[samlasker]

A friend told me about this great forum. I've spent the last couple of days reading up on various amp designs, different op ams, caps, and so on... Needless to say, I'm totally confused!

OK, I'll start my diy efforts with a simple cmoy.

That said though what I really want to know is what people think is the best portable headphone amp for Grados and why. To qualify as portable, I think the amp should run for at least eight hours on two 9V batteries, perhaps a bit more in the battery compartment, and fit in a (roomy) pocket.

 

[Sugano-san]

Quote:

Originally Posted by samlasker A friend told me about this great forum. I've spent the last couple of days reading up on various amp designs, different op ams, caps, and so on... Needless to say, I'm totally confused! OK, I'll start my diy efforts with a simple cmoy. That said though what I really want to know is what people think is the best portable headphone amp for Grados and why. To qualify as portable, I think the amp should run for at least eight hours on two 9V batteries, perhaps a bit more in the battery compartment, and fit in a (roomy) pocket.

The Xin Supermacro-3. Because of its sound.

 

[samlasker]

But the supermacro comes assembled and all, right? I had kinda hoped for an opportunity to curse as I fry various components and go through yards of desoldering braid.

Supermacro's better than diy projects for $350?

 

[n_maher]

My advice, take it for what it's worth (not much

)

Step 1: Build a Cmoy - just for practice.

Step 2: Build a MINT with an OPA2227 and see if it's performance matches your expectations. I happen to think that it's a great portable amp for my Grados and is pretty dang cheap to build. Will it best a $400 SR-71, no, but then again it'll only cost you $60 to build

.

Step 3: Hide your wallet, forget this site, move on, be happy, have money.

HTH,

Nate

 

[Porksoda]

I second the MINT recommendation, or perhaps a PIMETA. PIMETAs get a bad rap for being harsh, but once they burn in they are nice and smoooooth if you have the right op-amps

 

[thrice]

I would second what n_maher said. If you are looking to get into this hobby (headphones and DIY) cut your teeth on a CMOY and go from there.

The MINT and PIMETA amps are pretty flexible since you can choose different op amps. The PIMETA might be a better choice since you can socket the op amps and roll them where the MINT has SOIC pads and that makes rolling a pain if not unreasonable.

You can also roll op amps in a CMOY as well, so it's a great little amp to get started.

 

[robbneu]

Sam,

You can get very good performance out of a "entry-level" C-Moy that will really compliment your Grados. I've built a number of C-Moys, using Tangent's instructions, and have been very pleased with the sound, although I'm starting to hear the murkiness of the OPA2132PA amp and will be trying out the OPA227 on my next "batch" of C-Moys.

After completing my first C-Moy, I quickly bought a Pimeta and crossfed board from Tangent, but haven't touched them since getting them in the mail a year or so ago. I thought it would be more benefical for me to really start to understand the C-Moy circuit before moving on and so I've built a number of C-Moys, with more parts on the way, and plan to eventually move to the MINT, before trying a Pimeta. If you're really interested in the hobby and want to learn, I would recommend going a little slow. The C-Moy might be a little limited, but I've been having a blast with it and have really enjoyed working on them. As I said, they provide pretty good sound with Grados.

Robb

 

[ajt976]

I've also used both my cMoy and Pimeta with my Grados. My cans benefit greatly from both amps. I would start out with a cMoy, but do some research and find the right op amp for you to start with (I hear some are more forgiving than others). It shouldn't be to awful hard to build and they are very cheap, so if you burn up some parts they won't be expensive to replace. Also, thrice makes a good point in that you CAN roll the op amps in the cMoy to vary the sound you get. Pretty neat little project, you will have fun, and in any case you will not be dissapointed. After all, it's a great opportunity to learn something and you will take pride in knowing that you have built it yourself

. Have fun!!!

 

[ECM]

i own a pair of sr-125's and the "recommended" grado amp is very similar to a cmoy. i have built one and it sounds pretty good with my cans. be sure to lower the gain and use a chip with some current capability.

the headphone amp on the buf634 datasheet also sounds pretty good and can be made to fit inside a tin.

 

[Porksoda]

you COULD try making an RA-1 clone, as it is basically just a CMoy with some careful parts selection. Do a little searching on the DIY forum and you should be able to find a handful of threads on how to make them.

 

[wwap]

is portable pimeta really much better than a maxed out cmoy?

what are other suggestions on a maxed out pimeta?the only improvement I can think of is only more buffers on each channel

 

[wwap]

sorry double post

 

[skyskraper]

a pimeta will poo all over a "maxed" cmoy. it's a fantastic sounding amp. i still used mine all the time until it moved in with one of my friends. i'm thinking about building a "maxed" out one myself for long plane journeys and the such, what a poor excuse. i just wanna build another amp and have the pcb here

 

[samlasker]

After doing more reading, I've become really interested in a basic 3-channel CMoy. Judging from this thread, reliance on virtual ground is one significant weakness of the CMoy design. A three-channel design doesn't add more than a few parts compared to the classic CMoy. So it would still be easier and cheaper than a PIMETA and provide a nice introduction to this kind of amp. PPA and M3 are 3-channel designs, too, right?

Guess I'll just have to figure out how to modify the existing CMoy... uh, right.

Of course, there's this, but I don't really want to mess with bipolar op-amps.

Edit: found Morsel's 3-channel design!
http://elvencraft.com/downloads/minidiffsch.gif
http://elvencraft.com/downloads/minidiff.gif

 

[MisterX]

Morsel's Minidiff is well worth the effort if skillz are up to the task.
It never fails to impress me.