[crapback]

I get especially suspicious when it involves some of the most popular opamps on the market. If you or Spud will vouch for them that's good enough for me.

 

[12Bass]

Quickly auditioned the OPA1641 tonight. Somewhat surprised me with how it seemed more open than the OPA827. In comparison, OPA827 seems a bit warmer and maybe "golden" sounding. OPA1641 might be a bit less colored, but I haven't had a chance to give it a proper listen yet.

Just for fun, I made a dual OPA1641 8-pin DIP:

Definitely NOT ROHS....

 

[12Bass]

After a little more listening, I'm finding that my preferences between OPA827 and OPA1641 vary depending on where the chip is used. Still finding the OPA827 a bit warmer overall and generally pleasing sounding, while the OPA1641 might be a tad on the thinner/more open end of the continuum.... sounds a little less musical, perhaps?

 

[ROBSCIX]

Quote:

Originally Posted by fzman /img/forum/go_quote.gif no, there are some weird opamps with are dip14, which only use 8 pins, and the rest are nc -- not sure why, but i have seen them

Really? That's different, I have never seen an opamp like that.

 

[ROBSCIX]

Quote:

Originally Posted by crapback /img/forum/go_quote.gif I get especially suspicious when it involves some of the most popular opamps on the market. If you or Spud will vouch for them that's good enough for me.

All I said, is I have seen them painted in such a way. I cannot vouch for a supplier I have never dealt with. Not sure if that helps.

 

[MikeW]

I got my browndog adapters in today. Soldered up the AD825 and 797. Im listening to the 825 now, I have not tried the 797 yet. What can I say? Im really really enjoying this 825 at the moment. It's a clear step over anything else i've tried in this amp. (LME49860, PA2227, OP275, AD743JN).

One problem though, the first time I put them in backwards.. I was worried I might have orientation wrong, there's no documentation on these browndogs which way is which. I watched them carefully and saw a tiny puff of smoke start and instantly switched the amp off. I flipped them and put them back in the right way and they seem to be working fine. What's the chance of them not being damaged?

 

[Spacehead]

Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif Just for fun, I made a dual OPA1641 8-pin DIP: Definitely NOT ROHS....

I have some OPA1611 op amps that could be used to replicate what you did, that looks pretty cool idea.

How long that took to finish?! Very precise work.

 

[Spacehead]

My current favorite is OPA2107.
I get DC Offset of 0.3 mV with it. That is pretty low

Sound is very spacious but still laid back and relaxed.

My previous favorite was AD8599 but I think my two chips are broken, one gives weird hissing sound that is very audible and another has DC offset of over +10V so it is definitely broken.

 

[12Bass]

Quote:

Originally Posted by Spacehead /img/forum/go_quote.gif I have some OPA1611 op amps that could be used to replicate what you did, that looks pretty cool idea. How long that took to finish?! Very precise work.

Took maybe an hour or so. Not for the faint of heart! I've cleaned it up a bit since the photo was taken. Sounds just fine.... OPA1641 is a nice chip.

First I cut off all of the NC pins from each op amp, then soldered in the bottom chip. Pins 2, 3, 4 all connect to their partners on the socket, while 6 goes to pin 1, and 7 to pin 8 of the socket. The top chip is more complicated, as its inputs (2, 3) have to be rerouted to 5 and 6, while output (6) goes to pin 7, with power again to 4 and 8.

Given the risk of ruining the chips and the fine soldering required, I'd suggest using a BrownDog 020302 (or similar) adapter instead.

 

[12Bass]

Quote:

Originally Posted by MikeW /img/forum/go_quote.gif One problem though, the first time I put them in backwards.. I was worried I might have orientation wrong, there's no documentation on these browndogs which way is which. I watched them carefully and saw a tiny puff of smoke start and instantly switched the amp off. I flipped them and put them back in the right way and they seem to be working fine. What's the chance of them not being damaged?

Pin 1 on the top of the 020302 is square, while the others are round. Releasing magic smoke is usually a bad thing. Hard to tell what the damage might be unless you have known good chips for comparison. Putting things in backwards will often kill them, but sometimes they survive and continue to function. Might want to put a small dot on pin 1 with a marker for future reference.

 

[itszdenny]

Do the numbers on a msop chip mean anything? I mixed up a few of my op amps

 

[opamp_addict]

Some more listening....
I must say the EL2125CSZ really gives me some suprise.

I've seen soic16 to dip8, emm may be going to build some of that later.

 

[MikeW]

I did not solder it backwards, that's not the issue, as the chip and adapter are clearly marked. I put the completed (properly soldered) adapter into the dip-8 socket (on my amp) the wrong way.

Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif Pin 1 on the top of the 020302 is square, while the others are round. Releasing magic smoke is usually a bad thing. Hard to tell what the damage might be unless you have known good chips for comparison. Putting things in backwards will often kill them, but sometimes they survive and continue to function. Might want to put a small dot on pin 1 with a marker for future reference.

 

[12Bass]

Quote:

Originally Posted by MikeW /img/forum/go_quote.gif I did not solder it backwards, that's not the issue, as the chip and adapter are clearly marked. I put the completed (properly soldered) adapter into the dip-8 socket (on my amp) the wrong way.

Right... and pin one on the BrownDog adapter is square, and has a small number 1 just to the left of it. So, yes, there is marking on the adapter to indicate which way is which.

 

[MikeW]

ahh, yeah i see it now. Thanks