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WIGGLING 'LITE' IN GUEST MODE

Trevor Marshall VCA/Ring modulator - Eurorack
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3  Next [all]
Author Trevor Marshall VCA/Ring modulator - Eurorack
Ayab
Confirming my interest in the project.
whoop_john
New layout. I decided to use a PCB mounting switch that goes up and down, not across as I had before. If people have the usual tag version switch it will be easy to wire onto. I've ordered some switches to check sizes.

Pins added for non-euro fellahin. The unused slots from the 3.5mm sockets could be used for cable ties.

The other holes I have on the board are 2mm (Male/Female, Female/Female 2mm standoffs are easily obtained in 1mm increments),

Ayab
Looks like the Ring Mod/Vca pcb is coming along very nicely. Looking forward to it.

I particularly enjoyed reading 'The Perception of Sound' p.30/31.

http://trevormarshall.com/synth/Synth_Oct73.pdf
whoop_john
A couple of pics of my old 4600 built back in the 1970s. Solid mahogany case with mitred corners.



diablojoy
I will definitely take a couple john thumbs up
Panels , yeah it's the bane everyone struggles with DIY wise
finally decided I am going to buy a CNC machine this year so hopefully that sorts it for me
As for PCB fab panels - I am liking some of them at least the O & C, temps utile , elements and grids panels , I received recently were all very good.

regarding the 1496 - mouser seems to only have soic14 in stock
utsource have plenty in DIP though
Ayab
Really enjoyed looking at the pictures of your 4600. A very stylish design and in really great condition. Always good to have a pin matrix for the flexibility and avoids the bowl of udon noodles issue!

Mr Marshall was certainly an innovator.
forbin
Trevor Marshall was one of my lecturers at WAIT years ago and I thought that the vcf was one of the more interesting elements of the 4600. He was heavily into switched capacitor filters at the time and made an ETI modem design using them. I have one of the envelope generators as well... he was a bit of an eccentric chap and had a gas mask at the ready if people were smoking...,
whoop_john
Some progress on this project. I received 10 MC1496 ICs from China - they don't look like pulls or blacktopped knockoffs. I have one original to test against.

The PCB is currently looking like this. What might I do with that middle strip? Sensible suggestions only please. It isn't wide enough for a row of thonkiconns. How about some tiny attenuvertor cards or something?

whoop_john
The Trevor Marshall VCA/RingMod PCB is on its way to UK from China. The strip in the middle is 2 attenuvertors, to fill up space.

Not an easy birth this one. The board was bounced because of some rogue duplicated code in the Gerbers. This is down to a bug in Osmond PCB and the use of custom-defined pad shapes. I've emailed the software author. A manual edit of the files sorted the problem out.

The person at Elecrow then said they don't allow V-grooves unless I paid extra. I must have been lucky before, as I haven't been charged in the past. They do still allow profile milling as standard, so I did slots and tabs between boards.

fitzgreyve
Put me down for two of these if you have any spares (is that actually one PCB looking at the above ?).

Will go nicely with the Transient.

Did you manage to find a solution for panels ?
Ayab
whoop_john wrote:
dubtoms wrote:
…i haven't mentioned in the other thread that Philip who run the "Pusherman" group buys on Facebook managed to break down his "retail" price for small panels to around 2 or 3 British Pounds.

I am already part of the Pusherman group - I should pay more attention to it perhaps.

Julian's panels are £2 per HP, so for a 5 HP panel that is £10. It only includes pilot holes, all at 3.3mm. Is that what people want?


Sounds good to me - am happy to do some drilling. (Do have a cheap crappy drill press which I bought impulsively but I can't find a drill to fit. Must look about for an old corded one that may fit.)
whoop_john
fitzgreyve wrote:
Put me down for two of these if you have any spares (is that actually one PCB looking at the above ?).

Will go nicely with the Transient.

Did you manage to find a solution for panels ?

The PCB I showed above in red is 2 VCA/Ring Mod boards and two attenuverter boards.

I have ordered just 5 boards, ie I get 10 of everything. The design is not yet tested.

If I sell boards then you will only get one, not the whole sheet - but I might add one attenuverter as a free gift.
Zaibach
Am I too late for the party to sign up for one pcb? Well, if you have a spare pcb I would be happy to build this...
whoop_john
Zaibach wrote:
Am I too late for the party to sign up for one pcb? Well, if you have a spare pcb I would be happy to build this...

The party has not yet started. I am currently out of the country, but hopefully the PCBs will arrive soon after my return next week.
muffdiver
definitely interested in this as well.
whoop_john
muffdiver wrote:
definitely interested in this as well.

Boards are in, but there is a wrinkle that has affected both this and the utilities boards that have also arrived.

I used a part I had made for the PJ302M:



This involved slots for the socket tags and as you can't drill an oval hole, this was designated as a routed-out shape on the mechanical layer. Fair enough, only way to do it really.

I had a request back as to whether I wanted this slot plated through to the pad either side. In a previous design, the Bissel board, someone had done this automatically - exactly what was wanted. I said yes please.

But the highly-creative person decided to also connect every top pad with the top copper layer, thus shorting out all socket pins to 0v. Cosmic.

So I am in dialogue with the PCB factory to redo them and they are asking me for more illustrations of the problem.

The VCA/Ring Mod is not so much of a problem, just four tiny cuts on the board, but I am not going to offer these for sale, as it is not my fault as I see it and it does not meet my quality standards. I can at least test the boards using what I have been sent.
dubtoms
Bummer. I was looking forward to build the utilities and Bissel boards with my brand new Hakko iron. waah
oberkorn
interest here also, 1 or 2 boards if the PCB issues are resolved
slowly coming back from 6 months SDIY hiatus...
whoop_john
The PCB manufacturer now understands my problem and has asked whether I want the boards remade or a refund. I have said remake them. I think this means they accept that the problem is theirs. Either way, boards will be remade, but we need to get to the bottom of why the issue happened, so that it doesn't do so again.

The engineer who dealt with my orders was on holiday on Friday, so they have been unable to ask him why he did what he did, but they promise a response once they have done so.
KSS
It's Generally a good idea to put a "+" and "-" in copper on the trace side of a PCB's power input. Other labels can be helpful too.
A permanent backup plan against silkscreeen failure.

Okay, it's really because we dint useta have silkscreen with our DIY bds. So anything important was put in copper labels. Not a bad habit to have.
whoop_john
KSS wrote:
It's Generally a good idea to put a "+" and "-" in copper on the trace side of a PCB's power input. Other labels can be helpful too.
A permanent backup plan against silkscreeen failure.

Okay, it's really because we dint useta have silkscreen with our DIY bds. So anything important was put in copper labels. Not a bad habit to have.


Someone will manage to plug it in backwards anyway. And if he or she can't read the "+" and "-" on the top layer silkscreen, what hope do I have that they will look at the copper on the bottom? There are diodes on the inputs. I am sure someone will figure it out once nothing works.
whoop_john
New PCBs are on their way to me

Ayab
Looking good!!
julian


This design isnt spot on yet, as i need to confirm the pot type / positions.

There's also a bit of an oddity with the incline of the text making the writing look off-center, which i need to adjust for, but its close.
audiohawk
Interested in 2 PCBs and 2 Panels when the time comes.
Thank you both for your work we're not worthy
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