I'm designing an active filter for quite an high-end system and need some advice concerning the op-amps to use : there will be 4 opamps in series for the midrange driver !
I plan to use some AD797 but they are really really expensive so I won't use them everywhere.
I have found some very contradictory information about the old NE5534 and NE5532 :
http://fnt-www.ss.titech.ac.jp/~hajime/uec/distortion/opa.html
-106dB for NE5532 and -114dB THD for NE5534 (-134dB for AD797 !)
This looks respectable for 0.30$ opamps
http://www.dself.dsl.pipex.com/ampins/webbop/5532.htm
0.002% ?! But that's huge for an opamp !
And finally : http://focus.ti.com/lit/ds/symlink/ne5534a.pdf
0.002%, but this time a big increase in THD above 2kHz !
Who should I believe ?
Also, are there any other more important parameters to look at (such as suggested here : http://www.octave-electronics.com/lcaudio/ad825.shtml ), like slew rate (which is always theorically sufficient) or something else ?
Considering more recent and not too expensive opamps, I was considering the OPA2134 which has low distorsion under 10kHz. Is it worth its price ? (10 times the price of a 5534 though !)
I'd be glad if someone could help because I'm really lost !
I plan to use some AD797 but they are really really expensive so I won't use them everywhere.
I have found some very contradictory information about the old NE5534 and NE5532 :
http://fnt-www.ss.titech.ac.jp/~hajime/uec/distortion/opa.html
-106dB for NE5532 and -114dB THD for NE5534 (-134dB for AD797 !)
This looks respectable for 0.30$ opamps
http://www.dself.dsl.pipex.com/ampins/webbop/5532.htm
0.002% ?! But that's huge for an opamp !
And finally : http://focus.ti.com/lit/ds/symlink/ne5534a.pdf
0.002%, but this time a big increase in THD above 2kHz !
Who should I believe ?
Also, are there any other more important parameters to look at (such as suggested here : http://www.octave-electronics.com/lcaudio/ad825.shtml ), like slew rate (which is always theorically sufficient) or something else ?
Considering more recent and not too expensive opamps, I was considering the OPA2134 which has low distorsion under 10kHz. Is it worth its price ? (10 times the price of a 5534 though !)
I'd be glad if someone could help because I'm really lost !
hi,
let me share little bit experience, during I test in my dac ( 151a with digital filer & reclock, & I try different Op-amp in the LPF.
if lower price acutally I will choose Philips 5534. 5532 not good. TI5532 & NE5532 forget it. ths is my opinions.
pls considerate choose philips 5534. expensive than NE & other brands, but really in this price range better.
thx
thomas
let me share little bit experience, during I test in my dac ( 151a with digital filer & reclock, & I try different Op-amp in the LPF.
if lower price acutally I will choose Philips 5534. 5532 not good. TI5532 & NE5532 forget it. ths is my opinions.
pls considerate choose philips 5534. expensive than NE & other brands, but really in this price range better.
thx
thomas
FWIW, I have two active XO systems using NE5532s (Fairchild, IIRC) - 6 op amps (1/2 NE5532) in the tweeter line, 7 in the mids and 4 per woofer. I am very happy with the sound of both. They responded very nicely to a good power supply that replaced 7815s.
I bought a bunch to prove out the concept of active XOs to myself, without spending a lot. I haven't been tempted enough to replace them - they are soldered into the circuit without sockets.
I have a system or two in the works that will use OPA2134s, so we'll see about those. They will be socketed, so I can swap if I think I need to. I hope not, since I bought 200 recently.
I bought a bunch to prove out the concept of active XOs to myself, without spending a lot. I haven't been tempted enough to replace them - they are soldered into the circuit without sockets.
I have a system or two in the works that will use OPA2134s, so we'll see about those. They will be socketed, so I can swap if I think I need to. I hope not, since I bought 200 recently.
Walt Jung has made rather many distortion measurements in his book "Opamp applications" and in the chapter about audio, chapter 6.
http://www.analog.com/library/analogDialogue/archives/39-05/Web_Ch6_final_I.pdf
http://www.analog.com/library/analogDialogue/archives/39-05/op_amp_applications_handbook.html
http://www.analog.com/library/analogDialogue/archives/39-05/Web_Ch6_final_I.pdf
http://www.analog.com/library/analogDialogue/archives/39-05/op_amp_applications_handbook.html
Thx everyone for your answers !
The OPA2227/227 are not available for me so if I choose one of the TI models, I'd rather use the OPA2134 (though is has higher THD)
They seem to be quite load-dependant though, so not very suitable for buffering or so.
But before "investing" I must know if new opamps compare really better at low gains (1~4) with the 553x :
I think you are talking about threads I've read too on Home-cinema.fr aren't you
You say there are quality/performance differences between the different manufacturers ? Did you experience or measure this personnaly ?
tschrama : could you tell me how better the 227 performs ? Do you obtain this ugly rise in THD above 2kHz on the OPA227 ? Is there a rise in THD on the 5534 ? I'd be glad to know that !
Oh BTW what do you think about those units : AD 825 and AD 8099 (in the tweeter filter section) ?
The OPA2227/227 are not available for me so if I choose one of the TI models, I'd rather use the OPA2134 (though is has higher THD)
They seem to be quite load-dependant though, so not very suitable for buffering or so.
But before "investing" I must know if new opamps compare really better at low gains (1~4) with the 553x :
I think you are talking about threads I've read too on Home-cinema.fr aren't you
You say there are quality/performance differences between the different manufacturers ? Did you experience or measure this personnaly ?
tschrama : could you tell me how better the 227 performs ? Do you obtain this ugly rise in THD above 2kHz on the OPA227 ? Is there a rise in THD on the 5534 ? I'd be glad to know that !
Oh BTW what do you think about those units : AD 825 and AD 8099 (in the tweeter filter section) ?
I have listened to OP27 and 5532/5534 and I feel the 5532/5534 is more musical, more flowing. The 5534 to me is slightly cleaner sounding than the 5532, especially at the top end (probably due to the custom compensation to suit the application). To me the OP27 sounded a little more accurate, but a little dry/dull by comparison.
FWIW: relatively speaking it hasn't been that long ago when pricy audiogear was made that still employed the 5534, not just $3000 German preamps.
All the posts i've read on this crate in the park stating the 5534 sucks is crapiola in my book. Can't comment on the 5532, never used it, i dislike double opamps. Of course you can do better with pricier models. I'm a longtime Burr Brown fan, as much as Carlos the Canned. The $8 BB OP27 did much better in preamp and opamp entry power amp circuits than the $1.50 NE5534 at the time. About 15 years ago, stepping up to a $30 OPA627 was a big improvement. Exchanging NE5534s in a CD-player for LT1028s again cost $15 a pop, i couldn't even get those suckers overhere in those days.
I don't think you'll build a state of the art X-O by using 5534s only. But unlike ancient history when even using 5532s in an active crossover cost plenty molla, you could start by constructing one with 55**s for pennies. Don't like it, can the 55**s and step up to the fancy league.
With the current 5534/32 price tag level you'll get a heap of a return for the investment.
Le truc avec les billes sur les encientes est tres ingenieux, guardianangel.
All the posts i've read on this crate in the park stating the 5534 sucks is crapiola in my book. Can't comment on the 5532, never used it, i dislike double opamps. Of course you can do better with pricier models. I'm a longtime Burr Brown fan, as much as Carlos the Canned. The $8 BB OP27 did much better in preamp and opamp entry power amp circuits than the $1.50 NE5534 at the time. About 15 years ago, stepping up to a $30 OPA627 was a big improvement. Exchanging NE5534s in a CD-player for LT1028s again cost $15 a pop, i couldn't even get those suckers overhere in those days.
I don't think you'll build a state of the art X-O by using 5534s only. But unlike ancient history when even using 5532s in an active crossover cost plenty molla, you could start by constructing one with 55**s for pennies. Don't like it, can the 55**s and step up to the fancy league.
With the current 5534/32 price tag level you'll get a heap of a return for the investment.
Le truc avec les billes sur les encientes est tres ingenieux, guardianangel.
Hi,
sounds like sense, build it with sockets and 5534s and listen.
An alternative to expensive chips is the discrete opamp, You can select for more voltage or more current or low load impedance or any combination upto all three.
Most builders who have gone down this route rave about the sound quality improvement.
sounds like sense, build it with sockets and 5534s and listen.
An alternative to expensive chips is the discrete opamp, You can select for more voltage or more current or low load impedance or any combination upto all three.
Most builders who have gone down this route rave about the sound quality improvement.
I've seriously thought of discrete opamps but searching the net it seems that it's hard to do better than ICs opamps.
I have done a little schematic that uses a long-tailed pair configuration, with a gain of 1. Do you think this thing could outperform an IC with a very clean PSU ? Or would the output impedance not be low enough to use this circuit in an active filter ?
Concerning AD825, has anyone got numbers about it ?
I have done a little schematic that uses a long-tailed pair configuration, with a gain of 1. Do you think this thing could outperform an IC with a very clean PSU ? Or would the output impedance not be low enough to use this circuit in an active filter ?
Concerning AD825, has anyone got numbers about it ?
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I suspect your circuit's output impedance may be high enough to interact with the filter you are trying to buffer.
See the diy opamp article on www.passdiy.com - add a follower and you should be fine. Whether this amounts to anything better than you could buy is another question.
See the diy opamp article on www.passdiy.com - add a follower and you should be fine. Whether this amounts to anything better than you could buy is another question.
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