[meat01]

I was just wondering how people prefer to tweak there CMoys for better sound or for their particular headphones.

 

[Ghostie]

Well here is a link to Tangents suggestions for tweaks:
http://www.tangentsoft.net/audio/cmo...al/tweaks.html

When I build Cmoys now I always use a precision voltage divider, (the TLE 2426). This will increase the battery life and also keep the power rails balanced for high loads. Before I used the TLE 2426, I would get distorstion during crecendos in music with my 300ohm Senn HD580's unless I used 2 batteries. Now I can use one battery without any distortion! Which is great especially if your Cmoy is portable.

I also use panasonic FC 470uf electrolytic caps or panasonic FC 340uf caps for the power supply(available at digi-key). The 340uf caps you can get in a short version in you need the space.

You could also try a different op-amp like the Burr-Brown OPA2227.

Ghostie

 

[Born2bwire]

Say, I've been wondering about something and Tangent didn't post this specifically if I recall correctly. Is there an advantage of using the OP634 buffer over the TLE rail splitter? I noticed that he said that the TLE has some current restrictions (but I'm assuming those don't arise in the operation of our circuits).

 

[Ghostie]

You still need a voltage splitter with a buffer, whether it be 2 resistors or the TLE. The Meta42 uses the the TLE with the El2001 buffer. I think using the buffer in conjuction with the TLE helps lessen the restrictions of just useing the TEL alone, but I'm not sure.

Ghostie

 

[guzzler]

yeah, the TLE only supplies about 20mA, which is plenty for a normal CMoy, but if you start adding buffers and increasing your output, you need to buffer it...

g

 

[puppyslugg]

You can play around with the opamps; bias class A. For stationary listening, use a regulated ps.

 

[Born2bwire]

Well, I used the buffered ground circuit that was suggested in Tangent's website and used the values for the resistors and capacitors from the data sheet of the BUF634. It works very well from what I can tell from my Rat Crap multimeter. I need to snag a Fluke from the ECE department to see how close it really is. Anyway, the other thing I did to my CMOY was turn into a global feedback circuit by adding another OP2134PA to act as a buffer.

 

[was ist los?]

Just two basic tweaks. TLE2426 and 1000uf caps.

 

[rickcr42]

only one tweek works for me

[size=medium]MORE POWER[/size]

either current doubling ("mackie " console style or buffer in the loop) and battery pack.

I don't much worry about rail splitters unless using the buffer.Mostly i use dual supplies and when i go "ultralight" the resistor divider suffices.
Op-amps have pretty good psrr

Other than the above i upgrade the parts,though of less importance than the above for me.Even the radio shack blue film caps sound pretty good in a pinch

Oh yeah,RF filtering can make or break an amp in some situations : input rc network and loop filter

 

[guzzler]

a splitter is actually better than two resistors: smaller, more accurate and doesn't draw as much power... TLE all the way!

g

 

[rickcr42]

simple all the way !

Actually i don't sweat too much over my portable rig.
there are far more distractions on the go than worrying about the nTH degree of reolution from an op-amp (of which there are none in my home listening system)

far better to go for reliability , nothing pissess me off more than "glitches" or breakdowns when out listening to music , far from my tools

fresh batteries ,bullet proof construction ,intelligent layout for easy use,Rf protection and of course the ever present car adapter and ac wall wart , plus cord adapters for demos

basic dual op-amp x 2 with a 12 volt battery pack does it for me