"tail"
Let's forget over-masterred music (techno, funk, rock etc.) and consider acoustical instruments, classical music.
If you listen e.g. to the sound of the recorded piano, sometimes you may hear a sound that comes "behind" the piano tone. That's what I call "tail". It means unclear, masked, blurred sound.
Let's forget over-masterred music (techno, funk, rock etc.) and consider acoustical instruments, classical music.
If you listen e.g. to the sound of the recorded piano, sometimes you may hear a sound that comes "behind" the piano tone. That's what I call "tail". It means unclear, masked, blurred sound.
This is very interesting, I use AD8610's in the tweeter section of my active xover, OPA627's in the midrange and OPA2134's on the bass.
Id be interested in biasing my OPA627's in class A etc if it really is worthwhile. Bare in mind this is 10 opamps lol. Now I take its exactly the same with an active filter with the resistor use?? Also if you are using 12volt supply lines what resistor value would you suggest? Baring in mind some of the stages within the xover have high gain (open baffle compensation etc).
Cheers for any help.
Id be interested in biasing my OPA627's in class A etc if it really is worthwhile. Bare in mind this is 10 opamps lol. Now I take its exactly the same with an active filter with the resistor use?? Also if you are using 12volt supply lines what resistor value would you suggest? Baring in mind some of the stages within the xover have high gain (open baffle compensation etc).
Cheers for any help.
Re: Now try this
Instead of reading anything you find on the net and take it serious, to have an oppinion you should test the method I described, with similar values, like Pavel (PMA) did, and listen .
You won't feel the need to use fets, believe it or not.
Sometimes people find it hard to make it simple...
Don't take conclusions just by testing an op-amp on an I/V stage of a dac, as in some cases a bipolar op-amp may work better there.
In that case, you're comparing different things.
Try the output buffer/filter stage too.
Try a pre.
etc.
Dr.H said:
Instead of reading anything you find on the net and take it serious, to have an oppinion you should test the method I described, with similar values, like Pavel (PMA) did, and listen .
You won't feel the need to use fets, believe it or not.
Sometimes people find it hard to make it simple...
Dr.H said:
Don't take conclusions just by testing an op-amp on an I/V stage of a dac, as in some cases a bipolar op-amp may work better there.
In that case, you're comparing different things.
Try the output buffer/filter stage too.
Try a pre.
etc.
Qoute...''The OPAs, and most of the modern/fast op-amps, need a good layout and PSU bypassing. They are very picky. The fact that an NE5534 works better on a circuit doens't mean nothing to me...''
Carlos, correct me if I am wrong but the OPA627, which has a unity gain bandwidth of 16MHz, is hardly any faster than the NJM2114 (15MHz) or the NE5534 (10MHz). To put it another way the difference is one semi-tone (insignificant) and six semi-tones (hardly significant) respectively.
Sunsun 22.
In my experience both the OPA2604 and the AD823 benefit from a 2mA c.c.s. on their output. I have not found an op-amp that doesn't...yet.
Tim.
Carlos, correct me if I am wrong but the OPA627, which has a unity gain bandwidth of 16MHz, is hardly any faster than the NJM2114 (15MHz) or the NE5534 (10MHz). To put it another way the difference is one semi-tone (insignificant) and six semi-tones (hardly significant) respectively.
Sunsun 22.
In my experience both the OPA2604 and the AD823 benefit from a 2mA c.c.s. on their output. I have not found an op-amp that doesn't...yet.
Tim.
A clarification
Carlosfm, PMA,
Gentlemen, it appears that I have been misunderstood, but then I may not have expressed myself clearly.
Your very positive findings on class A biasing using a simple resistor is a well understood and accepted mod for most op-amps. And I can confirm that I have tried it as well on the humble OPA2604.
I was simply, in the name of progress, suggesting the reading on the website to show that, when using the simple R, modulation of the op-amps output can occur, that some of the benefits of the high input impedance of the buffer can be negated, etc.
And so, I was suggesting that as good as resistor-based biasing is (and there is no doubt at all that it brings meaningful sonic benefits), there are better methods, like JFET for example.
So, I agree, R biasing is good, but if you liked that, you owe it to yourself to try JFETS, I think you'll be happier with the sound, whatever the theory.
Yes Carlosfm, I agree that I refer to the use of the THS4061 in a specific application, but in fairness remember that I have posted my impressions of the same op-amp in the very pre that made all gaincloners so happy and I came to the conclusion that in my specific set-up, I preferred THS4061 over OPA627 in the pre.
Of course I will be posting my results on the biased THS4061...
Happy DIYing and lets continue sharing impressions, opinions, experiences etc. That's what makes this a good place.
Ryan
Carlosfm, PMA,
Gentlemen, it appears that I have been misunderstood, but then I may not have expressed myself clearly.
Your very positive findings on class A biasing using a simple resistor is a well understood and accepted mod for most op-amps. And I can confirm that I have tried it as well on the humble OPA2604.
I was simply, in the name of progress, suggesting the reading on the website to show that, when using the simple R, modulation of the op-amps output can occur, that some of the benefits of the high input impedance of the buffer can be negated, etc.
And so, I was suggesting that as good as resistor-based biasing is (and there is no doubt at all that it brings meaningful sonic benefits), there are better methods, like JFET for example.
So, I agree, R biasing is good, but if you liked that, you owe it to yourself to try JFETS, I think you'll be happier with the sound, whatever the theory.
Yes Carlosfm, I agree that I refer to the use of the THS4061 in a specific application, but in fairness remember that I have posted my impressions of the same op-amp in the very pre that made all gaincloners so happy and I came to the conclusion that in my specific set-up, I preferred THS4061 over OPA627 in the pre.
Of course I will be posting my results on the biased THS4061...
Happy DIYing and lets continue sharing impressions, opinions, experiences etc. That's what makes this a good place.
Ryan
In the name of progress?
Sorry, Ryan, but we better look for a real light at the end of our audio tunnel, because better specs (modulation, distortion) seem not to be in the same field as good audio results. By audio results I mean sounds which are more life like, instruments that sound natural and not amplified.
Constant current sources seem to be contradictory, perhaps very much like current mirrors. Specs look better, but sounds worst. So what do you go for?
The best compromise seems to be to listen to it and see how it sounds. Using a FET with a resistor is easy to arrange, to anyone who is willing to try. But a resistor is so simple!...
Carlos E. Martinez
Dr.H said:
Sorry, Ryan, but we better look for a real light at the end of our audio tunnel, because better specs (modulation, distortion) seem not to be in the same field as good audio results. By audio results I mean sounds which are more life like, instruments that sound natural and not amplified.
Constant current sources seem to be contradictory, perhaps very much like current mirrors. Specs look better, but sounds worst. So what do you go for?
The best compromise seems to be to listen to it and see how it sounds. Using a FET with a resistor is easy to arrange, to anyone who is willing to try. But a resistor is so simple!...
Carlos E. Martinez
TimA said:
Check slew rate too, and settling time.
Anyway, my point and my experience is: put these op-amps on, for instance, a cdp or a pre, and you won't be impressed.
Because most commercial products have miserable layout and psu bypassing.
Put some caps under the circuit, where they are needed, and it sings.
AD op-amps are not so picky, im my experience.
And the NE5532/4 works everywhere, even with psu caps at 5 cm distance.
Why do you think manufacturers like and use them so much?
Less parts needed!
PMA said:
The OPAs NEED special care.
I'm talking PSU bypass here.
The OPA627 and OPA134 will have overblown bass that mucks up everything on a bad circuit.
Then some people don't like it...
The only BB OPA that I know and tested that works everywhere without special care, like the NEs, is the OPA227 and 228.
PMA said:
Oh yes, measures well, not bad spects, etc. but sounds like
.My oppinion too.
Upupa Epops said:
I understand what you mean. Was pussled for a while though since I use the term "tail" most often regarding lowlevel reverberation and maybe fading of acoustic instruments.
No tails (by your definition) in my home though, no opamps, no feedback loops. Balanced class A single end in SACD and class A power amps with only metalfilm shunt attenuation in between. BW DC-1MHz in amps.
/Peter
Re: A clarification
Ryan, I haven't tested the THS, so I can't comment.
I have them here to make a test.
With those beautiful specs I have a feeling...
It may even be that working with the BUF634 they outperform the OPA627.
And alone?
Possibilities are plenty, but I have no time now.
Dr.H said:
Ryan, I haven't tested the THS, so I can't comment.
I have them here to make a test.
With those beautiful specs I have a feeling...
It may even be that working with the BUF634 they outperform the OPA627.
And alone?
Possibilities are plenty, but I have no time now.
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