Which OPAMP in DAC for smoother sound TL072 or OPA1612

Jump to Latest
westsounds

westsounds

Member
Joined 2009
#1
Hi all.

I fancy giving one of these cheap DACs a try, but I have two OPAMP options. Can anyone help please with regards to the differences? I am looking for a smoother, lusher, organic more euphoric sound then, especially on vocals, and something not over etched digital with less glare then if thats possible between the choice of the two. Any one any ideas to the differences please?

Hope someone can help me choose.


https://www.aliexpress.com/item/1005001966656478.html?spm=a2g0s.8937460.0.0.55012e0efO6PWn
 
#2
Why not solder a DIP socket into the board, and then listen to both? Yourself? It's not a high cost experiment, and at the end, you'll know which one YOU like best. You won't be relying upon someone else's ears and someone else's personal tastes.

I recommend you buy five of (these) boards to assist with the experiments. There are four adapters on each $2.95 board. Now you are able to audition the AD746 and the LT1124 and the AD8599 and the OPA2209 and the LME49723 and the OPA1656. It's a big beautiful world out there!
 
  • Like
Reactions: Elias Zacharopoulos
#3
🙂 well there is always that option Mark, wouldn't know where to start but I bet its not rocket science and I could tinker I suppose. Was hoping there might have been more of a clear black and white answer than having to try myself. But it is a good suggestion to explore.
 
#4
I also thought there is one or two opamps you can be sure is good. ? I am curious about it too.
If you decide to try the opamp rolling, which ever opamp you try make sure you scope for hf oscillations. The added inductance of piggy backing opamps into sockets may or may not be problematic. The only way to know is to scope.
 
#5
ok, perhaps I was wrong, and this is not so straight forward. Now we are talking about equipment I do not own or have used for that purpose ever. I think I'll stick to just modifying speakers, it's far more straight forward than digital front end electronics. I've actually always thought this is something that is better left to the experts. Even amplifiers are kind of easier to play with but digital electronics, now we are starting to complicate things nicely.
 
#6
The article linked below isn't the be-all and end-all on op amps tests, but very informative. He does test the TL072 against some more modern ones, but not the OPA1612 due to there being no DIP version I think. He gives strong recommendations for some applications and also caveats about ill-informed op amp rolling. Summary: you can do a lot better than the TL072.

NwAvGuy: Op Amp Measurements
 
#10
Try the venerable JRC 5532, some people still swear by it.
OPA 2134 too.
But you may have to change the input and output impedance, and also check up how well the DAC renders the output, in terms of bit depth, set it as high as possible.
And proper shielding, with earthing, for the unit is needed to avoid RF interference.
 
#11
With my experience of DACs it's probably going to be some sort of let down anyway. Most DACs to me usually sound a bit sterile and have a digital edge to them. Clarity yes and detail usually all there but when it comes to natural reproduction on things like human voice, they don't really capture that well. Hence my habit of tossing them to the side and looking for the next. I still try though and there are the odd one or two out there which come close. Even some of the overly digital sounding ones can be impressive if they do it in a good way. About some of the worst I've heard though may be ones that some people seem to love, Chord.
 
#12
This looks like a stock implementation of the pcm1794 datasheet output stage. They probably used the stock resistors values too, which are too low for the tl072 to work comfortably. Go for the opa1612 given the choice.

If you're comfortable desoldering soic8 opamps, you can consider swapping opamps but I wouldn't suggest it. This doesn't look like a high quality pcb and it would be easy to lift traces.

edit: looking closer at the pics, the I/V resistors are 390R (about half the datasheet values, which makes sense as they // the outputs). You really don't want a tl072 dealing with 20mA into such low impedances.
 
Last edited:
#14
westsounds said:
With my experience of DACs it's probably going to be some sort of let down anyway. Most DACs to me usually sound a bit sterile and have a digital edge to them. Clarity yes and detail usually all there but when it comes to natural reproduction on things like human voice, they don't really capture that well.
Click to expand...

Maybe you want to try a diy build of one the more unconventional designs floating around the web.
 
#16
OPA1642 on adapter, make sure to check decoupling and make sure to check for oscillation. OPA1656 (CMOS) on an adapter is a winner too. For some reason I refuse to use it as often as I can though, being CMOS.

TL072 is not in the same league, I replaced those decades ago already for better performing types.
 
Last edited:
#18
Octopart dot com says that Quest has stock of the Signetics parts. I've bought NOS devices from Quest (NSC LH0033 multichip module most recently) and have been pleased with the quality. Naturally they gouged me on the price, but when you're buying obsolete parts you only get two out of three

  • the parts really are new, they're not pulls from discarded boards
  • the parts aren't counterfeit, they really ARE what the part number and datecode claim
  • the price is low
And of course you never get Mouser-speed packing and shipping when buying NOS; 2-4 weeks is normal.
 
You must log in or register to reply here.
Top Bottom