Thanks for the reply. Leak shouldn't be problem because I am in a good distance from my colleagues. HD280 sometimes feels a bit to tight and can get too hot.

I just started a new job and is thinking about finding a good replacement for my HD280, because my new work place is very quiet. I am thinking about SR-60 because it does not require an amp. But I might also consider bring an amp to my office in case there is a big gain in sound quality...

That's normal among flat screen CRT monitors, if yours is of this type. The Dell (SONY Trinitron) and Mitsubishi I had used both have these two grill lines. It's perfectly normal and it's there because the whole screen can not be made in one part but three.

Cable: 16 AWG silver plated copper with teflon insulation, 2 strands for each signal line. Connector: gold plated RCA connectors Need a short cable to connect my PPA to my laptop and desktop in the office. This one sounds pretty nice, very detailed probably due to silver plated copper...

Quote: Originally Posted by eweitzman koladd, there will be clicks on turn-on and turn-off because of (1) contact bounce (2) load changes on the amp and (3) double load changes on the amp: the M³ has an active circuit on both hot and "ground" so you have two amps per channel being...

Quote: Originally Posted by eweitzman A 4P3T switch between amp and hp jack will introduce it's own turn-on/turn-off clicks and noises. And it will be in the circuit when the amp's in use, so it has to be a high quality switch. If you're switching the AC along with the output, you'll...

It remember the same problem occured to me before. With the HD580 I used to have, sometimes it gives unbalanced channels, pretty much depending on the Amp I use. I listened out of three amps with HD580, CMOY, Szerkerez and my Yamaha Compact Stereo at home. With the Yamaha, the channel problem is...

I guess I was wrong. The resistor rating should be RMS, so a transient probabily won't matter at all. But since during the switch off, the capacitors and 1 Ohm resistor from a R-C loop with initial voltage 24V due to the charge in capacitor, the peak power calculation would still be correct...

Quote: Originally Posted by JohnFerrier I = sqrt(P/R) = sqrt(0.25 W / 1 ohms) = 0.5A. This should work. It will only be a brief spike too... JF You're probably right. However, P_peak=U^2/R=24^2 V/1 ohm=576W. That's the peak power at the moment of switching. My concern is if this...

Quote: Originally Posted by morsel I suggest using a DPDT power switch, which connects the amp circuit either to the power source or a 1 Ohm resistor which rapidly discharges the onboard power caps, reducing or eliminating turn off noise. Sounds great, Morsel. This will totally...

Quote: Originally Posted by JohnFerrier You'll need to verify that between positions 2 and 3 that power doesn't turn off... Make before brake. JF JF, thanks for the suggestion. There're several "shorting" rotary switches available at Mouser, e.g. 10WA367 and 10WR046. For my PPA...

Quote: Originally Posted by amb We didn't design any pop-elimination scheme into the PCB, but you could always do whatever you want when you build the amp. Relays, switches, whatever. I find, though, on the M³ prototype and listening through the HD600, there is virtually no turn-on pop...

I just finished building PPA. And I'm really impressed with its improvement over my previous setup (CMoy and Szekeres). Thanks guys for your contribution. I'm considering taking a course next spring in analog IC design so I might be able contribute later to the society. I was excited to find...

Thanks for the reply. I placed an order at Tangentsoft.net. It seems like the only place that carries the POT.

It seems like that RS Components doesn't carry ALPS RK27 anymore. I got one from Mouser. But it turned out to be not the one that would work for PPA. I need help from folks here on where to find the ALPS POT's. If there're other alternatives that works as well as the ALPS, please also recommend...

I found some cheap Flexo-PET on sale at Silicon Valley Compucycle . $1.39 for five feet 1/8" sleeve. I thought it's not bad deal. They ship with First Class Mail so it could be really cheap if you don't order a large amount.

Quote: Originally Posted by flecom the sleeve was some regular black sleeve i had left over from doing my power supply a few months ago, i made it 10 ft + ~1ft for the Y... it ended up a bit too long for my taste... Flecom, where did you get these sleeves, what kind of material...

Quote: Originally Posted by RickP The Acopian is really overkill for the PPA if you build it with the full complement of rail splitters and capacitors. This is where the real work of power regulation and filtering take place and IMO you should not skimp. As long as the power supply...

I'm selecting parts now to build a PPA during the Christmas break. I got a question here concerning the power supply. I know that Elpac is much recommended. But I own an Acopain power supply which I think is very decent. It's a linear regulated isolated DC power supply. Could somebody who's...

Quote: Originally Posted by Xanadu777 Internally they are the same from what I've seen, with a beefed up exterior on the 650. I haven't counted the Litz wire in the 580-600, but internal thickness wise it's the same as the 14 wire Litz per signal 650... Thanks! That's helpful...

Anybody has any suggestion on how the stock cables of HD-600 and HD-650 compare. Did anybody try to put HD650 stock cable on the HD600 and was there any improvement in sound? I recently got a pair of HD-600 and was wondering if it's worth to get a cheap HD650 stock cable to replace the crappy...

Quote: Originally Posted by kunwar How are you outputting the signal is it via Optical or the line out jack. Next check to make sure high sampling rate is enabled. Also there are a couple of ways of making it work. One is with using an external ASIO exe setup, the other is using the...

I just got my AV710 and was playing around with it. I was trying to setup ASIO using foobar DLL plugin and Wushel's ASIO4ALL. Foobar gives me the erros message "INFO (foo_output_asio(dll)) : open : 96000 Hz, LINEAR PCM, 24 bits, 2 channels ERROR (foo_output_asio(dll)) : unsupported sample...

Quote: Originally Posted by tangent Do you know for a fact that this is a problem, or are you just hand-wringing? I know this is a problem. That's what the MOSFETs are for. By having large input impedance for the MOSFET driver, the output current of the Op-amp can be limited to a...

I used a TLE2426 "rail splitter" to creat the virtual ground. The noise is gone. I think you were right, using resistors to cut the input voltage by half is not stable so the Virtual ground was floating around, which created the noise when there was no input source. The TLE2426 seems to perform...