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There's New LME49990/LME49600 Based amp over at diyaudio

post #1 of 13
Thread Starter 

OPC over at diyaudio has designed a very simple headphone amp based around LME49990 opamps and LME49600 buffers that looks promising, at least from the measurements. Have a look here: http://www.diyaudio.com/forums/headphones/179298-wire-ultra-high-performance-headphone-amplifier-pcbs.html

post #2 of 13

yep, I should have the boards any day now, should be interesting

post #3 of 13
Thread Starter 

Heh, I should be more on the ball, I live in the same town as Owen.. ;)

post #4 of 13

haha dont worry its not you being slow mate. i've known about this since before he started the thread through my involvement with his Pass D1 style IV for sabre GB and my commications with Owen about that (i'm gathering the matched Fets, Zfoil power resistors and Vcap CuTF for some of the members and doing some SMD soldering for people). AFAIK noone else has them on the way 


Edited by qusp - 1/12/11 at 12:05am
post #5 of 13

 

well guys, if anyone is keen on pushing for another run of these pcbs, i highly recommend it, this is one of the best headphone amps i have heard period; anyone with a prejudice against chipamps really should rethink it when it comes to this little big amp. 

post #6 of 13

Some pretty impressive specs listed. Might have to give this amp a try... whats the approximate price for building one of these?

 

Edit: This may be somewhere in that thread that I haven't found yet, but what voltage swing is it capable of? The full +/-15V rails?


Edited by bcg27 - 3/20/11 at 7:41am
post #7 of 13

 

its not a really cheap build, as the opamps and all other components used on the amp pcb are top shelf, probably around 120 plus case, connectors, pot (if you need one), transformer etc. thats with the stock power supply, which i'm not using, not for any real reason as its decent and the psrr is so massive that the difference between a s22 like i'm currently running and the stock lm317/337 supply at the output is likely to be little to none. 

 

i'm putting together a smaller lt1764a/lt1175 supply for it in its final form.

 

there arent any pcbs left though, so you would have to make your own, although there is interest growing for a second run, so post in the thread if you want to help make that happen. 

 

built as spec its set for unity voltage gain, which when fed by sabre is enough for ear bleeding volume and transient attack as good as i have heard with hd600, or jh13. pretty sure it'll swing to or very close to the rails if you feed it with a signal that large, or change the 2nd stage gain. its designed for balanced input and single ended output, not such a common format, but given i'm used to using all my cans balanced i was blown away by the performance of this little thing


Edited by qusp - 3/20/11 at 10:42pm
post #8 of 13

I also have these boards, but I don't have a balanced source...yet.  I am contemplating running it in SE mode for the time being as I read you can jut short the - inputs to ground.  Either I do that or I wait for my balanced DAC down the road...  I am also not sure if 1x gain setting will be enough, so I bought extra resistors to change the gain if needed.

yea the chips are kind of expensive but the measurements of the amp are great and it'll be interesting to read impressions rolling in as people get them assembled...I might just hook it up SE for now to hear it...

post #9 of 13

I was thinking a S22 would be a good PS for this, but if it doesn't make a difference maybe I won't bother. Would love to hear your comparisons between the two power supplies when you get it up and running.

 

I have no intention of moving to a balanced source anytime soon so I would have to run it in SE mode. I would also probably up the gain to at least 2, maybe higher since my source only outputs 1.4Vrms... either that or up the gain of my pre-amp, but then I would have to decrease the gain of my beta22... decisions decisions.

post #10 of 13

in for results

post #11 of 13

I would love to build one if there is a second run.  Would gladly buy a pcb.  Kind of exciting.

post #12 of 13
Quote:
Originally Posted by bcg27 View Post

I was thinking a S22 would be a good PS for this, but if it doesn't make a difference maybe I won't bother. Would love to hear your comparisons between the two power supplies when you get it up and running.

 

I have no intention of moving to a balanced source anytime soon so I would have to run it in SE mode. I would also probably up the gain to at least 2, maybe higher since my source only outputs 1.4Vrms... either that or up the gain of my pre-amp, but then I would have to decrease the gain of my beta22... decisions decisions.


ok, will update the thread when i have built the ic based power supply for it. with that sort of low input swing and a SE signal, you will definitely need to add some gain somewhere, but to be quite honest, i really dont see the point of using this amp like that. the strengths of this amp are its linearity and low noise, both of which will be compromised under these conditions. there are probably other amps that are more suitable.

 

post #13 of 13

*nudge*

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