[yeast]

For those of you following my dogged determination to make the AKG 501's sing, I have finally found the answer...not with my $1200 AES SE1, or my former X Cans, or even the ASL MG DT....its the diminutive CMOY by JMT.

I have been struggeling to make the AKG 501's sound good period. Through other posts, many others have too. I had given them up and listened contently with my Sony MD7605's.....until my CMOY arrived. It was worth the wait and it is clearly the only amplifier I have used that will handle the idiosycracies for the 501's....and at a very low investment. By all means get on JMT's waiting list! Workmanship and build are excellent, no worries here(Jon...hope this does not cause you any untold greif!)

Open, airy, clean, smooth, detailed....Rhythmic and(Any other audiophile type cliches are also appropriate as well). PLUS...more than enough gain and absolutely no distortion or clipping!I am rarely shocked by improvements in audio setups, but this is the case....AND, I am a "tube guy" making this all the more weird since the CMOY is an op amp device.

So, if you get the CMOY and the 501's you have a very,very fine audiophile treat awaiting you...add the Sony 25S to the system and you'll sell your Krell (maybe a little over the top here)!

ADDENDUM...just in..My Porta Corda arrived and it has some of the magic of the CMOY, but at a much higher cost

 

[Neruda]

I wish I knew how the Cmoy compared to the CHA47 with high impedance headphones; I have a feeling that the cmoy would do better with the K501 than my cha47 does...

 

[Joe Bloggs]

I thought K501s needed at least a HeadRoom Blockhead to make it sing?

To those 'buy better amp' proponents:

 

[yeast]

JMT has a great product for the 501's and I am shocked at how good this synergy really is....I was ready to dump my 501's quite literally. These headphones are still a paradox to me because I wanted a portable setup to travel with and the CMOY fits the plan, but not the 501's....I would say the 501's are definitely component restrictive. that is to say, they must be considered as a system to achieve the Class A/B+ sound with CMOY (and appears that the Porta Corda is Class B+/B)

As far as the better amp proponents, why wouldn't the CMOY qualify as a "better Amp?" because in this case, it clearly is.

 

[slindeman]

If you use the same parts (same board, opamp, power supply, potentiometer, etc) and a similar layout and gain, then the CHA47 and cmoy sound very similar driving high impedance headphones. When I had my 47 amp on breadboard and could easily convert it back and forth between it and a stock cmoy, I couldn't tell the difference. I didn't have a K501 to test it with though.

Of course once you start changing factors, like whether it uses the hansen board, the OPA2132 or OPA2134, the power supply, the gain, the build quality, then you'll get larger differences. How large? I don't know. My 47 amp sounds better to me than my first cmoy, but they have different layouts, different opamps, different power supplies, different input jacks (RCA vs. mini) and my soldering skills were much better when I built the CHA47.

My point: The cmoy and 47 are similar enough that part selection, layout, and build quality will likely make more difference with high impedance heapdhones.

 

[Beagle]

Interesting. When I use my K501 with my RA-1 amp. Not a lot of gain but you don't need it when they begin to sing. If you have to keep turning up the volume, you're probably looking for something that's not there that you hope to get by turning it up. If it sounds real and the natural dynamics are there, I can do without deafening volume.

 

[Neruda]

Despite how good they sound on the CHA47 or Cmoy, trust me, they sound waaaay better on the SAC

 

[Joe Bloggs]

riiight.

 

[brosselle]

Quote:

Originally posted by slindeman When I had my 47 amp on breadboard

Are there any schematics around for amps like this?

Brett

 

[JMT]

Brett

Check out the Projects Library at HeadWize. Specifically, for the 47 amp look in Apheard's Scrapbook.