[NEW] Serge Resonant EQ for Euro by R*S

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lcf
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Post by lcf » Tue Apr 19, 2016 7:15 pm

Ok I build mine and tested it with VCFQ as a VCO, all the bands are working, it made crazy sounds with the feedback, more than I expected!!
The 29 band does not make a lot of bass but I have speakers that only go higher than 50hz.
So first question: is it normal?
Next I tried it with both Ipad and Focusrite soundcard to inject drums to check how it sounds with it but it made horrible larsens. The point beetween normal sound and larsen was 1/4 milimeter on the knob. I almost broke my speakers. :hihi: And it was impossible to get feedback through the 2 OUT, just COMB 1 and 2.
Is it an impedance problem please??

Thanks.

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ludotex
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Post by ludotex » Thu Apr 21, 2016 7:52 am

Finished builded one I got from Thonk. This is my second RandomSource Serge module (QVCF was first) and the same build and sound quality. Theses modules are some of my favorites so far. They just feel right sounding and I like the simple design of the faces and sturdy pots.

So what was going to be a demo of the module ended up in a pretty tune. Not so pretty when it goes into feedback territory though :banana:



[video][/video]
---
Latest patchings and experiments: https://www.youtube.com/user/plutotex/videos

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fluffymuff
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Post by fluffymuff » Thu Apr 21, 2016 9:12 am

That video has given me the final push to buy this thing... sounds amazing!

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Post by nikbee » Thu May 12, 2016 9:13 pm

sorry, im quite new at this and want to double check with you all before i order (again) from mouser..

does anyone have a mouser part number for an IC socket that fits the OPA2134PA?

also, is there a switch that fits? the one i got has legs that are too wide. i can cut them and wire it in i guess, but would prefer to have the correct part.

i think i have the rest covered, so far at least! really excited for this one..

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lcf
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Post by lcf » Thu May 12, 2016 10:37 pm

nikbee wrote:sorry, im quite new at this and want to double check with you all before i order (again) from mouser..

does anyone have a mouser part number for an IC socket that fits the OPA2134PA?

also, is there a switch that fits? the one i got has legs that are too wide. i can cut them and wire it in i guess, but would prefer to have the correct part.

i think i have the rest covered, so far at least! really excited for this one..
This socket would be the good one: http://www.mouser.fr/Search/ProductDeta ... 5-11043308

For the switche you can check here there is the mouser references with description of the two options available: http://randomsource.net/docs/RandomSour ... Q_Euro.pdf

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Post by DMR » Fri May 13, 2016 9:02 am

ludotex wrote: So what was going to be a demo of the module ended up in a pretty tune. Not so pretty when it goes into feedback territory though :banana:
This is great!

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Post by nikbee » Sun May 15, 2016 11:23 am

lcf wrote:
nikbee wrote:sorry, im quite new at this and want to double check with you all before i order (again) from mouser..

does anyone have a mouser part number for an IC socket that fits the OPA2134PA?

also, is there a switch that fits? the one i got has legs that are too wide. i can cut them and wire it in i guess, but would prefer to have the correct part.

i think i have the rest covered, so far at least! really excited for this one..
This socket would be the good one: http://www.mouser.fr/Search/ProductDeta ... 5-11043308

For the switche you can check here there is the mouser references with description of the two options available: http://randomsource.net/docs/RandomSour ... Q_Euro.pdf
thank you for the help!

both of the switches in the build guide PDF are out of stock. i ordered these two:

1) http://www.mouser.com/Search/ProductDet ... -200-C1121

2) http://www.mouser.com/Search/ProductDet ... 1-T103-001

i checked all measurements of these two against the ones in the build guide, and they should work. fingers crossed. will update when i receive them.

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HipDestroyer
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Post by HipDestroyer » Sun May 15, 2016 11:33 am

ludotex wrote:Finished builded one I got from Thonk. This is my second RandomSource Serge module (QVCF was first) and the same build and sound quality. Theses modules are some of my favorites so far. They just feel right sounding and I like the simple design of the faces and sturdy pots.

So what was going to be a demo of the module ended up in a pretty tune. Not so pretty when it goes into feedback territory though :banana:



[video][/video]
Really nice!

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neilbaldwin
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Post by neilbaldwin » Mon Jun 06, 2016 4:06 pm

Having problems with mine and have stepped away from it for the evening to give my eyes a rest! :)

With nothing plugged into the inputs, gain all the way down, feedback down, I get high pitched feedback from the outputs (all of them). Turning the 2.8K pot up has the greatest effect on the output but otherwise nothing affects it. Feeding a signal in (white noise) the high pitched tone is still present. If I turn the input gain all the way up it is diminished.

I'll go back and try again tomorrow but I wondered if anyone recognised this and could offer a pointer or two.

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Post by Kirr » Sun Jun 19, 2016 6:18 am

EarlJemmings wrote:So the BOM calls for either 100K or 50K pots- What's the difference? I notice the slider version used 50K, what're yall using?
Same question here. 100K should give more range and 50K more presicion, but which is better in this case?
thelizard wrote:Ahhh, the joys of sourcing parts.

At this point, anytime I need 1 resistor for a project, I order 10-20 on Tayda:
https://www.taydaelectronics.com/
I use them for all knobs, resistors, non-critical caps, ICs, headers, sockets, diodes, and transistors. If Tayda doesn't have the value (16.5k... damn you ResEQ!!), I'll order from Mouser.
Just substitute a missing resistor with two or three of those you have. Way cheaper than buying 1 or 2 from Mouser. (Although you don't necessarily get 0.1% error that way, if you combine 1% resistors). [plug]You can use Resistor Network Finder to find the best network[/plug]

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Post by PWM » Sun Jun 19, 2016 6:36 am

I used 50k's for my slider version and am very pleased with the response!

Kirr
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Post by Kirr » Tue Jul 05, 2016 9:57 am

I finally got around to finishing this build. PWM, thanks for the answer! I used 50k pots and it seems working perfectly.

First of all, this is simply a fantastic module of great utility. A resonant 10-band EQ says it all, but the actual module sounds even better than I imagined. Big thanks to Random Source for bringing this design to Euro format. Even bigger thanks for making it an easily manageable completely through-hole build, available as PCB+Panel.

Now, one potential issue new builders might want to know about: This module is a dog to solder (same like their VCFQ that I've build before). The thick ground plane surrounds ground pads closely, and the pads themselves are microscopic. When the iron tip is pressed against a component lead and a solder pad (ground plane), the pad really takes its time to heat up so that solder can flow on it. All the while, where do you think the 400 C heat goes? That's right - into your precious component, possibly frying it or making it out of spec. And if you hurry up or not pay close attention - you easily end up with cold joints. I am particularly anal about getting every joint perfect, but this might not be a suitable project for someone less meticulous. (This very thread has example pictures of absolutely horrible soldering of ResEQ board. Of course it's too easy to put all blame on the builder)

In your (or anyone else's for that matter) future designs, I really hope to see big-ass ground pads, separated from ground plane by wider gap and longer trace. Befaco goes as far as eliminating the ground plane entirely, replacing it with an ordinary trace - and it's a breeze to solder. I bet they correctly figured that fried components and cold joints leave much larger number of disappointed users, than any suboptimal performance resulting form thinner ground. For another example, see RYO Paths PCB (e.g. here) - every single ground pad is separated by a wide gap from the rest of the ground plane - big thumbs up and I'll be sure to try building more of their stuff.

Other than the issue above, the module is terrific! Please, more designs like this one in the future! I am not especially thrilled about buying PCB with a hundred of pre-soldered SMT parts, as it doesn't seem DIY to me anymore (i.e., not much different from buying a ready-made module). If you think some project really requires SMT, at least make the bare PCB available too. (Also, if you take requests, please bring more Hiable projects back to life in proper redesign in Euro format, starting with String filter). Recipe for success: Bare PCB + Panel, through hole, no wiring, no arcane NOS parts, IN STOCK (both PCBs and panel!), detailed BOM and instructions.

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neilbaldwin
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Post by neilbaldwin » Sun Jul 24, 2016 7:24 am

Is there any scope for using capacitors other than the polys? Had two dodgy ones (4n7) and they are so hard to find in the UK at a reasonable price.

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Sleipnir
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Post by Sleipnir » Mon Jul 25, 2016 11:15 am

neilbaldwin wrote:Is there any scope for using capacitors other than the polys? Had two dodgy ones (4n7) and they are so hard to find in the UK at a reasonable price.
The Thonk kit replaces polys with metal film for the larger caps and it's fine.
I imagine the caps are poly for the same reason guitarists go crazy for Paper-in-oil: It's how it was done 'in the day', (possibly) more pleasing distortion when overloaded, (slightly) different falloff curves. :despair:
Build it with MF, then if you happen to come across poly's at some future date and wonder what you're missing, you can replace them easily enough.

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Post by thermionicjunky » Mon Jul 25, 2016 10:54 pm

neilbaldwin wrote:Is there any scope for using capacitors other than the polys? Had two dodgy ones (4n7) and they are so hard to find in the UK at a reasonable price.
Try polypropylene.

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doomglue
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Post by doomglue » Sun Aug 07, 2016 6:29 am

Hello!

I was wondering if using 100k for RG1 and RG2 is the cause of the follwing issue I have with my built: feedback via self-oscillation is not happening following akrylik's test described earlier in the thread:

"- have no input signal and turn the IN1 and IN2 gain all the way down
- turn all the bands down to zero
- turn the feedback all the way up with toggle in the up position
- check each band by turning each up one by one, they should each oscillate at their center freq at around 1 or 2 o'clock. Higher frequency bands will oscillate sooner on the knob than the lower frequency bands."


All the bands are working fine however no feedback kicking in it seems...

Wondering if I should try re-soldering the pin connectors as first step?

Any input/pointers are highly appreciated...

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doomglue
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Post by doomglue » Mon Aug 08, 2016 4:54 pm

- tried a different switch
- resoldered a few things...

If anyone has an idea which points are crucial for the feedback to work (it is the only thing not working...), thanks for letting me know.

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cane creek
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Post by cane creek » Wed Aug 10, 2016 3:23 am

neilbaldwin wrote:Is there any scope for using capacitors other than the polys? Had two dodgy ones (4n7) and they are so hard to find in the UK at a reasonable price.
Not hard to find :mrgreen: Rush-on-line

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doomglue
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Post by doomglue » Tue Aug 16, 2016 3:01 pm

doomglue wrote:- tried a different switch
- resoldered a few things...

If anyone has an idea which points are crucial for the feedback to work (it is the only thing not working...), thanks for letting me know.
Seems I had used a broken 100k (left bottom of the main pcb) or managed to not get it soldered correctly.
:bang:

I changed it, now it is working fine.
:party:



I love the quality of these modules!
:hyper: :hyper: :hyper:

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muffdiver
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Post by muffdiver » Fri Oct 07, 2016 12:21 am

Have been using my RS Res EQ for months now and loving it - such a unique sound shaping tool - very organic. With sadness though I do have a couple of issues that are still unresolved with my build.

My plan is to take it out of the rack next week and attempt to resolve them.

Here it goes:

1. Dead band 115hz: I'm beginning to suspect I overheated the capacitors during soldering. Have reflowed everything within that band zone on the PCB and double checked resistor values. Just ordered some new 10n polysystrenes so hopefully that will solve that one once they arrive and I replace them.

2. This is the one I'm really puzzled on - The left side bands only send output to comb1 output. Right side bands output fine on Out 1&2 and Comb 2. Obviously something is a bit mixed up somewhere. Have tried reflowing the various sockets connecting the two PCBs but unsure of where to zero in on on the PCB to troubleshoot.

-

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maaaks
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Post by maaaks » Mon Oct 24, 2016 10:38 am

Has anyone done any experimenting with different opamps?. The build doc states that OPA2604 has nice clipping behaviour - has anyone tried these?

I used the standard OPA2134. and while it sounds great I'd love to hear some different results.

Can anyone recommend any other opamps that might be worth trying?

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muffdiver
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Post by muffdiver » Mon Oct 24, 2016 5:34 pm

BTW...managed to fix the 115hz band by swapping out the poly caps.

Still mystified by the output behavior. Just out of curiousity how are the outputs supposed to work or how are they working for everyone regarding L EQ bank / R EQ bank.

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ym2612
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Post by ym2612 » Wed Nov 02, 2016 9:35 pm

Anybody else have trouble with the screen printing coming off really easily? All I have to do is brush it or lightly scrape it and it comes off.

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cane creek
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Post by cane creek » Thu Nov 03, 2016 2:51 am

Seems odd, never had any problems like that with random source boards they always seem really good quality.

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muffdiver
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Post by muffdiver » Tue Dec 06, 2016 5:24 pm

Can anybody give an explanation of the how the outputs should route the various bands?

I'm still not convinced my build is working properly in this respect. :despair:

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