My homemade Mark IIc+ preamp

[bancika]

Hi yall,

Just wanted to share my latest creation. It's another IIc+, but this time I went for two-channel version using relays to switch channels. Also, I built it on PCB to make it easier to share the layout and inspire people to build their own

There are no electrolytics in signal path or power supply, only used some in relay supply. Also, I used two russian 6N2P-EV military equivalents of 12AX7 and one JJ ECC83 sandwiched in between (thus the socket adapter).

You can find schematic and PCB layout together with more pix here http://diy-fever.com/amps/mesa-mark-iic-pcb/





very quick clip with my Mini homemade LP (http://diy-fever.com/guitars/mini-les-paul/), will add more soon.



Still need to finish stained maple shell for the chassis, will be done soon, but it's fully functional.

Btw, there's plenty more clips from the first single-channel build here http://diy-fever.com/amps/mesa-mark-iic-preamp/

Greetings from Serbia and happy holidays

Bane

[Lazarus1140]

Re: My homemade Mark IIc+ preamp

Sweet!! Were you using any pedals other than the delay?

[bancika]

Re: My homemade Mark IIc+ preamp

Only MXR 10 band graphic EQ, set to relatively moderate V and some treble cut

[JOLLY]

Re: My homemade Mark IIc+ preamp

Nice job. That sounded great!!

[alteredbeast]

Re: My homemade Mark IIc+ preamp

Good work! Plus frank gambale licks!

[DankStar]

Re: My homemade Mark IIc+ preamp

wow, those are like huge batteries for testing? or are those the caps you're talking about (the big white cylinders)

sounds good! awesome you can slap that kinda stuff together.

what's wrong with electrolytics? I understand that after a few decades they might leak or whatnot, but that's a pretty long-term/down the road issue (and seemingly a minor one if you can do your own repairs).

[Toe-Knee]

Re: My homemade Mark IIc+ preamp

Hi Bane! That's some great work that you have done there. I am going to be starting a IIC+ after Christmas. Keep it up I always enjoy following your DIY exploits.

[zzmoore]

Re: My homemade Mark IIc+ preamp

If the Fender HRDlx had THAT PCB in it..... those amps would be a pleasure to work on.
Well Done

[bancika]

Re: My homemade Mark IIc+ preamp

thanks guys!
Those large capacitors are motor run poly film. What's wrong with electros, other than the fact that they have much shorter life span, is that they are much worse for audio, especially in signal path (often found in cathode bypass), but also in power supplies. One of the reasons is higher ESR than any, even the cheapest poly film. Another reason I use them is that I can't get fancy brands of electrolytics here, and even these motor run should perform better than any electro there...Now, maybe those imperfections are good for guitar, who knows

@zzmore, tnx, I put a lot of effort into the PCB layout. Too bad I didn't have it fabricated professionally, but it should be fine, I don't plan to mess around it too much. Good performance and low noise were the main design goals. Heater wiring is off-board, signal goes left->right, power supply right->left. AC is as far as possible from signal, grounding should be very good, etc.

[Surgeon]

Re: My homemade Mark IIc+ preamp

Awesome, I'M having a blast building pedals but an amp is in my near future... hopefully!
Great stuff!

[bancika]

Re: My homemade Mark IIc+ preamp

Uploaded one more clip

[bancika]

Re: My homemade Mark IIc+ preamp

And something a bit different, going back to my Blackmore roots It's RG into MXR Classic OD set to mild settings into cranked clean channel of my DIY IIc+ preamp and a touch of TC Nova Repeater