Cmoy headphone amp update.

Looking at my blog statistics I noticed some visits on my now old and very dead Cmoy project. Out of respect for the people who are visiting I wanna give an update on my electronics projects. Since I built that Cmoy headphone amplifier and crossfeed my life changed quite a bit, I don't have the... Continue Reading →

Beyerdynamic A20 Review

A fair review on the Beyerdynamic A20 headphone amplifier!
I don’t often reblog articles on my blog but this one is so well written that I’ll share it.
Hey! I’m a Beyerdynamic fanboy, so I’m biased! 🙂


I remember a customer from very early on in my 3.5-year career working in the build your own PC department at Micro Center who insisted that he had to have an AMD video card because his computer has an AMD CPU. When I explained to him that this was inaccurate, he told me another sales associate had said otherwise. “He was wrong,” I said flatly. It went on like this for some time until I told him that it really didn’t matter to me whether he bought an AMD video card or an Nvidia video card and it was true: I couldn’t possibly have cared less. I remember it clearly because it was one of countless interactions to come in which the customer would question my expertise, which always came as a slap in the face because I prided myself as a guru. When I went home for the day…

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The hero of DIY audio, Pow Chu Moy.

It came to my attention that Pow Chu Moy the man behind Head-Wize and the Cmoy headphone amplifier passed away in Reno Nevada (US)  on February 12, 2016. Kevin Gilmore was the bearer of the sad news in the headphone community Head-Fi. I never had the pleasure of talking with Chu Moy, mostly because his... Continue Reading →

The NwAVGuy mystery.

I have a deep respect for the NwAVGuy work on the O2 amplifier and like so many other enthusiasts around the audio circle I wonder what happened to him, so I really wish he is well and happy. There are some theories behind his disappearance. NwAVGuy’s death or the death of someone near him, got a job on... Continue Reading →

JRC4556, shipment prices and other rants.

Sometimes I really hate living in Portugal, If I want to buy some JRC4556 for my low impedance headphone amp I must pay 18€ of shipment doesn’t matter if it’s 1 or 30 op-amps, if the purchase doesn’t go above 65€ the shipment must be paid. I get people must get paid to make my shipment but 18€... Continue Reading →

Revision to my headphone amplifier.

I need to revise my cmoy headphone amp because that DC offset still bugs me a lot. I want to know what I did wrong or at least reduce the offset to an acceptable voltage 20mv to 25mv max. After some light reading my conclusion is that the problem can be from: A bad ground plane, a bad... Continue Reading →

Cmoy board using a darn Burr-Brown 2132PA. The JRC’s that I got need at least 9V in each rail to work fine…darn. Next crossfeed section from Jan Meier. I really need to shield these boards.

The DC regulator and rail splitter boards in the headphone amp enclosure. 12VDC to a 9V 7809 regulator to a dual TLE2426 rail splitter that outputs 4.2V to the V+ & V- rails. I flipped the RCA and power back panel after taking this photo, now the PWR jack is closer to the PWR switch.... Continue Reading →

Headphone amplifier in the works. Not sure if I’ll use 9V batteries or a regulated source, maybe both. Believe or not that’s a lot of money on a table.

Image: What does Burr-Brown, JRC and Grado have in common? The Grado RA1 headphone amplifier, beautiful enclosure and sound until someone discovered that it uses a JRC 4556 opamp in a circuit similar with the popular Cmoy. Fanboys went nuts…an expensive headphone amplifier that uses a cheap opamp!? No way! We shall upgrade it to... Continue Reading →

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