NorthernLightX

And Seagal sensei is a wise man indeed ;D

Bottom line: Don't assume. Assumption is the mother of all f*ckups, a wise man once told me. Check Smash's site, he has dozens of close-up pictures revealing the pinouts of the boards. You should know where to find his site since you ordered from him in the first place. Cheers, Alex.

I thought that these things where supposed to be stuck on pushbuttons like the digitaster from Reichelt; was I mistaken? I'm not looking for a different sollution...

Hi dengel, I assume the buttons can/should be cut loose from the keypad? If so, I'd be interested in a couple of those, like 200 or so - if the price can be made reasonable by placing a large (group-)order. Cheers, Alex.

That looks suspiciously much like a compressor...is it finally finished? ;D

Hi Julien, your keyboard looks broken too ;) Are you sure the problem with the LCD is not just a short or a miswire of some sort? I'd be happy to test it for you as soon as I have a Core online... (I'm in Holland) Cheers, Alex.

I think (and hope) you didn't upload MIOS yet, because if you didn't, the behaviour you're reporting is exactly as expected. As in "perfectly normal working order". The MIDI message must be the PIC reporting itself as ready to be supplied with MIOS.

Hi Stryd, if you have some cool schematics to accompany those IC's (the delay for example) I might be interested. If you're aquiring those OTA's for the CV control stuff I'd be interested in those too. Speakjet is currently not something I am planning to build, too much other stuff to finish, and 50$ is not something I should spend lightly. Cheers, Alex.

Thanks TK, I understand now. The -12v being available was a reading error from my side, I thought the behringer PSU did +12v/-12v. I will not add the -5v rail to my PSU design, I believe it would be better to include the -5v power rail on the CEM filter board instead since it is only used there. Do you plan to release your CEM filter as a midibox module? I definitely would want to build one or more! Cheers, Alex.

Great! If -12v procudes more headroom, I'd prefer that over -5v, and -12v is already in the current design Indeed, if -5v is really needed one could branch off from the unregulated -12v, and then regulate it with a few caps and a 7905 off-pcb. Luckily, untill now I haven't seen interesting designs to add to midibox, where -5v was a must. Last question: If you already had -12v available, and the CEM accepts that, why did you opt for -5v instead? Cheers, Alex.

I didn't see his page before, but had a look just now. He does like the retro look doesn't he :) Can't really tell when the last update to his page was, but I sure hope his project does make it into the Open Source domain.

Currently I have only researched some distortion FX units. Most use 100K pots, LIN for the FX settings (Drive, Tone) and LOG for the volume (Level) setting, but I've also come across a schematic that uses 500k for every pot. I have to state my knowledge is very limited though. ;) Cheers, Alex.

Hi Thorsten, Please excuse my ignorance, but I thought the AOUT(_LC) and the CEM filter both used 12v and -12v, The datasheet I have on the CEM3378 isn't too clear on this (the pinout says -5v on pin 9, but it isn't explained why the -5v is needed, it just says the operating voltage is between +4,75v and +12,5v. I ask this because of the PSU I am designing, I never tought of a -5v rail to be necessary, but now this seems useful for the CEM filter option. Will -12v be sufficient, or will an additional 78L12 (or equivalent) be necessary if one would want to connect a CEM3378 filter to a -12v supply? Cheers, Alex.

Looks like Sheepslinky is not going to do anything like that, his last post was 9 months ago.

FYI I picked these: AD5206BN10, AD5204BN50, AD5204BN100. I went for 2 factors: PDIP and as much pots in one package :) Cheers, Alex.

I'm still waiting for the parts from Reichelt to arrive, until then I don't have much to build or report :( I'm pretty confident we'll get a working sollution, either the noise will be neglectable because of good star topology grounding, or we'll use a separate analog ground if the noise can't be made quiet enough. Anyway, as soon as the parts are in, I have a few other things to sort out first (PSU design, Distortion design), so don't expect any results from me soon on the digipots. Cheers, Alex.

Hi TK, Why do you need -5V? Is it for the AOUT_LC or for the CEM filters? Cheers, Alex.

OK, so if we take one of those 4 channel ICs you mentioned, effectively we have available one 8bit out and one 16 bit out if we'd want the high resolution, right? Aren't there IC sockets for SMD chips? I remeber from the old days when you could upgrade the memory of your VGA card in the PC, by placing DRAM ICs in special sockets (I have a few lying around with this option). Could that be used for the smd ICs? If so, I'd be a little more confident about the SMD route :P I don't like the fact that SMD ICs won't fit into my breadboard though :-\ About the LOG behaviour: you need to remember how you did this! LOG behaviour is also needed on some effects, where you need to adjust overall volume of the sound since the human ear behaves logaritmically (is that a correct word?) as well. Cheers, Alex. [edit] addition: It is mentioned that this cascade story is a low-cost version of a 12bit DAC, but less precise and all. Instead of re-inventing the wheel (AOUT already provides a high-end 8-channel 12bit DAC with additional gates) perhaps we should research that OTA-thing for the 12-bit part instead. Digipots can be used where 8-bit is sufficient. Do you agree? [/edit]

Nice work Stryd! Only a few short questions: - Why do they need 3 channels to double the resolution, not 2? - If we want 12 bit, we need 6bit pots instead of 8 bit, right? (I received some 8 bit pot samples a few days ago) - Can we keep it PDIP? Cheers, Alex.

Yeah, just fear of the unknown :-[ But also, I like to have least parts necessary, so as long as there's no sound theoretical solution for the fine/coarse pots (you might have already provided that but in that case I didn't understand it enough) I'm sticking with one IC for my test case. If I can get that quiet enough (zipper noise not included) I'm willing to expand that into your coarse/fine solution, but I think it would be better if both of us (and as much as possible other midiboxers!) develop their own solution while staying in contact with eachother ofcourse, so we can share experience while building. Then we can test which solution works best, and which solution is the simpelest (hopefully, both are true for the same design, so we'd have one uniform solution to improve on further). Can you? probably. Can I? Don't believe so. True bypass is where you want to switch an effect on or off, when it is routed hard in your signal path, e.g. not patchable with a wire. so your first pole is at the input of your effect, and the second one is at your output, so you can short those so truly bypass the entire effect. Non-true bypass is where some parts of the effect still influence your sound, e.g. input and output are not shorted, but some parts in the effect are turned off (clipping in a distortion unit fr example). True bypass is something I would want on the SID distortion unit, so It can be switched on and off via MIDI. If it's not in sync it's no use, right? Back to the drawing board then... Cheers, Alex.

I have considered that, so when I do react for that purpose (encourage the builder) I always highlight a specific thing I find particularly nice in the post, to show I'm genuinely interested an d not merely posting for sheer numbers.

Sometimes I get the idea that this is exactly the reason why those posts are made... Well I can tell you, at 300+ posts I'm still a friggin n00b, so to post many posts does not increase ones eliteness. Reading many posts does, on the other hand. 8)

My confidence only pops up if i'm confident about something :D And I'm only confident about something if I know the theory and/or the practics, which is not the case with potmeters...yet. I think you made another error, afaik two 1k resostors in parallel provide 1k/2 in resistance, that's 500 Ohm instead of 500 KOhm, right? But I think the rest of your equations are based on the 500 Ohm so this might be just a typo. I understand what you're poiting out, I'm just not feeling very fine with it yet... I like separate grounds I think, but testing will provide measurements that will be real grounds for decisions. I estimate it will be a few months before I'm ready for tests, with some unfinished projects to attend to... Also the AD52xx is an SMD only IC, and AD84xx PDIP is not available in all resistance sizes. Also, the PDIP IC's are not selectable as samples, I'm not going to pay big bucks for IC's I fear I can't solder properly myself, and am not even sure if thay'll do what I want. I don't like SMD. I'm not very experienced at soldering, I manage to mess up normal PDIP pins, so not SMD for me. And, as TK points out so frequently: other users have to be able to make the boards too, so if it's possible to stick with PDIP I would. The IC's you listed are SPDT switches, for true bypass you need DPDT switches. ADG888 is a dual DPDT switch, but it's SMD again... Another tought about your course and fine pots: could you drive one with SPI, and the other with I2C at the same? If so: solved your bitbanging problem 8) Still not sure if I want to walk that path though... Cheers, Alex.

I have no idea what OTA's are, do you have a link with some info? I wouldn't say a finished digipot design would be 90% functional, just lower resolution. I was not implying any argument at all, just making a little fun, no worries! ;) What I meant was that you can sweep away anyway you like, and it's still possible in 8-bit resolution, which produces no audible artifacts with some FX. The more crude FX like distortion for example, you won't notice any zipper noise between the rest of the signal, I'm sure. Maybe the original SHX8 IC's are still available somewhere, but Reichelt doesn't stock them and they're not available anymore at mouser. Digital switches have to be easy to implement. Do you pehaps already have a particular IC in mind? I have no idea If potentiometers work in series, let alone digital ones. Sounds tricky though. Bit gang banging dual SPI?... sorry you lost me. What have you conjured up this time? ;D Cheers, Alex.

Hi, I have found some very nice RCA jacks between the stuff in my room (girlfriend had me cleaning up :-[ :P ;D). They are branded "Schultz Kabel", are made from aluminum, have a blue rubber band around them, are gold plated, and have never been used or soldered. Here's a B&W pic: Thomann.de sells these at 2 euro a piece. Since I don't use RCA plugs, I'd like to trade them for anything I can use. Just make me an offer, anything goes. If you don't have anything to trade for, money will do ;) . I'll throw in a couple of RCA PCB mount connectors, so you'll have something to toy with (these have been used before). Cheers, Alex.