Opamp compressor mod question

famous beagle

Well-known member
Hey y'all,

I have a couple of DOD R825 compressors. These are older ones that feature a DBX 2150A VCA chip. They're actually pretty decent compressors, IMO, and I've heard about a nice mod for them in which you replace the 5532 opamps with AD826's.

They're in sockets, so it should be a really easy job, but I've never dealt with switching out opamps before, and I'm not sure exactly which one I should get. I did a search for AD826, and found this:

AD826 datasheet and product info | Low Cost, High Speed, Low Power Dual Operational Amplifier | High Supply Voltage Amplifiers (>=+12V) | Analog Devices

When I clicked on "Check Price and Availability," I found that there are several different AD826 models from which to choose:
AD826ANZ
AD826AR
AD826ARZ
etc.

Does anyone know which one I would need? And could you explain why/what these suffixes mean?

Thanks!
 
Pretty sure you want the AN or ANZ to go in the socket. The rest are surface mount packages, I think.
 
Hey y'all,

I have a couple of DOD R825 compressors. These are older ones that feature a DBX 2150A VCA chip. They're actually pretty decent compressors, IMO, and I've heard about a nice mod for them in which you replace the 5532 opamps with AD826's.

They're in sockets, so it should be a really easy job, but I've never dealt with switching out opamps before, and I'm not sure exactly which one I should get. I did a search for AD826, and found this:

AD826 datasheet and product info | Low Cost, High Speed, Low Power Dual Operational Amplifier | High Supply Voltage Amplifiers (>=+12V) | Analog Devices

When I clicked on "Check Price and Availability," I found that there are several different AD826 models from which to choose:
AD826ANZ
AD826AR
AD826ARZ
etc.

Does anyone know which one I would need? And could you explain why/what these suffixes mean?

Thanks!
In his book "Small Signal Amplifier Design" Douglas Self (Googe 'im) examines the properties of many of the current bipolar and bifet op amps that might be suitable for high quality audio. He concludes that the LM4562N is the ONLY device that shows any significant improvement in ALL parameters to the NE5532 but is 10x the price and since the 5532 hits the floor of his analyser for most tests the audible benefits are questionable.

Then, the AD862 is optimized for VIDEO work! It is highly unlikely to have the low noise performance of an NE and you simply do not need that colossal slew rate for audio and the high bandwidth could cause stability problems...In what particular area of perfomance do you think the NE5532 is lacking? A large number of high end audio peeps still use the NE, Neve, Microtech Gefell OTTOMH.

In general the ad hoc swopping of chips is fraught. Often the swopper fails to notice a higher current consumption and much "prosumer" audio, mixers especially have power supplies that are marginal at best. The same applies to off the cuff Re-Capping. Is the kit out of spec in any way? Do you HAVE and UNDERSTAND the spec? Do you have the equipment to CHECK the spec? If not, best to leave TFAlone IMHO!

Dave.
 
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