freestompboxes.org

Hey,

Amazing job guys, impressive !!
do you think you can share gerber files ?

Sorry, I have no Gerber files to share

I've bought a secondhand SCF (serial number 021995 which I believe is one of the earlier ones?) and there's a problem with it:

When Bypass is enabled, the output from the 'mono' channel is 23dB lower than the 'stereo' channel. I've got a basic understanding of electronics, but this schematic is a bit beyond me! Can anyone suggest what the problem might be?

Furthermore, when not bypassed, the signal level of both channels (although both roughly the same) is 8dB higher than the 'stereo' channel when bypassed - is this normal?

It's a great sounding device and I'd love to get it working properly. Thank you!

Problem solved. I was using balanced cables on the unbalanced outs from the SCF. Schoolboy error.

jdub wrote: ↑10 May 2020, 01:33Not gonna lie, this is definitely not an easy build, and I undertook it simply for the challenge- if you want to do it for the effect itself, you might be better off buying one.

To be frank, it's exactly what I did after having ripped the circuit : I spent a very long time just doing the rip, actually hand drawn a PCB that was partly populated, but... I had a serious health issue and needed surgery that stuck me at the hosptal for 3 weeks... The, my mother and cousin decided to make me a favour, taking profit of my absence of my place, because, you know, the wallpaper had long turned from white to yellow-brown, so they decided to change this despite I told my mum : "No way, I have jobs at works, you will do a mess"... As they will always do the contrary of what we ask them, well, both came, and did put all the PCBs, parts and gear around into cardboard boxes. There were about 40 apparatus being built at the same time, added with a dozen+ machines being here for repairs, and probably about 10-20k parts ending mixed...
Well, they simply f-ed up my little business, at the same time of all my posters from 80's magazines, the only one that survived being Hendrix as this one was under glass... It took me 8 months to find back where the original SCF was hiding, had to ask a friend to take over the repairs, lost my clients, my O-scope was f-ed up too...
Nonetheless I had no more courage to try to finish my SCF build, but with the thousand and thousands of parts mixed with unfinished projects, cables etc, never had the courage to sort it all or to finish anything that was started before and never recovered from the blow.

Conclusion : if you let your mum with a key of your place in case of emergency, remember to keep your lab locked! I was 36y old then and couldn't believe she dared to do this to me... Moreover, the new wallpaper was freaking ugly and the job poorly done...

I had a bunch of tube amps, an old Atari 2600 and games, my old MSX computer stored at my fathers place, all vanished, unfortunately...... A few things that he himself had bought me as a kid, and remembered were "expensive" I do stil have, but yeah. Luckily they are just things.

But given the prices SCF's fetch these days, makes more and more sense to build yourself. I think I sold mine for about 100 euros, 6-7 years ago, but I saw one being offered for 250 euros now, in the same state mine was ("well used").

Did anyone try and respin the boards using surface mount components and double sided? I think that would make the build easier, seems to be quite a tight fit now.

Hello everyone. I have corrected the scheme given earlier. Use it with pleasure.

I have found some mistakes on schematic, see red circles on it:
https://www.dropbox.com/s/1fkfnx1pwjztf ... s.JPG?dl=0

Thanks for taking the time to check the schematic. I will fix it and post it here later tonight.

I Think I got them all... thanks again!!
EDIT : Fixed the pinout of the LM339. I added a LM393 in one of my layouts to try and see if I could make the routing easier. I don't think it helped much...lol Lani

Corrected version 1.2, after building and checking proto.

Are you saying you have built a working unit from this schematic? If so I will start working on a PCB to share with everyone.

Sprintlayout files:
https://www.dropbox.com/s/8pfr1gxcm4lv5 ... .lay6?dl=0
https://www.dropbox.com/s/ncf1dt8rx0v9f ... .lay6?dl=0
This work was initiated by dimebuGG.

jazzade wrote: ↑11 Apr 2021, 12:24 I've bought a secondhand SCF (serial number 021995 which I believe is one of the earlier ones?) and there's a problem with it:

When Bypass is enabled, the output from the 'mono' channel is 23dB lower than the 'stereo' channel. I've got a basic understanding of electronics, but this schematic is a bit beyond me! Can anyone suggest what the problem might be?

Furthermore, when not bypassed, the signal level of both channels (although both roughly the same) is 8dB higher than the 'stereo' channel when bypassed - is this normal?

It's a great sounding device and I'd love to get it working properly. Thank you!

I have a similar problem
The mono side has a lower volume both when off and on

Is this normal?

#107916 serial

?