I have just done a comparison test of these chips for my own girly-man amp, and I thought I'd share.
I used P.Daniels minimized circuit. 600VA 18-0-18 trafo = +/-26VDC rails. Standard components.
Remember these are only first impressions.
I hadn't really expected much difference between the chips, and I certainly didn't expect the audio quality they produced!
OPA549 (max +/- 30V, 8A/10A continous/peak)= BIG sounding chip! Heavy bottom, a little laid back. Reminded me of the Audio Note Kit Two I used to have. Very nice.
http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=OPA549
OPA541 (max +/-40V, 5A/10A cont./peak, FET input)= More neutral. More open and detailed, but not fatigueing. My preference so far. Sounds more like my Aleph 30.
http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=OPA541
I used P.Daniels minimized circuit. 600VA 18-0-18 trafo = +/-26VDC rails. Standard components.
Remember these are only first impressions.
I hadn't really expected much difference between the chips, and I certainly didn't expect the audio quality they produced!
OPA549 (max +/- 30V, 8A/10A continous/peak)= BIG sounding chip! Heavy bottom, a little laid back. Reminded me of the Audio Note Kit Two I used to have. Very nice.
http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=OPA549
OPA541 (max +/-40V, 5A/10A cont./peak, FET input)= More neutral. More open and detailed, but not fatigueing. My preference so far. Sounds more like my Aleph 30.
http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=OPA541
No, because I can't get it. They only have the LM3886 where I buy my parts, and National wouldn't sample me any. Haven't tried the 3886 either. I have tried the TDA2050 though. I found it to be much more colored, and a lot less stable.
I have to moderate the differences mentioned above, after switching back and forth a couple of times (and a few hours of burn-in). They seem a lot more alike now. The 549 clearly has more power, and less percieved distortion. I also added a 0,1uF between the rails and between testing them, and it seems this made up most of the sonic difference mentioned above. (First 549 without, then 541 with and now 549 with the 0,1uF). I think they would be more alike with 35V rails on the 541.
For my first clone, I'm going with the 549...
I have to moderate the differences mentioned above, after switching back and forth a couple of times (and a few hours of burn-in). They seem a lot more alike now. The 549 clearly has more power, and less percieved distortion. I also added a 0,1uF between the rails and between testing them, and it seems this made up most of the sonic difference mentioned above. (First 549 without, then 541 with and now 549 with the 0,1uF). I think they would be more alike with 35V rails on the 541.
For my first clone, I'm going with the 549...
pundip said:Mad_K,
I am thinking about building an amp based on the opa541. What current limiting resistors did you use? Also does anyone know if the opa541's have thermal protection?
Didn't use any Since this was only a test-setup...
Read the datasheet, it's all there
pundip said:Mad_K,
I am thinking about building an amp based on the opa541. What current limiting resistors did you use? Also does anyone know if the opa541's have thermal protection?
Mad_K said:
Didn't use any Since this was only a test-setup...
Read the datasheet, it's all there
pundip said:Hi,
Are you going to be using current limit with your gc? I am not sure I should just short the limit pin to output out limit resitor
Mad_K said:I depends on what load you are going to drive, and wether you are going to short the outputs.
I would use a 0,1 ohm for opa541am or a 0,15 ohm for opa541ap ina final design. Caddock MP930 looks good here...
i am using the OPA541 and OPA549. im glad you found them good. i just shorted the current limiting pin to output on the OPA541, and to -v on the OPA549.
Mad_K said:
Didn't use any Since this was only a test-setup...
Read the datasheet, it's all there
Mad_K said:I depends on what load you are going to drive, and wether you are going to short the outputs.
I would use a 0,1 ohm for opa541am or a 0,15 ohm for opa541ap in a final design. Caddock MP930 looks good here...
millwood said:the datasheet for the opa541 has very detailed instructions on how to calculate the current sensing resistor and its wattage requirement. check it out.
Ahaaa
Where does it say wether you are current limited or not if you use 0 ohm CLR?
Mad_K said:Where does it say wether you are current limited or not if you use 0 ohm CLR?
the answer critically depends on the voltage drop off the zero ohm CLR,
Mad_K said:
Ahaaa
Where does it say wether you are current limited or not if you use 0 ohm CLR?
-found it here:
http://www-s.ti.com/sc/psheets/sboa057/sboa057.pdf
(table 1)
CLR=0 Ohm -> CL=10A (peak)
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