Altitude

Hmm, Interesting power supply you have there.. I wonder if the quatro has better ripple current performance

I dont think that is an issue. Microchip is has over a billion in sales and saw an increase of 12% over last year and the synth DIY portion of their business accounts for nothing so if everyone on this list sampled as many chips as they could, they would not even bat an eye.

Yeah, everything is done via the core. MIOS studio is in Java so it is cross platform

No, just something with midi. Everything is sent via sysex files with MBHP

I would say go ahead and build everything and worry about the V2 stuff when they wrap it up. There will be some changes made to the hardware but nothing that will stray that far from the current hardware. SID chips can be found here, on ebay, or i'm sure at your local flea market

Unless you are directly going to the 4xSID then you dont need to worry about it, both 1x and 4x have the first core as 0000000000. You will also need to take into consideration that you will need a display and a DIN module for some of the controls so I recommend you get all the goods at the same time(IDC Cable, connectors, Memory for bankstick, connectors) You will have to at some point since you will not be able to program the PIC, Tim only preloads the bootloader and MIOS, you still have to upload the SID application

Here is some reading that may clarify some things: http://www.kpsec.freeuk.com/powersup.htm

Rutger. I updated my msg. Usually, you will want a transformer with dual secondaries, using 2 transformers with one referenced ground can be problematic. Search this forum for some various PSU designs there are several including mine. I use the 2Amp 7805 and it works well

2nded about the 1 bridge rectifier for the 5 volt rails. Also, your transformers are rated really high for what you are doing voltage wise. Remember that voltage rating is RMS so you will have a 1.4V drop across 2 diode in the bridge (7.6 V RMS) and with your smoothing caps that will raise that to almost the peak of 10.6V which is a lot of voltage for the 5V regs to burn off as heat. Consider using a 6V transformer. Plus the way you have your grounding set up is wrong. You can not just tie all the grounds to case, I am sure someone more knowledgeable than I will explain why but the general idea is that with 9v transformer, you are referencing ground to the lowest point of the wave and the with the center tapped one, you are referencing it in the middle of the wave (thats how you get your +/-). With a mixed signal chip like the sid, this will be VERY bad to have 2 different grounds. Plus your signal ground and case ground should not be tied together.

Here, I made a PDF for you: http://no-ho.com/MB_Sid Step C.pdf Umbuntu should have a PDF reader installed by default IIRC. You can print it out on 2 A size pieces of paper just make sure that the page scaling is set to none. PDF is a vector format so you dont have to deal with bit resolution, just print it 1:1

Just print it as PDF

I have been using the new lasertran with excellent results. More to follow...

Look at the bright side, at least you accomplished your original goal of reducing noise ;D

Um, that was a BAD idea. Chances are you can say bye bye to all your pics, they are not designed to take more than 5.5V. If your using a 6N138 Opto, then that could have been damaged also

Thats a good question. The regulator should be OK to 35V (it will just get hot) so I suspect that the problem lies somewhere else. Check your supply voltages to the PIC while it is running

Thats actually really good advice, i'll definitely do that

I got it, ;D This was a loooooong topic last year and hopefully I'll have something to contribute soon

It kinda become my quest to design an efficient one. I have a good step down design on the protoboard using a mosfet with a pair of caps that discharge in parallel but charge in series and it seems to be a very efficient system but it needs some tweaking since it is designed for 18V AC and I'll be using 12V AC for powering a 4 x 6581. Dissipating almost 10V before hitting a 5V regulator pulling over 500 mA and keeping everything from becoming a space heater is not trivial (at least for me)

Sorry, not familiar with the SMPS term, but yeah, thats the source for sure. I thought is was mentioned in the walk-through that you should use a linear supply, but i cant seem to find it anywhere. Unless you want to dive into the linear power supply happy fun design world I would look for a C64 psu

My guess is that its power supply related. Are you sure that its a linear PSU and not a switcher? What is the max current and output rails for the PSU? A 4xsid will pull quite a bit off of the 5v rail and if there are not enough smoothing caps in the system, you could be getting ripple noise. How hot are your 5V regulators getting? They could be shutting down if they dont have heat sinks and you are running 12V directly to them and that would explain your freezing

What are you using now?

The slim LCDs are 27.99 USD directly from crystal fonts and I am moving forward with that but I'll probably hold out for V2 before committing to anything else

Have you shorted the audio in's? That will reduce the noise significantly. Just make sure this is done with everything off

My 8580 will be 1u. The big problem I have encountered is finding a display small enough for a 1U rack. Generally, 1U racks which are 1.75" in height will only have 1.4-1.5" of usable height before you hit the top and bottom lids most 2x20 LCDs are more than this (40mm). The one I finally arrived at was this thing: http://www.crystalfontz.com/products/2002d/index.html#CFAH2002DTMIET Which comes in at 21.5mm/0.81" in PCB height which will clear the top and bottom by a wide margin AND allow for all 5 buttons underneath (which is critical IMHO) You can pick and choose the other controls but real estate is real limited The problem however is that the LCD is interfaced via a damned contraption by the name of ZIF connector. This is the 1mm pitch super flat ribbon cable which can only be terminated by another ZIF connector and there are no commercially available ones that will convert it to DIL so its either solder the ribbon cable from the IDC to a ZIF connector (thankfully they make thru hole mountable ones) or etch an adapter board. My desktop is at a premium so a 1u is the way i am going for sure. Just have to find and build a suitable flat transformer (I hate wall warts)

what about the EUSART bug?