[ORDER] Roland 100M VCA PCBs/panels

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frequencycentral
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[ORDER] Roland 100M VCA PCBs/panels

Post by frequencycentral » Mon Jun 03, 2013 1:13 am

The classic Roland VCA redesigned to use CA3080 instead of BA662. The PCB is designed to fit nicely into your Euro system. Fabbed PCBs and front panels are now available from myself.

Image

Panels are on order and will in stock in a week or so, similar to below, with the exception that the 'Frequency Central' logo will be in reverse.

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PCBs in stock now...in fact lotsa PCBs in stock now. :tu:

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Roland 100M VCA PCB: £15 GBP

Roland 100M VCA panel (10HP): £15 GBP

International shipping £3 GBP

Paypal to payments AT frequencycentral.co.uk

Build Documentation: http://www.frequencycentral.co.uk/wp-co ... ld-Doc.pdf

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Skaput
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Post by Skaput » Wed Jan 22, 2014 12:21 pm

A very enjoyable build, sounds good to . But has anybody else struggled with the pots from tayda. Couldnt get them to fit until I chopped away those dust covers, and the pins took a little persuading before they seated properly in the board.

Also Looking at the picture above I think i wired my switch back to front.
Can anyone confirm if those hookup wire cross over, with the top switch contact going to the lower hole on the pcb

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Post by amdagan » Wed Jan 22, 2014 2:51 pm

Skaput wrote:A very enjoyable build, sounds good to . But has anybody else struggled with the pots from tayda. Couldnt get them to fit until I chopped away those dust covers, and the pins took a little persuading before they seated properly in the board.
Yeah those dust covers are a really good idea, except for tight panel layouts.
I had the same problem with tayda pots on the VCF and Phaser boards. I didn't want to take the dust covers off completely so I ended up grinding them down with a dremel in a few places; ironically creating lots more dust...

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dougt
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Post by dougt » Wed Jan 22, 2014 3:09 pm

I'm sure it's a cool VCA but if the main component has been changed how is it a "100M" VCA?

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Skaput
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Post by Skaput » Wed Jan 22, 2014 3:44 pm

dougt wrote:I'm sure it's a cool VCA but if the main component has been changed how is it a "100M" VCA?
Its not, if you look at the front panel its called system x amplifier.
Also if you read the sub miniature, microscopic ,infinitesimally tiny small print you will see the disclaimer
"The characters in this film are fictitious and any resemblance to persons living or dead is purely coincidental." :hihi:

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frequencycentral
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Post by frequencycentral » Wed Jan 22, 2014 6:23 pm

No need to cross the wires for the lin/exp switch. They are crossed on my PCB which is a prototype version, we fixed this for the production version.

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Post by Cablebasher » Mon Mar 03, 2014 5:59 pm

Are the points on the board where the toggle switch connects labeled the wrong way
Around?

On my board and the one shown above, the linear and exp points are opposite to where the trim pots are for them and the other way around to the wording on the front
Panel.

If the board is correct ,does that mean we cross the wires from the switch to the board?

Sorry if I've missed something?

Also, what are the trimpots actually doing? What am I trying to achieve with them?

Sorry,not used trimpots before.

Thanks as always.

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frequencycentral
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Post by frequencycentral » Mon Mar 03, 2014 6:11 pm

No you don't need to cross the wires for the switch, wire them direct. Trimpots are for matching the relative levels of lin and exp response. If in doubt, turn them both fully anticlockwise.

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Post by Cablebasher » Thu Sep 11, 2014 1:15 pm

Hello wigglers,

I built this great module a little while ago and it is realanswer at but I have always had this one issue I am finally getting around too and any help would be great.

My linear Vca output is lower that the input going into the Vca.

When a 5 volt sawtooth (or any) wave is going into either input and with a full constant sustain from a System X ADSR going into cv input 1 or 2 and with the cv attenuator fully open and the initial Gain fully off I always get around 3.4 volts output from the high output.

Every other aspect of the module works perfectly.

When I switch to exponential output I get unity with any input (5 volt) and can even get more than that when I turn the trim pot for exp.

Turning the trimpot for the Lin has no effect on its output (at least in terms of voltage). The trimpot itself is working however and as I turn it I can see its output leg on the PCB change in voltage as it is turned.

I have tried swapping both of the op amps with no difference.

Is there anything else I could try?

Sorry, I know it's needle in a haystack stuff but though I'd check in case there is maybe an obvious answer someone might think of.

Thanks as always.

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woodster
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Post by woodster » Fri Sep 19, 2014 4:54 am

Tayda don't do a 22k 6mm top adjust trimmer that is called for in the BOM.
Can I get away with using 20k ?

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Post by Reality Checkpoint » Fri Sep 19, 2014 5:23 am

woodster wrote:Tayda don't do a 22k 6mm top adjust trimmer that is called for in the BOM.
Can I get away with using 20k ?
Get them from Steve at Dr Tweek:

http://www.doctortweek.co.uk/shop/artic ... d%3D691%26

Fast, reliable and he is a wiggler too!

I have just checked my stock of trimmers and I am afraid I haven't got any 22k otherwise I would have sent you a couple!

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woodster
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Post by woodster » Fri Sep 19, 2014 5:53 am

Cheers for the link :tu:
they seem to be a different footprint though unfortunately.
Need the 3 pin type, like these -

Image

I'm hoping that I can just sub a 20k one, as I have some on hand.

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Reality Checkpoint
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Post by Reality Checkpoint » Fri Sep 19, 2014 5:56 am

Oooooops.

I only have 2k, 10k and 50k of those so still unable to help! :doh:

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Post by Jop » Fri Sep 19, 2014 8:15 am

Hi Woodster,

I have used a 25K without problems, this was also confirmed by Rick here:

viewtopic.php?t=52171&start=all&postday ... torder=asc

But looking at the actual build picture I see Rick uses a 20K himself. So I think in the end both 20 or 25K will do the trick :tu:

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woodster
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Post by woodster » Fri Sep 19, 2014 8:24 am

Many thanks Jop!

I didn't see that thread, some good info in there :tu:

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zvonx
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Post by zvonx » Sun Mar 01, 2015 12:47 pm

The initial gain knob, if turned up all the way overrides the incoming envelope. Is this the expect behavior? It seems to act as an additional attenuator - of sorts - on the incoming amp envelope.

Cool, because it adds a large variety of sounds just wanna make sure I have this working properly.

Thanks!

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frequencycentral
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Post by frequencycentral » Sun Mar 01, 2015 12:53 pm

Yes that's correct, it opens up the VCA.

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SmartBits
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Post by SmartBits » Tue Sep 22, 2015 9:41 am

I'm thinking about changing the frontpanels on my two FC System X VCA's but I'm wondering if they could be made to fit into 8 HP instead of 10. It looks like there is quite a bit of room on either side. Has anybody here done that? Changing both would give me an additional 4 HP of space which I could use for a FC Waverunner...

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Post by fitzgreyve » Wed Sep 23, 2015 4:53 am

SmartBits wrote:I'm thinking about changing the frontpanels on my two FC System X VCA's but I'm wondering if they could be made to fit into 8 HP instead of 10.
I have all my FC "10hp" modules installed on 8HP front panels (VCO, VCA, VCF).

The clearance is fairly tight between the PCB and sockets.

The main issue is that ground/0V connection to the sockets is a bit messy (you have to turn the sockets 90 degrees in relation to the FC 10hp orientation, so then can't just run a wire straight along all the ground connections as FC does).

PM me if you want a copy of my FPD file.

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SmartBits
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Post by SmartBits » Wed Sep 23, 2015 9:44 am

PM'd! :party:

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ZZ Ardoz
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Post by ZZ Ardoz » Wed Oct 21, 2015 9:29 am

So happy with the build and the result!! Thanks Rick!

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BrettAdams
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Post by BrettAdams » Sat Jun 25, 2016 3:06 pm

Any tips on finding CA3080's now? I just ordered the PCB/Panel for this and finding CA3080's seems to be painful now a days.

Any help appreciated.

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Post by synthdude » Sat Jun 25, 2016 4:46 pm


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Post by BrettAdams » Sat Jun 25, 2016 5:40 pm

I completely forgot to check smallbear. Thanks synthdude! Sorry for missing the obvious.

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Post by SMonk » Mon Feb 06, 2017 8:08 am

I'm having trouble with mine. It just sends whatever i put into the audio inputs straight through, CV and initial gain has no effect whatsoever. High out is louder than low, just as it's supposed to be

If i replace the LF351 with a TL071 it kind of works, but "backwards", ie CV in the CV inputs reduce the (otherwise continuous) output rather than the other way around.

Tried replacing literally every component, but no dice.

Does anyone have any suggestions where to start probing?

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