BlakeN 0 Report post Posted September 4, 2006 (edited) I have been lurking for a few weeks now and I want to build my first DIY amp. I will be using it for a pair of HD595s. I thought the cmoy 2 would be a good place to start. Where is the best place to buy the pcb? I saw 1 person on ebay selling "pre-order" pcbs but I was hoping somone knew a trusted source for them. I can solder fairly well but I don't know jack about circuit design so if anyone could point me to some good instructions for building the cmoy 2 with dc jack that would be great. I can sort of read a schematic. If anyone else thinks there is a better diy amp for the same money that would better match for these cans I am all for it. I will be using this at work 100% so it doesn't even need battery power. Edited September 4, 2006 by BlakeN Share this post Link to post Share on other sites
mb3k 0 Report post Posted September 4, 2006 jasonhanjk may still have some PCB's left. I bought some from him just recently. Shoot him a PM. Share this post Link to post Share on other sites
RancidM 0 Report post Posted September 4, 2006 in another post it was advised to use a 12V dc regulated PSU. sort of cheap ones you can get from most places. the only other consideration would be when calculating the resistor for the LED to take into account the extra 3v over a battery. Share this post Link to post Share on other sites
BlakeN 0 Report post Posted September 4, 2006 Thanks to both of you. RancidM, a typical wall wart will work? I think I have a 12v 1000mA one arround here somewhere. Its one of these but 1000 instead of 1500 . What are the power requirements of the cmoy 2? I have sent John a pm I hope he still has some Share this post Link to post Share on other sites
RancidM 0 Report post Posted September 5, 2006 Hi Blake... i must point out that im as much a newbie to this as you are... dont take my word as if it is gospel. im only relaying information ive got from other peoples.. and sort of relying upon common sence.. as the Cmoy2 was originaly ment to run off a 9v Battery i cannot see it requiring too much current at all. im pretty sure a 1000Ma will be more than enough to run the amp.. (maybe Jason or Heady will confirm) there is one issue concerning the AC adapter mind you, the link you gave dosnt say if the ac adapter is regulated or not. as i understand it a regulated AC adapter will give a cleaner supply than unregulated. i also understand that audio circuits are suspectable to unregulated supply. it may well be that this just isnt an issue.. if it is then regulated ac adapters are cheap enough. my build is going to be using a 12Vdc 500MA unregulated PSU as thats what i happen to have spare. if i find it introduces "noise" into the amp then i will swap it out. make a not that Jason in his post takes about a dual +12v -12v supply with a 0v ground. this is a different kettle of fish and best left alone for the moment. im just waiting for a new PCB and i will be posting a very simple guild on how to build the cmoy2 for the very novice. like youself im not too shabby with a hot stick but a circuit diagram and im lost. i did however learn the forumular for working out resistors for leds so maybe theres hope for us yet. Share this post Link to post Share on other sites
pegasus21 0 Report post Posted September 5, 2006 Ok, the reason why a 12V supply is recommended... It allows you to play with the higher end chips like the OPA627 as they require higher voltages to work well. Current draw is estimated to be less than 100mA cos the LM6171 handles up to 80mA. So if your circuit requires more than 80... you're out of luck unless you put another LM6171 in parallel or you redesign that part a bit... I myself just finished a CMOY 2 with a 12V regulator. The LED resistor... you can use 2K Ohms. That'll give your LED about 5mA (Assuming red LED is used Vd of 1.778V) of current to light up with. You can decrease the resistance if 5mA isn't enough. Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted September 5, 2006 Hi guys. Remove the dual supply version as it cause too much confusion. Visit here and tell me any more improvement you guys like to see. http://www.sgheadphones.net/index.php?showtopic=3220 Share this post Link to post Share on other sites
vixr 0 Report post Posted September 15, 2006 are there any of these PCBs left? Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted September 16, 2006 YGPM. Share this post Link to post Share on other sites
vixr 0 Report post Posted September 16, 2006 Jasonhanjk, thank you for your kind reply. PM returned... Share this post Link to post Share on other sites