The AD8610 to replace OPA2134 in a JMT Cmoy
Aug 21, 2002 at 7:07 AM Thread Starter Post #1 of 7

Jeff Guidry

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I am interested in upgrading the excellent Cmoy that JMT built that uses the OPA2134pa. I have heard many good things about the AD8610, but I am unsure how this chip would synergize with the Cmoy. I am not a DIYer, I have been in contact with JMT about upgrading this Cmoy, and I have up til now considered the AD823. But, since I use low impedance headphones, I fear this may be a poor choice. I will be substituting battery power for a wall wart, so voltage should not be an issue.

Any thoughts/advice would be appreciated.
 
Aug 21, 2002 at 7:35 AM Post #2 of 7

wilsonjm

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hi,

first of all you cannot substitute a single AD8610 for the OPA2134PA because the AD8610 is a single channel chip.

you could use a brown dog adapter, with two AD8610, or a brown dog adapter w/ a single AD8620.

in my META42, there is definitely an audible difference between the AD8610 and OPA2134PA. so i believe this would be a worthwhile upgrade.

you should keep the voltage under/around +/- 12V. I have an Elpac linear regulated 24VDC wallwart, and it works well
 
Aug 21, 2002 at 8:16 AM Post #3 of 7

tangent

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What wilson said...only more so.

You may also wish to consider the AD8620 plus a Brown Dog adapter as it will perform to within 99% of a pair of AD8610s and it's easier to solder up. You're not a DIYer (yet!), so I imagine soldering surface mount parts is something that may concern you.
smily_headphones1.gif


Also, on the voltage issue, the absolute maximum voltage for this chip is 27.mumble volts, and its maximum recommended operating voltage is 26V rail-to-rail (+/-13V, same thing). If your "24V" power supply is not well-regulated, you could actually get more than 24V out of it with low loads like headphone amplifiers. Measure the supply without a load to be sure. Also, ppl says that the chip starts sounding a little less good beyond about 22V, IIRC. Or maybe it was 20V?
 
Aug 21, 2002 at 8:46 AM Post #4 of 7

Jeff Guidry

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Well, there are two chips on the board of the Cmoy, so I assumed I would need the 8610, which I assumed was two single channel chips. Am I wrong? I assume the 8620 is the single channel version of this chip?

I intended to look at those Elpac's, thanks. Could you provide a link? How much did it cost you?

Thanks for your help, fellas.

Jeff
 
Aug 21, 2002 at 4:45 PM Post #6 of 7

antness

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there are 2 OPA2134PA? and the amp is not a CHA-47? To find the power supply you need, check out Elpac's website and it will give you the part # for the voltage you want. They are available at Newark, Digikey, and Allied Electronics
 

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