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LM3875? For speakers right? Must be the 20W Gainclone monoblocks. Hehe.... Superbly simple project! But they're said to sound very good. =) One thing to note, it's solid state, not transistor based. The LM3875 is an audio power amplifier; Like an opamp with alot of juice. It's not a transistor like the BD139/ BD140's.

For those who are getting the amp for 240v use, I can modify the wiring for the amp's PSU to use AC 240v by default as the step-down transformer might affect the sound.

I fully concur.

Just to let you know... The prices we quoted are in Singapore dollars, not US$. So you have to multiply your costs by about 1.75 to get the price in Singapore dollars. Nice to see that someone is willing to help though. =) We can get Hammond cases locally but not Serpac. So you might be able to help us there.

How's about sandals?

Not really. You want clear sound so you can differentiate where your enemies are coming from for FPS games.

No, it depends on how the output stage is in the source. Usually, there are already capacitors in the CDP for opamps based outputs. Hence, any DC offset would have been removed. Some outputs are tube outputs and those have their own compensation for removing DC. Some use transistors in push-pull configurations and the DC is removed using other methods.

To conclude, the input capacitors are still essential when it comes to removing DC offset from your sources. However, for personal amps where you know the source(s) do not have DC offset on the output, you may safely omit the caps. Thus, removing the problem(s) of degraded sound quality (if any) & the high-pass filter.

I don't have transport so I can't bring my NAD 521i along. LOL. Tentatively, I'll be bringing my HD570's with my upgrade cable + stock cable. Might bring some other "stuff". =)

You can try the Sennheiser HD200's or HD270's depending on how large your ears are.

Frankly, if opamps could get rid of DC voltage on the input, you're going to have major problems using them in amps. The capacitors are for removing DC offset from the source, not from the output of the opamp as you might have thought. Most Fet opamps are pretty okay but bi-polar opamps do need some special configurations to prevent offset on the output.

Opamp DC offset? Care to explain?

They can be played on PCDP's as long as the players don't try and digitally rip the tracks. ie. use ESP.

I agree that the some of the Mac machines look good. I myself had wanted a custom dual G4 tower (old variant case) but had not been able to find anyone who could make one. LOL! But in the event that you can find someone who could, help me inquire on the cost of the following: Dual G4 1GHz, 1MB cache 1GB DDR-DRAM ATTO UL3D RAID controller 2 * 18GB Quantum Atlas 10K IV 17" ACD

Rameish is one of them. LOL.. Most Mac's that are built for audio engineers do come with pretty good sound processors.

Not everyone can build a gilmore, dude.. It's not a filter to reduce noise actually. The capacitor's purpose is to reduce DC offset from the inputs. Given a 100K ohms resistor and a 0.1uF cap forming a high pass filter, there is significant phase distortion & attenuation up to 100Hz. That explains why the change to a 5uF cap improved the sound. It's not because the cut-off at 15.9Hz is too high. BTW, a 5uF cap. with 100K ohms resistor forms a cut off freq. @ 0.318Hz, not 1.5Hz. To obtain nominal power transfer to the headphones, you need to measure the impedance of the output and add a resistor in series with the output to obtain a TOTAL resistance/impedance equal to the impedance of the headphones. Secondly, obtaining maximal power transfer to the headphones doesn't mean better sound. Most headphone amps have lower output impedance because that allows the amp to better control the drivers in the headphones.

Using Winamp 2.xx with MAD plug-in and Waveout is pretty much better than the default Winamp plug-ins. Coolplayer isn't shabby either. Matching up to the above while being less of a resource hog. Testing out Foobar now. Ain't too bad. But I'm not a MP3's freak...

I think a well lighted (white light) table that the legs can rest under and a soldering iron holder would be much better.

I might be bringing a new pair of cans to the meet... Depending on a few factors.. =)

Your dad an audiophile?

When I said noisy, I meant electrically noisy. As in noise + ripple. You could get a hum using the amp off the PSU.

Good luck on that then... Computer PSU's are all switching units and are very noisy.

OT: You don't happen to be Rohit Balkishan, do you?

It might have afflicted the old opamps as well. At least we know it's from your source. *grinz*

You might want to try getting a dual power supply just to feed the AD8620's on the soundcard. They might not be getting enough voltage and unhappy about the single rail power.