[AVAILABLE] Blacet VCO2100 + build thread

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[AVAILABLE] Blacet VCO2100 + build thread

Post by synthcube » Wed Jul 22, 2020 2:51 pm

The Blacet VCO2100 is the first of the Blacet modules that we are re-releasing, with availability as a PCB+Panel set or a full kit. We've already had a number of people purchasing the pcb+panel sets, so we are starting this thread for build narratives, pictures, questions, troubleshooting, demos, mods, etc. We hope these Blacet build threads end up as helpful to DIY builders as other threads have been for us over the years.

If you care about this sort of thing, synthCube kits for Blacet modules will use Blacet original stock parts while supplies last. We are converting the Blacet BOMs to a format we can use for individually labelling each parts bag, like we do for our other kits.

We had a (very) lengthy debate on the issue of documentation et al. Those of you who bought from Blacet in the past will remember that John was quite protective of his documentation; paper copies sent with kits and assembled modules, no pdfs etc. Consistent with more of the 'standard' for diy now, we are going to make the original PDF files openly available and encourage DIYers to use them to bring more examples of DIY Blacet module designs to life.

Pretty soon here, we will launch the Blacet DIY parts store, where we will have any part required for a Blacet build on-hand for ala-carte ordering.

If you have a Blacet VCO2100 and are willing to post a few pictures, a demo, a fun build story from the past etc-- that may help get the thread activated while people starting their builds get organized with parts etc...

hope to see some great examples here ....

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by KSS » Wed Jul 22, 2020 7:44 pm

This is great news!

Heads up that the notice on pg 14 is at odds with what you've shared here.

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by werock » Thu Jul 23, 2020 1:54 pm

My VCO panel & PCBs arrived here today. I'll probably stuff the board as much as I can with the parts I have on hand and then see what that leaves me to source. But I expect the LT1013 & LS318 to be tricky - I know I haven't got any of those.

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by johnchantler » Thu Jul 23, 2020 3:13 pm

werock wrote:
Thu Jul 23, 2020 1:54 pm
My VCO panel & PCBs arrived here today. I'll probably stuff the board as much as I can with the parts I have on hand and then see what that leaves me to source. But I expect the LT1013 & LS318 to be tricky - I know I haven't got any of those.
I'm still waiting on my boards (planning to build 3), but have already been looking through to see what is available where, still looking, but for now:

LT1013 is available at mouser
https://www.mouser.se/ProductDetail/Tex ... MVQw%3D%3D

LS318 seems to be available from Micross at GBP 3,72 each, but they have a 25 GBP minimum order:
no direct link, but search: https://shop.micross.com/shop-default.aspx

2N4391 (TO-18) will be restocked at Mouser 25 Sept, but costs a whopping 12,88 euro each !?
https://www.mouser.se/ProductDetail/Int ... 1FRA%3D%3D

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by werock » Thu Jul 23, 2020 5:02 pm

Thanks for the links.

It looks like there is an alternative 2N4391 at Mouser, lead free I think @ £2.18. Maybe the other one is so expensive as it's not RoHS.

https://www.mouser.co.uk/ProductDetail/ ... U4m0%2Fg==

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by johnchantler » Thu Jul 23, 2020 5:26 pm

oh, great. thank you. not sure how I missed that.

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by KSS » Thu Jul 23, 2020 7:12 pm

When searching 2Nxxxx transistors, don't forget to search PNxxxx also.

Beware of 'magic part' thinking. Although the 4391 does have better specs than its '92 and '93 cohorts listed on the Datasheets. It's being asked here to very quickly short out a capacitor. There are MANY transistors that will work in that duty.

alltransistors.com is a good resource for parametric 'equivalent searching.

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by fluxmonkey » Thu Jul 23, 2020 7:37 pm

Very nice. Does anybody have a source for the pots?
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by chachi » Thu Jul 23, 2020 8:23 pm

+1 on the pots, hopefully synthcube will offer those with this a la carte service (which is super exciting)?

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by synthcube » Sat Jul 25, 2020 1:08 pm

for now, just email us for what you need for pots-- we have a few boxes from the original Blacet stuff, we just have not put them into the inventory system yet---
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by werock » Wed Jul 29, 2020 5:44 pm

Has anyone got a part number (Mouser or anywhere) for the little black switches on the front panel? The choices are mind boggling.

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by uniqview » Wed Jul 29, 2020 11:43 pm

Just in case useful, here is the web page of the original equipment manufacturer of the LS318:
http://www.linearsystems.com/product-se ... mber=LS318
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by KSS » Thu Jul 30, 2020 10:18 pm

werock wrote:
Wed Jul 29, 2020 5:44 pm
Has anyone got a part number (Mouser or anywhere) for the little black switches on the front panel? The choices are mind boggling.
Looking at the PCB images in the build doc, they appear to be PCB mount right angle SPDT slide switches. They have three leads and two mechanical mount points outside these.

Start by measuring the distance between the pins and then the distance between the outer mounting tab holes. This will give you slide increment -distance between pins- and the body size of the switch -since the mounting tabs are at the end of the body.

From this, you should be able to quickly drill thourgh the many options to see if they have something suitable in their stock.

The final gotcha is to be sure the switch actuator is long enough to protrude through the panel and be activated by your fingers. This is the single most often seen problem in generally stocked slide switches at distributors like mouser and digikey. They tend to stock the cheaper varieties which wil tend to have shorter actuators. John probably had the switches specially made in this regard. That's common practice nowadays for slide switches.

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by synthcube » Thu Aug 06, 2020 2:24 pm

we are also doing some archeology to see if we can find part numbers and/or custom orders for all the parts in John's inventory and if we find this reference we'll post it
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by J3RK » Mon Aug 10, 2020 11:19 am

Quick note on the 4391. It's fairly easy to solder an SMT MMBF4391 to a through-hole footprint. I've done this on some of my own VCOs in the past before I added the separate SMT footprint. Just make sure to compare the pinouts closely so it's oriented correctly. The SMT ones are cheap and easy to find.
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by emmaker » Mon Aug 10, 2020 4:37 pm

synthcube wrote:
Thu Aug 06, 2020 2:24 pm
we are also doing some archeology to see if we can find part numbers and/or custom orders for all the parts in John's inventory and if we find this reference we'll post it
My Blacet system is pretty much done.

But one thing I'd like to see for it is a spare parts kit. One that contains pots, switches and other hard to get parts.

Thanks
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by Synthnerd » Fri Aug 21, 2020 5:11 pm

I built 2 Rev A VCOs many years ago. I took pictures of the assembly process; lost in a recent PC crash, but I'm trying to recover them.

Anyway, the first one worked fine straight off, but the second one did not. When I first powered it up it didn't produce sound, the LEDs in the CV Wave section dimly lit and IC U3 got really hot. I contacted John who suggested I pop out the IC and check power rail voltages. Sure enough, the 5V line off the voltage regulator was zero, indicating a short to ground. I poked around and couldn't figure it out until for some reason I can't explain, I removed the front panel off the pots, powered it up... and it worked! Checking around with an ohmmeter, I tracked it to a short from one of the standoff ears of a Panasonic pot that punched through the thin layer of epoxy over a 5V rail trace on the top side of the board right under the pot ears. Must have happened when I pressed the pot into place. Current was passing through that short to the pot frame into the front panel and then to the jacks that are all grounded at their panel contact. I used a Dremel tool to carefully grind the one metal pot ear away at the board (careful not to damage the trace), then use a dab of my daughter's clear nail polish to cover the trace.

Got back with John and explained what happened. He thanked me and said that this was a first and was surprised that the anodized later of the panel didn't insulate it. He also said that if he redesigned the board he would move that trace out from under the pot frames. I looked at the PCB layout for the later rev B posted by Synthcube, but can't tell from it if the move happened. It looks like John split the PCB to have the oscillator core on one board, and the waveshapers on a second one, but it's basically the same circuit.

As an aside, I have a 3rd VCO that I bought used and assembled. While still a rev A board, it is a later version with an AC/DC coupling switch with associated labeling on the front panel that was a common simple mod people were doing at the time. I suspect the PCB splitting for the rev B model was probably in large part due to him reducing module depth in the racks as well as reducing the number of fly wires.

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by johnchantler » Sat Aug 22, 2020 6:38 am

My boards arrived. :party:

I will be putting 3 of these behind a 4U panel (3" wide per VCO). I see now that there are no mounting holes on the #3 PCB and would love to take some advice on the best way to mount them.

Currently thinking I could stack each type of board behind each other, using the holes already there on board #2, and by drilling two holes for standoffs in board #3 in the spaces marked with red circles in the attached image. thoughts? These would then be fixed to aluminium rails that are fixed to the panel.
blacet VCO drill holes.png
blacet VCO drill holes 2.png

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by KSS » Sat Aug 22, 2020 4:37 pm

I would want better support than you have shown. At least three holes per PCB. I'd move R6 -easily done since you're not using the board mounting of panel components. Actually I'd just solder it under the PCB to the pads it shares with R1 and R2. 90 degree bent legs so its body lies over what was its top hole.
This then lets the hole location next to J4 be used for both large boards. Now we want something as far to the right of that -as oriented in your post- and that means between the jacks just below A1 of J11. Again there's a single trace 'in the way' which is easily re-moved.

You could instead use the existing hole you marked red and move the trace going to R20. But I'd make new holes, and not use the existing one you marked.

Then you want a third shared hole and fortunately there is *plenty* of room for that on both PCBs. The red hole you've marked at top in the larger board can be mated to one in the smaller board with a short strip of metal atop a 'normal' standoff on the larger board.

VCO2100-1 PCB can be used or not since it is only holding 'panel' wiring you can do direct. If used, there is room in the area of its J1 and J6 which is also free near J2 and J7 of VCO2100-2. Narrow board will be fine with only two supports.

Edit: you'll have a six PCB stack with three metal strips between pairs of standoffs to mate with the new third holes of your VCO2100-2 boards.
PNL==|=+|=|=+|=|=+|
text description of above ASCII graphc: Panel, long standoffs, VCO2100-3, standoff,alum strip,VCO2100-2, shot standoffs in place of those longerst between PNL and 1st PCB, repeat two more times. The "+" represent the alum strips to support -2 PCB from 3rd hole of -3 PCB.
Use washers as needed in the two standoff stacks that don't have aluminum strips to keep things even. I'd make these 'washers' from the same alum as the strips myself.

If you *do* include -1 PCB in the stack you'll have nine PCBs and can or must use shorter standoffs to keep the whole thing being too unwieldy and deep. Each -3 PCB gets two new holes and has one trace moved. Since you have 9 inches of horizontal space these could instead mount direct behind panel in their own stack using their existing holes. /edit

VCO2100-4 is going to be the most tricky. Since i'm familiar with your layout, I'd suggest trading these switches for something panel mounted like toggles. They'll fit nicely in the area they're assigned to, and toggles are more in line with the SERGE vibe of that layout.

Note that I might have the RefDes wrong in this description but hopefully you can sort out what is meant. Pictures of the actual board woulf make it easier to give solid advice. Due to scaling and uncertainty of layers and refdes. But I'm confident what's described above will work.
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by fluxmonkey » Sat Aug 22, 2020 7:53 pm

google "pcb edge mounting hardware" and you may find something that will work for you; i've used these: https://www.adafruit.com/product/1116
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by sneak-thief » Sun Aug 23, 2020 12:33 am

Fun fact: Blacet shipped many of these VCO DIY pcbs with all the resistors already stuffed (but not soldered).

My guess was that there was a non-insignificant amount of build issues due to incorrect resistor placement.
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by synthcube » Sun Aug 23, 2020 11:20 am

sneak-thief wrote:
Sun Aug 23, 2020 12:33 am
Fun fact: Blacet shipped many of these VCO DIY pcbs with all the resistors already stuffed (but not soldered).

My guess was that there was a non-insignificant amount of build issues due to incorrect resistor placement.
For those fans of synth archeology, there's a manual crank lead-bending tool in with some older Blacet items here, and some baggies filled with pre-bent resistors, we presume John was pre-stuffing some of the boards but elected NOT to bend all the leads by hand :)

We considered offering pre-formed leads for all of the resistors in all of our kits, an idea that lasted all of eleven seconds. :mrgreen:
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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by diophantine » Mon Aug 24, 2020 12:29 am

Kits from John often contained a combination of resistors with cut & bent leads, ones with cut leads, and ones with uncut leads.

I always found it helpful for sorting! :-)

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by johnchantler » Mon Aug 24, 2020 9:24 am

KSS — thanks for this suggestion. I'm going to try the PCB edge mounting kit that fluxmonkey suggests first... will be much simpler if it works. I think the aim is for two 3 PCB stacks: all of board 2 behind each other and all of board 3 behind each other.

the switches I've bought for this are panel mount, so I will skip boards 1 & 4 — wiring the jacks directly...

edit: I've also ordered some of the LS318 TO71 from micross in UK and will have 4 spare (needed to order more to make up the minimum order). Worked out at 6,50 euro each. If anyone in EU wants to buy these spares please get in touch — though they probably won't be here for a few weeks at least.

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Re: [AVAILABLE] Blacet VCO2100 + build thread

Post by johnchantler » Thu Oct 01, 2020 2:10 am

anyone know if it is possible to run this on +/-12v?

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