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DIY amp for grado sr80

post #1 of 9
7/16/10 at 1:12am
Thread Starter 

Hi all!

 

I've been lurking around the forums for a while, however I have a couple questions on choosing an amp to build.

 

This is going to be my first build and I don't have a large budget (less than 100, preferably less than 50) and while I currently own sr80s I am planning to upgrade to sr225s or sr325s as soon as I find the money.

 

I looked at threads recommending building a RA-1 clone, however the threads are years old. Would there be a better (newer) option for an amp, or is the RA-1 still recommended? Where could I find a schematic to build it?

 

Thanks a lot for helping a newbie out

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post #2 of 9
7/17/10 at 1:03pm

RA-1 clone is basically the same thing as a CMoy. See http://tangentsoft.net/audio/cmoy-tutorial/ for more info on the CMoy. You can also find CMoy printed circuit boards from a few places, such as JDSLabs. Order the other parts from Digi-key or Mouser.

 

Other (newer) DIY amps to consider are:

PIMETA - http://tangentsoft.net/audio/pimeta2/

Mini^3 - http://www.amb.org/audio/mini3/

 

 

 

 

[edit: added "on the CMoy" for clarity]


Edited by Yoga Flame - 7/18/10 at 1:27pm
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post #3 of 9
7/17/10 at 2:21pm

There is nothing wrong with a CMoy. I use the OPA2227 and like the sound (apparently some others don't). The input capacitors are important if there is any risk of the music  source having or developing high DC offset which will be amplified by the CMoy and damage your headphones. I replaced the input caps with 1K resistors and the audio improved. Do that at your own risk of course.

 

F

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post #4 of 9
7/17/10 at 5:06pm

pm sent

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post #5 of 9
7/18/10 at 12:34pm

 

Quote:
Originally Posted by Yoga Flame View Post

RA-1 clone is basically the same thing as a CMoy.


Except that it uses a very specific op amp and gain, and has a strong track record for its sound with Grados. So yes, the RA-1 is a cmoy, but a cmoy isnt an RA-1.

 

Cary on.

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post #6 of 9
1/15/11 at 8:16am

Is there a tutorial/PCB out there for an RA-1 clone (or which opamps, etc does the RA-1 use)?

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post #7 of 9
1/15/11 at 8:12pm
Thread Starter 
Quote:
Originally Posted by Netdewt View Post

Is there a tutorial/PCB out there for an RA-1 clone (or which opamps, etc does the RA-1 use)?


YAY! You just bumped my 1st or 2nd post. High Five!

 

Anyway, talking about cloning amps isn't allowed on these forums. Read the rules.

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post #8 of 9
1/16/11 at 3:55am

Heres something about the differences between Grado RA1 & CMOY.

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post #9 of 9
1/16/11 at 8:13pm
Quote:
Originally Posted by BobSaysHi View Post



Quote:
Originally Posted by Netdewt View Post

Is there a tutorial/PCB out there for an RA-1 clone (or which opamps, etc does the RA-1 use)?


YAY! You just bumped my 1st or 2nd post. High Five!

 

Anyway, talking about cloning amps isn't allowed on these forums. Read the rules.

 

I wasn't the first to bring up clones in this thread. I couldn't possibly read all the rules for every forum I visit, but thank you for the friendly nudge.

 

Thank you ESCS.

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