Depends on what your intent is for this amp...
I'd have a go at the coupling caps to start... unless they are already good quality... if they are electrolytics, there are some nice low voltage mylars in small packages that are a better choice, imo...
Depending on what that input board looks like in real life, one could consider a replacement for it with a better balanced to single end circuit...
Otoh, just use it?
😀
_-_-bear
I'd have a go at the coupling caps to start... unless they are already good quality... if they are electrolytics, there are some nice low voltage mylars in small packages that are a better choice, imo...
Depending on what that input board looks like in real life, one could consider a replacement for it with a better balanced to single end circuit...
Otoh, just use it?
😀
_-_-bear
ask an engineer a question, get 2 "it depends" replies
depends on the environment, balanced source it is used with, if the "problems" are audible
and how much mod you are willing to do
really nice audio input Xfmr are pricey but hard to argue with the results
depends on the environment, balanced source it is used with, if the "problems" are audible
and how much mod you are willing to do
really nice audio input Xfmr are pricey but hard to argue with the results
Doing duty right at the input you might find that a JFET input opamp sounds better, due to having better RFI immunity. Also it will allow (as jcx points out) choice of higher resistor values. If you're serious about getting the best sound, I'd add a decent common-mode choke to the balanced pair and also double check the wiring of pin1 of the XLR. It needs to go to chassis, not the PCB.
For a promising JFET input opamp (I've not listened to this) you could do worse than OPA827. OPA627 is its predecessor and has a sterling reputation for sound quality - fairly expensive though.
For a promising JFET input opamp (I've not listened to this) you could do worse than OPA827. OPA627 is its predecessor and has a sterling reputation for sound quality - fairly expensive though.
...btw, I resent being grouped in with "engineers"... 😛
_-_-
There is a "T" position, this bypasses the input circuit entirely - you can try whatever you want by connecting there! 😀
_-_-
There is a "T" position, this bypasses the input circuit entirely - you can try whatever you want by connecting there! 😀
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Maybe I should try the AN version in that case, are there any downsides to go with the low noise or is it all positive?
Good advice, thanks. I have just received a set of WIMA MKS polyester caps to do just that, the two in each signal path were electrolytics and it looks as though they are about 25 years old.
I think the T position is for the transformer coupled inputs. The is also a U position which (unsurprisingly) is the Unbalanced version which I am currently using. I suppose I could make an external circuit with a socket and try the different types, it's an idea!
I intend using it for a domestic HiFi and have WIMA caps to swap. I have been using the amp and am very happy with the way it sounds so far. I think changing the caps and going to Balanced i/ps would improve it though.
Changing from electrolytic may give improvements.
Going to balanced will improve the rejection of interference.
Going to balanced will improve the rejection of interference.
If the chip is dead also check the protection diodes. As you consider many chips try both the NE5534 from TI and also from Onsemi. Find out the difference if any.
kind regards,
Harrison.
kind regards,
Harrison.
I think it was D Self that found differences in those chips by different manufacturers especially in the THD department. If I remember correct he found the parts from TI superior to other manufacturers although it doesnt say anything about how they would sound.
No, the TI part was the worse but still very good. The NE5534 is a very good Opamp.
One measure of excellence is the gain at 20kHz and the NE has a lots of gain there.
The LME49710 beats it slightly but not in current noise.
One measure of excellence is the gain at 20kHz and the NE has a lots of gain there.
The LME49710 beats it slightly but not in current noise.
Does the amp have an integrated input transformer? If it has (which usually is a budget transformer) I believe it will not go down to 20-30Hz. Just be prepared for that.
My 3 cents:
1. 5534 and 5534 are quite different beasts.
2. 5534 is a nice opamp for audio applications where it was used, and I doubt some modern opamp can be better.
3. Usage of opamps in audio is like usage of tanks to deliver bread. They are both suboptimal for such purposes.
1. 5534 and 5534 are quite different beasts.
2. 5534 is a nice opamp for audio applications where it was used, and I doubt some modern opamp can be better.
3. Usage of opamps in audio is like usage of tanks to deliver bread. They are both suboptimal for such purposes.
How about a photo? Usually, with opamps the devil is in the detail of the surrounding circuitry.
I guess you meant 5534 and 5532 are quite different? I would be very interested to know what the differences are.