RIP Mike

The board has provisions to set it up like a stock OBX card with the 2-pole LPF. I am trying to finalize the docs for this board as there are a number of revisions, but in this case you omit the DG508 and strap a jumper across the JP6 "OBX" pads near The (optional) notch trimmer T15. I'll have more ...

That kickstarter seems under-funded for assembled boards.

Hey folks,

The last eight weeks have been crazy 12-hour workdays (including some weekends) but I now have 5 days off and all remaining boards will be shipped in that time. Sorry for the delays, the bonus is new BoMs will also be ready.

Crow
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Just make sure the fuses are set as noted in the source file. I use the avrdudess program which has settings for them, although you can also put them on the CLI/command line in a shell window. The .hex file should have these fuse settings and show up in the GUI when the file is loaded. Crow /**/ Cod...

The MOTM-480 and RR-480 aka MOTM 480 mkII are the result of me spending a long time hand-selecting parts to test as a CS filter in place of the Yamaha parts in my CS-80. In the end, I got it as close as can be brought into this world. The thing to remember is, the filter is only one part of a much l...

Sure, I'll get some prepared over the long weekend. --Crow

jean_schön wrote:crow, will you be putting up noise PICs for sale? or would someone burn one for me?

I do provide pads for an axial tempco part on the newer rev boards as well. As I'm thinking of this it should be an easy solution to piggyback a 1k Akaneohm Tempco 3300ppm/°C on the LS318 like done on many other designs... Piggyback it from Pin 2 to Pin 7 of the LS318 et voilà... Then you could even...

Please note, the v2.3/v2.4 voice boards do not use LS318s, or DIP matched transistor parts at all. These use LM3046MX (SOIC14) or FMB3904 (SOT23-6). The older parts are just getting too rare, so I try to keep actively-produced devices as options. The LM3046 is on the last time buy list, which is why...

FYI: I've put up pre-orders for both a backplane with 4 voice boards set and a backplane with 8 voice boards set. These are of course bare board sets. The voice boards are my latest v2.4 type that use the AS3310 re-issued envelope generator ICs. The 2.4 boards are backward-compatible with the v2.0 e...

It is in fact a small OLED display. :sb: Given the OBX had presets and autotune, I plan to have the same thing here. The display is not strictly needed, but when I go to write and debug the patch manager program, it helps to have something I can use to show information. Hey Crow, is that a 4 pin SPI...

It is in the preliminary phase, but the control panel will look something like this: https://www.muffwiggler.com/forum/userpix2/6440_8vox_panel_v01_brd_1.jpg The 12mm buttons will all have integral LEDs. The section in the lower right area are individual voice panners which connect to the backplane ...

For those interested, I will be opening a pre-order page on my sales portal later this month for the 8-voice board sets. There will be full sets and as well as partial sets for those with existing voice cards. I am working on the front panel and control boards currently. Delivery of the backplane an...

I did this spacing on purpose to avoid having to resort to creative capacitor lead-bending.

jimfowler wrote:The 8 voice backplane does afford more space. The amount of space is uniform for all voice cards and is the same as the space between voices 2 and 3 on the 4 voice backplane. See attached photo.

I got sidetracked onto other stuff, but I still want to make this thing. It may be better to do a board-level replacement vs. chip-level. --Crow

The schematic for the module is slightly different vs. crowbx. With the AS3310 chip being made again, I might make a run of this version for the curious builder, but I will also make a 3310 (chip) version too.

KSS wrote:Crow, the panel shows trig, but it's not on the schematic?

Right, this card will have its own backplane, etc. It was not meant to work in a crowbx/OBX setup. I will deal with that when I test the board. Changing the resonance control profile is not very hard for either filter. :sb: Just checked the schematics. OBXa voicecard has some signals that are not TT...

I will deal with that when I test the board. Changing the resonance control profile is not very hard for either filter.

tobb wrote:

(as drop-in for vintages it will be problematic due to the resonance of the AS3320!)

@randel Very very very nice job sir! I will have to get the rackmount stuff finished.

FYI yes I saw the Behringer UBXA thing. I'll believe it when I see it. This project is about making cards that work in vintage machines and for the general DIY wanderlust.

Heya folks, With the return of certain chips courtesy of Alfa Rpar and Erica Synths, I can now make the crOwBX-A voice card. As with the crOwBX cards, these will be drop-in compatible for vintage machines but also able to be used with my 8-voice backplane. Right now it is a work in progress, but I s...

The 4011 is either defective or the +5V going to it has an issue. VCO tuning issues are usually due to a bad timing cap or bad trimmer. --Crow Some updates about how my crowbx is behaving. VCO2 keeps going out of tune on two out of four voice cards. It takes several days/weeks for the tuning to go b...

Heya folks, a quick note. I am working on getting 8-voice stuff finished among my other projects. Since 3310 EGs are going to be made again I am going to try a 3310 edition of the crOwBX voice card. It will not replace my non-custom EG version, but it does simplify the build somewhat: https://www.mu...

This diode is part of the negative rail voltage protection used on each 2164. If the 2164s are powered on the V+ pin with the V- rail missing/disconnected/unpowered a condition exists where a significant current flows into V+ which can damage the part. V+ internally tries to pull the free-floating V...

The essential item for any SMT soldering is a flux pen. It is ten times easier soldering using one vs. without one. I use the water soluable flux pen model, Kester 2331-ZX such as http://www.techni-tool.com/488CH450 Even for the 688 pieces of 0805-size 100nF ceramic bypass capacitor it will help. Be...