LM3875 vs OPA541

[GregGC]

Hi Guys,

I looked at the two ICs. One of them (opa541) has jfet inputs which IMO makes it easier to implement without caps (or very small input cap) reasonably high input impedance and less DC offset, but I'm not sure about the performance comparison.
I did spend some time reading treads containing discussions about that but didn't find anything specific.

I was wondering if you can share some feedback on the performance differences (how much different they sound) between the two ICs (if you have a practical experience with them). And if you have a favorite one for whatever reason.

Are they in the same league performance wise?

Thanks a lot for your time and help!

Greg

 

[Mad_K]

http://diyaudio.com/forums/showthread.php?postid=204832#post204832

😉

 

[GregGC]

Thanks Mads!

When you say you like it better aside from the tecnikal side (oscilations ....) what about the sound?

Greg

 

[Mad_K]

-I think the 541 sounds much better. 😉

 

[Peter Daniel]

From what I noticed people are usually very decided about which chip they prefer. While most are stuck with LM3875, some prefer OPA chips. The difference isn't that big and the best way is to try it yourself than rely on someone else's taste.

While my preference tends to be on LM, I'm not sure that if I did try it today, I wouldn't like OPA better. From what I remember, the OPA sounded less romantic, more "proper" and maybe less involving, but nothing really to complain about.

 

[GregGC]

Thanks guys,

Appreciate the input/output! You are right. Since they are that close, I should try them both and decide for myself.

Greg

 

[GregGC]

I don't mean to start a new war or suggest that one sounds better than the other, but just found out:

OPA541 has 22db better CMRR than the LM3875.

I think at the end my ears will decide though.

 

[GregGC]

It looks like I answered my own question:
http://www.diyaudio.com/forums/showthread.php?postid=261657#post261657

So, on paper LM3875 would be the better choice if designed and executed properly.

 

[Peter Daniel]

Don't think too much, or you will miss all that "non-inverting fun"😉

 

[GregGC]

Now that I have the samples of both IC's I had to decide on which one to use, but I think I'm fine.

LM3875 is the one.

I'm still undecided on the housing and it's your fault Peter.😉

 

[Peter Daniel]

How about using one of the Hammond boxes available from Active Components, Electrosonis or Sayal. The size doesn't really have to be big. Check the link in a first post of non-inverting fun thread. That's what the guy used and after painting it's not that bad looking.

 

[GregGC]

Thanks Peter, I'll go tomottow to Sayal on Victoria Park. I was thinking of getting the toroid transformers from Electrosonic $65 eac for two. 220VA, 2x22VAC Hammond. I haven't ask at Sayal if tthey have them too. Am I on the right track for those parts?

 

[Peter Daniel]

Sayal doesn't carry toroids. Plitron would be nicer, but it's more expensive and you'd have to wait four weeks. In that area (beside Electrosonic) there's Active Components store and they also carry Hammond boxes.

2 x 22v / 225VA seems like a good choice

 

[GregGC]

Thanks Peter,