do you have a multimeter? if not, get one. then check if the tle really splits the voltage like it should, and then remove the opamps and directly test the voltage supply pins on the opamp socket. also, check how much ampere your amp draws, and compare it with the sum of the idle current draws...

hi, I got a mail from Analog Devices a few days back, about a new opamp (among other things). And the new AD8646 looks quite interesting. Here's the sales pitch: Quote: AD8646 24 MHZ RAIL-TO-RAIL DUAL AMPLIFIER The AD8646 and the AD8647 are the dual, and the AD8648 is the quad...

Maybe one of this tutorial will help you Tangent Tutorials SparkFun Electronics Curious Inventor - Guides : Surface Mount Soldering especially the last one is quite good

you're blocking out the voltage supply to your opamp with those caps.. they should go from V+ and V- to GND, NOT on the opamp pins directly Working with Cranky Op-Amps this site describes what you need to do to make a cmoy which will work with almost all opamps (also shows the right way to...

...there doesn't seem to be much in this amp... well... you could change the ad8620/ad8610 combo with ad8066/ad8065. but because they are soic chips, changing back and forth is rather tedious. and you would first have to know which opamp sound you like more. Maybe NelsonVandal has some...

Well, you could always replace the opamp. maybe there are other mods that could be done, can you make a pic of the pcb? (replacing caps for instance)

For an unbuffered design, the biasing current would have to be higher than the maximum expected output current. let's assume a grado headphone at line-level voltage of 2v. U = R * I 2V = 32 Ohm * I 2/32 = I 2/32 = 0.0625 A = 62.5 mA so the biasing current would have to be higher...

I once thought about ordering a bunch of custom made adapters from a pcb prototyping company like olimex. it would cost 36 euro for about 100 adapters. if there's some interest, a group buy could probably be arranged

many people chose 75 ohm, as this is the same value as the cable of the etymotic er4s (er4s is just like the er4p, just with a cable which has 75 impedance). but anything between 50-100 ohms should be fine

are you never able to remember which channel is which on rca/mini jacks and cables? the 3R rule: * Ring * Red * Right the ring on the 3.5mm jack, the red RCA connector and red wire are all the right channel

Quote: Have to solder one resistors on both cables ? (Left and right) Means 2 resistors to solder ? Yep. And remember, 75ohm is not the same as 75k ohm (don't laugh, somebody asked me that question...)

TzeYang, I think I was a bit unclear, I meant monolithic all-in-one chip amplifiers, not opamps. altough upon closer inspection, the tpa6120 looks much more like a dual opamp than your average chip amplifier - the latter usually require DC blocking caps at the output, and their max, output is...

schematics plz I'd really like to hear this amp - monolithic chip amps don't have a superb reputation around here, but the pure technical specs of this amp are quite interesting. but.. um... I first have to build my B^3 amp and a pimeta board which has been lying around for about half a year now

mkay, but I'm sure Basil101 wants neither 50 nor 1400 pots, just one or two edit: yeah, this post doesn't make to much sense

I once put an AD8066 opamp (on a browndog) the wrong way around in a socket. it still works, but it has developed a considerable noise floor. it's now serving its duty in a cmoy for my radio (it's a rack-style radio without any amp inside of it). 95% of the time the hiss of the radio is bigger...