My DIY IIc+ preamp (build plans for PCB available)

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bancika

bancika

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Finished it a couple of days ago. It's only lead channel of the preamp with some switching omitted and few changes. No EQ as I'll use the EQ pedal.

Here's a gut shot

full_guts.jpg


A couple of clips

http://www.diy-fever.com/wordpress/wp-content/uploads/2010/09/mark_iic_lead_1.mp3
http://www.diy-fever.com/wordpress/wp-content/uploads/2010/09/mark_iic_lead_2.mp3
http://www.diy-fever.com/wordpress/wp-content/uploads/2010/09/markIIc_rhythm.mp3

and web page with more info

http://diy-fever.com/amps/mesa-mark-iic-preamp/

Here's the board layout http://diy-fever.com/temp/iic+i_full.pdf
And toner transfer mask http://diy-fever.com/temp/iic+i_trace.pdf

Cheers,
Bane
 
Sounds good, albeit, a bit too dark. Now all you need is a DIY Simul Class power amp, and you're set! 8)
 
Great sounding preamp!!! Got to admire someone that dives in and does it themselves. You should keep the group informed of any tweeks you do and the results.
 
Thanks!
There are a few tweaks, but all are listed on the website. One of them is that I got rid of electrolytic capacitors altogether. That's why those filter caps are so huge, they are poly film which means they won't dry out after a couple of years and will perform better sonically, as electros are the worst caps there are :) Most of the capacitors in the signal path are paper-in-oil. Also, I converted the last stage to a buffer to drive the effects better. There are a few component value changes but nothing major.
I did a very similar thing with soldano/recto preamp a few months ago, if anyone's interested http://diy-fever.com/amps/black-box/
Cheers
 
Absolutley fantastic! I'm jealous beyond belief and hope to have time some day to do the same.
 
Thanks guys!
I'm working on a PCB which makes it easy for inexperienced builders to make it without much trouble. I'll post build plans and etch transfer when it's ready and tested. It will have both channels, for versatility.
Cheers
 
You did a great job on that first preamp. I have also been following your website and several other posters at slocloneforums. I can't wait to see your PCB build as I'm very interested in building one!
 
Recorded a clip today that shows some higher gain settings (80-90%)

http://www.youtube.com/watch?v=AmIzyH_9F-s

There are few mistakes here and there, but who cares :)

Cheers,
Bane
 
Thanks guys! Tomorrow I'll order a PCB prototype for the two channel version. If it sounds as good as this perf board prototype I'll release the layout to public together with the BOM and other info. There are several people waiting for it to start their own builds.

Cheers,
Bane
 
Tnx!
I still haven't got the board but I got a report of a successful build from somebody else, so I figure it's ok to post.

Here's the board layout http://diy-fever.com/temp/iic+i_full.pdf
And toner transfer mask http://diy-fever.com/temp/iic+i_trace.pdf

Everything is in scale and correct orientation (no need to mirror trace mask and do not use "fit to page" when printing).
Other than stuff shown on the board, you'll need a transformer with 300V@40mA min and low voltage secondary for heaters and switching (either 12.6 or 6.3V). I ordered a custom tranny so I had a luxury of getting separate secondaries (6.3V for heaters and 12V for switching), but it will work with a common LV secondary.

Clean/lead switch is shown as a panel mount switch, but you can do footswitch as well, just wire it in parallel with (or instead of) the panel switch. Switching is done with relays, so you can do it remotely.

Let me know if you need more details.

Cheers,
Bane
 

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