CS-80 filter v2.3 for Euro & 5U

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ZZ Ardoz
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Post by ZZ Ardoz » Fri Feb 02, 2018 5:03 pm

Any news on a new run of these?

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Sugarfree
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Post by Sugarfree » Fri Feb 02, 2018 5:05 pm

would like to know as well.

dustinosity
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Post by dustinosity » Tue Feb 13, 2018 5:02 pm

I would love to get one of these too!

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yan6
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Post by yan6 » Thu Apr 19, 2018 7:39 pm

I just got this built and am having some troubles i thought the video might better help describe them.

[video][/video]



Image

Image

kashmir
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Post by kashmir » Mon Apr 30, 2018 2:22 pm

Is the output on this filter supposed to be really quiet? When I take audio from single either SVF1 or SVF 2 (split mode) the level is like cca 80% of input volume, but when they are chained hp/lp, volume drops a lot to like 50% of input volume. When I do the chaining manually (HP1 out -> IN3, split mode) the volume from this chain is quite ok - 80% of input. Is this how it is supposed to be? My jumpers are positioned correctly.

And one more thing - the LPs outs don´t fully open, so the high frequencies are missing considerably. On both filters sounds the same. Do your filters work the same way or there is something wrong with mine?

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yan6
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Post by yan6 » Sat Oct 13, 2018 10:51 pm

After some time off I want to try and pull this from the fuck-it pile.

I was trying to go right back the basics and trace the input signal through. What I'm noticing is some kind of frequency dependency/response issue. I'm putting a sine wave into Input 1 and am monitoring LP1 out. I am finding that as the frequency increases the output volume decreases and is gone before 4KHz. Everything seems cool until Pin7 of IC2B :despair:

Hopefully someone can give me some pointers on this module and help me get it going.

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Post by kashmir » Tue Oct 16, 2018 4:58 am

yan6 wrote:After some time off I want to try and pull this from the fuck-it pile.

I was trying to go right back the basics and trace the input signal through. What I'm noticing is some kind of frequency dependency/response issue. I'm putting a sine wave into Input 1 and am monitoring LP1 out. I am finding that as the frequency increases the output volume decreases and is gone before 4KHz. Everything seems cool until Pin7 of IC2B :despair:

Hopefully someone can give me some pointers on this module and help me get it going.
I checked your video and the your filter seems to work fine. There is confusion with the HP/LP FREQ+RES pots, imagine they are named Filter1/Filter2 to make things more clear.

HP1/BP1/LP1 OUTS are effected only by Filter 1 /=HP/ knobs
HP2/BP2/LP2 OUTS are effected by Filter 2 /=LP/ knobs

AND

HP1 out is prewired into INPUT of filter 2, so if you take LP2 out it is affected by Filter 1 + Filter 2 knobs. Filter 1 knobs are controlling HP on first filter, so the pots are labeled HP and filter 2 knobs are controlling LP on second, so the pots are labeled LP. This is how it is configured on original.

If you want to separate the filters you use split switch and feed filter 2 with INPUT 3.

hope it makes sense :)

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yan6
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Post by yan6 » Tue Oct 16, 2018 10:50 pm

Kasmir amazing description thanks very much. I checked it out and it works exactly as you described.

The output is a bit low which seems like other have experienced this too. I'm going to see if that can be adjusted with some resistors. I also made these tiny tl072 pcbs for a similar issue with the CGS48 vco outputs not being balanced. Maybe I can cut the LPF2 output trace and bump it through on of these.

Thanks again!!

:bananallama:

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Post by kashmir » Wed Oct 17, 2018 2:39 am

If you take HP1 out and patch it into IN3 in split mode and monitor LP2 OUT you have the same setup as it is internally prewired but it is a bit louder since HP1 out it amplified at its output. Probably there might be some sonic difference due to the staging, but I guess it is minor.

I´m still not convinced about LP outs on my build, they both sound the same but I have the feeling they don´t open enough, the output it still filtered a lot with LP fully open. Does anyone have the same experience or hint what could be adjusted to make it better? I triple checked all the parts and found nothing wrong....

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yan6
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Post by yan6 » Thu Oct 18, 2018 9:36 pm

I can concur my LP outs have a slightly subdued sound to them as well. Its close but there is a bit of top end missing even with the filter all the way open

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Post by kashmir » Fri Oct 19, 2018 4:28 am

yan6 wrote:I can concur my LP outs have a slightly subdued sound to them as well. Its close but there is a bit of top end missing even with the filter all the way open
Thanks yan6, I have the feeling there is a LOT of top end missing on my build. I will try to do some measurements on scope to see how much it really cuts. I also found this document with some interesting info and sweep images with this kind of filter http://synthtech.com/docs/MOTM-480_manual.pdf

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Re:

Post by thetwlo » Tue Apr 07, 2020 5:59 pm

oldcrow wrote:
Mon Oct 24, 2016 8:54 pm
The M480 mk2 v2.3.2 build doc is here:

http://www.cs80.com/motm480/v232/M480Mk2v232_boards.pdf

I will have some images up to detail headers, etc. later this week.

Crow
/**/
Is there an updated/correct BOM for this?
I ordered parts based on this, but it seems to be missing several things/incorrect.

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thetwlo
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Re: CS-80 filter v2.3 for Euro & 5U

Post by thetwlo » Thu Apr 09, 2020 9:54 pm

The current panel is a PCB, it's sturdy, but has modelling all over it it certain light. Nothing like other black PCB panels from others.
A few quantities and items on the BOM are still wrong. They don't match the boards. So build your own BOM from the PCB.
EDIT: From many angles and under different light the modelling on the panel is barely noticeable. It is possible to take a pic without it showing up, still a bit bothering. I had to take a few pics to get it to at its worst.
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Last edited by thetwlo on Thu Apr 16, 2020 3:39 pm, edited 2 times in total.

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tvh
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Re: CS-80 filter v2.3 for Euro & 5U

Post by tvh » Fri Apr 10, 2020 9:54 am

This reminds me that I need the BOM and/or build guide for the 2.2 version I bought years ago. Don't suppose anyone has it laying around by chance?

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Norgatron
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Re: CS-80 filter v2.3 for Euro & 5U

Post by Norgatron » Sun Jun 14, 2020 4:44 pm

I just finished mine after a few weeks of ordering and building.
IMG_20200614_132758.JPG

It's an amazing tone and I had fun putting the Braids' CSAW through it to try and get that Brass 1 sound.

The BOM is still wrong, as noted just above. I have made notes and wish I'd re-read this thread before ordering, because I didn't realise that it has never been updated (at least the version I got from Modular Addict).
IMG_20200614_132811.JPG

Notes

There are two notes on the BOM
Note 1
R33, R33, R34 - 150K - DNP (do not place) on the mainboard, instead place on the Host Board
This has no effect on the BOM as the parts are still located on one of the boards

Note 2
R75, 76 - 150K - Only place if input signal (audio) is >5vpp
Eurorack is 10Vpp for audio, so these should be fitted.

Issues with the BOM
Missing/Wrong

These are the errors on the BOM which should be updated to match the PCB, or you will end up with missing parts when you order (unless you have them in your own stock):

C47 - 100nF 0805
C37,C40 - 180pF not 100pF - I used some large old radials which I had in stock.
C49,C50 - 10uF 25V 0805
R35 - 68K not 100K
R101 - 3M3 not 4M7
R55, R58 - 130K 5% not 200K - I used 120K

JP30 - is SW1 and the jumper is not needed.
On Schematic Filter (fig 1) it is next to VCA IN 2 JP21 and JP23A
Annotation is 'AC (open) DC (closed)'.
On Host board schematic (fig 4.) it relabelled SW1 with the same annotation.

Obsolete:
Regulators LM78/7910 are not available anymore.
Equivalents are available though and I just grabbed whatever was rated right and fitted okay.
Issues with panel
Jack sockets
The 3.5mm jack sockets specified are CUI PJ-301B (Erthenvar PJ-301B)
http://erthenvar.com/files/pj-301b.pdf
The height of this part is 10.5 - board to panel.

I bought Thonk PJ301BM, with the same height.

However, the actual panel to board height must include the 'collar' between the top of the base and start of the thread. The Old Crow panel does not cut out for this collar and so the panel to board height is actually 11.5mm.

Potentiometers
The 9mm pots in the BOM are Smallbear 1012A 1203 http://smallbear-electronics.mybigcomme ... -pc-mount/

That is Alpha RD901F-40-15R1-Val. https://www.mouser.co.uk/datasheet/2/13 ... -40-15R1-B(resistance_-1627810.pdf

These are the same as the parts I got from Thonk and are 10mm board to panel height.

I had to buy some M7 1.6mm nylon washers to get the heights to match.
x3 of the washers or x1 nuts that come with the Alpha pots also work, if you have plenty to spare.
IMG_20200614_132855.JPG
Switches
There's a similar issue with the switches. I used x2 spare jack socket nuts to fill the space, although they are too large and something else more suitable could be found.

Additional Parts
Nuts and bolts for the regulators. I used M3 from stock.

11.5mm stand offs for joing boards.
Old crow said " I also went with 12.7mm nylon board locks, much faster to assemble vs. screws, pillars, etc.", but that is too high and you can see there's a gap in connectors. I ended up using M3 10mm brass threaded pillars and some locks washers. It went together quite snug and whilst not essential I'm glad it's all secured.
IMG_20200614_132929.JPG
Curses
I ordered the wrong 3u3 caps. They should have been bipolar and I ordered polarised. Grr.
Weirdly I orderd bipolar parts for the DC section, which should have just been cheaper polarised caps. Go figure. I probably miserad the BOM as they are next to each other.

Panel Scales
And finally, the scales on the pots are 270 degrees but the Alpha pots are 300 degrees. Modular Addict don't have the .fpd file but if you order from CS80.com they say you can get that and, if it offends you enough, make your own.
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Yamaha SS30 strings - rack-mount with MIDI project - http://ss30m.blogspot.co.uk/

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thetwlo
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Re: CS-80 filter v2.3 for Euro & 5U

Post by thetwlo » Mon Jun 15, 2020 12:21 pm

Norgatron wrote:
Sun Jun 14, 2020 4:44 pm
I just finished mine after a few weeks of ordering and building. ....
Excellent! already built mine but this should really help others! :tu:

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soup
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Re: CS-80 filter v2.3 for Euro & 5U

Post by soup » Tue Sep 15, 2020 7:26 pm

I finished building a frac version...
DSCF2117.jpg
DSCF2101.jpg
Nice filter!
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forbin
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Re: CS-80 filter v2.3 for Euro & 5U

Post by forbin » Wed Sep 16, 2020 6:53 am

There was a version of this filter for the Shruthi on GitHub if people want a schematic to help out.
see: https://github.com/cs80/cs80_shruthi
I suspect that it is very similar?

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