On a CHIP hunt.

soundfreak1

Rebuilding a vintage Nakimichi EC100/PS100 external cover for my biased system, have recapped both with nichicon caps but what's the best opa''s put in pin sockets so I can "roll" chips easily using TI- NJM 4560''S right now but looking for the best possible chip price no object! TI, BURR BROWN opa 2134, or other offerings??? Would like some input. Check dignitary for the system. Thanks.

heiney9

Discrete would be the best.

soundfreak1

Heiney9 could you be a little less discreet?

SCompRacer

I don't think he has that much room in the xover box for discrete unless he lays them flat and does extension leads. Watch for power requirements though. IIRC the 4560 is up there for mV/mA while some replacements are a bit less, discrete could be way more than current PS allows for.

FTGV

I'm using the National/TI LME49720's in a couple of active crossovers and can recommend them without hesitation as my preference over the OPA2134 and 2604. They are clean,stable(won't oscillate) very low noise and neutral sounding. (They were rumoured to be discontinued but Digi Key still has stock). In fact it is getting harder to find 8pin DIP devices since many new parts are being introduced in SMD packages only so require the use of an adaptor board to work in the DIP socket. If you want to mess with adaptors it does open up more choices.
As Rich mentions a discrete design will likely pull more current from the supply so that needs to be a consideration if you are using several. On the other hand just because it is a discrete design does not necessarily mean it will be sonically superior to one of the better IC opamps.
While your at it you might want to make sure there are decoupling capacitors close to the two power pins of each IC socket.

SCompRacer

FTGV wrote: »

I'm using the National/TI LME49720's in a couple of active crossovers and can recommend them without hesitation as my preference over the OPA2134 and 2604.

Nice op amp that LME49720! Twisted Pear uses those in their DAC I/V stages, the IVY and the SE side of the Legato.

soundfreak1

Have used the TI'S in a couple of DAC'S but was curious as the price range I'm hearing is from 7 to 30 buck's not much different "for top of the line " at those price points points. Dip's are already installed as well as a full recap in each piece.

msg

I don't really know what you guys are talking about, but sure sounds fun. Whatever it is, I'm pretty sure two CHIPs would be best, and I recommend these vintage ones.

heiney9

Ditto on the LME49720. Used those before I went discrete and they were very nice. Maybe slightly tilted towards the highs, but not grainy or over the top. Of course as Rich pointed out, space is probably an issue for going discrete.

If the dips are there, then it's like tube rolling only with solid state! Get a few and roll them to see which you like best. Just be careful and make sure when swapping that they are oriented correctly or you might let out all the magic smoke!

H9

soundfreak1

My tech is checking his inventory and see what he has to play with, he likes the njm4560 for all around sound as I listen to mostly (90%) acoustic jazz it might be worthwhile in rolling a set of opa 2134''s to see what if any advantages may arise. Just trying to see what other peeps have experience with. Thanks all and any more input is appreciated.

doctor r

Replaced my OPA2604 chips with OPA627BP Chips Mounted on Brown Dog adaptors. Excellent sound but one of the 8 chips I have did oscillate if I remember. I have 8 of these chips and 4 prefabricated brown dog adaptors if you are interested. They have been sitting idle for a few years since I parted with the CDs they were used in and really need to find a home where they are appreciated.
Rick