Son of Screamer - my first ever perf build

[thermionix]

Hey, it actually works!  And sounds pretty good to boot.  Other than a few slightly different caps, I followed this schematic:

http://www.muzique.com/tech/scream.htm

About 5 minutes into it I was swearing I'd never use perf again, but by the time I finished I was enjoying it pretty well.  Gonna try a 100k volume pot because I've seen others use that, maybe a few other experiments before I box it up.  I have a TL072 in now, will try other types.

Pretty cool pedal for sure, sounds like a TS but not exactly any particular one I've used before.  Nice and simple, good circuit for a first perfboard attempt I reckon.

A little sloppy, but cut me some slack, it was my first time and I was using a 1/8" screwdriver tip, not the best choice for this type of work.

[GibsonGM]

Good job, man! That's how I do all of my stuff.  ALL of it.  You get used to it.  That's not messy at all! 

If you keep using it, you'll get faster, and may forget what making PCB's is all about, ha ha....I like that I can grab my crap and make something like that in an hour instead of a weekend...

[amz-fx]

Nice perf build. Good job!

Best regards, Jack

[thermionix]

Thanks.  I've never made a PCB, don't have the stuff.  Don't even own a printer!  I've built a couple kits, but all of my "from scratch" builds previously have been on eyelet boards or terminal strips.  Simple circuits with discrete components, obviously.

[Ben Lyman]

Looks great to me, better than my first, that's for sure. In no time at all you will have the hang of it.
I made this Green Ringer in about an hour from DIYLC design to final soldering. Only 10 unused pads! 

[GibsonGM]

Those are both way too neat! 

[thermionix]

Just an update for anyone playing along at home.

I mentioned in the OP that I used a few slightly different caps compared to the AMZ schematic.  Well to be specific, I used a 51p instead of 47p in the feedback loop, for that Original TS Mojo, and surely it makes no audible difference anyway.  I used a 63u instead of 47u on the Vr, because I had that on hand, and though the math changes somewhat, I don't think it matters in this case.  Lastly I screwed up ordering parts and only got one 47n when I needed two, so for the input cap I grabbed what was near me on the bench, a 56n.  Close enough, right?

I said that it sounded good and very tube screamer-like, and it did, but I also knew there was some experimenting to do.  The sound was just a bit what I would call "flubby."  Pretty minor, but a certain lack of definition on the low strings.  Like it had a little too much low end up front that was bottlenecking somewhere and not making it through, if that makes any sense.  I figured this might be the result of different impedance relationships due to the lack of in and out buffers.  Nature of the circuit, maybe.

A few more seconds of digging around on the bench and I found a suitable 47n, so just to be on the safe side, I changed the input cap.  As expected, didn't sound any different.  I also switched the volume pot from 10k to 100k, and if there's any sonic difference there, it's extremely subtle and I can't hear it.

Last thing to try was swapping out the opamp.  First one I grabbed was an old RC4558P, I have a stash of those I robbed out of a 1980 Peavey Deuce.

Fired it up and...DING!  There it is!  That was the missing piece of the puzzle for sure.  Now it sounds like the smoothest 808 I've ever heard, and I used to own a primo original some years ago.  It's super creamy and at full gain the sound stays together and defined, no more flubby low strings.  I couldn't be happier, it's the perfect tube screamer sound to my ears.  Not even gonna try other opamps.

I have an enclosure and related bits on the way from Small Bear.  I got most of the components from them too, and finally got around to trying their #24 pre-bond wire.  Can't recommend that stuff enough, it's just perfect for pedal building.  The insulation is great, it strips easily and doesn't melt so bad like some other types out there.

I will post pics when done.  It's gonna be very, very orange.  Orange box, orange knobs, orange LED.  No, it's not a Donald Trump endorsement, just that I don't yet have any orange pedals.

[287m]

as a perfboarder, im in right gig when see guts of perf 

nice build Thermionix and Ben, love it

[bool]

... Only 10 unused pads! ...

.... a really good job at that!

(personally I care less for unused pads on the "traces" side compared to unused space at the perf's "component side" -  I'm pretty obsessive at the latter; I find this translates to a final PCB layout pretty well)

[duck_arse]

I'm with 287 and gibson on the nice looking builds. I'm with bool on holes uncovered by parts: it hurts so much to see the waste.

sorry therm, I don't have any orange gags for you.

[Ben Lyman]

...I care less for unused pads on the "traces" side compared to unused space at the perf's "component side"...

Yes, I tried, sorry I didn't take pix as I built it, I was concentrating very hard on recycling this very old 1590A that was already drilled out, it was hard for me to fit everything. Here's a bad "screen shot" of my layout though 
BTW Duck, you see them thar yeller 47n's?


Sorry for the Hi-Jack Therm. Back to the SOS:
Where else can we get the magic opamps? Are the oop?

[thermionix]

Sorry for the Hi-Jack Therm. Back to the SOS:
Where else can we get the magic opamps? Are the oop?

No worries about hi-jacking, I'm the worst for doing that to other folks' threads.

Nothing special about the opamp, it's just the Texas Instruments version of the 4558.  They're still made, and I don't hear any difference between new ones and old ones.  I just used an old one because I had it.  They do sound just a bit different than the JRC version.  Vintage Tube Screamers usually came with the JRC, but sometimes the TI, so both are "correct" for repros.

The AMZ page doesn't suggest the 4558 for the SoS.  Not sure why.  I was wondering if it had some impedance issue that made it a poor choice for use without the buffers, but no, it sounds awesome.  What's kind of weird about all this is that my other TS pedal is an exact clone with the buffers, but I could never get it to sound as close to my old 808 as this stripped-down SoS does.

One other deviation I didn't mention before is clipping diodes.  I used Toshiba 1S1588s, which is one of at least four different types* found in vintage original TS808s and TS9s.  They are definitely part of the smoothness I'm hearing now.  I did quite a bit of experimenting in my other pedal using sockets, and different clippers create different distortion characteristics, even when they look very similar on the data sheets.  Panasonic MA150, one of the other original types, gives a cleaner, slightly edgier tone compared to the 1S1588s.

The unused holes don't bother me.  Kind of reminds me of the turret boards seen in the earlier plexi Marshalls, on a smaller scale of course.  I didn't spend much time on the layout, I'm sure it could be a little more efficient, I was just happy to have a useful circuit fit on the dinky little board that I bought impulsively at Radio Shack.  It's going into a 125B, so no problems with space.



*From my research, which consisted mostly of examining gut shots online, also reading whatever I could find on the subject, I see these clipping diodes in vintage units:

Skinny white band:  Panasonic MA150  (MA150 is the originally spec'd part in the Ibanez service manual)
Fat blue band:  Toshiba 1S1588
Skinny blue band:  I'm guessing Panasonic 1S1588
Skinny black band:  No idea

[bool]

... it hurts so much to see the waste. ...

Yep, but the "to-PCB" translation is usually easier with a properly squeezed prototype layout - at least with the smaller circuits. Actually, you can use the space you saved this way for a slightly fatter groundfill etc..

[Fndr8875]

I hate both of y'all,. Haha jk! Those both look great, can't believe that SoS was your first build. Congrats!

[thermionix]

As promised above, some "done" pics.  Looks like a big ol' piece of Halloween candy, don't it?  That wasn't intentional, pure coincidence.  I had some difficulty, somehow I managed to drill all the holes a couple mm to the right (Doh!) but I was able to correct that with needle files.  Washers cover the oblong holes, you would never know if I didn't tell you.  Not the neatest wiring job, but good enough, and still much less wire than the real ones.

No graphics or wall wart jack, as has become my MO.  The controls and jacks are arranged the same as a factory TS.  Knobs came with white indicator lines, I painted them black for better visibility.  Can't swear that I won't change them some day.

Fndr, this was my first perf build, but not my first build.  Maybe my 8th pedal build (including 2 kits), and I've been building tube amps for 20 years.