tropicalrips

if u use the line out jack u must a volume pot to control it or it will be too loud u can't control the volume output on the line out side problem on one side of headphone could be damge headphones cause your volume was too loud

but once u get it to work , u would hav learn a lot of things & see how simple it really is

signs of the op-amp dying it happened to me too, thought everthing fixed, then put into case...then no sound at all u used meter to measure the voltage? try (+) and ground & (-) and ground, they should be about the same

good luck augustineRS my first sucessful cmoy took abt 1 week go though the drawing again, i think the tricky part is at the output / R4 / R5 side, the rest of it is quite stright forward

i should be going too if eveything goes well, my offday is on friday. i'll be bringing the CHA47 & mini Cmoy or Cmoy with LM6172 op-amp if i can finish it, still listening to it on the proto-board

the koss plug sound on the cmoy i tried it, never try the PX200, i think its 32ohm rite? i also thought the gain is too high with my first Cmoy, but it end up being the headphones are too effecient (low impedance) so they pickup lots of noise. u can try 4.7k for R3 which will giv u 10/4.7 + 1 = 3.1 gain 3k = 10/3 +1 = 4.3 gain i'm using 2k so its a gain of 6 original design is gain 11 if the gain is too low, the high ohm cans will get distortion/cliping, they sound like the amps has not enough power "took out R1" do u mean the voltage divider? which op-amp are u using? if its too loud i guess the op-amp is still alive can still try

do u mean hissing AugustineRS ? like its raining outside, i got that on my first cmoy too, are u using the same resistor values i posted? try it with higher impedance headphones, those 16ohm headphones pick-up a lot of noise from the amp, or u can try what i hav above, solder 2 43-50 ohm resistors to the stereo plug to test if its the amp giving problems the Cmoy works really well with high impedance phones like Sennheiser, which can't be driven properly with portable devices, but with cheap earphones the R4 is connected to R5 (op-amp pin 1 > R5 > R4 > R3 > op-amp pin 2) this forms the feedback loop i think the output is connected to 2 resistors - R4 & R5 before going into the op-amp i didn't really hear any different with the volume pot thats why i left it out of my newer amps, but the resistors does make a difference, but thats the wrong way to go, will just end up with a cmoy with lots of components

and also &

got the LM6172IN today still testing it on the proto-board, this op-amp really is "cranky" got it to work using the drawing by tangent, but it sounds really bad with low impedance headphones lots of hissing & distortion, i got all the components execpt the 2.2uf C2 & 10pF C4 caps made a plug with 2 43ohm resistors, this made most of the hissing go away. going to change the resistors to 50 ohm the plug has a strange effect on the sound...the low frequencies sound up-front, but the rest of the music sounds like they are behind. but i only use this on the cheapo headphones to simulate a high-impedance phones for testing the bass with this op-amp is really heavy, more so then the OPA2132 also got the OPA2134PA today, they work in the cmoy & cha47 without any problems and they cost half the price of the 2132 guys, still don't know what rail-to-rail means

i think thats ok price, the cheapest i got was $2 / each so 1 pair was $4

PPA vs CHA47 + mini CMOY handicap match

i found the 4xAA case for it, its actually use for charging PDA, it also has a build-in on/off switch & its smaller then a mint box it can fit 1x9v batt + 1xAA batt + the mini Cmoy i'm thinking mini cha47, if 1 want to hav the AA & 9v together, should i connect them in series or parallel? the 9v is rechargable i still don't know what rail-to-rail means, anyone can explain

new type u hav to defend the gundams cause they can only work with "new type" pilots

the Ety foam comes with the tube glued to the it, u just need to remove the koss foam & tube and it will fit. its a bit tight so hav to do it slowly

i hav never seen the A1000, only pictures of it. i think it should at least sound as good if not better the my D40fs rite? Gundams are build in japan , Transformers are cheap copies Transformers hav brains but Gundams hav soul

i'll be there if can get off day kenshinz, is it the same place as the last mini-meet? i'll see if i can finish the super-mini by then, already hav the case for it

sorry not my its Xin's super-mini not my i'm looking at his design to improve my own i think it works with the AD823 cause of its low voltage requirement, my cha47 with 2 AD823 op-amps has already lasted longer then the cmoy with 1 OPA2132 on 1 9v batt according to Xin this super-mini will last 75 hrs on the 3 AA , thats very impressive, i'll see how long my CHA47 last anyone knows if the cha47 will work with AD823 as amp with LM6172 as buffer? will be getting my LM6172 after the holiday

i'm still trying to build my super-charged Cmoy for me the PPA is too big as a portable amp, i want somthing thats the same size or smaller then my mp3 player. maybe pimeta in the near future one more thing guys, the AD823 is "rail-to-rail" what does that mean? it will work without the rail-spilter? i'm looking at the super-mini now since i hav the AD823 op-amp

the 0.1uf polypropylene caps will replace the rail-spilter? or the power caps (i'm using 25v 470uf) or its added on to these 2 components? on tangents site this cap is optional & the C3 2.2uF cap as well, only when "all else fails" in his "notes on OP Amps page" his test amp for this op-amp only the R3 & R4 was change (R3=120k , R4=470k) the rest of the amp is the same as the original Cmoy should i try this test amp layout first or go for the design below?

i normally use at 300-350 degrees orderd OPA2134pa & LM6172in today to try out any comments? the LM6172 is suppose to be a high speed op-amp, but not as stable, so can use it to test how good the board is rite? can the cmoy work with 3 AA batts? found a new case that will fit the micro cmoy & hold 3 AA batts

they are there to improve the sound mar isolators made with hot glue-gun the ones on top are pins used on PC, u can connect them to IDE cable, they can also be cut to different length, can get them in SLS or SLT its a re-worked board, i hav changed the resistors on this board about 3 times, so the solder looks funny firefox, i'm using a weller 921ZX up to 450 degrees, don't think its not hot enough

i got my from SLS Hung Bros

sure

"chao ta" op-amp from my pic, the (+) is on the left (-) on the right the power goes to pin 4 (-) & pin 8 (+) on the op-amp