jojjelito

The theory would be that the switcher can output some 7.1-7.5 VDC. The heat dissipation is very small, and the capacitors used by the 7805 plus the regulation of the 7805 will somewhat smooth out the 60kHz switching noise that this particular switcher emits at its' switching frequency. The switcher data sheet also lists a variant with lower noise using an extra, small inductor attached to the output. Add a garden variety 60kHz filter before the input of the 7805 and we're golden. Also, there is a good trick in AoE by Horowitz/Hill where they insert a 4001 diode (which is strictly for output polarity protection) between Vout and Vadj in parallel with a small resistor, 10uF to GND and a 5k trimmer to GND for improved ripple rejection. It's on page 386 in the 2nd edition, but I'm too lazy to draw up a complete schematic at this late hour :sleep: It's not impossible to come up with a low-noise switcher as long as you know what you're doing and can tolerate the somewhat higher component count. Hint, commercial switching PSUs are normally optimized for cost, thus low component count and therefore they are :nuke: I used the AoE trick above for a very low noise toroid/LM317/337 solution that has good performance at a low component count. The switcher is the research part here. I'm about to slap the above together as an alternative to a seriously old c64 PSU in any event, so I'll report my impressions in due time.

Hmm, what about getting a 9VAC toroid and use a LM2576-5 switcher, or use an LM2575t-adj as a pre-regulator to a vanilla 7805? Less heat and not exactly a very noisy switcher. In order to get to 12VDC we can use a LM2588 or a similar contraption. Or go with a dual, say 12/9VAC toroid? Any thoughts?

Thank you TK! It's looking good so far :sorcerer: . I have yet to connect the MS-10 though. Will report back later this week I hope :)

Thank you and cheers! I had a hunch it might come, but I had to check so I didn't start some parallel hacking :poke: This will be interesting, a USB/Ethernet sequencer with SD-card storage containing a now beefy octal MIDI-CV converter! It's ultra-modern and retro in one box. Trip the light fantastic! Kind regards, Johan

Nicely spotted! I was using xoxshop.de last time I needed a PT-10, but this could save you a couple of Euros, depending on shipment costs. Can't vouch for PBE Shop yet, but xoxshop.de runs tight. Take care, J

Buenas tardes! I have yet to experiment with the A_OUT and my SEQ_V4. However, I was taking a quick glance at the sauce code and wasn't able to spot some useful (to me at least) functions related to CV output: namely gate polarity, output curve and possibly interpolation. Then there's the issue of calibration. It's probable that I've missed something, or is just plain crazy or - just dreaming out loud. Have I missed something, or would I be free to add those to some Aout channel setup menu? My MS-10 says it wants to be connected :hug: The modular growls and purrs that it wants to make weird sounds under MB_SEQ control too. The match is entirely seemly.

I guess we're pretty well covered in the stereo 16-bit area :sorcerer: Then there's only the mythical quest of finding a decently accurate multi-channel solution for VCOs without resorting to PCM1680 ΔΣ-type devices. Or be happy with 12bits since it's analog with some inherent instability and therefore we don't worry too much about precision... Gotta read up more on the I2S synth instead of just browsing the repository one of these days. Plus check what the kaffeSEQ is doing. Sounds like replacing filter, grinding beans, heating water, pumping and... STOP daydreaming!

Mmm, figures... Since I was already under the impression that the performance benefit was marginal at best I guess this one was killed in the bud :whistle: With some luck we'll find better alternatives for higher precision later on. The deal with 16-bit for me is in VCO control and in direct wavetable synthesis if one is so inclined. The added precision does nothing for VCF/VCA etc control. Maybe there's some I2S-alternative out there? As for the homemade board this was intended just for experimentation and hardware-bringup. Once the driver is done and preliminary performance data obtained with my trusty Tektronix then it would be time for a proper board. Noise issues and layout tricks will be far more critical with these multibit monsters. Summing it up: 12-bits it is for now. TSSOP vs SOIC is not going to go away, unfortunately. If you can mod a PS2 then you'll be fine with TSSOP. I'll be surprised to see anything but bump-grid (BGA) nastyness a few years down the road for mass-market applications. Then we DIY peeps will be SOL. I guess more cards will go with pre-soldered bits and pieces. - PIC core, is anyone using those for new MIDIbox projects? Not to knock them, but where's the USB firmware download on those old things :frantics: It's been a good ride with MIOS8, but times are changing. Thanks Seppo! /J

Haha, unfortunately they're not pin-compatible with the TLV5630 used in the AOUT_NG :tongue: That would have been too convenient for someone else to not have noticed already. There are two families from TI and AD who just happen to share the same pinning, characteristics etc which the two chips are part of. I was planning to investigate an AOUT_16 if there is some additional performance/precision to be had, but it will require new boards with a redesigned footer for these chips. I'll whip something up for kitchen etching for myself at first :ninja: Then I'll have some fun with a couple of VCOs in the form of a couple of different CEM chips and a discrete transistor thingy from the bakelite, metal and wooden end cheeks-era. When I was quickly skimming the datasheets I saw that the relative accuracy is 4 bits LSB of the TI DAC. The AD DAC also comes with some inherent INL error, but you're bound to see those on any DAC.

I was investigating DACs due to circumstances involving analog synthesis and came across the pin-compatible DAC8568 (octal 16-bit DAC, 10uS settling time at worst) and the AD5668 with similar characteristics. It looks like any of these two could be mounted on a PCB in order to attain 16-bit resolution with hopefully better precision than the current Aout_NG (which isn't that bad!). The datasheets don't guarantee better than 12-bits resolution at worst case but at 14.81€ (Digikey) for the AD, and at 22€ (Mouser) for the TI DAC it's not worlds apart from the TLV5630 at 18.13€ (Mouser). I was thinking of getting a couple of each in order to do some experiments. Any thoughts about the worse settling time, or if this endeavor would be at all worthwhile? I was thinking it could be fun to write a SPI driver for these 2 ICs in the long, dark of fall. Cheers!

Should work fine! If it doesn't (I don't see how) you could always stick it into a camera :ahappy:

As per Wikipedia there are also references to the old way of using 1.2Mbps as the base for x-speeds. Somewhere in the Wiki it is stated that you should get a card that is safe for 100x, or 15MB/s write speed so that MB_seq can write data while still operating in real time. I think it sounds a bit demanding, but I found some nice 4GB SDHC cards that were ok for less than 20 USD so there's no need to skimp on the cards. Please note that the amount of data you'll likely write is very small (a few MBs or so), and that 4GB is the absolute maximum amount that can be addressed. MB_seq doesn't do exFAT or any such tricks used to address higher capacity SDHC or SDXC cards.

Thanks Seppo! Haha, had this been pure analog or high-power pins I would have been really careful. You can get away with more in the digital realm :whistle: Official SD-card specs... *facepalm*, thought those were secret or proprietary so I didn't bother faffing around with those :fear: . DUH! *EDIT* 'Twas working fine yesterday. Before this I only had the standard I/O mapping, now I run the full Wilba version with my front panels. Now for some SSM fun... /J

Hmm, finally weekend so I thought I'd had a go with the soldering iron. Anywho, now I noticed that we have some RC components on the SD-card PCB. The WIKI doesn't mention these. Is there any schematic for this, or should those be bypassed in the event of a CORE_32 connection? Anyone?

Got my stuff! Vielen Danke Seppo! Hmm, this means I can have some good, unclean fun with the MB_seq :frantics: . Sex on a stick! :drool:

Yarr! I see that the JSF guidelines references my old arch-enemy: The MISRA (misery) guidelines. So we meet again! Takes me back to when I was working as a programmer for a living... Then I de-evolved, ha-ha. Does anyone know of a good freeware alternative to PC-Lint by Gimpel? It still costs 389 bucks, so it's a bit steep for hobbyists. Sometimes a little static analysis is what the doctor ordered. There are of course plain vanilla Lint implementations but is there something more comprehensive which is still free? I did quickly check Wikipedia out of curiosity. Cheers!