ARP 3620 clone project

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: luketeaford, Joe., lisa, Kent

Post Reply
gruvsyco
Wiggling with Experience
Posts: 329
Joined: Fri May 18, 2012 1:55 pm
Location: Kalispell, MT

Post by gruvsyco » Mon Oct 30, 2017 10:10 pm

Sweet! I've got a Fatar 37 key waiting and it looks like the 1601s are imminent. Hopefully, the 3620s are not too far behind. I've got a sheet metal design in the works to make an all in one TTSH/1601/3620 37 key monster.

:hyper:

JanneI
Wiggling with Experience
Posts: 370
Joined: Mon Oct 19, 2015 3:28 am

Post by JanneI » Mon Oct 30, 2017 11:32 pm

Good news! I'm interested!

User avatar
dingebre
Wiggling with Experience
Posts: 323
Joined: Tue Mar 24, 2009 1:28 pm
Contact:

Post by dingebre » Tue Oct 31, 2017 12:36 am

gruvsyco wrote:Sweet! I've got a Fatar 37 key waiting and it looks like the 1601s are imminent. Hopefully, the 3620s are not too far behind. I've got a sheet metal design in the works to make an all in one TTSH/1601/3620 37 key monster.

:hyper:
I'm really sorry, but the 37 note keybed uses a different connector wiring and won't work with this decoder board. This decoder will work for 49 and 61 note keybeds only.

David
David M. Ingebretsen
AnalogueRealities.com

dingebre@3dphysics.net
dingebre@CFandE.com

gruvsyco
Wiggling with Experience
Posts: 329
Joined: Fri May 18, 2012 1:55 pm
Location: Kalispell, MT

Post by gruvsyco » Tue Oct 31, 2017 8:10 am

dingebre wrote:
gruvsyco wrote:Sweet! I've got a Fatar 37 key waiting and it looks like the 1601s are imminent. Hopefully, the 3620s are not too far behind. I've got a sheet metal design in the works to make an all in one TTSH/1601/3620 37 key monster.

:hyper:
I'm really sorry, but the 37 note keybed uses a different connector wiring and won't work with this decoder board. This decoder will work for 49 and 61 note keybeds only.

David
Awww :cry:

User avatar
dingebre
Wiggling with Experience
Posts: 323
Joined: Tue Mar 24, 2009 1:28 pm
Contact:

Post by dingebre » Sat Nov 25, 2017 7:39 pm

Quick update. I got my order for the decoder PCBs, and they had errors. Short version, I have placed a new order with a different manufacturer and should have them in hand in 2-3 weeks.

David
David M. Ingebretsen
AnalogueRealities.com

dingebre@3dphysics.net
dingebre@CFandE.com

JanneI
Wiggling with Experience
Posts: 370
Joined: Mon Oct 19, 2015 3:28 am

Post by JanneI » Sun Mar 25, 2018 12:41 pm

dingebre wrote:Quick update. I got my order for the decoder PCBs, and they had errors. Short version, I have placed a new order with a different manufacturer and should have them in hand in 2-3 weeks.

David
Any news on this fatar decoder project? Thanks!

User avatar
dingebre
Wiggling with Experience
Posts: 323
Joined: Tue Mar 24, 2009 1:28 pm
Contact:

Post by dingebre » Sun Mar 25, 2018 5:47 pm

JanneI wrote:
dingebre wrote:Quick update. I got my order for the decoder PCBs, and they had errors. Short version, I have placed a new order with a different manufacturer and should have them in hand in 2-3 weeks.

David
Any news on this fatar decoder project? Thanks!
Sorry, I have the decoder PCBs and will get a purchase page on my website soon.

Is anyone interested in the relay PCBs? I have designs for single buss and dual buss that should accommodate Steiner Duophonic (tested working), ARP 3620, Aries 313, Moog 952, and Minimoog. I tried to implement options to deal with some of the extra circuitry that the ARP and Aries adds to the keybed buss itself.

David
David M. Ingebretsen
AnalogueRealities.com

dingebre@3dphysics.net
dingebre@CFandE.com

User avatar
dingebre
Wiggling with Experience
Posts: 323
Joined: Tue Mar 24, 2009 1:28 pm
Contact:

Post by dingebre » Tue May 22, 2018 7:58 pm

Yes, finally. I remembered to add the page to my website. If you purchase one, I'll have to email you the documents. I have not made time to put them together, sorry.

http://analoguerealities.com/projects/f ... d-decoder/

PM or email with any questions or comments.

David
David M. Ingebretsen
AnalogueRealities.com

dingebre@3dphysics.net
dingebre@CFandE.com

User avatar
solar1
Learning to Wiggle
Posts: 49
Joined: Fri Jul 31, 2015 5:14 pm
Location: USA

61 note keyboard for 3620

Post by solar1 » Sat May 26, 2018 3:05 pm

Hello Folks,
It's been awhile since I've looked in on this thread.

I wanted to check in with the group to see if there is anyone interested in a 61 note Pratt Read keyboard for use with their 3620 project.
I seem to remember some folks were looking for a suitable keyboard assembly for their project.

If there is interest, I will offer it here on the Muff Wiggler first in order to give our group first opportunity to complete their 3620 project.
I understand this thread is not for buy/sell. I just wanted to see if there is any interest at all.

For those folks whom may question the extended range being an issue concerning the added CV resistors, I can tell you that I used a 61 note board and it is working fine. Calibration was successful.
Thanks

JanneI
Wiggling with Experience
Posts: 370
Joined: Mon Oct 19, 2015 3:28 am

Re: 61 note keyboard for 3620

Post by JanneI » Wed Nov 21, 2018 2:59 am

What's the status of this project, Fatar keybed + 3620? I would like to build it if there's a pcb for Fatar decoder that works with the 3620 project. Thanks!

User avatar
dingebre
Wiggling with Experience
Posts: 323
Joined: Tue Mar 24, 2009 1:28 pm
Contact:

Re: 61 note keyboard for 3620

Post by dingebre » Wed Nov 21, 2018 9:36 pm

JanneI wrote:What's the status of this project, Fatar keybed + 3620? I would like to build it if there's a pcb for Fatar decoder that works with the 3620 project. Thanks!
The current FATAR decoder PCB works with either a 49 key or 61 key keybed. The dual reed relay PCB I designed was designed primarily with the Moog 952 and ARP 3620 keyboards in mind. The FATAR PCB fits nicely, if a little tight, between the mounting studs on a typical FATAR keybed. The dual reed relay PCB (needed for the dual buss ARP keybed) is bigger than the decodere PCB and may need some thought about where it can be placed. I'm not sure if jhulk redisgned the relay PCB or not. It's big enough that it's a little expensive to make and I've had a little trouble finding a reasonably priced PCB manufacturer who can handle the relay PCBs. I had a few prototypes made at OSH Park and I'm happy to make the project public if anyone wants.

David
David M. Ingebretsen
AnalogueRealities.com

dingebre@3dphysics.net
dingebre@CFandE.com

JanneI
Wiggling with Experience
Posts: 370
Joined: Mon Oct 19, 2015 3:28 am

Re: 61 note keyboard for 3620

Post by JanneI » Thu Nov 22, 2018 2:32 am

dingebre wrote:...and I'm happy to make the project public if anyone wants.
hmpf.. I'm a little confused who's selling exactly what and which pcb's are needed. I already have a couple of Fatar keybeds (3/4/5 octave versions) but for completing 3620 build with Fatar keybed I'll need: keybed, decoder pcb, "main 3620 pcb", what else? Thanks!

User avatar
dingebre
Wiggling with Experience
Posts: 323
Joined: Tue Mar 24, 2009 1:28 pm
Contact:

Re: 61 note keyboard for 3620

Post by dingebre » Thu Nov 22, 2018 5:09 pm

JanneI wrote:
dingebre wrote:...and I'm happy to make the project public if anyone wants.
hmpf.. I'm a little confused who's selling exactly what and which pcb's are needed. I already have a couple of Fatar keybeds (3/4/5 octave versions) but for completing 3620 build with Fatar keybed I'll need: keybed, decoder pcb, "main 3620 pcb", what else? Thanks!
Hi,

This is not sarcasm, but what you need depends on what/how you build it. You need the keyboard electronics (PCB, parts, panel), a keybed, and a case.

If you use a dual buss Pratt Read keybed or a NOS Kimber Allen organ keybed, you don't need any additional keyboard stuff except for the precision resistors for the ladder and the resistors for the gate switches.

If you want to use a modern FATAR matrix type, you will need a way to take the FATAR data, decode it, and then drive some sort of switch array so that you get an independent switch closure (well, two switches to emulate the dual buss for the ARP electronics) for each key press. The solution I pursued uses reed relays arranged so that the CV relay closes first and then also closes the GATE reed relay switch so the CV voltage is set first, then the GATE is output.

The FATAR decoder PCB that is on my store works great. Jhulk may also sell them at some point as he helped tremendously in its layout and design. Roman Sowa designed the circuit and generously put it in the public domain (long story here, for a different post. Thank you Roman!!!). This PCB works with a 4 or 5 octave keybed only.

You then need another PCB that has your "switches". I have just a copule of spare dual buss emulating PCBs that use reed relays configured as I described. As much as I tried to pack the parts on the PCB, it's still kind of big. I have photos in an earlier post, maybe a couple of pages back. Depending on your case, you may have to be creative on where you mount it. The decoder PCB fits between the mounting studs and under a FATAR keybed (you may need to add spacers under the keybed to give a little more vertical room), but the relay PCB won't fit between the mounting studs.

All I know for sure is I am selling the decoder PCBs actively on my web store, and like I said, I think I have one or two spare relay PCBs. For the other stuff, you'll have to look back through this thread to see who is doing what, sorry.

David
David M. Ingebretsen
AnalogueRealities.com

dingebre@3dphysics.net
dingebre@CFandE.com

User avatar
Kipling
Ultra Wiggler
Posts: 958
Joined: Tue Dec 10, 2013 3:31 pm
Location: South-East England

Post by Kipling » Thu Nov 22, 2018 5:43 pm

Hi all

I had intended to produce another small batch of the 3620 PCB and panel sets some time ago but so far have not, principally because several parts are now obsolete and/or getting hard to find and expensive.

I believe Jammie (jhulk) is working on a new version with modern parts with extra features. He doesn’t visit here these days but you can find him on FB as Logan Soloman. He posts under his Wife’s FB account as he doesn’t have an account of his own.

User avatar
fuzzbass
Super Deluxe Wiggler
Posts: 2082
Joined: Thu Feb 06, 2014 6:08 pm
Location: Florida, USA

Post by fuzzbass » Thu Jan 31, 2019 11:31 am

One of my TTSH commissions has obtained the PCB/Panel for this project, and has asked me to integrate a connector for it on the TTSH.

The OP here shows a six conductor + shield interface connector. Are these the suggested signals/lines:

1. 0 volts
2. +15V
3. -15V
4. Lower CV
5. Gate CV
6. Trigger CV

Also, is the connector type shown available at retail?
Wired for weird

User avatar
LED-man
Super Deluxe Wiggler
Posts: 1475
Joined: Wed Aug 08, 2012 1:48 pm
Location: Wolfsburg Germany

Post by LED-man » Thu Jan 31, 2019 11:36 am

################################
TTSH Support Page and other DIY Projects:
https://www.DSL-man.de

User avatar
memristor
Learning to Wiggle
Posts: 6
Joined: Sat Nov 01, 2014 8:19 pm
Location: sad lad

Post by memristor » Sat Feb 02, 2019 4:37 pm

I am looking for a 3620 board/panel set.

There is a board on oshpark, but it is a bit pricey at $273 due to the square inch costing. The picture show JR Daniels, rev 2.

Please tell me if you can, what are the hard-to find/expensive components for that board revision?
I'm not mean to Bambi

User avatar
Kipling
Ultra Wiggler
Posts: 958
Joined: Tue Dec 10, 2013 3:31 pm
Location: South-East England

Post by Kipling » Sun Feb 03, 2019 3:44 pm

memristor wrote:I am looking for a 3620 board/panel set.

There is a board on oshpark, but it is a bit pricey at $273 due to the square inch costing. The picture show JR Daniels, rev 2.

Please tell me if you can, what are the hard-to find/expensive components for that board revision?
The PCB price is way too high - my original batch of four cost around £60 (GBP) if I recall from a local PCB manufacturer, so with the gerber files you should be able to get a one-off made somewhere for a fraction of that price. The files are posted somewhere in this thread.

I have my original hand-made panel available for a nominal sum plus postage. I think there are pictures of it earlier in the thread with the white lettering.

The obsolete parts are 2N5459, 2N5461 and 2N3958, all of which can be found with a little searching.

The toggle switch is a Mouser part # 633-M2044TNW01 and the paddle 633-AT4149A which are in stock.

It needs two polycarbonate 0.47uF capacitors with 22mm lead spacing (Philips or Wima MKC 344 ideally). I have a number of these and will throw a couple in if you buy the panel, along with a six-pin panel connector and line socket.

User avatar
dingebre
Wiggling with Experience
Posts: 323
Joined: Tue Mar 24, 2009 1:28 pm
Contact:

Post by dingebre » Mon Feb 04, 2019 12:43 am

Kipling wrote:
memristor wrote:I am looking for a 3620 board/panel set.

There is a board on oshpark, but it is a bit pricey at $273 due to the square inch costing. The picture show JR Daniels, rev 2.

Please tell me if you can, what are the hard-to find/expensive components for that board revision?
The PCB price is way too high - my original batch of four cost around £60 (GBP) if I recall from a local PCB manufacturer, so with the gerber files you should be able to get a one-off made somewhere for a fraction of that price. The files are posted somewhere in this thread.

I have my original hand-made panel available for a nominal sum plus postage. I think there are pictures of it earlier in the thread with the white lettering.

The obsolete parts are 2N5459, 2N5461 and 2N3958, all of which can be found with a little searching.

The toggle switch is a Mouser part # 633-M2044TNW01 and the paddle 633-AT4149A which are in stock.

It needs two polycarbonate 0.47uF capacitors with 22mm lead spacing (Philips or Wima MKC 344 ideally). I have a number of these and will throw a couple in if you buy the panel, along with a six-pin panel connector and line socket.
Mouser has 32 2N3958 in stock, pricey :)
https://www.mouser.com/Search/Refine?Keyword=2N3958

You can get the Linear Systems brand from Trendsetter Electonics for about 1/3 the price compared to Mouser
https://www.trendsetter.com/Transistor- ... 1%206l.htm

Jameco has the 2N5461 and 2N5459
https://www.jameco.com

With Kipling's permission, I also have a Front Panel Express file for the panel I can post. A little expensive, about $110.00 USD, but you can also edit the file to accommodate which ever plug you want, or use a cable gland with a hard wired cable to the keyboard. I have it with both new and old ARP logos, gray or black.

David
David M. Ingebretsen
AnalogueRealities.com

dingebre@3dphysics.net
dingebre@CFandE.com

User avatar
MrRoper
Common Wiggler
Posts: 147
Joined: Fri Nov 28, 2014 8:24 am
Location: London

Post by MrRoper » Wed Feb 06, 2019 5:21 am

memristor wrote:I am looking for a 3620 board/panel set.

There is a board on oshpark, but it is a bit pricey at $273 due to the square inch costing. The picture show JR Daniels, rev 2.

Please tell me if you can, what are the hard-to find/expensive components for that board revision?
I was also looking for a pcb, so perhaps if it's convenient and want to split the costs of getting a couple made up please PM. Was thinking about trying to etch but never done double sided before.

User avatar
Jaytee
Veteran Wiggler
Posts: 739
Joined: Mon Mar 11, 2013 5:12 pm

Post by Jaytee » Wed Feb 06, 2019 11:07 am

Osh Park is simply a bad choice for a project like this. Their pricing is oriented toward very small boards; anything more than a few square inches gets real expensive, real quick.

That said, it wouldn’t be too hard to do a small run of PCBs/panels from a more traditional PCB fab. The PCB fabs don’t make quite as nice of panels as folks like FPE, but they’re “good enough” and much cheaper.

I’m in the US and could probably be coaxed into running a group buy for these if there’s interest. Let me know and I can get some rough quotes.

User avatar
fuzzbass
Super Deluxe Wiggler
Posts: 2082
Joined: Thu Feb 06, 2014 6:08 pm
Location: Florida, USA

Post by fuzzbass » Tue Feb 12, 2019 12:11 pm

One of my TTSH commission customers has asked me to add a connection for the 3600 series keyboard. The build has a gate booster embedded in the standard way, as documented here: viewtopic.php?p=1789587.

Bringing the 3600 gate to the input of the Booster would result in loss of multiple trigger capability. Tying the gate and trigger CV outputs from keyboard and booster together at the TTSH inputs would not adequately isolate those outputs from each other.

I have devised a simple circuit that will merge the gate and trigger CVs coming from both the 3600 and the booster, using OR gates. This is a simplified drawing that omits the required 100n decoupling caps and 1u power rail caps.
Image

Here it is built on a breadboard style protoboard. I used 1M input resistors and a CD4071 (quad, two_input OR gates). Notice all unused CD4071 inputs and outputs are tied to ground. The decoupling cap for VDD on the CMOS chip is hiding under the big orange jumper.

Image
Last edited by fuzzbass on Wed Feb 13, 2019 11:06 am, edited 2 times in total.
Wired for weird

User avatar
MrRoper
Common Wiggler
Posts: 147
Joined: Fri Nov 28, 2014 8:24 am
Location: London

Post by MrRoper » Wed Feb 13, 2019 5:36 am

Jaytee wrote:Osh Park is simply a bad choice for a project like this. Their pricing is oriented toward very small boards; anything more than a few square inches gets real expensive, real quick.

That said, it wouldn’t be too hard to do a small run of PCBs/panels from a more traditional PCB fab. The PCB fabs don’t make quite as nice of panels as folks like FPE, but they’re “good enough” and much cheaper.

I’m in the US and could probably be coaxed into running a group buy for these if there’s interest. Let me know and I can get some rough quotes.
I'm certainly interested a pcb if the groupbuy happens although im based in the UK

Also that's amazing work Fuzzbass! I'm actually looking to add a gatebooster to my TTSH at some point so this is great info to have when I get my 3620 working again. Thanks!

Dan

Quadram
Learning to Wiggle
Posts: 38
Joined: Thu Feb 19, 2015 4:28 pm
Location: Paris FR

Post by Quadram » Wed Feb 13, 2019 11:33 am

I'm also interested in a pcb if there a groupbuy.

thanks Fuzzbas for this circuit :yay:

User avatar
fuzzbass
Super Deluxe Wiggler
Posts: 2082
Joined: Thu Feb 06, 2014 6:08 pm
Location: Florida, USA

Post by fuzzbass » Sat Feb 16, 2019 8:19 am

Quadram wrote:I'm also interested in a pcb if there a groupbuy.

thanks Fuzzbas for this circuit :yay:
I only have one request for this, so unless there is a groundswell of interest here, it does not make much sense for me to take this past the prototype.

However, if you want to make a little board for it, you have my permission so long as you give attribution. :bananaguitar:

I also experimented with a concept for incoming pitch CV from the keyboard (CV1 in this case). By adding a high accuracy CV summing circuit and a DPST switch, it is possible to select the function of the KBD-CV jack a. insert (interrupt CV1) or b. sum (mix with CV1). For example, in sum mode, with both the 3620 and 1601 connected, use the keyboard to transpose the sequence. The utility is not limited to the 3620; any configuration where the pitch CV source is internal (ex: MIDIImplant) could benefit.

I built a summing mixer using 1K .1% resistors and a TL072 (two inverting unity gain stages) with the final feedback resistor a 2K multi turn trimmer. I got accuracy down to ~5 cents - OK but not good enough for Donald Fagen. It could probably be improved using the OP285 op amp. Since I see my little line of TTSH building sunsetting here, I probably won't take this past the drawing stage. I don't mind sharing the drawing, if you are interested.
Wired for weird

Post Reply

Return to “Music Tech DIY”