[rsaavedra]

Quote:

Originally Posted by diablo9 I had the same problem and went SOIC type with adapter.

You can't stack them that way though, or can you?

 

[diablo9]

haven't tried stacking yet but I suppose SOIC over adapter over SOIC over adapter over SOIC over adapter should work.

 

[rsaavedra]

Quote:

Originally Posted by diablo9 haven't tried stacking yet but I suppose SOIC over adapter over SOIC over adapter over SOIC over adapter should work.

Yes I guess it's possible. But seems too much clutter though, and also too expensive overall.

Digikey indicates the earliest they are getting the DIP buffers in stock will be in December. This shortage is making me lean towards simply using three SOIC buffers, each one soldered directly on the PIMETA board.

Correction, SOIC buffers are also out of stock everywhere. I guess I'll put together an initial version of the PIMETA without the buffers since they are optional, and later on will add them when they become available.

 

[ericj]

Quote:

Originally Posted by rsaavedra Correction, SOIC buffers are also out of stock everywhere. I guess I'll put together an initial version of the PIMETA without the buffers since they are optional, and later on will add them when they become available.

Some guy on ebay is selling them in lots of 5 for about $20 shipped.

Perhaps he bought a large lot several months ago, or maybe they are counterfeit?

I know this doesn't help anyone planning to manufacture several boards.

And how could a person who doesn't have any from reputable sources verify whether they are genuine?

I've purchased various lots of BB opamps on eBay - for example i bought five OPA2107KP for something like $12.

The printing and packaging is very convincing, even has the same markings molded into the underside of the plastic as BB parts i bought from Digikey - and they sound very good in my mains-powered regulated +/-15v cmoy - but I've never used a 2107 before so how the heck would i know, right?

Most counterfeit parts don't stand up to even casual scrutiny when the physical item is compared to the real thing, but that doesn't mean that all counterfeit parts are crude mockeries of the original.

If anyone wants i can take very high resolution photos of my ebay difet parts, that should have been more expensive than they were.

Are any of the other buffer parts acceptable substitutions? I know they have different pinouts.

 

[darkisz]

Quote:

Originally Posted by ericj Some guy on ebay is selling them in lots of 5 for about $20 shipped.

I bought some from that guy last month. My 5 are working fine, there didn't seem to be anything 'fishy' about them. Unfortunately, I don't see him listing any ATM...

 

[ericj]

Yeah, doesn't have any listed at the moment. Over the last couple months they seemed to come and go, and i finally jumped a few days ago. Maybe i got some of his last pieces.

There are a few sellers who are constantly listing small lots of better quality opamps. I bought 5x 2132u, 5x 2107kp, and 5x 2132p from one guy a few months ago, and 5x 2227p, 5x 2111kp, and 5x opa404kp from some other guy this week.

In all cases, I paid $2 or less per part. Either there's a lot of leftovers from large production runs, or, something.

Which means i have way too many dual opamps.

And oughta build an smt a47 or something. I can't recall my what my logic was in buying the 2132u parts.

fwiw, I can't tell the difference between an eBay opa2132p and a digikey opa2132pa, sonically.

And i can tell the difference between a 2132 and a 2107 in the same board - it seems like the sound coming out of the 2132 is sweeter than the sound coming out of a 2107, and the 2107 sounds more, idunno, pure? It's very relaxing to listen to mellow music coming out of the 2107 into good cans. It doesn't seem to color the sound much, if at all.

Oh, but, this thread was about what amp people should build next.

If money is no object, since the cost of the parts does add up pretty fast, the m3 is a pretty easy build. Took me about 3 hours, not including time spent mounting heatsinks properly. Though i haven't gone through the biasing adjustments yet. Or finished building my power supply. Or enclosure.

I hear they sound great - I hope to be listening to it tomorrow. Probably arranged on plywood with standoffs and wire ties . . . .