opa1656 in front end of FOSI V3 Mono

[jokan]

I tried my trusty opa1656 with otherwise stock op-amps in the V3 mono 5Amp PS, and what I heard was a noisy presentation. It wasn't noise in the sense of white noise or popping, or clipping. It just was harsh. I swapped to opa1622's as I had several sitting around and the noise was gone instantly.
I've played with the other 2 op-amps also and have been trying several front-end RCA/XLR op-amps to see if there is anything to be gained, so far there seems to be very little in it.

Just out of curiosity, have others noticed that the stereo V3 with the extra venting holes might be swappable to with the mono V3. It looks like many of the holes line up, just not sure if it will actually work. Someone, maybe I have to give it a shot. Though I've never had the issue of the V3 mono shutting down, the do get a little warm for comfort.

Going back to the original OPA1656 question, does anyone have a recommendation for the RCA/XLR op-amp? I'm open to any and all suggestions including ancient op-amps if they sound right. Thanks guys.

 

[JSmith]

There is no need to alter the stock opamp... you're chasing fairies.


JSmith

 

[jokan]

There is no need to alter the stock opamp... you're chasing fairies.


JSmith

I'll chase Greek fairies or Persian ones, I just want to know if there is something that has even a marginal improvement.

I'm with you with chasing fairies. I know the operation is purely for RCA/XLR use but there must be some separation, some gain, some slew rate advantage to something else. I won't spend a thousand dollars on op-amps nor do I think I'll use discrete for this use, but perhaps there is something that is better than stock. I have the stock op-amps saved up. I'm very impressed with FOSI with how they design their products. Sound is their priority. I can appreciate that!

 

[GXAlan]

I'll chase Greek fairies or Persian ones, I just want to know if there is something that has even a marginal improvement.

best investment would be an E1DA Cosmos ADC to do the measurements yourself. When I op amp swapped my phono equalizer to MUSES, it worked great and I could measure the difference. What was cool is that the MUSES op amps are super expensive and have mediocre advertised specs but the actual performance was stellar.

You have no idea if your existing op amp happens to be a golden copy or a regular one, etc. etc. Measuring it lets you get an answer.

 

[JSmith]

I just want to know if there is something that has even a marginal improvement

There won't be... at best there will be no change, at worst the amp will go into oscillation and things will sound bad.

Continuous oscillation can potentially put stress on the amplifier too, leading to overheating or damage.


JSmith

 

[KSTR]

Replacing the stock 5532 with something as fast as an OPA1656 on a DIP adapter is inviting trouble. Next time try OPA2891 for even more trouble ;-)
Rolling OpAmps is plain silly and should never be done by lay-people who have zero clue of what's going on under the hood of a circuit.

 

[jokan]

I was well aware of the performance of the opa1656 being far in excess of what was required, I tried it anyway having had a lot of luck with it in the past.

I might go Can style, pre lme47920HA which I have several NOS condition. I have even older ones such as the LH1458H.
I know that it will likely disappoint me but what the hell, it's worth a shot.

If you guys have any legitimate suggestions please let me know, I'm happy to try it out.

 

[AnalogSteph]

What are you hoping to gain over the stock part? Looking at measurements for the V3 Mono, the limiting factor in distortion performance clearly is the Class D power amp section, not the input buffer.

 

[jokan]

What are you hoping to gain over the stock part? Looking at measurements for the V3 Mono, the limiting factor in distortion performance clearly is the Class D power amp section, not the input buffer.

Yes, I was looking at the typical op-amp RCA/XLR converter, I don't think there is any return in time or investment.

i guess I'll give up on this one.

thanks everyone for the help!

 

[jokan]

My current solution and op-amps that are to my liking.

RCA/XLR op-amp replaced with OPA1622 which I had lying around, it also seems to improve transients and attack slightly.

OP-Amp *2 as stated by Fosi I replaced with several until I settled on the OPA1656, I tried combinations with OP-Amp *3 with various combinations to see what sounded the least shouty and most detailed while not sounding too forward.

Op-Amp *3 was eventually replaced with LME49860. I found this combination to be the most pleasing to my ears and listening habits.
I found the sound to have a sort of analogue sound to the lower octaves, never seemed to run out of steam and could play complex classical music with relative ease *Yes there are better like my 3 tube amps sitting in my closet*.

Has anyone tried running the 10amp power supply to each amplifier with success? I'm afraid of component failure. And the cost seems rather ridiculous.
If anyone has experience, please let me know!

 

[JSmith]

legitimate suggestions

These have already been provided...

RCA/XLR op-amp replaced with OPA1622 which I had lying around, it also seems to improve transients and attack slightly.

OP-Amp *2 as stated by Fosi I replaced with several until I settled on the OPA1656, I tried combinations with OP-Amp *3 with various combinations to see what sounded the least shouty and most detailed while not sounding too forward.

Op-Amp *3 was eventually replaced with LME49860. I found this combination to be the most pleasing to my ears and listening habits.
I found the sound to have a sort of analogue sound to the lower octaves, never seemed to run out of steam and could play complex classical music with relative ease *Yes there are better like my 3 tube amps sitting in my closet*.

So how did you test to arrive at such conclusions?

I'll give up on this one

That would be for the best.


JSmith

 

[Scrivs]

Should have quit whilst you were sheepishly getting ahead brotha

Too early in the year for trolling here in Hawai’i, only Aku around