Not audio line buffering! Damn, the OPA2134 is used even in high-end players!
I agree that the OPA627 should work better in I/V conversion though.
Thanks for this little tip, I have just checked mine that I got from eBay and they measure up ok. I tried it with an OPA134 and got an open circuit, so at least I know it isn't one of those!
Its an interesting thread and one I am going to get a chance to experience since I am running a buffer for my chipamp with a 134 with the intention of swapping to the 627 once I was happy that the circuit was operating as expected and also for me to finish my speakers (which are more revealing that my current Monitor Audios). I'll report back my findings in due course.
Ouch I had missed this sentence... so my entire discourse on tonal quality is not too appropriate here 🙂
Could be but depends - OPA2134 requires +-2.5V minimum, OPA627 requires +-4.5V, so if your DAC doesn't have at least that much supply voltage then you got your culprit. But unless you're using USB or 6-9V powered-DACs I think there should be enough power.
Can you please do me a favor, if you bypass the op-amp, does the circuit sound dull? 🙂
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Recently I used the OPA627BP in a 24V-powered "cmoy" and... it's quite decent, but what I use now, i.e. the AD845KN, sounds much better. It has much more sonic color, and doesn't have that touch of upper midrange dryness.
I think I will have to try something else. I used these in my DAC and sounded like 10-20K were a bit missing and the ambience was a bit missing too. However the sound is more dynamic , more fluid and more controlled. Vocal is more present and intense. it sound like a bit of boost in 315 to 600 range and a bit cut in the 10K onward. The hi hat sound doesn't extend like it used to. that might change once it went passed 100 hours. finger crossed
And yes I did try to get R readout. it is definitely 627. it may not suited my test I would say.
And yes I did try to get R readout. it is definitely 627. it may not suited my test I would say.
I have just ordered some AD4627-1 samples to try, will need a SMD to DIP8, but that is fine. You have to love free stuff!
Update...
after 1 full week of burning in. I found that this thing sound great indeed. very refine top-end and very good dynamic. it still improving so 200 hours++ might stabilize the sound. Once again thank for every comment.
after 1 full week of burning in. I found that this thing sound great indeed. very refine top-end and very good dynamic. it still improving so 200 hours++ might stabilize the sound. Once again thank for every comment.
You're talking of the ADA4627-1, correct? It looks very interesting indeed.
What is your supply voltage?
What is your supply voltage?
Andrea,
I've gotta disagree. IME there is no way the OPA2134, OPA134 or OPA132 op amps sound any where near as good as the OPA627BMs I use. I've done extensive listening tests in my preamp circuit with a wide variety of source and amplification. To my ears the OPA627 wins out against newer, purpose designed op amps.
The OPA627 is in another league all together. The OPA2134 sounds slow and bloated compared to the OPA627. I have not found another op amp that has the speed, detail, soundstage, frequency response and "air" of the OPA627 in my application (line amp).
I have swapped op amps, changed feedback resistors, changed bypass caps and the OPA627 is still best to my ears. I've auditioned pre amps costing over $1K in my system and none of them have bettered my OPA627 based pre.
It has a well deserved reputation in my opinion. The OPA627 has also been used in a number of well received commercial products as well. Take a peek at the latest:
DAGOGO Review: Accustic Arts Preamp I Mk3
You're talking of BM = metal can version? No wonder then... they tend to sound better indeed than the plastic correspondents.
I think I'd enjoy trying the metal OPA627. For the OPA627BP, I stand by what I said. It's clearer than the OPA132UA, but it still manages to sound worse (because sound is an organic whole) for my ears. There may be applications and circumstances where the OPA627BP is preferable, though, one of them being I/V conversion.
I think I'd enjoy trying the metal OPA627. For the OPA627BP, I stand by what I said. It's clearer than the OPA132UA, but it still manages to sound worse (because sound is an organic whole) for my ears. There may be applications and circumstances where the OPA627BP is preferable, though, one of them being I/V conversion.
The metal can tends to give a certain chip an improved midrange smoothness, and an improvement in tonal fidelity ...both things are much needed by the OPA627.
So I do think that the OPA627BM/AM must sound good. But...how much? 🙂
Also...I'd want to compare with the OPA1611 (plastic), which costs $2 and sounds almost like perfection to me
So I do think that the OPA627BM/AM must sound good. But...how much? 🙂
Also...I'd want to compare with the OPA1611 (plastic), which costs $2 and sounds almost like perfection to me
I did all my listening comparisons with the OPA627BP, which has the same specs as the BM.
I just recently swapped it over to the BM and there was still improvement.
The tonality of the OPA627BP/BM in my pre-amp is unmatched by any other pre-amp, or passive I've auditioned/experimented with in my system.
I haven't auditioned anything over $1.5K though, so I'm not saying it's the be all end all compared to commercial products. Compared to a few SS discrete projects that I've completed lately it's held it's own. While the discrete designs have bested it in one or two areas they still miss the mark holistically. I mean, who can listen to cymbals that sound like white noise even if the soundstage is 1' wider on each side.
I don't know that sound is an organic whole onto itself.
I would think recorded music is an organic whole in this context.
The circuits used must also be an organic whole. For instance, I am using a Shunt Super regulator which has a dramatic impact on the performance as well as the sound of my preamp.
I just recently swapped it over to the BM and there was still improvement.
The tonality of the OPA627BP/BM in my pre-amp is unmatched by any other pre-amp, or passive I've auditioned/experimented with in my system.
I haven't auditioned anything over $1.5K though, so I'm not saying it's the be all end all compared to commercial products. Compared to a few SS discrete projects that I've completed lately it's held it's own. While the discrete designs have bested it in one or two areas they still miss the mark holistically. I mean, who can listen to cymbals that sound like white noise even if the soundstage is 1' wider on each side.
I don't know that sound is an organic whole onto itself.
I would think recorded music is an organic whole in this context.
The circuits used must also be an organic whole. For instance, I am using a Shunt Super regulator which has a dramatic impact on the performance as well as the sound of my preamp.
I think we must be calling tonality two different things. Have you tried the LME49710HA (the metal version of the LME49710, definitely better sounding), BTW? That is one 'tonally capable' chip.
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If you mean tonal quality then I'm right there with you.
I have tried the LME49710MA. It' performance is close to the OPA627, however, it sounds to my ears like it's a little sterile and lacking in low frequency "effort". Both sins of omission and I would say I rank it right up there after the OPA627. It's not slow and bloated like the OPA2134/134.
I have 2 LME49710HA samples I just received on Friday. I will try them in both my phono pre (LME49710MA based) and my line driver (probably, I have tried the LME49710MA so I don't know).
I also have LME49713HA and LM4562NA samples to play with too. 😀
I don't think the circuits I use for the voltage feedback IC op amps I experiment with will be optimal for these current feedback IC op amps though.
I'm able to run my OPA627 line driver with no coupling caps. They are also not needed for the LME49710 circuits either.
I don't think the circuits I use for the voltage feedback IC op amps I experiment with will be optimal for these current feedback IC op amps though.
I'm able to run my OPA627 line driver with no coupling caps. They are also not needed for the LME49710 circuits either.
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Yeah, the LME49710NA/MA is like that. You've gotta hear the HA, though. 🙂
For duals, I prefer the LME49723 to LM4562NA, LME49720NA... because it doesn't lack bass/body and has a bit more musicality. I really have to try the LME49725, too.
Also, tried the LT1028ACN8?
I have, sorry, I'm not a fan of LT stuff so far. I find I like NS and BB/TI.
I haven't found any AD stuff I like either. ?????
The recent discrete SS line driver stuff has been BJT not JFET. Not really a fan of the BJT small signal stuff. I'm finding myself a big fan of JFETs while experimenting too.
I did build a JFET buffer with BF246s that is by far the best sound I've gotten from discretes. I thought the soundstage extended into my side yard!
No gain though so I've been working on that part lately.
I haven't found any AD stuff I like either. ?????
The recent discrete SS line driver stuff has been BJT not JFET. Not really a fan of the BJT small signal stuff. I'm finding myself a big fan of JFETs while experimenting too.
I did build a JFET buffer with BF246s that is by far the best sound I've gotten from discretes. I thought the soundstage extended into my side yard!
No gain though so I've been working on that part lately.
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