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previous: R.G. There isn't any magic about the 473... -- 8/25/1999 11:34 PM

Re: RC4739 Dual op-amp

8/26/1999 1:05 AM
Dave James	Re: RC4739 Dual op-amp The 4739 is a dual op-amp but may not be pin compatable. It's in a 14-pin DIP with the supply pins on 4 and 10 as I recall. Also, it's a non-compensated device and so has pins across which a capacitor would be connected to set the maximum gain bandwidth (in order to reduce oscillations). I have a Heathkit AA1214 stereo amp that uses the 4739 and over the years is has developed some "popcorn" noise. I attempted to replace it with a NE532(?) to no avail. I think the 4739's compensation caps where part of the RIAA playback curve circuitry as this was the phono cartridge preamp. I put the noisy 4739 back and left it... Later, DJ

8/26/1999 1:05 AM

Dave James

Re: RC4739 Dual op-amp

The 4739 is a dual op-amp but may not be pin compatable. It's in a 14-pin DIP with the supply pins on 4 and 10 as I recall. Also, it's a non-compensated device and so has pins across which a capacitor would be connected to set the maximum gain bandwidth (in order to reduce oscillations).

I have a Heathkit AA1214 stereo amp that uses the 4739 and over the years is has developed some "popcorn" noise. I attempted to replace it with a NE532(?) to no avail. I think the 4739's compensation caps where part of the RIAA playback curve circuitry as this was the phono cartridge preamp.

I put the noisy 4739 back and left it...

Later,

DJ

Replies:

R.G. Oh, it's guaranteed not to be pin c... -- 8/26/1999 2:14 AM
Mark Hammer The 4739 comes in two flavours: int... -- 8/26/1999 6:04 PM