Author Topic: Infinity: an universal guitar preamplifier!  (Read 37611 times)

DSV

Infinity: an universal guitar preamplifier!
« on: February 12, 2009, 03:12:47 PM »
Hi all!

About 2 months ago, I posted a thread showing how I transformed a BSIAB into an universal guitar preamp for DI applications. Now that I have received all the PCBs and the components, I'd like to share pics the build of a single channel preamplifier for my home studio. Of course, the module presented here can also be used in multi-channel configurations, for live use.

A short presentation can be downloaded here:
 :icon_exclaim: http://www.techniguitare.com/projets/ChaosPreamp/infinity_en.pdf
And the schematics of Infinity here:
 :icon_exclaim: http://www.techniguitare.com/projets/ChaosPreamp/Preamp-Schems-V1.1-En.pdf

This youtube video shows the first prototype, and contains some samples:
 :icon_exclaim: Here!
And here are 2 additional samples (sorry for the sloppy playing):
 :icon_exclaim: Vox style
 :icon_exclaim: Comfortably Numb (2nd solo) (delay added through Audacity).

I'll add the layouts and the bill of materials later, as I am verifying the printed PCBs through this build.

Finally, here are some photos of:
 :icon_exclaim: the prototypes

 :icon_exclaim: the current build (beginning)


Stay tuned for updates (as soon as I buy new batteries for my camera  ;D).

PS (a bit of advertising): this poject is born on the french forum, www.techniguitare.com . There are many more interesting project, so visit it  ;D
« Last Edit: February 12, 2009, 03:47:19 PM by DSV »

dano12

Re: Infinity: an universal guitar preamplifier!
« Reply #1 on: February 12, 2009, 03:31:56 PM »
Very impressive!

Just finished a quick look at the schematics, looks to be a great build.

petemoore

Re: Infinity: an universal guitar preamplifier!
« Reply #2 on: February 13, 2009, 11:42:01 AM »
  Big build.
  Huge sound in the clip though !
Convention creates following, following creates convention.

Ice-9

Re: Infinity: an universal guitar preamplifier!
« Reply #3 on: February 13, 2009, 02:27:28 PM »
Thats looking really good, and sounds good also. looking forward to seeing the finished build
www.stanleyfx.co.uk

Sanity: doing the same thing over and over again and expecting the same result. Mick Taylor

Please at least have 1 forum post before sending me a PM demanding something.

DSV

Re: Infinity: an universal guitar preamplifier!
« Reply #4 on: February 13, 2009, 05:07:11 PM »
Thanks!

And the finished building is one step nearer ... box is drilled and jumpers are soldered on the main PCB.

Uma Floresta

Re: Infinity: an universal guitar preamplifier!
« Reply #5 on: February 13, 2009, 05:29:24 PM »
Wow, nice work!

DSV

Re: Infinity: an universal guitar preamplifier!
« Reply #6 on: February 14, 2009, 10:48:33 AM »
 :D

Little update: resistors, sockets, capacitors and the trimmer have been soldered on the main board.


Paul Marossy

Re: Infinity: an universal guitar preamplifier!
« Reply #7 on: February 14, 2009, 10:58:12 PM »
Looks like a very cool project!  :icon_razz:

I'm going to do something similar with my ADA Flanger clone, as soon as the PCB arrives...  :icon_surprised:

liddokun

Re: Infinity: an universal guitar preamplifier!
« Reply #8 on: February 14, 2009, 11:10:21 PM »
Looks really cool! Good job!
To those about to rock, we salute you.

DSV

Re: Infinity: an universal guitar preamplifier!
« Reply #9 on: February 16, 2009, 06:48:39 AM »
 :D :D

But now it's getting messy  :icon_redface: ... offboard wiring!

Paul Marossy

Re: Infinity: an universal guitar preamplifier!
« Reply #10 on: February 16, 2009, 10:37:22 AM »
Messy? Say what?!  :icon_wink:

DSV

Re: Infinity: an universal guitar preamplifier!
« Reply #11 on: February 16, 2009, 02:48:38 PM »
I always have the feeling that wires are running over the place, even if they are cut at approximately the right length  ::). Anyway, I made a test with the jacks and PSU on perfboard, and it works pretty well. I am still waiting for the PCB supports, so I'll have to slow down the construction a bit, but I'll post the layout soon, since it's verified.

DSV

Re: Infinity: an universal guitar preamplifier!
« Reply #12 on: February 17, 2009, 05:17:29 PM »
Here is the PCB:
http://www.techniguitare.com/projets/ChaosPreamp/guitar_preamp.pdf
And here is the parts layout:


Enjoy  :)

DSV

Re: Infinity: an universal guitar preamplifier!
« Reply #13 on: February 21, 2009, 08:24:23 AM »
Finished!

Here are the last photos ...


Enjoy!!!

DSV

Re: Infinity: an universal guitar preamplifier!
« Reply #14 on: February 23, 2009, 06:16:53 PM »
Here is a .zip file with all the photos:
http://www.techniguitare.com/projets/ChaosPreamp/infinity_photos.zip

And, about the transistor biasing, Q5 in the common source stage is biased at 6V.

I'll post the values of Vth and Idss for the transistors as soon as I find the sheet where I wrote them.  :P

Paul Marossy

Re: Infinity: an universal guitar preamplifier!
« Reply #15 on: February 23, 2009, 06:43:43 PM »
I always have the feeling that wires are running over the place, even if they are cut at approximately the right length  ::). Anyway, I made a test with the jacks and PSU on perfboard, and it works pretty well. I am still waiting for the PCB supports, so I'll have to slow down the construction a bit, but I'll post the layout soon, since it's verified.

Yeah, I know what you mean. But your wiring is far from messy.  :icon_wink:

DSV

Re: Infinity: an universal guitar preamplifier!
« Reply #16 on: March 06, 2009, 04:27:09 PM »
Thanks, Paul ;D (I had completely missed your reply) 

And here are some new clips. After listening to them again, here are my impressions:

Two minutes to 2h in the morning: Iron Maiden style. Probably thin. I scooped the mids on this one
Plexi style!: maybe a tad too fizzy
Thunderstruck: instrument placement ain't that good, nor is playing
Sharp dressed man: difficult to capture the ZZ-Top tone, I tried to do my best ...

Enjoy!


petemoore

Re: Infinity: an universal guitar preamplifier!
« Reply #17 on: March 06, 2009, 08:47:55 PM »
  Not to disagree but I disagree, these aren't
  thin, The IM was really full of fine 'big guitar' sound !
  Plexi style!: fizzy, nope, this one has really cool playing and the mix is a fine example of your wizardry applied !
Thunderstruck: instrument placement ain't that good, nor is playing
  Rythms sound really nice thick and grindy, the leads maybe could have used a bit more 'push'.
Sharp dressed man: difficult to capture the ZZ-Top tone, I tried to do my best
  Ok you got me on this one. Try playing it through the plexi-style or IM settings, or the rythm tone for the T-struck...they're outstanding, Impressive !
Convention creates following, following creates convention.

tednet

Re: Infinity: an universal guitar preamplifier!
« Reply #18 on: March 07, 2009, 06:58:09 AM »
pure awesome :)

also, if it's not too much trouble, could you post the parts list  ;D

punkin

Re: Infinity: an universal guitar preamplifier!
« Reply #19 on: March 07, 2009, 03:09:04 PM »
Wow! Cool...BUMP!

That's at the top of my list of "must-build" list. I'm thinking a 1 RU rack unit enclosure with a rotary/switchable tone stack and an effects loop.
Ernie Ball Music Man - JPM, THD Univalve, Grace Big Daddy, PepperShredder, BSIAB2, FireFly Amplifier.