[Blackwheel]

Super Slim Metal cMOY Headphone Amp (Silver Ver.) - eBay (item 250502776350 end time Jan-20-10 07:58:37 PST)

Is this a good deal?

 

[lozanoa11]

Seems reasonable. I spent $30 in parts on mine and it didn't even work lol.

 

[juniperlater]

I don't particularly like the 2227 chip, but you can switch it out and opamp 'roll' and see which you would like.

 

[Blackwheel]

Quote:

Originally Posted by juniperlater /img/forum/go_quote.gif I don't particularly like the 2227 chip, but you can switch it out and opamp 'roll' and see which you would like.

Which chip do you prefer? I also stumbled across this:

Cmoy Portable Headphone Amp for IPOD, Zune, MP3, CD,DVD - eBay (item 110472799972 end time Dec-29-09 14:30:24 PST)

It has the same chip but it also has TLE2426 power divider. Is this a better option?
thnx

 

[juniperlater]

I don't know about that chip. I use OPA2134 and OPA2132P. They are easy enough to come by. But most people on ebay don't use them. It is personal preference.

 

[AcousticDreams]

Quote:

Originally Posted by Blackwheel /img/forum/go_quote.gif It has the same chip but it also has TLE2426 power divider. Is this a better option? thnx

That's not an option, it is a basic part of the circuit. A Texas Instruments TLE2426™ precision rail splitter is for the resistor divider power system found in standard cMoys, also called virtual ground. The advantage of it is the possibility for a higher voltage supply, so that you can also use HP's with higher impedances.

There are also alternative op-amps theoretically usable, but this is not a question of the sound, but rather the absolute maximum ratings resulting from it. The Texas Instruments OPA2227™ is in this case the best choice, the chip has very fast signal transitions and a extremely low power consumption. If you are interested in development, than you could also try to change something. But don't forget, it has always consequences for the remaining circuit.

 

[Mad Max]

So many options for opamps... @_@'

 

[Blackwheel]

Quote:

Originally Posted by AcousticDreams /img/forum/go_quote.gif That's not an option, it is a basic part of the circuit. A Texas Instruments TLE2426™ precision rail splitter is for the resistor divider power system found in standard cMoys, also called virtual ground. The advantage of it is the possibility for a higher voltage supply, so that you can also use HP's with higher impedances. There are also alternative op-amps theoretically usable, but this is not a question of the sound, but rather the absolute maximum ratings resulting from it. The Texas Instruments OPA2227™ is in this case the best choice, the chip has very fast signal transitions and a extremely low power consumption. If you are interested in development, than you could also try to change something. But don't forget, it has always consequences for the remaining circuit.

Thanks for your response. I'm new to all this so forgive me for this question, but:

"not a question of sound, but rather the absolute maximum ratings..."

What are these "maximum ratings"?

Also, do you think I should go with the first purchase or the second link?

 

[AcousticDreams]

Quote:

Originally Posted by Blackwheel /img/forum/go_quote.gif What are these "maximum ratings"? Also, do you think I should go with the first purchase or the second link?

One of the most important maximum ratings for portables is the current consumption measured in mA/h, and for the HP output mW/ohm for example. The impression of the sound is much more difficult to discuss.

Compared with the second link is the first one more credible, he has nothing to hide. The problem with the second link is, it is one of so many primitive creations of the cMoy.

Forget it!

 

[the search never ends]

Quote:

Originally Posted by AcousticDreams /img/forum/go_quote.gif One of the most important maximum ratings for portables is the current consumption measured in mA/h, and for the HP output mW/ohm for example. The impression of the sound is much more difficult to discuss. Compared with the second link is the first one more credible, he has nothing to hide. The problem with the second link is, it is one of so many primitive creations of the cMoy. Forget it!

Yes, that second link is rubbish. Not a good way to go.
Are you looking for a cmoy that can be used to recharge batteries? There is a geat cmoy bbcmoy, I don't think it's listeed on ebay right now because of the holidays. But you van find it from jds labs, a few forum members hre make outstanding amps, not all of them cmoys. And the pocket amps v2, is about on par with a cmoy, although not everyone will agree, I find ot quite neutral.

 

[teds headfood]

i just got an amp from headfi member fred fred2004 off ebay and he usually has 5 different choices (cmoys,others)when he lists.right at this moment he doesn't have anything listed but he has had for the last few weeks and they sold like hotcakes.check his feedbacks on ebay under fred_fred_2004
the amp i bought is rechargeable (battery included)and works great,haven't been able to run the battery down yet.

 

[the search never ends]

Quote:

Originally Posted by teds headfood /img/forum/go_quote.gif i just got an amp from headfi member fred fred2004 off ebay and he usually has 5 different choices (cmoys,others)when he lists.right at this moment he doesn't have anything listed but he has had for the last few weeks and they sold like hotcakes.check his feedbacks on ebay under fred_fred_2004 the amp i bought is rechargeable (battery included)and works great,haven't been able to run the battery down yet.

Yeah, Fred makes good stuff.......no doubt!

 

[Blackwheel]

Cool, thanks for the tip! I sent Fred a message to see what he thinks.

 

[krmathis]

Yeah, why not? If $50 is all you can or are willing to spend...