[Jeff Guidry]

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.

 

[wilsonjm]

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

 

[tangent]

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.

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?

 

[Jeff Guidry]

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

 

[andrzejpw]

Nope, you have it backwards. The 8610 is the single channel (you'd need 2), while the 8620 is the dual channel version(only need one).

 

[antness]

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

 

[Jeff Guidry]

Thanks for your advice guys. JMT has advised that the cost would be too prohibitive to be practical for me.