Where to post original design schematics

[Fancy Lime]

Hello everyone,

I am new to the forum and already making mistakes. I posted an original schematic I developed in the "Schematics & Layouts" subforum:

http://www.diystompboxes.com/smfforum/index.php?topic=118341.0

which is apparently the wrong place for that (thanks Hatredman for the hint). I could not find a subforum whose name or subtitle sounds like original schematics belong there. Am i missing something? If it does not exist yet, anyone else for starting it? I have a bunch of original designs lying around that I really like and I think others might too. Well as original as it reasonably gets without reinventing the transistor, you know what I mean. Not clones or modified clones, in any case. I'd like to post those where people will actually find them.

Thanks and Cheers,
Andy


EDIT: The post has now been moved to the Building your own Stompbox subforum. Thanks to the editor for that and thanks to duck_arse for the suggestion to ask for this!

[KarenColumbo]

AFAIK this here is the best place to post original ideas. And this one is excellent

[swever]

Hello Andy!

That design of yours looks really interesting and tempting! Since I am currently hunting for a bass overdrive, I will definitely try it out.

Do you think I would work well with dry signal mixed in parallel? Should I expect phase issues?

Anyway, welcome and thank you for sharing your work!

[Fancy Lime]

Hi Alexander,

thanks! You could add a clean path for mixing wit the overdriven signal. The best way to do this would probably be to add a buffer on the input (can be designed just like the output buffer Q4), split the signal after that and then reunite the two with a blend pot before the output buffer Q4. The only inverting stages are Q1 and Q2, so as long as you take the clean signal before Q1 and merge the two paths after Q2 you should be ok in terms of phase issues at fundamental frequencies.

However, I don't think that that is necessary. First of all, the Eemu Preamp does not have very much gain. Secondly, the first stage is designed to increase the mids and highs much more than the bass when the Gain Control is cranked up. That means that the low frequencies stay a bit more dynamic and do not get mushy whereas the higher frequencies are more overdriven. The mid and treble controls can be used to fine-adjust this. The resulting sound is quite similar to a dual signal path, where only the mids and highs are overdriven and then mixed with a more or less clean and only somewhat compressed bass.

But if you are looking for a bass overdrive, the whole thing may not be the best choice. It sounds quite good when driven hard but the gain is limited and it is not very versatile. It really shines when used as an "almost overdrive". I have an interesting bass fuzz schematic lying around which I will upload as soon as I find the time to make it pretty and check it for errors. I also have a dedicated tube sound overdrive on my breadboard, which I think sounds absolutely fantastic and is extremely versatile (has a very similar 3-band eq as the Eemu preamp) but still needs a bit of tweaking. But that will also come sometime in the next weeks.

Cheers,
Andy

[KarenColumbo]

Aaaaand ..... just ordered a buncha BS250ies

[swever]

So did I

[Fancy Lime]

@ Andreas and Alexander

I'm glad you like it! In my experience, the BS250 is an almost criminally underrated replacement for the much-loved BS170, especially in gainy circuits. With just a few changes you can redesign any BS170 boost or overdrive pedal to use a p-channel MOSFET like the BS250 instead and get much less noise. I also think it sounds a bit better but that may be my imagination, I never conducted any controlled environment A-B testing.

Cheers,
Andy

[swever]

That sounds really interesting, Andy. My idea was not to add a clean blend to the circuit, but rather to use it in conjunction with ROG splitter-blend as a separate box – modularity and versatility ftw

And yes, I am not really looking for a very high gain overdrive. Basically my idea is to simulate the bi-amping/di+amp/layering recording techinques that they use to make the modern metal bass tones – but "in-a-box" and through one relatively clean amp. In fact, my bass playing friend asked me to build a box for him that would get him closer to the 90-00's metal tones (think metallica, pantera) that have a big, open and clean low end, but also have the clang and sparkle, suitable for fast playing in low register and low tuning. Regular guitar-oriented od/dist/fuzz cictuits usually sound choked and mushy with bass, in my experience at least. Judging by your description, Eemu may get me there without resorting to mixing dry signal. Will let you know in a while when I build it 

A tube sound bass OD sounds like something I would defenitely like to try, so I'll be waiting for the schematic. Will it also be p-channel mosfet BS250 based?

[Fancy Lime]

@ Alexander

What you are describing sounds very much like the (very expensive) Alpha-Omega by Darkglass Electronics. I think you might like my upcoming bass overdrive. it does not use BS250s. Instead there is an op-amp stage first which uses BS170 as clipping diodes for a soft, fat, triode-like overdrive, followed by two CD4069 stages for a more direct, dynamic, rough and dirty overdrive (like in Craig Andertons legendary tube-sound-fuzz), that actually sounds quite similar to an overdriven BS250. Both stages have individual gain knobs for maximum control. But I am also toying with the idea to replace the op-amp stage with a BS250 stage and adding adjustable Russian-Muff clipping diodes to one of the CD4069 stages for a heavier sludge metal or stoner rock tone. But that will probably end up a different pedal. We'll see.

For the metal-bass-layering: A friend of mine once worked as a sound tech for a Motörhead cover band. With Rickenbacker basses you can send the two pickups to different amps using a stereo cable. The bass player played the neck pickup through a PA-sytsem 18" Woofer he had on stage and the bridge pickup through a Marshall guitar full stack. I was not there myself but the description sounds quite impressive.

Cheers,
Andy

p.s. I will also upload the Adrenochrome Fuzz in a minute. Found the schematic and cleaned it up. Great for Bass too, but rather "special".