[deadlierchair]

I recently built a CMoy and have done some tweaking with resistors and gain but I still don't really like how it sounds. Granted, it has made things TONS better than just my plain CD player powering my headphones (currently MS-1's), but I am not yet satisfied. Also, I have the building bug and want to keep working on stuff

I plan on sticking with low impedance headphones for a long time because I listen to rock about 90% of the time and I love how the Grado style sounds with it. My question is what amp should I build? I am looking at the Apheared 47 with the buffer because many say that it has the current necessary for low impedance phones. However, I would like to do something more complicated if it will sound better. I have looked at the Pimeta also but will that run okay with the low impedance phones? Or is there another design that I should be looking at?

 

[MisterX]

Yes... the Pimeta is a very good match with low Z cans.

 

[aeriyn]

My AD8620 PIMETA rocks with my DT440s! (32ohm cans) Set the gain down pretty low though or you'll have to use micron precision in volume control.

Mine's set to a gain of 3.

Edit: Oops. Analog Devices opamps aren't the greatest with Grados, IMO. Too bright. Try using OPA2227 or if you've got the money to blow, OPA627s.

 

[bg4533]

Quote:

Originally Posted by aeriyn My AD8620 PIMETA rocks with my DT440s! (32ohm cans) Set the gain down pretty low though or you'll have to use micron precision in volume control. Mine's set to a gain of 3. Edit: Oops. Analog Devices opamps aren't the greatest with Grados, IMO. Too bright. Try using OPA2227 or if you've got the money to blow, OPA627s.

With my MS-2s the AD8620 in a Pimeta has a certain appeal to it. For some music and when I am in a certain mood it just sounds awesome. Not bright at all. At other times it can be a bit annoying. Overall I just stick to the OPA627. Sometimes it doesnt sound quite as fun and aggressive as I would like, but I never dislike it.

 

[aeriyn]

I think OPA627s make my DT440s sound too neutral. The AD86x0 opamps are so much fun in comparison!

 

[deadlierchair]

With my CMoy I had to add the R5 resistors and also lowered the gain to make things sound better. Are there any tweaks like this that I will have to do with the PIMETA that I should know about, or is it all in the build article?

 

[aeriyn]

Quote:

Originally Posted by deadlierchair With my CMoy I had to add the R5 resistors and also lowered the gain to make things sound better. Are there any tweaks like this that I will have to do with the PIMETA that I should know about, or is it all in the build article?

There's a lot of tweaks you can do to a basic pimeta to make it "maxed out," i.e. stacking the buffers, class A bias with JFET cascodes, etc. It's all in tangent's articles.

 

[PinchyCM]

Quote:

Originally Posted by MisterX Yes... the Pimeta is a very good match with low Z cans.

MisterX, what's the gain you usually set Pimeta's to?

 

[MisterX]

Quote:

Originally Posted by PinchyCM MisterX, what's the gain you usually set Pimeta's to?

Depends on the cans.

 

[miketriple]

i wasn't a big fan of my cmoy, but it's sole purpose was practice. i had already ordered parts for my mint when people suggested to build a cmoy first, so i put off the mint a little longer and built that. i use e3cs a lot (z=26ohms), btw. for my first amp, portability was very important, so i made the mint amp after the cmoy. big improvement

if that's important to you, i'd highly recommend going for the mint and tweaking that a bit.

my next plan is to make a pimeta, though! then, when the ppa v2 is out, i'm sure that i'll make one of those, too.

i know what you mean about the building bug! 2 down, 50 to go