I have an Ultech that has the OPA2604/OPA2604 combo on the output.
I recently took it all apart to do PS mods and install DIP sockets. I have been listening to various op amps with the LM4562 sounding pretty good in all positions.
I've listened to the OPA2134 followed by the OPA2134 which I thought sounded slow and muddled. I have the OPA2134s followed by LME49720s now which is sounding better but a little diffuse to my ears.
The stock OPA2604/OPA2604 is looking more and more like a pretty good choice.
Really, Scott, what the hell do YOU know about op-amps? Stick to your day job!
Excuse me, I have to finish these tests for Dr. Bronner.
Wow, this must be the most mentally deviated post I've ever read on the web.
That's because you're doing things (supposed upgrades) with a too basic approach, and without taking advantage of the better opamps (which include the TO99 LM4562, BTW). 🙂
That is totally wrong, I'm sorry. 4 + 5 + 6+ 2 = 17, which is an 8, yet again! Two fours! Why do you keep recommending these VERY unsuitable parts???
Absolutely false. Let's examine the evidence, shall we? If we break down Scott's name, it's 19-3-15-20-20. That adds up to 77, which is 14, which is 5. But not so fast! If we understand that the 19 is a 1, the 3 remains a 3, the 15 is a 6, and each of the 20s is a 2, we have 14, which is two 7s! That's 77!
Coincidence? I don't think so. Clearly, you should only use opamps that Scott designed.
it does not make sense!
Funny.
I don't claim that I've come to make sense of the number (reduced to 1-9) that results by summing the individual numbers in an opamp code/name. Here things are still somewhat mysterious to me. You never know enough...🙂
But when it comes to associating (by an undeniable experience of real things) every number (1-9) to a precise color in sound... here it's sacred territory, for me. 😉
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I included the LM4562. I'm "rolling" op amps and apparently some are better than others in this application.
What is your suggestion?
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It uses the OPA2604 in the D/A and audio outputs. The pin outs on the OPA2604 is compatable with those I've mentioned. Also, the specs are similiar with the OPA2604 being superior to all mentioned.
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It's a single chassis cd player with dual 20 bit Burr Brown PCM1702 DACs. Pacific Microsonics PMD-100 HDCD decoder/filter. IC outputs, (OPA2604s) and Wima 3.3uf output caps.
There is an RCA digital out.
There is an RCA digital out.
Have you read the link I posted (somewhere in this lot I think) on a possible interaction of the HF noise and hash from a DA convertor affecting the bipolar input of opamps causing small non linearities, something the FET opamp is unaffected by.
The OPA2604 (604 single) is as good as I have found to date. It also has even harmonics as the predominating spectrum of distortion.
The OPA2604 (604 single) is as good as I have found to date. It also has even harmonics as the predominating spectrum of distortion.
Yep, I would agree with you on that. The OPA2604 is very good in this application.
PCM1702 + OPA2604 = 12467 without repetition (I'm considering the single version of the 2604) 🙂 So I'm not surprised that you like it. 🙂
Myself, what I'd use is the OPA2604 for I/V, and (as if I understood correctly there currently are two stages made with the same opamp) a LT1358 for the output buffer, or alternatively an AD8599. 🙂
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Andrea, are you sure that the numbers on the opamps aren't just a specification of the dominant harmonics? Avoid 5s and 7s like the plaig. Try to get a good balance between 2s and 3s. Maybe spice it up with a 4, 6 or 8. This could be the reason why you like LT1028 and OPA1612. I'm not quite sure how to interpret the letters - AD, OPA, LT, LM etc.