Another Tangent CMoy Amp [6 pics]

Hi all, I posted this quickly in the build thread but have a few questions i wanted to ask about the cmoy...

This is my first diy electronics build ever ... ok I've fitted a new engine & wiring into an old Honda VFR400 NC21, fitted auxiliary lighting to other bikes I've owned & built PC's etc, but thats all mainly plug & play stuff...

I wanted a desktop sized amp rather than a pocket amp so selected a suitable enclosure based on that (and making wiring easier), apart from that everything is as Tangentsoft outlined for the standard build...

Re-build with larger 1uF input capacitors & OPA2227, first build used 0.22uF caps & OPA2132.

first time round it took 8 hours to build the circuit and wire it up, second time round, everthing took 3 hours including removing the first board from the case.

All encased and in use...

Thank you   the build was done in the first instance to see how good/bad the headphone stage on my Denon 2310 AV amp is ... As money is always a concideration, I wasn't sure if spending £500 on a dedicated head'amp would bring much improvement. The CMoy amp with opa2227 fitted, has proved to be the equal, maybe slightly better than the Denon, just how much better are the Burson or Beta 22 amps?

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Controling volume - first time round I set the gain to 3 [10kOhm pot] but could only use the fist 15% on the pot before it got to loud  to listen to [for me]. On the second board I've dropped to a gain of 1 but am only able to use the first 25% before things get to loud again...

Should I be thinking of swapping pots from the 10K to a 50K, or can I drop in a resistor [47k] between the pot and input caps?

I've enjoyed building the CMoy and have read through most of the extras on Tangent's site about improving the v.ground and class-a bias for the opamp's... is it worth building an up-rated version of the cmoy next or trying a two channel Beta 22 [more expenssive]? Or foget the building and buy a Burson HA-160?

Thanks,

Paul

Fantastic, just the info I needed, thanks.

With the basic CMoy design in mind, is it feasible to expect an increase in audio quility if it is modified using the better virtual ground design, buffers & class-A biasing [JFET Cascode design] as discused on the site?

Was thinking of a two board layout using single channel Opamps, each board built as a mono version of the CMoy amp [plus mod's]... worth the experiment?

Good analogy and a very good question to ask...

In building and hearing the CMoy I acheived my main goal of proving to myself that a dedicated amp is worth getting.

Taking the trip would be nice, ultimately though, it's the final destination that's of greater intrest. It's just that I'm not yet 100% sure on the destination!

Going to have one more go at building a better CMoy amp before moving onto a Betta 22, 2 channel build....

Tangent - your site has been a massive inspiration, helping me learn and understand the basics of a subject I knew nothing off 4 weeks ago ...  Thank you!

Spot on ... going to try scratch building something close to the pimeta on Radio Shack's protoboard. If that doesn't work out I'll order the pimeta v2 board and do it properly :o)

Currently using the ad823 opamp with the CMoy & Senn hd650's, slightly to forward (aggressive) sounding but preferable to the opa2312 & opa2227 (this one's good with Led Zeppelin). Have the ad8620 & 8610 on order ...

Hi Grant ... they're Panasonic 1uF 250V caps from RS components (uk store) - http://uk.rs-online.com/web/p/products/727-0017/ . Think these are the highest rating that are recommended for the cmoy, iirc.

Paul