Pete Brown

I've looked on the forums and the wiki, but couldn't find an answer to this question. (Direct answers or pointers to the info I missed are both welcome, thanks) How complex a control surface can you make with the midibox SID? For example, could I break it out so I had discrete controls for each of the three oscillators if I wanted to? Or is the MB6582 kit essentially the extent of the control surface you can support. I'm sitting here looking at my JP-8080 thinking it would be wonderful to have something that rich for the SID. What's the limiting factor? Thanks. Pete

I bought a proper splitter cable and plugged it right into my Motu 828. SID sounds much better now (through same headphones, but with the mixer in between) Plugging headphones directly into the back is not a good idea: too loud and noisy. Pete PS. I can see on the front panel of the 828 that the SID is still throwing a fair bit of noise, but the 828 is filtering it out (gate or whatever). Nothing I ever set up, but nice to see it in play :)

Thanks :) Nope. I have the 6582As. I'll swap out the power supply for grins and see if that changes anything. The supply I've used isn't a particularly cheap one (it's a "medical quality" one from SL Power / Ault) with a three-prong grounded power cord, but you never know. If you listen to my favorite sammich demo, there's no noise at all, not even when notes are playing (that I can hear, anyway), so I assume this isn't quite normal, and isn't just the result of turning off oscillators when not playing: Pete

Completed my sammichSID build. :) [insert dancing banana here] http://10rem.net/blog/2011/10/22/just-completed-my-sammich-sid-build I haven't used it a whole lot yet. I did notice that If I plug in a set of phones to the output, the SIDs are super noisy (I can hear the LFO sweep and the usual C64 noise). In the videos of the sammich, I don't hear any of that. What's the trick? Does regular amplification make it mostly go away, or do I need to do more work with the post processing? It was very loud, which I assume is some of it. I'll be able to tone it down a bit after I run to the store and get a proper stereo splitter cable. Not sure if that will be sufficient, though. Pete

You were right, it must have been the diodes throwing off my testing. Voltages all checked out and, after some hiccups with the opto-isolator, everything is now up and running.

And now, it's suddenly working! Hmm. Badly seated isolator maybe? Solder joints look fine.

Ok, I figured out a way to test the isolator. I took that same LED and wired it up to the common (center pin) part of the JMI pin and ground. It stayed dimly lit, but pulsed in time with the MIDI messags coming from MIOS Studio. So now I'm thinking this is uglier than a blown chip or some other hardware problem, but I don't know what else to test or do. Suggestions welcome :) Pete

Did the LED test by removing the isolator from the socket and sticking an LED from the input to ground. During the sysex upload, it lights up nicely. So, I assume bad 6n138 then? Would figure if so, since I have to order those online :P I have a bunch of 6n136 around, but they don't seem to be a drop-in replacement. Pete

Hi All I've completed my sammichSID build, but I can't get MIOS Studio 2.2.2 to recognize the device. I double-checked that I have the right resistors in the right places I've done the loopback test and it passed I did the sysex test and it passed. The MIDI light on my MOTU 828mk3 blinks as the firmware is being sent to the sammich (although the sammich never changes from "Ready.") I have the JMI and JMO jumpers in the correct positions When I power on my sammichSID, I see the upload request. When I try and scan for the device, I get the "No response from MIOS8 or MIOS32 core...". The MIDI troubleshooter starts getting specific at that point, and doesn't seem to apply to the sammichSID. IOW, the resistor numbers and other things don't really mean anything to me in the context of a sammichSID build. Ideas on what to test? With the opto coupler in there, it's not like I can check continuity ;) I suppose I could bypass that, but I'm not sure that's the first thing I want to try. That said, the soldering *looks* ok to me. There's not much there in any case, it's pretty much a straight shot to the PIC. Next step is to try the LED test on the MIDI in. Other suggestions? Pete

Thanks for your help, @nebula. Since I get the correct voltage at all the right points when I use a 12v power supply, and no blue smoke, I'm going to assume it's just my testing approach like you described. I'll check one last time before putting chips in, of course. I should have a proper 12v power supply waiting for me at home (I was using my bench supply with a cobbled up connector for testing 12v). I can't stand wall-wart types as they use up too much space on the power strip, so I ordered one with a separate cord. Now I'm looking forward to getting back and making some noise :) Pete

Thanks. The meter (BK Precision) is a good one with a dedicated continuity test mode. I tested for continuity with the power unplugged from the board. Interestingly enough, I only get continuity if I have the polarity set a certain way (red probe on ground vs. +12v, although I forget which one it is). I assume that's due to a diode or something, but I'm really new at troubleshooting stuff like that. I'm much better at code :) I don't get a similar result on any of the other voltage traces on the board, just hte 12v stuff, both over at the LCD power jumper and the regulator and jumpers the power input section. I'll double-check that when I get home. It was lined up with the outline on the board and matched the photos, however. I'm really at a loss as to what it could be. I assume no one else with sammichSID boards has continuity between +12v and ground, and that this is a soldering error on my part. of course, I don't think I checked before I started soldering, so I can't guarantee it isn't a defective board. O_o. Pete

Replaced the 7809, made up a plug and attached the whole thing to 12v power supply and I get the correct voltages at the couple points I tested. However, I still see continuity between ground and input voltage. I have to hop on a plane so I can't debug any more this week, but unless someone tells me this is normal, I'm not plugging any chips in :) Pete

It was some email Jason and I exchanged when I first got the kit. Since I was using 6582a, I didn't need 12v. Maybe I misunderstood. No worries, as I can dig up a 12v supply if needed. I've been using the 1.0 build guide. Thanks. Nevertheless, I have continuity between ground and the 12v lines. I assume that isn't correct. I did the painful removal of the 7809 9v regulator and I still have continuity between the input (12v in the guide) and ground, so it wasn't the regulator. Bummer, I was hoping that was it. It's only on the 12v (input voltage) side of things, though, not on the regulated 9v line or 5v lines on the board. Thanks. :) Pete

I just completed my build of my sammichSID kit. I've had the kit for a while, but just now got some time to wrap it up :) I'm doing the voltage tests, and just not getting what I had expected. My power supply is tip positive 9v, as recommended in the build email. I'm using 6582a SIDs. I haven't connected the control board yet, just testing the base board. I do not have any jumpers installed so it is as-shown in the build guide testing pic. On the power supply, I measure 9.06v On the +5v locations on the base board, including the leg of the VR, I only measure 4.05v On the +9v locations on the base board, I measure 6.43v On the +12v location on the base board, I measure 7.78v I did a continuity test in several places and the +12v (or 9v in this case) and ground test points are shorted. +5v and ground are not shorted. I assume that isn't normal :) I'm at a loss as to where the ground fault could be. There's no continuity with the heat sink, so that's not the cause. I don't see any obvious solder bridges. I suspect the fault is inside something, but I have no idea where to begin looking (I'm new to this). If the VRs were toast, I assume they'd just let full voltage through. Any ideas? Pete