ANALOGUE WAVEFORM GENERATOR MODEL 25S

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APETECHNOLOGY
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Post by APETECHNOLOGY » Fri May 04, 2018 11:09 pm

monzelio wrote:hi all- i recently got my 25S PCBs, they are version 2.0
Has someone built this version?
On Electric Music Store i found only version 1.0 BOM..
there was a lot of mods on the version 1,
i would hold off and wait for a bom for the version 2!
hopefully all the funky stuff got fixed!

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Post by cygmu » Sat May 05, 2018 1:29 am

APETECHNOLOGY wrote:
monzelio wrote:hi all- i recently got my 25S PCBs, they are version 2.0
Has someone built this version?
On Electric Music Store i found only version 1.0 BOM..
there was a lot of mods on the version 1,
i would hold off and wait for a bom for the version 2!
hopefully all the funky stuff got fixed!
I hope the same... but "waiting for a bom" from electricmusicstore can be a long process. So additionally I hope the BOM appears. Argh!

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Post by monzelio » Sat May 05, 2018 4:24 am

yes i saw on the build page, he added some resistors that are included in version 2,the only component not mentioned is a trimmer called"Timbre range" in series to the wiper of the "Timbre" trimmer..i contacted Shawn of Electric Music Store but he has'nt any information about it.
In attachment i posted the V2 PCB with highlighted the new components.
Another mod is the one suggested by Dave Brown
https://modularsynthesis.com/roman/25s/25sawg.htm
he wrote"
The MO buffer has too much gain so the waveforms clip. Change R245 on PCB3 to 1K so it is the same value as R248
."
Has someone done successfully any modification in V1?
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Post by livefreela » Sat May 12, 2018 7:57 pm

cygmu is being a gentleman, but this undocumented revision craziness has gotten tedious. off the top of my head, there are four modules currently being sold that are unbuildable - with only the 248 being identified as a new version on Ems; the others are less-pleasant 'surprise! you're a beta-tester!' affairs and have been awaiting a BOM for 10 months now. As long as the CEM poly synth jobs continue to iterate from Tokyo, I'd venture that we're likely keep on waiting.

In Shawn's defense, he really does seem to be picking things up wherever he is able / isn't hamstrung by supply or engineering. I purchased a 258 set (almost went with a 25s) a few weeks ago and had it in about 6 days - a new EMS record for me. Moving forward though, I'll be confirming stock is current revision before ordering - I've got no interest in claiming another spot in the revision queue / tenuously reverse-engineering an undocumented circuit.
cygmu wrote: I hope the same... but "waiting for a bom" from electricmusicstore can be a long process. So additionally I hope the BOM appears. Argh!

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Post by gigasturtz » Wed Nov 21, 2018 3:49 pm

building a 25S now. glad to have found this thread and the link to info about Rev 2 boards.

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peti » Fri Feb 21, 2020 7:42 pm

@ gigasturtz

did everything go well with building the 25S? i am thinking about building one, but i would also prefer the V2 without all the necessary corrections and modifications.

has something like a new, improved version come out yet?
peter

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peake » Sat Feb 22, 2020 2:21 pm

I'm unaware of any planned revisions to the PCB, unsure if ems are doing anything like that now. If you look at the build threads you'll have all you need to get the most out of a V2. Very nice oscillators. Remember to pay attention to getting the right part into the wavefolder for the best results.
This is not the place I'd imagined it to be.

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peti » Sun Feb 23, 2020 7:53 am

hi peake,

so version 2 PCBs is out there somewhere? because the EMS is V1 i think!
https://electricmusicstore.com/products ... -model-25s

i wrote an email to Shawn Clearly, waiting for a reply : )
are there other stores to purchase Buchla Format DIY PCBs as well?

thank you
peter

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by jimfowler » Sun Feb 23, 2020 10:31 am

www.samodular.com though it doesn't appear he has a 25s on offer

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by maxl0rd » Sun Feb 23, 2020 10:46 am

Got a question about this module. It appears that the internal cv connection between the mod osc and the primary is ac coupled. Is that a deliberate design decision, optimizing for audio rate fm? A bug?

You can still patch the cv out banana to get slow fm.

This was surprising to me as no other Buchla complex oscs that I have used work this way.

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peti » Mon Feb 24, 2020 3:21 am

jimfowler wrote:
Sun Feb 23, 2020 10:31 am
www.samodular.com though it doesn't appear he has a 25s on offer
yes unfortunately he hasn't. i sent him an email as well

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peake » Mon Feb 24, 2020 1:05 pm

Peti wrote:
Sun Feb 23, 2020 7:53 am
hi peake,

so version 2 PCBs is out there somewhere? because the EMS is V1 i think!
https://electricmusicstore.com/products ... -model-25s

i wrote an email to Shawn Clearly, waiting for a reply : )
are there other stores to purchase Buchla Format DIY PCBs as well?

thank you
peter
Error on my part, apologies. This is why I waited to see if anyone else would reply to your question before chiming in. I've built one or two 25s from that PCB and with the few easy mods indicated on the ems build page they work fine.
This is not the place I'd imagined it to be.

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peti » Tue Feb 25, 2020 11:31 am

Error on my part, apologies. This is why I waited to see if anyone else would reply to your question before chiming in. I've built one or two 25s from that PCB and with the few easy mods indicated on the ems build page they work fine.
[/quote]



Alright sounds fine. I think it will be doable, the mods on EMS does not sound too hard!
but i didn't completely understand a quote in Dave Browns Modification description on his website :

"None of the 3.5mm jacks have a ground wire so the front panel and 3.5mm jacks have to be grounded through the boat. The CCW terminal of either FM control at the bottom is ground so I ran a wire from these to the 3.5mm FM jacks. The grounds should be routed to all 3.5mm jacks so grounding does not rely upon the anodized panel."


did you do that to to ground the module? or is it enough to go along with the notes on the EMS 25S build modification build page?
thank you

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peti » Tue Feb 25, 2020 11:33 am

and.. i noticed the potentiometers a a bit different, they are D-shaft. can i put conventional 6,35mm round shaft knobs on the module like them for example? --- https://www.thonk.co.uk/shop/rogan-buchla/

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peake » Tue Feb 25, 2020 11:54 am

I built one where the person wanted Rogan knobs and yes, they don't work on D-shaft pots...I managed to fill out the D-shafts with epoxy and shaved it down. Its been a while so my advice is based upon fading memory...I believe the pots are RV9 so you'd have to found round-shaft pots of the correct length.
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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peti » Tue Feb 25, 2020 12:15 pm

ok good to know that!

and if i would use the regular D-shaft distributed in the BOM 1, are the pots reversed D or regular D (knob line on curved side of D) ? :hmm:

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peake » Tue Feb 25, 2020 12:36 pm

I don't remember, sorry.
This is not the place I'd imagined it to be.

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peti » Tue Feb 25, 2020 2:33 pm

no problem, i think i will use the 200e style ones Sammodular offers :)

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by captnapalm » Tue Feb 25, 2020 8:36 pm

I'm pretty sure I put Rogan Alphas on mine and they still worked on the D-shaft pots. I'm out of town so I can't prove it at the moment...

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by tobb » Mon Mar 02, 2020 5:13 pm

Peake wrote:
Tue Feb 25, 2020 11:54 am
I built one where the person wanted Rogan knobs and yes, they don't work on D-shaft pots...I managed to fill out the D-shafts with epoxy and shaved it down. Its been a while so my advice is based upon fading memory...I believe the pots are RV9 so you'd have to found round-shaft pots of the correct length.
https://reverb.com/uk/item/14406374-ep- ... r-hardware

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by Peake » Mon Mar 02, 2020 5:21 pm

Very nice, thanks!
This is not the place I'd imagined it to be.

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by solaranus » Sun Apr 05, 2020 2:24 pm

I am building one right now and was wondering what's the ideal lenght of standoffs between the panel and pcbs when using Selco knobs? I will have to order them new and don't want to order every value between 10mm and 15mm to find the perfect match.

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by jimfowler » Sun Apr 05, 2020 2:36 pm

I use 12mm standoffs between panels and pcbs. The switches poke out a bit more than I prefer but the pots sit just right.

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Re: ANALOGUE WAVEFORM GENERATOR MODEL 25S

Post by solaranus » Mon Apr 06, 2020 3:27 am

Thanks, I will try that out!

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