The Opamp thread

[SpudHarris]

I have 2132's a plenty but they do not resemble the OPA132's in the slightest. Just ordered my SMD 2.2k resistors for my new modules and will post a pick when complete, this will do away with the DIP socket adapter.

 

[12Bass]

Interesting... I found the OPA2132 inferior to the OP827... sort of warm and veiled, though not as much as OPA2134. How does the OPA132 differ, and is it somehow better than the OPA827 (my current favorite FET)?

 

[SpudHarris]

I can't compare to the OPA827 yet as mine are back ordered but the OPA132 is just beautiful. I listened all night but can't say anything negative about it. Just to reiterate I also have OPA2132's lay around and to me they are just boring, flat and unimpressive and I'm amazed it's even related to the OPA132 they seem so different.

 

[FallenAngel]

Uhm... the chances that 2x OPA132 would sound absolutely any differently than a single OPA2132 is preposterous.

 

[SpudHarris]

^Well in my set up with Class A Adapters they absolutely do.

Edit:
There is much said within this thread about the benefits of single opamps compared to duals i.e. better channel separation, class A Biasing etc, etc.... I'll give the LME49710 / 49720 as another opamp comparison, the difference between the two is noted and even more so with the TO-99 versions. It is also worth mentioning that the OPA132 is said to be an 'updated' version. The margin of difference between the OPA132's and 2132 is the largest I've seen between a single and dual within the same family. I'm no techie but I do have a critical ear (as do most here) and can only speak as I find.

 

[12Bass]

My experience comparing 2 x OPA211 with the OPA2211A suggested that they sound very, very similar. Definitely curious as to why the OPA132 might be so much better than the dual version. Have you tried them without the biasing resistors in place?

 

[Voodoochile]

Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif Interesting... I found the OPA2132 inferior to the OP827... sort of warm and veiled, though not as much as OPA2134. How does the OPA132 differ, and is it somehow better than the OPA827 (my current favorite FET)?

The 134/2134 VS the 132/2132 is simply that the 132/2132 is the same chip, but with tighter and better specs- though those tighter specs fall outside the realm of applicability within the scope of an audio application. TI thus bins the 134/2134 as an "audio grade", meaning that in that application it will perform the same as the 132/2132, but at a lower point of price.

If you were pushing the chip anywhere near it's design limits, which doesn't happen in an audio application, then the 132/2132 would be a better choice between the two chips.

The dual-channel versus single-channel thing just means what it sounds like, there are two op-amps on the wafer, and they share power pins. You can share the rails inside the chip, or outside the chip, whatever your preference. Sure you could have discrete power supplies (for whatever reason you choose), but if you were going discrete with your PSU, you would probably not stop there and go discrete with the amplification and buffering stages as well.

I'd make the gross analogy that it would be akin to running a pair of really high-end tires on one axle, and running recaps on the other. It's an exaggeration of the difference, but the philosophy is about the same.

 

[qusp]

got some OPA1611 and OPA1612 and OPA2110A on the way, gonna play around with Class A on the 1611

 

[Slash47]

Quote:

Originally Posted by Voodoochile /img/forum/go_quote.gif The 134/2134 VS the 132/2132 is simply that the 132/2132 is the same chip, but with tighter and better specs- though those tighter specs fall outside the realm of applicability within the scope of an audio application. TI thus bins the 134/2134 as an "audio grade", meaning that in that application it will perform the same as the 132/2132, but at a lower point of price. If you were pushing the chip anywhere near it's design limits, which doesn't happen in an audio application, then the 132/2132 would be a better choice between the two chips. ...

On the platforms most people here 'roll opamps', the opamps work far below their capabilities.

The 132 seems to sound better then the 134 in 'bad' circuits but the same in very good ones. Probably because the tighter specs give it more buffer, ie more can go wrong before you start noticing. It's the same when people say the AD797B is better then the A, or that 2 LM49710HA's are better then a LM4562.

The same thing applies when people say the LM4562 has a fake soundstage and sounds dull. I wouldn't say a Benchmark DAC1 or TP Sabre32 sounds dull.

 

[ROBSCIX]

The idea that a dual opamps module sounds better then a single dual channel chip is not new. I think it has more to do with just the power rails.
The idea and results have been discussed in many places not just here.

The dual LME49710HA module does sound very different the a LM4562NA.

Have you tested a dual LME49710HA module?

 

[majkel]

I would rather say that there are applications so bad that you don't hear the difference between the AD797A and AD797B, or LT1028 and LT1028A because they don't yet become the bottleneck. The difference you hear is due to cleaner and tighter technology applied to the superior series production not the parameters themselves.

 

[ecclesand]

Quote:

Originally Posted by qusp /img/forum/go_quote.gif got some OPA1611 and OPA1612 and OPA2110A on the way, gonna play around with Class A on the 1611

I have been listening to the OPA1612AID for almost 2 weeks now and really like it. It has become my new favorite. Just yesterday, I received some OPA1611s and mounted them on some browndog adapters (2 to 1) and I'm burning them in now. If what other folks have said about 2 singles sounding better than 1 dual, I should be very happy.

I too plan to get some more OPA1611s and try the class A mod.

 

[ROBSCIX]

Based on my testing and testing done by others I have spoke with thais is generally the case. This is why I built two dual 1611's before I went to the 1612's as I figured the best sound quality would be found using a dual single channel module over a dual channel version. You have both there, let us know what you think by doing a comparison.

 

[ecclesand]

I'm still waiting on the 49710HA singles. I ordered enough to ensure if I screw something up, I have some backups. With the 1611s, soldering to the bottom of the adapter (between the pins) was much easier than I thought it would be. However, while soldering the top chip (which should be easier than the bottom), I ran into a problem and actually lifted one of the traces off the bd adapter and bent one of the pins on the opamp. I think the adapter was bad....yeah, that was it...bad adapter.

Anyway, I was able to repair the trace with some solder. Popped it into my DAC and nothing. Reflowed the solder on the repaired trace and still nothing. Looked at my other bd adapters and the other set of OPA1611s I had and realized there were markings indicating which way the chips should be soldered. Huge DOH!!!!

Needless to say, my first set of OPA1611s died an untimely death. I will try to desolder them, but I'm not optimistic. I will give them a proper funeral. After CORRECTLY soldering the second set, they work splendidly.

I will give impressions after about 40 hours of burn-in. That was how long I estimate it took for the 1612 to settle in and blossom.

 

[SpudHarris]

^ Nothing worse than those bad adapters Doug, I've had a few of them hehe.