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  1. balou

    A47 problem

    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...
  2. balou

    AD8646: new high current opamp suitable for cmoys?

    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...
  3. balou

    Go-Vibe V6 modding

    ...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...
  4. balou

    class A biasing kills battery life?

    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...
  5. balou

    Dual-to-single DIP adapter

    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
  6. balou

    DIY tips and tricks...add some.

    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
  7. balou

    DIY ER4p => ER4s Cable

    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...)
  8. balou

    My reference amp design TPA6120

    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
  9. balou

    Where to buy Alps RK097?

    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
  10. balou

    Where to buy Alps RK097?

    why must it be in europe? AMB audio shop Tangent's Parts Shop you can normally only buy them in multiples of 50 or so - amb and tangent just do that, and offer them for DIYers overseas shipping is quite fast, and you can conveniently pay with paypal (I ordered once from tangent, but amb has...
  11. balou

    Larocco headphone amp repair

    should be doable by any diyer. you do mean the larocco prII, do you? replacement of it's alps rk097 pot should be easy - pot costs 3.25$, and repair maybe takes half an hour
  12. balou

    2 sided pcb for audio?

    Quote: Usually I've just seen that the bottom layer is used for routing two reasons: commercial amps: costs less than double sided boards diy amps: easier to etch it yourself (no sub-millimeter aligning of both sides) Quote: I got the idea of putting half of the design on...
  13. balou

    1 AAA boost to 5.5v?!

    the exact chip in Xins amps is either MAX1795, MAX1796 or MAX1797 (they're pretty much the same, except for max output current). Xin once mentioned it that it was one of these chips, buried deeply in the forums. I first tried to id the chip with pics (to no avail), but then found this info on...
  14. balou

    DIY Line Out DAP possible?

    yes, unless this player has a all-in-one DAC/headphone amp chip (sometimes even dac/amp/mp3 decoder/ide-/sdcard-interface)
  15. balou

    TDA 2822 compatibility

    okay... the sources on the net i found always showed a 16-pin amp. do you have any datasheet with the pinout? but I don't think there's much to do. the datasheet of the 16-pin version showed that it's a chip which requires huge electrolytics, indicating that it's a rather cheap and low quality...
  16. balou

    TDA 2822 compatibility

    the tda2822 is not an opamp, it's an integrated power amp. and it's not compatible with any opamp. (opamp: 8 pins, tda2822: 16 pins)
  17. balou

    Impact of power supply upgrade for Pimeta

    I'd say no. Have a look at Power Supply Tests STEPS and TREAD are awfully close performance-wise. and modern opamps have quite some power supply rejection. and a pimeta is also not that much of an uber-amp. a sigma11 might have a lower output impedance than a STEPS/TREAD, but again, will it...
  18. balou

    Grados being sold outside the USA now?

    Quote: just for prices nobody is willing to pay. It's not like you have much of a choice. I have paid 170$ for my SR80s (ok, it was more like 150$ back then). And I think they have still much better value than sennheiser headphones.
  19. balou

    Best way for audiophile to listen to music at a concert

    bring a portable amp and your custom moulded IEMs and hook yourself directly to the soundboard about those musicians earplugs... I bought a pair of them for about 40$, and while they mostly preserve relative frequency, they do roll off at high frequencies - something not so good for a...
  20. balou

    Tube epiphany today

    hi, Today after my first week at university, I wanted to try out some Sennheiser headphones at Musik Hug in Zurich. Well, the HD600 was a rather big disappointment (it just sounds to boomy and undefined for me), but I have made some other nice discoveries. A nice sales guy noticed my Grado...
  21. balou

    Op Amps and C&C XO

    there are quite a few threads on this subject. it probably has a dual opamp in it - a few suggestions would be lm4562, opa2107, ad8066, ad8620. there's a statement on the manufacturer site that they use a JFET opamp - maybe a little hint that you should not use bipolar opamps in this design. all...
  22. balou

    1/4 adaptor for Canare F12

    hi, TTVJ sells them (gold version) or search for "1/4 adapter"
  23. balou

    CMOY battery question

    Quote: The only advantage I can think of is having power in the unit for a longer period of time. The opamp will actually draw more power with more voltage. Yes, you don't reach the minimum working voltage of the opamp as fast as with just one 9v, but I don't think that's the reason...
  24. balou

    DIY class D headhphone amps?

    I don't think that class D has enough benefits in already low-power headphone applications - but ymmv. And do you mean class D with commercial off-the-shelf amplifier chips, or everything built from scratch? You could find circuits for the former in any datasheet for low power amps, the latter...
  25. balou

    USB DAC need recommendations

    Just a note on jonnyrockets hint at that second eBay DAC: it's a rather basic PCM2702-based circuit, like the Alien DAC, with the added bonus of an integrated toroid transformer. And the discrete +/-12v regulator looks quite basic - dunno how good it's ripple rejection specs are. The first...