73-75 Serge panels from Zthee

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cygmu
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Post by cygmu » Fri Jul 19, 2019 12:54 am

nateflanigan wrote:I'm a little confused about the power supply voltages is it +12/-12/+6 or +15/-15/5 the text says 12 but the schematic shows 15. Can anyone clarify this?
On the 73-75 power supply schematic, what's happening is that a switching regulator produces +/-15V which is then regulated down to +/-12V by linear regulators, and it is the +/-12V that goes to the modules.

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Post by nateflanigan » Sat Jul 20, 2019 12:32 pm

nateflanigan wrote:
I'm a little confused about the power supply voltages is it +12/-12/+6 or +15/-15/5 the text says 12 but the schematic shows 15. Can anyone clarify this?


On the 73-75 power supply schematic, what's happening is that a switching regulator produces +/-15V which is then regulated down to +/-12V by linear regulators, and it is the +/-12V that goes to the modules.
Got it, thanks!

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Post by nateflanigan » Sat Jul 20, 2019 2:10 pm

Has anyone considered using something like this instead of the included psu board?

https://www.mouser.com/ProductDetail/709-RT50B

It's cheaper and easier, the 5v rail can be adjusted to 5.5v, maybe that's close enough, any issues any can see?

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Post by ashleym » Thu Jul 25, 2019 5:15 pm

nateflanigan wrote:Has anyone considered using something like this instead of the included psu board?

https://www.mouser.com/ProductDetail/709-RT50B

It's cheaper and easier, the 5v rail can be adjusted to 5.5v, maybe that's close enough, any issues any can see?
Yes but.......

With the existing you can use a line lump supply and all the dangerous mains voltages are tucked out of the way. Dont forget you need to factor in a mains lead, a panel mains inlet, all the relevant fusing and then making the right cut out for your case. I had to drill a hole for the encapsulated supply. From experience this is much easier than making a mains inlet sized and shaped cut out. Plus you get the correct 6v!

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Post by nateflanigan » Thu Jul 25, 2019 7:14 pm

From experience this is much easier than making a mains inlet sized and shaped cut out.
Eh, it's not so bad. I ordered one to test out I'll let folks know how it works.

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Post by Lento_Zoom » Tue Jul 30, 2019 2:20 pm

This was a fun build. I need to second the advice to not mess around buying eBay 3080's. I took the gamble and wound up having to order a second (working) pair from SynthCube.

I'm loving this Serge "everything is everything" module functionality.

Does anyone have any tips or resources for attaching the two boats together in a folding, Buchla style? I've got some ideas, but could always user more reference.

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Post by nateflanigan » Tue Jul 30, 2019 8:10 pm

I need to second the advice to not mess around buying eBay 3080's.
Just want to 3rd this. A friend had some from ebay that I tried, they were defective. I got some from smallbear that work great.

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Post by nateflanigan » Tue Jul 30, 2019 8:17 pm

While I'm here, my only gripe about the kit is the manual leaves a bit to be desired. My biggest problem is that the silkscreen legend on the boards identifies part values (as one does) and the schematic uses part numbers but the BOM doesn't cross reference these. I noticed these schematics on the other hand do indeed have part values, where did they come from? Also, what is the purpose of changing the 22k resistors to 47k on the oscillator (or any of the circuits for that matter). I have the first panel mostly built and calibrated, the oscillator seemed to calibrate fine, with 22k resistors. And since I'm asking questions, what pot is that that the 22k/47k resistors are connected to?

Thanks!
ashleym wrote:


50k is fine. Have a look what they do in a circuit and you’ll see their value is flexible. It’s onlt one set of resisters you have to change. You’re on the right path!



Thanks! I finally managed to figure out which ones to swap. I've circled them in these pictures for other ppl to see in case someone else has the same question.
So the 22k resistors marked with yellow and red in these schematics should be swapped for 47k if you use 50k linear pots.

This goes for Envelope Generator, Oscillator, Positive and Negative Slew.
PS. Bytes ej is swedish and means do not change




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Post by veets » Sun Dec 01, 2019 7:18 am

Been sitting on this project for two years. I built the power supply and have most the parts on hand for the remainder, but I haven't been able to take iron to solder on this one. Now that I'm contemplating it, I wonder if any of you builders are willing to share your advice, most important lessons learned... I would rather sell this set than botch the build.

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Post by nateflanigan » Sun Dec 01, 2019 1:43 pm

I'm wrapping up my second build. I don't know what your experience is so it's hard for me to give direct advice, but none of the modules are any harder to build or calibrate than your average delay pedal build. However, it is a really big build. I populated my two sets of boards at the same time then calibrated and finished one, procrastinated for a few months and am just finishing the 2nd. It's probably been about 30 hrs of build time for the two. I made a lot of little component mistakes along the way, 22k where 2.2k should go kind of stuff that I only caught because I was doing two boards at once. It would have been really hard to go back and find those errors had I finished it and it didn't work right. My biggest criticism of the 73-75 kit is that the schematics ID's parts by name (R3, C22 etc) and the board by value, but there is no BOM that cross references the two. So if you need to do any fault finding, using the schematic to find your way around the board is very difficult. All that being said, it's a really cool build, here are a few notes I've been meaning to add to this thread...

- Invest in a parts organizer for the project, label the drawers. Being really organized was a huge help to my sanity.

- Take pictures of the boards unpopulated. I've referenced these pics many times to re-confirm part values, IC alignment, all sorts of double checking.

- The crimp on spade terminals work great for the banana jacks. They're discussed earlier in this thread

- I used a meanwell powersupply, it works great.

- Get the CA3080's from a reputable source, I got mine from smallbear. I first tried some ebay ones from china and they did not work.

- Get an IC pin straightener, best $7 I've ever spent.

- Most of the calibration is easy, but some of the instructions are a little vague. The elby/cat girl instructions for the ring mod are a little easier to follow. It says to use a 0-5v saw wave, the saw from the serge oscillator worked fine.

- Calibrating the envelope generators: The elby instructions feel convoluted to me and the 73-75 is a little vague. It helps to read up on how these work, they're kind of counter intuitive, so just having a better understanding of how it's supposed to function is a good thing.
Turn the rise and fall knobs all the way up/fully CW looking at the component side of the board (I did this backwards first go). Follow instructions.
To set the HOLD trim pot, patch according to instructions. I used a 4x AAA battery pack to supply a constant "gate" signal but there are lots of ways you can rig this up. Set the trimpot to center. I found it easiest to monitor the output of the module with a DMM set to VDC, you're not looking for a specific voltage but you're adjusting the trimmer for the least amount of fluctuation.

Hope that helps.

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Post by veets » Tue Dec 03, 2019 5:12 am

Great advice, Nate. Thank you for taking the time to document this for me and future builders, should these ever become available again.

Veets

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ishi
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Post by ishi » Tue Dec 03, 2019 4:59 pm

veets wrote:.. for me and future builders, should these ever become available again.

Veets
They seem to be available at the moment.

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Post by ashleym » Thu Dec 12, 2019 7:27 pm

ishi wrote:
veets wrote:.. for me and future builders, should these ever become available again.

Veets
They seem to be available at the moment.
Do have a look now. There’s lots of new diy (or partial diy) goodness life n the shop or check his YouTube channel (I’m not on social media so there might be stuff there). :banana:

I posted similar in the Serge section, I hope this doesn’t count as a double post and upset the mods!! :sadbanana:

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Re: 73-75 Serge panels from Zthee

Post by xonetacular » Wed Jan 08, 2020 11:29 pm

What's the correct wiring of the 1/4" jack for the preamp? PCB has two pads, labeled tip and ring. The jack in the BOM is a switched jack with 3 tabs- tip, switch (ring?), and sleeve. Tip wiring is self explanatory but for the ring pad do they mean wire the sleeve or the switch? I'm guessing it's for the sleeve unless the switched jack has some significance.

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Re: 73-75 Serge panels from Zthee

Post by nateflanigan » Sat Jan 11, 2020 9:38 pm

I really don't know what that's about, the schematic just shows a regular TS jack and no connections for ring or any sort of switching. I used a regular TS jack with tip wired to the tip pad and sleeve wired to the ring pad. On the PCB IIRC the ring pad has continuity to ground. The preamp works as expected on my build.

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Re: 73-75 Serge panels from Zthee

Post by xonetacular » Sat Jan 11, 2020 11:44 pm

nateflanigan wrote:
Sat Jan 11, 2020 9:38 pm
I really don't know what that's about, the schematic just shows a regular TS jack and no connections for ring or any sort of switching. I used a regular TS jack with tip wired to the tip pad and sleeve wired to the ring pad. On the PCB IIRC the ring pad has continuity to ground. The preamp works as expected on my build.
I'm thinking maybe switch (ring) and tip should both be wired together and wire to tip pad. When the switched jack doesn't have anything inserted then the input would be shorted to ground through the sleeve connection, and broken when a cable is inserted. Someone else I was asking said this is common in preamp circuits for guitars and such but I don't know anything about that. Probably doesn't matter in this case honestly and doesn't need to be wired.

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Re: 73-75 Serge panels from Zthee

Post by xonetacular » Tue Jan 14, 2020 12:33 am

My build is finally complete.

Image

Image

Image

Image

Image

Managed to squeeze everything including the large accutronics tank and full sized power module into 2" shallow boats. Took some work and creativity to get it all to fit- it's one unit riveted together. Decided against LED mods as I think it looks cleaner without and this project was already a pain. Went with a Random*Source inspired color scheme and am happy with how it turned out.

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Re: 73-75 Serge panels from Zthee

Post by ashleym » Tue Jan 14, 2020 1:47 pm

xonetacular wrote:
Tue Jan 14, 2020 12:33 am
My build is finally complete.



Managed to squeeze everything including the large accutronics tank and full sized power module into 2" shallow boats. Took some work and creativity to get it all to fit- it's one unit riveted together. Decided against LED mods as I think it looks cleaner without and this project was already a pain. Went with a Random*Source inspired color scheme and am happy with how it turned out.
Generally all round brilliant.

Are you enjoying playing it?

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Re: 73-75 Serge panels from Zthee

Post by xonetacular » Tue Jan 14, 2020 1:51 pm

It's interesting, need to spend some more time patching it I just finished it yesterday. The envs are cool and more useful than expected.

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Re: 73-75 Serge panels from Zthee

Post by ashleym » Tue Jan 14, 2020 2:13 pm

if it makes you think differently about making music, it will give you different results. it is nice to be challenged.

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Re: 73-75 Serge panels from Zthee

Post by nateflanigan » Tue Jan 14, 2020 6:36 pm

Looks tight xonetacular!
if it makes you think differently about making music, it will give you different results. it is nice to be challenged.
So true, this really sums up my limited experience thus far with the homebuilt.

I should ad to the errata that I used this reverb tank
https://www.cedist.com/products/reverb- ... y-3-spring

It's the same impedance specs as the bom specifies, I bought both this and the longer medium decay tank. I liked the sound of the smaller long decay tank better. It's less boingy, more pillowy, a little more like a plate reverb. But, I don't want to overstate the differences, mostly they are very similar.

Here's a video of my build...


I built mine directly into an oak case, meaning I didn't use any boats.

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Re:

Post by krazh » Sun Jan 19, 2020 2:00 am

veets wrote:
Tue Dec 03, 2019 5:12 am
... future builders, should these ever become available again.

Veets
after having gone out of stock, it seems 2 more Homebuilts are back in stock, as off today.

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Re: 73-75 Serge panels from Zthee

Post by finlayshakespeare » Fri Jan 24, 2020 4:09 am

Hi all,

Just before I take measurements myself, does anyone know what the current draw of the two panels is from the One Inch Punch supply, and how much “headroom” in terms of mA there is left per rail? I want to add some more kit to this system, but need to figure out if another PSU is necessary to power it all.

Cheers!

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Re: 73-75 Serge panels from Zthee

Post by finlayshakespeare » Wed Jan 29, 2020 8:29 am

finlayshakespeare wrote:
Fri Jan 24, 2020 4:09 am
Hi all,

Just before I take measurements myself, does anyone know what the current draw of the two panels is from the One Inch Punch supply, and how much “headroom” in terms of mA there is left per rail? I want to add some more kit to this system, but need to figure out if another PSU is necessary to power it all.

Cheers!
Very rough measurements here, but should give some form of ballpark figure:

Oscillator, Shapers, etc. panel:
+12V = ~60mA
+6V = ~10mA
-12V = ~45mA

Slews + Envelopes panel:
+12V = ~50mA
+6V = ~40mA
-12V = ~10mA

So overall, both panels seem to consume (ish):
+12V = ~110mA
+6V = ~50mA
-12V = ~55mA
From some very quick calculations, in my build using the Traco Power brick (+/-15V at 500mA per rail), there should be enough power available for roughly another 200mA on the +12V and -12V rails. Ish.

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