SLP Posted May 19, 2007 Report Share Posted May 19, 2007 Hi,I've finished one SID and one Core of my dual-SID, I've loaded the SID testtone-app on my master-Core, switched it on and after 2 seconds of a (nearly) pure triangle-wave, I heard another strange sound.As it's very difficult to describe this kind of question, I've attached 2 pics and an audio-file.(I know it's pretty useless to zip a wma-file, but wma-files are not allowed).Parts of the audio-wave:1 ? no idea. quite loud noise though it's switched off.2 switch-on-click3 either the releasing of the power switch or the Relais which switches the 12V-line. (black box on the picture)4 here begins the pure triangle-wave5 here starts the additional strange noise6 triangle + noise7 the noise stops. triangle8 the noise starts again9 switch-off-clickMy "Class 2 Power Supply" also offers a GND-connection. should I use this one instead of the normal Vd ?thx,matthiassidnoise01.zipUnbenannt.JPGsidnoise01.zipDSCN06380001_1.JPG Quote Link to comment Share on other sites More sharing options...
dj3nk Posted May 19, 2007 Report Share Posted May 19, 2007 do you have 6581 or 8580 sids ? what powersuplly do you use ? the original c64 one in the "optimized version" ?greetz Quote Link to comment Share on other sites More sharing options...
SLP Posted May 19, 2007 Author Report Share Posted May 19, 2007 oh, I forgot to mention the most important things...the 2 cores run the V1.74685 firmware.Master: connected to 8580, no CSSlave: connected to 6581. not connected to master at the moment (CAN)I'm using the black powersupply you can see at the picture.I've just put the Master PIC into the slave-core. the 6581 works pretty well. (except for that "normal" noise)I'll try to connect the 8581 to the slave board tomorrow to see if it's the core that doesn't work. Quote Link to comment Share on other sites More sharing options...
stryd_one Posted May 20, 2007 Report Share Posted May 20, 2007 What kinda PSU is that? Quote Link to comment Share on other sites More sharing options...
SLP Posted May 20, 2007 Author Report Share Posted May 20, 2007 it's a "Skynet DMH-1202-A" "class 2 power supply".I've bought it at pollin.de.it offers +5V (1A)+12V (0,2A)-12V (0,2A)and 2 other lines. I don't know how you call them in english.there is a normal "minus" (Vs) wire and another wire that is connected directly to ground (earth, green/yellow cable).I think that the powersupply is just the reason for the 50Hz-buzz and the usual (white? pink?) noise.I'll try to solve this problem in the next step.The problem I want to solve now is this kinda disturbing second signal. It doesn't occur at the 6581.any ideas?matthias Quote Link to comment Share on other sites More sharing options...
SLP Posted May 30, 2007 Author Report Share Posted May 30, 2007 ok. problem solvedOne definition of an expert is "a person who has made all the possible mistakes in a narrow field". hmm.. there aren't very many mistakes left that I haven't done ;DI just didn't push one multiplexer entirely into the socket. New problem - same headline:If I upload the SID-application and start the MB, I hear some really weird sound.I'll record it later.I tried every single Core-SID combination, and tried with both the PIC18F452 and PIC18F4685. It's always the same.After booting up, i shouldn't hear any sound, right? There's no BankStick connected.thx,matthias Quote Link to comment Share on other sites More sharing options...
Sasha Posted May 30, 2007 Report Share Posted May 30, 2007 I suppose what you hear is the noise that comes from the powering the circuit, similar to what you heard when powe up the amp that have no delayed speaker output relay. I think it is normal. Quote Link to comment Share on other sites More sharing options...
SLP Posted May 30, 2007 Author Report Share Posted May 30, 2007 I do always hear that noise, not only after powering on..noise2.zipnoise2.zip Quote Link to comment Share on other sites More sharing options...
Sasha Posted May 30, 2007 Report Share Posted May 30, 2007 I hear same noise in the background after I turn the volume to the max, but seams signal to noise ratio is still 90 and something dB, as it should be. I`m probably not right person to answer it, but I think that noise is normal. MAybe it could be improved using some better PSU. Quote Link to comment Share on other sites More sharing options...
SLP Posted May 30, 2007 Author Report Share Posted May 30, 2007 I hear same noise in the background background? everything you can hear shouldn't be there.the 50Hz buzz and the "usual"-SID-and-PSU-noise isn't the problem.I turn it on and the noise starts. If I send any note-on messages nothing happens. Quote Link to comment Share on other sites More sharing options...
SLP Posted June 1, 2007 Author Report Share Posted June 1, 2007 No ideas? ???Is it likely that this problem is caused by the PSU? Quote Link to comment Share on other sites More sharing options...
TK. Posted June 2, 2007 Report Share Posted June 2, 2007 Last week I've heard exactly the same noise on a MBSID - the reason was a bad soldering joint on the C1 cap (connected to pin 1/2 of the SID).So, it makes sense to check the C1/C2 cap connectionsBest Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
SLP Posted June 3, 2007 Author Report Share Posted June 3, 2007 Unfortunately that's not the reason :( Quote Link to comment Share on other sites More sharing options...
SLP Posted June 5, 2007 Author Report Share Posted June 5, 2007 I tried something different (see attachment).result: No noise :Dnow there are 2 possibilities:- The noise was just because of the bad PSUor- I've just killed something (I'll try the testone-app tomorrow)...something inside of me sais that Murphy was right... ::) Quote Link to comment Share on other sites More sharing options...
Altitude Posted June 6, 2007 Report Share Posted June 6, 2007 Hmm, Interesting power supply you have there.. I wonder if the quatro has better ripple current performanceI tried something different (see attachment).result: No noise :Dnow there are 2 possibilities:- The noise was just because of the bad PSUor- I've just killed something (I'll try the testone-app tomorrow)...something inside of me sais that Murphy was right... ::) Quote Link to comment Share on other sites More sharing options...
TheAncientOne Posted June 6, 2007 Report Share Posted June 6, 2007 Wow! Are you are going MIL spec then? I'm just guessing by the environmental tests. High temp, vibration, etc.On a serious note, it might indicate a power supply problem. My first ever project from 'Practical Electronics' was a 3 transistor (germanium!) amplifier. It made all kinds of weird 'motor boat' noises until I shunted the dry battery I was using with an electrolytic. My first lesson in power supply stability. Looking at the noise in 'Audacity', and 'blowing it up', I notice a background 10mS rough half sine wave, plus the HF noise. You're coming out of regulation, unless you're pulling more than (say) 150mA, so I'd try a series inductor in the 12V make sure you have local decoupling capacitors on all your boards. You should have both a small electrolytic with a ceramic in parallel, (Electrolytic don't work too well at high - like PIC clock - frequencies). All in all my vote is for the PSU as a source of the noise. From the description, I'd say your supply was a switch mode. I prefer a linear for most audio kit. There are usable switch modes, (I've just bought an old Akai 3000 sampler that uses one), but they are 'instrumentation grade' and expensive. Try loading the supply with resistors - suggest 4.7Ohm on the 5V and 150 Ohm on the 12 V rails, (get big ones 10 watt for the 4.7 and 2 watt for the 150's), and then put a scope across the power rails, on AC coupling, an see what you get. I use a test like this often, before trusting the supply with the expensive stuff. I've just done something similar with both the Oakley 3030 I've just completed, (welll all bar 1 LED), I put the regulator chip in before any others and set and tested the power supplies before inserting the expensive stuff. With the AVRx board I've just started, I built the PSU section first, out of the normal order, both to make sure it worked, and as a first test of my surface mount skills. With surface mount a failure is usually a lot more expensive....Perhaps as an overall hint to MIDIboxers in general. A couple of bench power supplies, either second hand, or kits to save money, are a really worthwhile investment, second only to a test meter. I say a couple because you are going to need at least a 5V and the analogue power. Quote Link to comment Share on other sites More sharing options...
stryd_one Posted June 7, 2007 Report Share Posted June 7, 2007 Wow! Are you are going MIL spec then?Argh don't do it unless your funds are limitless hahahahah... I was gonna go that route but trust me, commercial will do (especially seeing as even the military don't bother with MS any more, it's all commercial rated) and even then it's a total mission... Let me know if you're gonna do it and need specs, I have a few hundred meg in a collection here. Quote Link to comment Share on other sites More sharing options...
SLP Posted June 7, 2007 Author Report Share Posted June 7, 2007 it might indicate a power supply problem. Don't you think the stabilizing caps on the Core and SID-Module are enough?I've downloaded my noise-record again and must say that the record-level was too low. it's much louder.There seems so be an other problem... ::) (This thread is never going to end :P )When I power only the Core, something seems to oscillate. There are some sounds that are generated and then led through the ground-wire to the SID and then to the audio out and to the amp.When I power the SID on now, there is a 1KHz triangle-wave (?-quite the same as the testtone-app, though the SID-app is on the PIC) and the additional noise from the Core.When I power just the SID, there's a quite loud noise....I'll make a video and put it on youtube ::)edit:I won't put a video on youtube..... modem.... :P Quote Link to comment Share on other sites More sharing options...
SLP Posted June 10, 2007 Author Report Share Posted June 10, 2007 [depressed mood]ok...I've completely disconnected the SID-module from the Core and removed every IC from the SID-PCB.If I power it on, I hear the strange noise. If I take the connector which is used to connect the Cables for the SID-Core-connection and move it closer to the PIC, the noise gets louder.It seems that the PIC sends some electromagnetic waves which are recieved by the SID-PCB and forwarded to the amp.Now I take the input-wire of my amp (TDA 7052,btw.) and connect it to every pin of the PIC, I can hear the loudest noise at pin#:6,19,28 (noise#1) and22,21 (noise#2)edit:Testtone application works well, btw. Quote Link to comment Share on other sites More sharing options...
SLP Posted June 17, 2007 Author Report Share Posted June 17, 2007 here you go:http://www.youtube.com/watch?v=rqWhOjqHhq8Crappy noise recorded with crappy Digital camera mic. :P Quote Link to comment Share on other sites More sharing options...
TK. Posted June 17, 2007 Report Share Posted June 17, 2007 It sounds like digital noise, couldn't this be a corrupted patch? You are writing that the testtone application works well - does it mean that you don't hear such noise in background anymore?Then I would say, that it is very likeley that you missed to solder the two 1k Pull-Ups for the SC/SD line of the BankStick?Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
TK. Posted June 17, 2007 Report Share Posted June 17, 2007 Second assumption: I guess that you are not using the audio input of the SID - is it connected to ground? (this is recommented)Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
SLP Posted June 18, 2007 Author Report Share Posted June 18, 2007 Second assumption: I guess that you are not using the audio input of the SID - is it connected to ground? yes. the 2 pins are shorted.the strange thing is that even though the SID-chip isn't plugged into the socket the noise occours.I'll try to fix the bankStick-issue now... and I pray that this was the error ::) Quote Link to comment Share on other sites More sharing options...
SLP Posted June 18, 2007 Author Report Share Posted June 18, 2007 I've put a 1K (2*2K in paralell) resistor between SC and +5V and another one between SD and +5V.still noise. :'(btw. the noise starts when the display shows the MOIS version. Quote Link to comment Share on other sites More sharing options...
TK. Posted June 18, 2007 Report Share Posted June 18, 2007 Once the MIOS screen pops up, the application starts to access the SID via the 74HC595 shift registers. If you would connect an amp to one of the 74HC595 pins, I'm sure that you would hear such digital noise.Are you sure, that there isn't a "hidden" connection between the 74HC595 and the transistor amp stage (compare with http://www.ucapps.de/mbhp/mbhp_sid_v3.pdf Schematic)Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
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