Cloney VCS3 Clone Builders?

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alka
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Re: Cloney VCS3 Clone Builders?

Post by alka » Thu Jul 30, 2020 8:02 pm

Some decent shots of my recent build

New album out now on Vince Clarke's VeryRecords
https://alka.fanlink.to/auguries

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KSS
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Re: Cloney VCS3 Clone Builders?

Post by KSS » Thu Jul 30, 2020 10:27 pm

That's very nice, alka!

Loving the patch bay behind the patch bay..

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Re: Cloney VCS3 Clone Builders?

Post by mOBiTh » Wed Aug 12, 2020 5:26 am

Hey guys

I have a pair of cloney builds on the go and I've run into two issues on the Y board

1) The filter is latched to 12V
2) The envelope is 0V on the output, however the trapezoid and all controls are working correctly.

Scoping the circuit board seems to point towards the FETs and I've heard these can be fussy value wise, however before I start a wild goose chase I wondered if anyone else has witnessed these issues please?

Cheers!

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Re: Cloney VCS3 Clone Builders?

Post by cnicht » Wed Aug 12, 2020 7:05 am

1. You shouldn't see a DC level at the output of the filter as it's AC coupled.

2. Are you seeing charge/discharge of C48?

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Re: Cloney VCS3 Clone Builders?

Post by mOBiTh » Thu Aug 13, 2020 6:50 am

cnicht wrote:
Wed Aug 12, 2020 7:05 am
1. You shouldn't see a DC level at the output of the filter as it's AC coupled.

2. Are you seeing charge/discharge of C48?
Hey cnicht, thanks for the reply!

1) Filter: Hmn. The output cap C39 was bad and was a short, however I dont think this was the root cause and had got damaged. Replacing it with a good one and testing momentarily showed, with the filter out routed to the scope out, the signal latched on 12V again. I'm new to this filter design so still trying to understand it better.

http://www.phutney.com/TechnicalInfo/Y_S2.pdf

2) Env: probing the neg term of C48 gives me a slewed version of the trapezoid output. I can trace the periodic signal as far as the gate of Q48. I can't see any signal around R151 and C50, hence I immediately suspected Q48 was at fault. I've replaced it though with the other one i had from the same batch, but with no joy. Perhaps they're both out of spec? Here's the schematic i'm working from:

http://www.phutney.com/TechnicalInfo/Mk ... 3_2020.jpg

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Re: Cloney VCS3 Clone Builders?

Post by cnicht » Thu Aug 13, 2020 7:01 am

mOBiTh wrote:
Thu Aug 13, 2020 6:50 am
cnicht wrote:
Wed Aug 12, 2020 7:05 am
1. You shouldn't see a DC level at the output of the filter as it's AC coupled.

2. Are you seeing charge/discharge of C48?
Hey cnicht, thanks for the reply!

1) Filter: Hmn. The output cap C39 was bad and was a short, however I dont think this was the root cause and had got damaged. Replacing it with a good one and testing momentarily showed, with the filter out routed to the scope out, the signal latched on 12V again. I'm new to this filter design so still trying to understand it better.

http://www.phutney.com/TechnicalInfo/Y_S2.pdf

2) Env: probing the neg term of C48 gives me a slewed version of the trapezoid output. I can trace the periodic signal as far as the gate of Q48. I can't see any signal around R151 and C50, hence I immediately suspected Q48 was at fault. I've replaced it though with the other one i had from the same batch, but with no joy. Perhaps they're both out of spec? Here's the schematic i'm working from:

http://www.phutney.com/TechnicalInfo/Mk ... 3_2020.jpg
Although I've not built a 'Cloney' I've built up some clone boards which have the same circuitry.

With the filter what are you seeing at the emitter of Q31?

For the Env the signal at C48 is correct, suspect Q48. Did you buy the batch from a reputable supplier? Do you have a component tester to test them? I had problems getting my Envs to self-cycle and needed to change some resistor values.

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mOBiTh
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Re: Cloney VCS3 Clone Builders?

Post by mOBiTh » Fri Aug 14, 2020 6:37 am

Re components - all the components are part of the Cloney kits - I have no knowledge of their origin or whether they tested in spec - I think I'll just order some more and see whether it fixes things.

The filter problem I hadn't really dug into other than measuring the 12V on the output. When I measured 12V on the decoupling cap (which had gone short - misleadingly) I figured the problem was upstream of that but actually I've removed that cap and the card pin for the output of the filter (Y19 iirc) is still shorted to the 12V supply (Y18 iirc). Should have done more tests with the power off before posting!

So that means there is a short between traces Y18 and Y19. Y19 is very short and there's definitely no bridging so it appears the short is somehow inside or underneath the connector. That's how it looks at the moment anyway, unless I'm overlooking something obvious. Pretty bizarre

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mOBiTh
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Re: Cloney VCS3 Clone Builders?

Post by mOBiTh » Fri Aug 14, 2020 6:40 am

20200809_141610.jpg
20200809_134051.jpg

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cnicht
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Re: Cloney VCS3 Clone Builders?

Post by cnicht » Fri Aug 14, 2020 6:58 am

I can't see anything obvious and think your conclusions are correct.

As I posted, I don't actually have a Cloney and my board looks like this:
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search64
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Re: Cloney VCS3 Clone Builders?

Post by search64 » Fri Aug 14, 2020 7:12 am

Where's that board from?

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Re: Cloney VCS3 Clone Builders?

Post by bsilverberg » Fri Aug 14, 2020 7:31 am

Your Y board looks good, which means either bad component(s) or, go back upstream and double check all pertinent panel and backplane wiring.

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Re: Cloney VCS3 Clone Builders?

Post by cnicht » Fri Aug 14, 2020 8:03 am

search64 wrote:
Fri Aug 14, 2020 7:12 am
Where's that board from?
A fellow Wiggler reengineered them have a look at https://sussexvcs.wordpress.com/

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Re: Cloney VCS3 Clone Builders?

Post by mOBiTh » Fri Aug 14, 2020 8:30 am

Thanks guys, I'll try to swing by Cricklewood this afternoon and grab some replacement FETs.

PCBs are from Derek Revell. They're mk4. I have another set of unpopulated PCBs and the short on Y18/19 is not there so it really seems to be the connector somehow.

These connectors are male and quite simple - L-shaped pins in a plastic housing - so a short would be pretty surprising. However it's there even with the board unplugged so I'm not suspecting any panel wiring. Will be fun to remove!

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Re: Cloney VCS3 Clone Builders?

Post by mOBiTh » Fri Aug 14, 2020 3:49 pm

Hey guys

I picked up a few more 2n5461's from Cricklewood from different manufacturers - alas I didnt have my transistor tester with me and they all measure about 1.3-1.5 Vgs compared to the supplied ones that were 1.2Vgs.

The circuit diagram from Derek specifies "2.5 - 3.0V" which I assume is the same measurement?

If I measure the impedance between source and drain during a long slow cycle, when the gate hits about 2V the impedance goes high - which seems to make sense. Seems odd that the circuit is this fussy but I don't really understand it yet.

What do you guys think - try to find some P-JFETs with higher Vgs values (suggestions very welcome) or do you think something else is amiss?

The filter output short is resolved - there's a short on the PCB under the connector which I've simply bypassed for now. Probably some copper swarf from where the PCBs were trimmed

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Re: Cloney VCS3 Clone Builders?

Post by cnicht » Sat Aug 15, 2020 1:57 am

Does your Env self-cycle?

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Re: Cloney VCS3 Clone Builders?

Post by mOBiTh » Mon Aug 17, 2020 8:04 am

cnicht wrote:
Sat Aug 15, 2020 1:57 am
Does your Env self-cycle?

The envelope was actually working fine all along - in my naivety I assumed the env out was also a CV output. It was only when I scoped the modulation input that I realised how it actually works :roll: should have read the bloody manual! In my (weak) defence I have never used a vcs3 so this hadn't occurred to me...

I had some fun trying to get the oscillators in spec, esp OSC1. In the end I replaced R180 with a 100K trimmer and found 53K was a workable value. I also replaced the 15nF caps with 2.2nF caps to get the offset in range for the vernier 6 = 261Hz spec.

I have two remaining issues as far as I can tell, one is the output VCAs - I'm not clear how they're supposed to behave exactly but mine are top heavy gain wise and easily distort. The other is the output filters - they both sound reasonable but sound different from each other. Haven't investigated either yet so too early to speculate. Will report back any interesting findings!

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Re: Cloney VCS3 Clone Builders?

Post by cnicht » Mon Aug 17, 2020 8:09 am

:sb:

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Re: Cloney VCS3 Clone Builders?

Post by chaosium » Tue Feb 09, 2021 5:34 pm

alka wrote:
Mon Jan 06, 2020 10:33 am
How's everyone doing with their builds? It was certainly the most challenging build I ever took on what with the crash course in carpentry and ALL those wires...! In the end after meticulously building I had an issue that was only tracked down by Derek that involved one bad transistor in the PSU section of Board A.

Anyhow after that was sorted and Derek did preliminary calibrating, I'm quite pleased with the sound. I've owned a 1972 Synthi A and the sound of the Cloney is spot on.

Ooh gah, that's beautiful. Any active / reliable builders in the US (Pacific Northwest, ideally!)

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Re: Cloney VCS3 Clone Builders?

Post by KSS » Wed Feb 10, 2021 7:32 am

mOBiTh wrote:
Fri Aug 14, 2020 8:30 am
soak [KOH]
:tu:

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Re: Cloney VCS3 Clone Builders?

Post by RadekTymecki » Wed Feb 10, 2021 12:04 pm

this one is mine. i have used mk1 boards from Derek. ps. i have chenged the joystick already

Image

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alka
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Re: Cloney VCS3 Clone Builders?

Post by alka » Wed Mar 31, 2021 12:30 pm

RadekTymecki wrote:
Wed Feb 10, 2021 12:04 pm
this one is mine. i have used mk1 boards from Derek. ps. i have chenged the joystick already

Image
nice work, but is this a Cloney?
New album out now on Vince Clarke's VeryRecords
https://alka.fanlink.to/auguries

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Re: Cloney VCS3 Clone Builders?

Post by search64 » Thu Apr 01, 2021 3:40 am

No it has a 20x20 matrix.

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Re: Cloney VCS3 Clone Builders?

Post by RadekTymecki » Sat Apr 03, 2021 7:09 am

It's not Cloney, however it's using the very early boards from Derek which evolved to mk2/3/4 v. which were used later on in Cloney

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Re: Cloney VCS3 Clone Builders?

Post by search64 » Sat Apr 03, 2021 7:21 am

RadekTymecki wrote:
Sat Apr 03, 2021 7:09 am
It's not Cloney, however it's using the very early boards from Derek which evolved to mk2/3/4 v. which were used later on in Cloney
Did you design the panels?

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Re: Cloney VCS3 Clone Builders?

Post by RadekTymecki » Tue Apr 06, 2021 3:08 pm

back those days i had no real contact with synthi or vcs3... so i did the estimated size of panels and wooden cabinet

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