and fit an extra socket for speaker out!

[nico13]

I'm defo going to build a combo with a Valvecaster, Ruby and 12" speaker - powered from a 9v battery!!

In fact I may even fit a Ruby in my Valvecaster enclosure and fit an extra socket for speaker out!

Nice idea !

How do you plan to wire the Valvecaster and Ruby together: will you keep the gain and volume pots on both of them ?

[frequencycentral]

I'm defo going to build a combo with a Valvecaster, Ruby and 12" speaker - powered from a 9v battery!!

In fact I may even fit a Ruby in my Valvecaster enclosure and fit an extra socket for speaker out!

Nice idea !

How do you plan to wire the Valvecaster and Ruby together: will you keep the gain and volume pots on both of them ?

At the moment its just one into the other, so two gain controls, which is quite nice - with everything up full I get serious sustain - serious feedback too! I guess ideally I would want to be able to get a clean sound, so maybe the Ruby gain should be on a switched potentiometer.

[andrew_k]

I'm defo going to build a combo with a Valvecaster, Ruby and 12" speaker - powered from a 9v battery!!

That'll be great! ...for the 47 second life span of the battery 

[frequencycentral]

Hahaha! maybe a car battery then, they're 12v - not so portable though! Unless - hmmm.........I could rig up a power feed from the car's cigarette ligher socket!

[Renegadrian]

quote author=frequencycentral
I built my Valvecaster on the tube socket - really easy. I don't think a perfboard is needed. I will build the Pepper Shredder the same way, its pretty much like two Valvecasters with a few mods.

I KNOW RICK, I BUILT MY FIRST VALVY THE SAME WAY - I WAS ASKING FOR A LAYOUT OF THE PEPPER SHREDDER, I SAW THE SCHEMATIC BUT I AM NOT THAT EXPERT TO TRANSLATE IT TO A LAYOUT

[Albot]

still debugging mine :/
please take a glance at my picture and tell me if you find any errors.
I've been checkng it at least 10 times now and i think i'll go crazy sometime soon 

[armstrom]

Does anyone have any thoughts on using this circuit as a preamp for my power amp?
-Matt

[frequencycentral]

quote author=frequencycentral
I built my Valvecaster on the tube socket - really easy. I don't think a perfboard is needed. I will build the Pepper Shredder the same way, its pretty much like two Valvecasters with a few mods.

I KNOW RICK, I BUILT MY FIRST VALVY THE SAME WAY - I WAS ASKING FOR A LAYOUT OF THE PEPPER SHREDDER, I SAW THE SCHEMATIC BUT I AM NOT THAT EXPERT TO TRANSLATE IT TO A LAYOUT

Ok, I will post my layout based on mounting the component onto the sockets once its completed - give me a couple of weeks though!

[frequencycentral]

Does anyone have any thoughts on using this circuit as a preamp for my power amp?
-Matt

I would think this circuit would make a perfect preamp for your power amp!

[Renegadrian]

quote author=frequencycentral
I built my Valvecaster on the tube socket - really easy. I don't think a perfboard is needed. I will build the Pepper Shredder the same way, its pretty much like two Valvecasters with a few mods.

I KNOW RICK, I BUILT MY FIRST VALVY THE SAME WAY - I WAS ASKING FOR A LAYOUT OF THE PEPPER SHREDDER, I SAW THE SCHEMATIC BUT I AM NOT THAT EXPERT TO TRANSLATE IT TO A LAYOUT

Ok, I will post my layout based on mounting the component onto the sockets once its completed - give me a couple of weeks though!

that would be great, I wait  to see it!!! Thank you Rick

[armstrom]

Does anyone have any thoughts on using this circuit as a preamp for my power amp?
-Matt

I would think this circuit would make a perfect preamp for your power amp!

Thank you. I think I will give it a try. I'm building a tiny 25W stereo amp that runs entirely on 12V DC so this circuit will fit nicely. The entire thing (minus the power brick) fits neatly into a 6" x 3" x 2" enclosure. When I'm done I'll post some pics and hopefully some sound clips.

Here's another question though... If I were to build two of these preamp circuits (one for each channel on the power amp) would it make sense to use half of each tube in each of the channels to help maintain the same gain characteristics on each channel? I know some of the tube vendors will "match" tube pairs for a fee, but would this be a better solution?

For example, "Tube 1 side A" and "Tube 2 side A" would be used as the first and second gain stages for channel 1 while "Tube 1 Side B" and "Tube 2 Side B" would be used for the channel 2.

Am I simply making things more difficult for myself with no real gain? (no pun intended).
-Matt

[Jimmy-H]

Hi there,

I just finished a Pepper Shredder.
I used the 12U7 tubes, which are specially designed for 12 volt DC (in car radio's)
I like the sound of it very much.
It has a good amount of distortion.
I also placed a Fenderish Tonestack in the end before the volume.
Also some of the capacitors were changed for a "fatter" sound.
You have to use a good regulated power supply for this, otherwise you get a lot of hum.
To bad that I don't have time for a while to box it up.
But anyway here are the layout and PCB for this project that I used.
If You use the PCB, scale it down to 56 percent.
I'm also planning to make a subcaster.........when I have the time for it

[frequencycentral]

Jimmy-H:

Well done and welcome! I would love to hear some sound clips of the Pepper Shredder if you have time. Have you tried it with 12au7's too?

[Jimmy-H]

Hi,

Have you tried it with 12au7's too?
No, but what I have read, the sound of the 12U7 is a little "fuller" compared to the 12au7.
The reason could be, that the 12U7 is made for low voltage.

.I would love to hear some sound clips of the Pepper Shredder if you have time.
Oke I'll try it, but I don't know how to post sound Clips.

[frequencycentral]

A few photos of my Valvecaster - this one I built to drive my VJ clone harder so I didn't feel the need for a stomp switch, the enclosure is so small it wouldn't fit anyway.

Want to make your tubes glow brighter? I fixed a red LED in the centre of the tube socket.

Here it is!

And in low-light conditions: