Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Preamps and Effects => Topic started by: danV on October 18, 2008, 05:08:21 PM

Title: An universal guitar preamp
Post by: danV on October 18, 2008, 05:08:21 PM
Hi all!

Enter Infinity, a guitar preamp offering great sound versatility, from clean to heavy distortion. It can be used for DI applications (in conjuction with the PA and a monitor), and for recording. A short presentation can be downloaded here (http://www.techniguitare.com/projets/ChaosPreamp/infinity_en.pdf).

(http://img413.imageshack.us/img413/8393/endoff.jpg)

 :) Samples
A Youtube video of first prototype, and containing some samples (direct recording to the PC soundcard): Here! (http://de.youtube.com/watch?v=BRB0erDUqHU)
Other samples:
- Here! (http://www.techniguitare.com/projets/ChaosPreamp/vox_mix.mp3) for a Vox style.
- Here! (http://www.techniguitare.com/projets/ChaosPreamp/pink_floyd_comfortably_numb_mix_delay.mp3) for Pink Floyd's Comfortably Numb (delay was added through Audacity).
- Here! (http://www.techniguitare.com/projets/ChaosPreamp/im_aces.mp3) for "Two minutes to 2h in the morning" (since I recorded it at 2AM), Iron Maiden style.
- Here! (http://www.techniguitare.com/projets/ChaosPreamp/plexi_uh_mix.mp3) for a Plexi style.
- Here! (http://www.techniguitare.com/projets/ChaosPreamp/inf_thunderstruck.mp3) for "Thunderstruck", AC/DC style
- Here! (http://www.techniguitare.com/projets/ChaosPreamp/inf_sharpdressedman.mp3) for "Sharp Dressed Man", ZZ Top style.

 :) Files
The latest schematics of Infinity (V1.1) are here! (http://www.techniguitare.com/projets/ChaosPreamp/Preamp-Schems-V1.1-En.pdf)
And the parts layout: (http://img155.imageshack.us/img155/6181/infinitypcblayoutjd8.th.gif) (http://img155.imageshack.us/my.php?image=infinitypcblayoutjd8.gif)
The .pdf format is here! (http://www.techniguitare.com/projets/ChaosPreamp/guitar_preamp.pdf)

 :) Building pictorial

Here (http://www.techniguitare.com/projets/ChaosPreamp/infinity_photos.zip) is a .zip file with all the photos ( size 4,73Mo).

The prototypes:
(http://img102.imageshack.us/img102/5963/proto00om4.th.jpg) (http://img102.imageshack.us/my.php?image=proto00om4.jpg)(http://img125.imageshack.us/img125/8772/proto01aic6.th.jpg) (http://img125.imageshack.us/my.php?image=proto01aic6.jpg) (http://img4.imageshack.us/img4/7449/proto01bvp3.th.jpg) (http://img4.imageshack.us/my.php?image=proto01bvp3.jpg)

The final version:
(http://img338.imageshack.us/img338/5919/pcballyl6.th.jpg) (http://img338.imageshack.us/my.php?image=pcballyl6.jpg) (http://img440.imageshack.us/img440/9508/pcbmainij9.th.jpg) (http://img440.imageshack.us/my.php?image=pcbmainij9.jpg) (http://img101.imageshack.us/img101/6306/pcbpsuld9.th.jpg) (http://img101.imageshack.us/my.php?image=pcbpsuld9.jpg) (http://img440.imageshack.us/img440/9733/pcbpsumountvw8.th.jpg) (http://img440.imageshack.us/my.php?image=pcbpsumountvw8.jpg) (http://img407.imageshack.us/img407/8207/boxfrontox5.th.jpg) (http://img407.imageshack.us/my.php?image=boxfrontox5.jpg) (http://img443.imageshack.us/img443/2717/boxrearxa1.th.jpg) (http://img443.imageshack.us/my.php?image=boxrearxa1.jpg) (http://img186.imageshack.us/img186/5934/pcbmainjumpersrk3.th.jpg) (http://img186.imageshack.us/my.php?image=pcbmainjumpersrk3.jpg) (http://img19.imageshack.us/img19/1853/pcbmainresvk7.th.jpg) (http://img19.imageshack.us/my.php?image=pcbmainresvk7.jpg) (http://img24.imageshack.us/img24/1703/pcbmainsocketsnr6.th.jpg) (http://img24.imageshack.us/my.php?image=pcbmainsocketsnr6.jpg) (http://img26.imageshack.us/img26/5930/pcbmainfullfronthw0.th.jpg) (http://img26.imageshack.us/my.php?image=pcbmainfullfronthw0.jpg) (http://img25.imageshack.us/img25/6856/pcbmainfullrearlu0.th.jpg) (http://img25.imageshack.us/my.php?image=pcbmainfullrearlu0.jpg) (http://img100.imageshack.us/img100/588/pcballmountzy6.th.jpg) (http://img100.imageshack.us/my.php?image=pcballmountzy6.jpg) (http://img172.imageshack.us/img172/2782/wiringoffboard1cd0.th.jpg) (http://img172.imageshack.us/my.php?image=wiringoffboard1cd0.jpg) (http://img223.imageshack.us/img223/8213/wiringoffboard2ku0.th.jpg) (http://img223.imageshack.us/my.php?image=wiringoffboard2ku0.jpg) (http://img5.imageshack.us/img5/8501/wiringbox1dm3.th.jpg) (http://img5.imageshack.us/my.php?image=wiringbox1dm3.jpg) (http://img5.imageshack.us/img5/2667/wiringbox2os9.th.jpg) (http://img5.imageshack.us/my.php?image=wiringbox2os9.jpg) (http://img18.imageshack.us/img18/5773/wiringbox3nz7.th.jpg) (http://img18.imageshack.us/my.php?image=wiringbox3nz7.jpg) (http://img19.imageshack.us/img19/6941/wiringpcball1.th.jpg) (http://img19.imageshack.us/my.php?image=wiringpcball1.jpg) (http://img24.imageshack.us/img24/9020/wiringpcball2.th.jpg) (http://img24.imageshack.us/my.php?image=wiringpcball2.jpg) (http://img26.imageshack.us/img26/5381/wiringpcbpsu.th.jpg) (http://img26.imageshack.us/my.php?image=wiringpcbpsu.jpg) (http://img27.imageshack.us/img27/8426/wiringjack.th.jpg) (http://img27.imageshack.us/my.php?image=wiringjack.jpg) (http://img100.imageshack.us/img100/3306/wiringled.th.jpg) (http://img100.imageshack.us/my.php?image=wiringled.jpg) (http://img153.imageshack.us/img153/3040/wiringcompletezj4.th.jpg) (http://img153.imageshack.us/my.php?image=wiringcompletezj4.jpg) (http://img413.imageshack.us/img413/8393/endoff.th.jpg) (http://img413.imageshack.us/my.php?image=endoff.jpg) (http://img527.imageshack.us/img527/9028/endon.th.jpg) (http://img527.imageshack.us/my.php?image=endon.jpg)

Enjoy!  :)
Title: Re: An universal guitar preamp
Post by: danV on November 24, 2008, 05:31:12 PM
400 views and no comment  :-[

Anyway, here are 2 pics of the new prototype:
(http://img155.imageshack.us/img155/804/cmpsidewe7.png)
(http://img529.imageshack.us/img529/6927/coppersideqf1.png)

A layout will be ready soon ...

 :tu:
Title: Re: An universal guitar preamp
Post by: syndromet on November 26, 2008, 02:50:32 AM
Looks and sounds great! Too many knobs for my liking, but it looks great.
Title: Re: An universal guitar preamp
Post by: Robin755 on November 27, 2008, 03:39:15 PM
Very nice work dude!
Title: Re: An universal guitar preamp
Post by: danV on November 28, 2008, 04:39:43 PM
Thanks!

I've finished the layout, and my PCBs will be probably made in 1-2 weeks.

About the number of pots, I would have liked to reduce it to 7 (without the bass control in the pre-equalizer), however fuzz tones and fine-tuning in the sound (especially for the samples of Scorpions and Dire Straits songs) would not be available anymore.
Title: Re: An universal guitar preamp
Post by: Streel on January 04, 2009, 01:13:47 PM
This preamp sounded great,wow I like this. Excellent controls and design. Very nice! Definitely on my project list to build. And very good video too, very good job.
Title: Re: An universal guitar preamp
Post by: STDog on January 04, 2009, 07:30:58 PM
Nice. A lot of sounds from that thing.

What would the parts to reproduce it run? (not counting the PCB or chassis).

Problem with so many variable is getting it to sound like something. I could turn nobs all day and never find the sound I'm looking for.
I've tried it with some other amps. Someone that know what they are doing comes over and in 2 minutes has the right sound for a given style/song. Then a few tweaks and it's sounding like a whole different amp.

More knobs and I'm even less likely to get anywhere.  :'(
Title: Re: An universal guitar preamp
Post by: zyggurat on January 27, 2009, 08:11:02 PM
Awesome! That´s what I´ve been looking for ! It´s really UNIVERSAL  8| I´ve got only one question  - what opamps have you used ???
Title: Re: An universal guitar preamp
Post by: danV on February 04, 2009, 02:32:15 AM
Thanks for the replies, and sorry for answering a bit late ...

anyway, the opamps are 2 TL074 and a TL072. You can use other ones, such as the TL06x or the TL08x.

I recorded a few other samples, sorry for the uninspired / bad playing:
- Here (http://www.techniguitare.com/projets/ChaosPreamp/vox_mix.mp3) for a Voxxy style.
- Here (http://www.techniguitare.com/projets/ChaosPreamp/pink_floyd_comfortably_numb_mix_delay.mp3) for the 2ns solo of Comfortably Numb (delay was added through Audacity).

I also did a new version of the schematics, since there were 2 mistakes in the component values:Here (http://www.techniguitare.com/projets/ChaosPreamp/Preamp-Schems-V1.1-En.pdf)

Now I'm working on a tutorial, and I hope to receive my PCBs soon. I have also decided to make a full opamp version, in order to avoid the biasing and selecting of the JFETs, and enable more PSU flexibility, mostly for switching in multi-channel configurations.
Title: Re: An universal guitar preamp
Post by: spraguetr on March 15, 2009, 04:28:02 PM
This looks pretty interesting and I like the combination of sounds so far.

I have a 13 Y.O. son - plays better than me ?;>) with a Roland Cube 15.  I have an old Marshall Lead 12/5005.  I'm thinking of doing some DIY amps to give both of us an upgrade on our equipment and keep us in a budget.  This looks like a good front end for a power amp built around an LM3886 sitting on a 2 x 12 case (or 2).

Great work - and thanks!
Title: Re: An universal guitar preamp
Post by: rogeryu on March 18, 2009, 09:22:03 AM
Hi all!

It's been a long time since I posted here ::). Anyway, I worked a bit and came up with this ... a Universal Guitar Preamp!  :tu:

It is based on a BSIAB II distortion stompbox, with a redesigned output filter section. I added (simple) pre- and post-equalizers for some extreme sound flexibility. The post-equalizer has also a tunable cabinet simulator included. The preamplifier can be used for recording, or for DI applications.

Here's a video with photos, and, more importantly, some samples.
http://de.youtube.com/watch?v=BRB0erDUqHU

Schematics are here:
http://www.techniguitare.com/projets/ChaosPreamp/Preampli-Schems-En.pdf

Enjoy!  :)

Hey Sebastian a.k.a DSV  8|, remember me rogeryu  :) Nice to see you also hear in this forum.... Great work pal...
Title: Re: An universal guitar preamp
Post by: spraguetr on March 20, 2009, 11:20:08 AM
Thanks for the replies, and sorry for answering a bit late ...

anyway, the opamps are 2 TL074 and a TL072. You can use other ones, such as the TL06x or the TL08x.

I recorded a few other samples, sorry for the uninspired / bad playing:
- Here (http://www.techniguitare.com/projets/ChaosPreamp/vox_mix.mp3) for a Voxxy style.
- Here (http://www.techniguitare.com/projets/ChaosPreamp/pink_floyd_comfortably_numb_mix_delay.mp3) for the 2ns solo of Comfortably Numb (delay was added through Audacity).

I also did a new version of the schematics, since there were 2 mistakes in the component values:Here (http://www.techniguitare.com/projets/ChaosPreamp/Preamp-Schems-V1.1-En.pdf)

Now I'm working on a tutorial, and I hope to receive my PCBs soon. I have also decided to make a full opamp version, in order to avoid the biasing and selecting of the JFETs, and enable more PSU flexibility, mostly for switching in multi-channel configurations.

I have a question for you - I noticed your schematic and the one BSIAB2 are identical near the 5th JFET (2N5457) trimpot.  I also noted that your board artwork has the center wiper tied to +9V leg of the pot instead of the leg going to the JFET.  Probably not much difference, but did it have an impact on the JFET bias voltage? 
Title: Re: An universal guitar preamp
Post by: danV on March 21, 2009, 04:13:14 AM
I completely forgot to update this thread  ::)

Hi rogeryu. Name's Daniele!  ;)

Hi spraguetr! The old schems have got 2 little errors: a capacitor in the output filters, and the source resistor of the 5th jfet. I'll update the 1st post with all the new info!
Title: Re: An universal guitar preamp
Post by: danV on March 24, 2009, 08:15:05 PM
1st post is now updated with the .pdf version of the layout.  :)
Title: Re: An universal guitar preamp
Post by: rogeryu on March 25, 2009, 06:15:21 AM
I completely forgot to update this thread  ::)

Hi rogeryu. Name's Daniele!  ;)

Hi spraguetr! The old schems have got 2 little errors: a capacitor in the output filters, and the source resistor of the 5th jfet. I'll update the 1st post with all the new info!

ugh! :loco Sorry Daniele, i thought somebody else. Anyway I'm also with Diystompboxes and I read your thread same here. Great job buddy  :tu:
Title: Re: An universal guitar preamp
Post by: iakirov on April 11, 2009, 12:33:48 PM
Hey great preamp, I'll give it a try as a part of a combo amp, I hope to do it soon, I'll tell you about it then.
Thanx for it!
Title: Re: An universal guitar preamp
Post by: wadehavens on May 24, 2009, 05:32:09 AM
Hi there! I've been working on building a guitar amp out of a chip I pulled out of a car stereo when I came across this thread. I listened to the sample mp3's and I was very impressed, so I decided to build this preamp.

I must say, this is the most awesome sounding DIY project I've built yet. This preamp can sound like almost anything you want it to. It's somewhat difficult to dial in specific tones, and you can get lost very easily, but once you learn the controls it's not very hard at all start enjoying the lovely sounds this baby can make.

There is one thing that I find puzzling though.
There aren't any directions on how to hook up the switch, so I had to spend some time looking at the schematic to figure it out. I'm pretty sure I have everything hooked up right, however, there's not much of a difference between any of the switch settings. I'm thinking that either I have the caps on the switch hooked up wrong, or the switch is not needed at all. I have to note that I'm connecting it to a chip amplifier and that may have something to do with it since it was meant to be a DI box. Any help with this would be greatly appreciated!
This is an absolute must build for EVERYONE. You will be amazed! Thanks for this!!
Title: Re: An universal guitar preamp
Post by: off1 on May 30, 2009, 02:28:19 PM
This one looks great!!

I only have a question. If I set the drive knob all the way down, will I get a really clean sound?  Coz I'm planning to use it sometimes with my external effects and I don't want any distortion from the preamp when that happens.


Congrats for such a complete preamp!
Title: Re: An universal guitar preamp
Post by: wadehavens on May 31, 2009, 03:20:18 PM
This one looks great!!

I only have a question. If I set the drive knob all the way down, will I get a really clean sound?  Coz I'm planning to use it sometimes with my external effects and I don't want any distortion from the preamp when that happens.


Congrats for such a complete preamp!


If you want a really clean channel this preamp is not for you. It does get clean, but never completly clean. It always has a small amount of distortion. At least thats my experience with the one I built. However, if you build this from scratch (using the schematic and not the current layout) you can include a switch to bypass the distortion section and it should clean up very nicely. If I were to build it again, that's what I would do.

Wade
Title: Re: An universal guitar preamp
Post by: off1 on May 31, 2009, 03:59:49 PM
Thanx Wade! that really clarified my concern.

Here's another question. I've always avoided using FET's in my projects coz I've heard it's like tossing a coin; they are very unreliable, sometimes they work but sometimes they don't.   What is your experience with these?


THANX AGAIN

Title: Re: An universal guitar preamp
Post by: wadehavens on May 31, 2009, 07:50:28 PM
Well, I'm not an expert by any means, but almost everything I've built has at least one FET somewhere, and I've never had any reliability problems. The only thing I've noticed is that some projects including the J201 sometimes have the pinouts wrong depending on the FETS manufacturer. As a mater of fact, I didn't even use J201's in this project since I couldn't get any localy. Instead I used a pair of 2SK55's that I found in an old cable box, and those pinouts were 180 degrees off. I'm not sure if these made any significant difference, but I love the way mine sounds. It is a little noisy though. But I expect that from a very high gain preamp. 

If nothing else, this preamp is proof that you 'can' get just about any distorted sound out of a solid state project.
Title: Re: An universal guitar preamp
Post by: off1 on May 31, 2009, 11:30:15 PM
Thank you man!!!