BUILD THREAD: 266-style PCBs

janvanvolt · Post by **janvanvolt** » Thu Aug 16, 2012 9:26 pm

Okay, 1nf soldered in. Everything as it should be - except the quatization. So another working Source of Uncertainty done :-)

So i'm now waiting for the frontpanel and the correction mods for 12V correct quantizing.

E.A.S. · Post by **E.A.S.** » Thu Aug 16, 2012 10:00 pm

janvanvolt wrote:Okay, 1nf soldered in. Everything as it should be - except the quatization. So another working Source of Uncertainty done :-)

So i'm now waiting for the frontpanel and the correction mods for 12V correct quantizing.

To fix quantizer on 12v version, change R46 (on board 2) from 68.1k to 46.4k.

Edit: Also you'd want to change R59 (on board 2) from 60.1k to 75k

I don't have the euro version, so I can't try this out, but I think it should work.

Someone try it out.

-Mike

JCM · Post by **JCM** » Fri Aug 17, 2012 7:54 pm

I got my Buchla version mostly up and running, but I'm getting nothing out of the noise source and S&H. I think I may have a bad noise chip, power and ground seem to be getting to the right pins. Also what is to be expected out of the "noisy triangle"? I'm just getting a steady triangle on the scope.

I suspect the triggers from the DIY topp 281 end outs are not good enough to trigger the S&H. Are there resistors I can change for this? My system is only DIY, so I need a little more forgiveness with what the S&H will accept for triggers/gates.

Also I need to upgrade my power supply, the LED's seem to be effecting the pitch of my VCO's.

JCM · Post by **JCM** » Fri Aug 17, 2012 8:43 pm

Or maybe I just don't fully understand a Sample & Hold. Do I need a sustained gate signal?

Luka · Post by **Luka** » Fri Aug 17, 2012 11:12 pm

(editing post for clarity)

the frv works a bit different to the qrv and srv in that it uses the noise and the 555 for the clock and crazyness. if the noise isnt working i dont think much else will.

the qrv and srv need to be triggered to get an event whereas the frv just runs

nickster · Post by **nickster** » Sat Aug 18, 2012 4:38 am

Sorry for the confusion but are we good to go now on the Eurorack version? What changes need to be done etc? Or are we still waiting on confirmation from Roman? Can someone kindly clarify this for me, reading previous posts would indicate that the 12v version is not working yet pending some alterations, am I correct in this?

JCM · Post by **JCM** » Sat Aug 18, 2012 11:30 am

Luka wrote:(editing post for clarity)

the frv works a bit different to the qrv and srv in that it uses the noise and the 555 for the clock and crazyness. if the noise isnt working i dont think much else will.

the qrv and srv need to be triggered to get an event whereas the frv just runs

Thanks for that. The FRV is giving me something, but it's not very "fluctuating". It just behaves like an LFO and will seemingly lock up at some settings.

The QRV and SRV behave as expected.

I ordered a new noise chip, we'll see if that does it.

Anyone on the S&H triggers? The end outs on the 281 trigger the QRV and SRV, but I get nothing from the S&H.

JCM · Post by **JCM** » Sat Aug 18, 2012 11:42 am

I'll try removing R16 & R35 and see if that helps.

roman_f · Post by **roman_f** » Sun Aug 19, 2012 4:51 pm

JCM wrote:I'll try removing R16 & R35 and see if that helps.

first of all you should check the NT pad (top right) if there's a noisy triangle
if it doesn't happen - then you should check the noise section
if it is happening - FRV is not ok

roman_f · Post by **roman_f** » Sun Aug 19, 2012 4:54 pm

i'm sorry i was out for a while
will help everyone with their questions

janvanvolt · Post by **janvanvolt** » Sun Aug 19, 2012 6:46 pm

Hi Roman,

did all the changes to R46 and R59 and it seems now everything is correct.
How can i actually verify ? My assumptions are based on various youtube videos comparing against the behavior and results..

jaidee · Post by **jaidee** » Mon Aug 20, 2012 5:39 am

Can anyone verify whether Switchcraft 112AX jacks as per the group buy happening on this list will fit the 5U/MOTM PCBs?

These jacks have solder terminals rather than PCB pins, but Roman's PCBs are clearly intended to accommodate a lug rather than a pin!

I've asked the same question on the group order thread, so apologies for the cross-posting.

Alternatively, does anyone have a UK source for a reasonable (in terms of cost and quality) alternative socket?

Unfortunately, the shipping cost of the Bridechamber sockets plus the likelihood of customs charges makes them a less than economic alternative.

My local supplier, ESR. has some dirt cheap sockets, but the quality is shite...

Thanks

ringstone · Post by **ringstone** » Tue Aug 21, 2012 9:33 am

janvanvolt wrote:Hi Roman,

did all the changes to R46 and R59 and it seems now everything is correct.
How can i actually verify ? My assumptions are based on various youtube videos comparing against the behavior and results..

I'd be grateful if you could verify for me that you didn't install these components:
D12, D13, IC15, IC14, L4, L3, R44, C14, C41, C40

as well as doing the changes to R46 and R59?

Thanks!
Blair

marvkaye · Post by **marvkaye** » Tue Aug 21, 2012 10:19 am

jaidee wrote:Can anyone verify whether Switchcraft 112AX jacks as per the group buy happening on this list will fit the 5U/MOTM PCBs?

These jacks have solder terminals rather than PCB pins, but Roman's PCBs are clearly intended to accommodate a lug rather than a pin!

I've asked the same question on the group order thread, so apologies for the cross-posting.

Alternatively, does anyone have a UK source for a reasonable (in terms of cost and quality) alternative socket?

Unfortunately, the shipping cost of the Bridechamber sockets plus the likelihood of customs charges makes them a less than economic alternative.

My local supplier, ESR. has some dirt cheap sockets, but the quality is shite...

Thanks

Question was answered yesterday on the group-buy thread. Go to this page, almost to the bottom. Yes, they fit. Sorry, I don't have an alternate source for you in UK, but I'm sure someone will.

<marv>

thebot · Post by **thebot** » Tue Aug 21, 2012 11:33 am

marvkaye wrote:
jaidee wrote:Can anyone verify whether Switchcraft 112AX jacks as per the group buy happening on this list will fit the 5U/MOTM PCBs?

These jacks have solder terminals rather than PCB pins, but Roman's PCBs are clearly intended to accommodate a lug rather than a pin!

I've asked the same question on the group order thread, so apologies for the cross-posting.

Alternatively, does anyone have a UK source for a reasonable (in terms of cost and quality) alternative socket?

Unfortunately, the shipping cost of the Bridechamber sockets plus the likelihood of customs charges makes them a less than economic alternative.

My local supplier, ESR. has some dirt cheap sockets, but the quality is shite...

Thanks
Question was answered yesterday on the group-buy thread. Go to this page, almost to the bottom. Yes, they fit. Sorry, I don't have an alternate source for you in UK, but I'm sure someone will.

<marv>

Here you go:

http://www.rapidonline.com/Cables-Conne ... et-20-1430

E.A.S. · Post by **E.A.S.** » Tue Aug 21, 2012 11:43 am

janvanvolt wrote:
did all the changes to R46 and R59 and it seems now everything is correct.

Glad to hear it seems to be working!

A little on what those changes do...

When when looking at the original schematics I saw the reference voltage to the comparators needed to be -5.6v. The voltage divider obtains it reference via a voltage divider hooked between the - rail and ground. Obviously when you change the rail voltage, your reference voltage will be off! When powered from 12v the reference voltage lowers to -4.488. Not gonna work right. With a little simple maths we find the value for R46 needs to be lowered to around 46.4k. (more precisely 46.491k, but the more common value of 46.4k gives -5.606v, still pretty good.)

The next change needed to be changed to bring range of the input back up.

With the quantization knob all the way up, you wouldn't get the full range out of the knob. R59 sets the gain of the quantization input mixer. Because we've lowered the voltage feeding the QRV pot (from +15 rail to +12v), you wont get the full 0 to -6v range you need out of the op-amp output to feed the comparators. So changing R59 to to 75k, gives you the -.5 x gain you need to scale the voltage correctly.

There could be more changes I'm overlooking, but at least these two parts should be changed.

-Mike

jaidee · Post by **jaidee** » Tue Aug 21, 2012 12:47 pm

Thanks for ths jacK socket info guys!

janvanvolt · Post by **janvanvolt** » Tue Aug 21, 2012 8:29 pm

ringstone wrote:
janvanvolt wrote:Hi Roman,

did all the changes to R46 and R59 and it seems now everything is correct.
How can i actually verify ? My assumptions are based on various youtube videos comparing against the behavior and results..
I'd be grateful if you could verify for me that you didn't install these components:
D12, D13, IC15, IC14, L4, L3, R44, C14, C41, C40

as well as doing the changes to R46 and R59?

Thanks!
Blair

I just followed the instructions for the 15V build, e.g. no PCB cuts,
some jumpers and R46 and R59 changed. Just got the panel today. Module is now fully finished and working here :-)

rowman · Post by **rowman** » Tue Aug 21, 2012 8:35 pm

Just removed the voltage regulators from my spreadsheet, thanks for figuring this out guys.

ringstone · Post by **ringstone** » Tue Aug 21, 2012 8:42 pm

janvanvolt wrote:
ringstone wrote:
janvanvolt wrote:Hi Roman,

did all the changes to R46 and R59 and it seems now everything is correct.
How can i actually verify ? My assumptions are based on various youtube videos comparing against the behavior and results..
I'd be grateful if you could verify for me that you didn't install these components:
D12, D13, IC15, IC14, L4, L3, R44, C14, C41, C40

as well as doing the changes to R46 and R59?

Thanks!
Blair
I just followed the instructions for the 15V build, e.g. no PCB cuts,
some jumpers and R46 and R59 changed. Just got the panel today. Module is now fully finished and working here :-)

Thank you! That reduces the BOM cost by about $15 I think

Cheers
Blair

numbertalk · Post by **numbertalk** » Tue Aug 21, 2012 9:25 pm

janvanvolt wrote:I just followed the instructions for the 15V build, e.g. no PCB cuts,
some jumpers and R46 and R59 changed. Just got the panel today. Module is now fully finished and working here :-)

Post some pics!

nickster · Post by **nickster** » Wed Aug 22, 2012 9:28 am

So for correct 12v Eurorack to function we actually need to follow the 15 v (eurorack) installation instructions omitting D12, D13, IC15, IC14, L4, L3, R44, C14, C41, C40

And changing R46 to a 46.4k resistor on Board 2,
also changing R59 to a 75K Resistor again on Board 2.

No traces need to be cut.

Can somebody confirm this for me and Roman if possible can you update the build documents.

Thanks very much in advance.
8_)

msprigings · Post by **msprigings** » Wed Aug 22, 2012 3:46 pm

I too would like to get started on this one. Just need the final working build instructions!

L-1 · Post by **L-1** » Thu Aug 23, 2012 12:01 am

I've almost finished my build but still wait for some parts.
Just fit panel with Kobiconn jacks and Alpha pots

- some thin about 0,5mm washers are needed for full happiness.

hellpony · Post by **hellpony** » Fri Aug 24, 2012 6:21 pm

Any word on the euro build corrections?

MUFF WIGGLER

MUFF WIGGLER

BUILD THREAD: 266-style PCBs