Re: Don't knock the 5532!
I'm with you there. The OPA2134 is a very nice audio op amp, and relatively easy to work with.
The AD797 is maximum overkill for most audio applications IMO. It's expensive and is more sensitive to layout as well.
All else being equal, there's not going to be any audible improvement over an OPA2134.
It's an equalizer after all, not a heart telemetry machine.
Chucko said:
I'm with you there. The OPA2134 is a very nice audio op amp, and relatively easy to work with.
The AD797 is maximum overkill for most audio applications IMO. It's expensive and is more sensitive to layout as well.
All else being equal, there's not going to be any audible improvement over an OPA2134.
It's an equalizer after all, not a heart telemetry machine.
Re: Re: Don't knock the 5532!
Hmm... if there is an audible difference in a preamp, DAC I/V or buffer stage or whatever, how can you say that there would be no audible difference in a EQ?
/Peter
schmad said:
Hmm... if there is an audible difference in a preamp, DAC I/V or buffer stage or whatever, how can you say that there would be no audible difference in a EQ?
/Peter
Re: Re: Re: Don't knock the 5532!
What I said was that there would be no audible difference between an OPA2134 and an AD797 for audio applications.
In other words, if there are two devices, each one using either an AD797 or OPA2134, and there is an audible difference
between them, it's not going to be those devices themselves that are causing it.
Pan said:
What I said was that there would be no audible difference between an OPA2134 and an AD797 for audio applications.
In other words, if there are two devices, each one using either an AD797 or OPA2134, and there is an audible difference
between them, it's not going to be those devices themselves that are causing it.
AD797, LT1115, LT1028 and similar opamps with extremely low noise are unsuitable for unitygain applications and you don't need the low noise. The application generates much more noise than the opamp itself. It's simply a waste and they don't like neither high impedance feedback nor high impedance signal source!
These opamps are suited for MC preamps, mic amps and similar with "high" (>>1) gain.
My advice is to use a modern JFET based opamp. OPA134/2134/4134/2604 is good choices, especially OPAx134 which I like because of it's very clean electrical performance, very nice step response and clipping characteristics. OPA134 works splendidly in my headphone amp. And yes, it sounds good also.... The LT1115 is my headphone amp don't like resistors above 10 kohms. I get a slightly weird HF behavior if the input has too high DC-resitance down too ground. I get much better results with OPA134. I can't hear a difference but it's clearly visible on oscilloscope. OPA134 gives a technically clean performance.
These opamps are suited for MC preamps, mic amps and similar with "high" (>>1) gain.
My advice is to use a modern JFET based opamp. OPA134/2134/4134/2604 is good choices, especially OPAx134 which I like because of it's very clean electrical performance, very nice step response and clipping characteristics. OPA134 works splendidly in my headphone amp. And yes, it sounds good also.... The LT1115 is my headphone amp don't like resistors above 10 kohms. I get a slightly weird HF behavior if the input has too high DC-resitance down too ground. I get much better results with OPA134. I can't hear a difference but it's clearly visible on oscilloscope. OPA134 gives a technically clean performance.
I tried 2134 to drive my HD600, sounded like crap. Maybe would be good with a buffer, but since I need no gain I use BUF634 only and in headphone driver (of course) it makes 700% difference or so 🙂
I also had 2134 in my SCD-XB940, I never listened to it that way, it sounded like... crap 🙂 after I modded the player with LCAudio´s Zapfilter it´s a HOOOOLE ´nother story.
(edited) I should mention that in my SACD player the 2134 was biased into class A, and normally that is considered sonically benificial with opamps. Even if it was "ok" it was far from enough.
I also strongly believe in LC Audio´s listening tests with several of the popular opamps, where they feel AD825 "outperform" the earlier/cheaper/other ones. I have listened to a pre amp with AD826
6dB gain, and class A buffer, that sounded real good and almost transparent.
So.. I strongly believe there is clear audible difference between opamps like 2134/32 OP627/637 AD825/811/797 and other popular alternatives.
One thing is clear, measurments and numbers only tell a part of the story.
Happy listening (without opamps that is 🙂 !!!
/Peter
I also had 2134 in my SCD-XB940, I never listened to it that way, it sounded like... crap 🙂 after I modded the player with LCAudio´s Zapfilter it´s a HOOOOLE ´nother story.
(edited) I should mention that in my SACD player the 2134 was biased into class A, and normally that is considered sonically benificial with opamps. Even if it was "ok" it was far from enough.
I also strongly believe in LC Audio´s listening tests with several of the popular opamps, where they feel AD825 "outperform" the earlier/cheaper/other ones. I have listened to a pre amp with AD826
6dB gain, and class A buffer, that sounded real good and almost transparent.
So.. I strongly believe there is clear audible difference between opamps like 2134/32 OP627/637 AD825/811/797 and other popular alternatives.
One thing is clear, measurments and numbers only tell a part of the story.
Happy listening (without opamps that is 🙂 !!!
/Peter
Pan said:
Peter, is crap like an cassette deck from the 70's, CD-player from the mid 80's or is it a very, very, very, very small difference from something else which is "top of the line"? Don't HD600 sound like crap compared to Stax phones and Sennheiser Orpheus????
Some headphones requires a certain output impedance in order to sound good. 2134 is used by many people in parallel connection. This dual opamp is used for one channel.
To be honest, TL07x, TL08x, LF351, LF356 etc and oldtimers like these don't sound bad either but they are old and for a small additional cost you can buy a top modern opamp. I think you have to choose from at least 20-30 types which are suitable but I think the OPAx134 is one the best is you compare the price also.
""OK, that doesn't mean much of anything though. That's like saying, I put one Brand X resistor in a circuit with 50 other components and it sounded like crap.
What did you do or not do to make the 2134 sound like crap?""
There are some people over at headvize that really knows about lowlevel circuits and opamps. To them and me it´s clear as a bell that an opamp like 2134 is far from the optimum (sonically) and also far from capable of driving headphones with really high quality. Have you tried it yourself or do you only read and trust THD numbers?
""Ugh, the rhetoric of pseudoscience again. Almost "transparent" -- what is that exactly?""
Almost transparent means it does not subtract much from the signal, but enough to be heard. Not enough to be of major importance and can still be enjoyable. A impedance matched high quality resistor network is the most transparent I have listened to, and no active preamp have managed to equal that resolution.
""That is not at all clear to me. In my view, measurments and numbers tell the whole story, only some people choose not
to believe them. I don't understand what it is that makes some people think that audio has properties which cannot be
explained by physics and math.""
Audio has NO properties that can not be explained with math or physics. Do you know anyone that says something else?
The problem here is we do NOT have good enough measurements teqniques yet, that can fully map all characteristics on electronic circuits for audio signals.
Otherwise two components that both measure 0.0005%THD would sound the same, I hope you understand that is not the case?
At the 70´s SS amps managed to reach 0.0001% THD or so, and cheap Japaneese amps still do, but these amps has very grainy highs and low level information is totally lost in the feedback loops because of the complex distortion on NOT sine signals.
The same with cheap (most) CDP they have THD numbers often at 0.001-0.0001%, that should be low enough, but listening to such a $1000 CDP drives me out of the listenig chair after minutes. These numbers does not show the IM and FM that a high jitter clock produces. Swapp the clock for a high precision one and suddenly the sound becomes clear and resolved, more transparent. After that, skipp the opamps in I/V and buffer stages and use discrete class A circuits free from fedback, that still lifts the sound up by several steps.
FM,IM, DIM measurments says a lot more than THD, but I don´t know if these methods is enogh still, as I´m no EE or expert, but I have some good understanding overall, and very good ears.
Do you buy your hifi gear by the numbers in the white paper,
or do you trust your ears?
/Peter
What did you do or not do to make the 2134 sound like crap?""
There are some people over at headvize that really knows about lowlevel circuits and opamps. To them and me it´s clear as a bell that an opamp like 2134 is far from the optimum (sonically) and also far from capable of driving headphones with really high quality. Have you tried it yourself or do you only read and trust THD numbers?
""Ugh, the rhetoric of pseudoscience again. Almost "transparent" -- what is that exactly?""
Almost transparent means it does not subtract much from the signal, but enough to be heard. Not enough to be of major importance and can still be enjoyable. A impedance matched high quality resistor network is the most transparent I have listened to, and no active preamp have managed to equal that resolution.
""That is not at all clear to me. In my view, measurments and numbers tell the whole story, only some people choose not
to believe them. I don't understand what it is that makes some people think that audio has properties which cannot be
explained by physics and math.""
Audio has NO properties that can not be explained with math or physics. Do you know anyone that says something else?
The problem here is we do NOT have good enough measurements teqniques yet, that can fully map all characteristics on electronic circuits for audio signals.
Otherwise two components that both measure 0.0005%THD would sound the same, I hope you understand that is not the case?
At the 70´s SS amps managed to reach 0.0001% THD or so, and cheap Japaneese amps still do, but these amps has very grainy highs and low level information is totally lost in the feedback loops because of the complex distortion on NOT sine signals.
The same with cheap (most) CDP they have THD numbers often at 0.001-0.0001%, that should be low enough, but listening to such a $1000 CDP drives me out of the listenig chair after minutes. These numbers does not show the IM and FM that a high jitter clock produces. Swapp the clock for a high precision one and suddenly the sound becomes clear and resolved, more transparent. After that, skipp the opamps in I/V and buffer stages and use discrete class A circuits free from fedback, that still lifts the sound up by several steps.
FM,IM, DIM measurments says a lot more than THD, but I don´t know if these methods is enogh still, as I´m no EE or expert, but I have some good understanding overall, and very good ears.
Do you buy your hifi gear by the numbers in the white paper,
or do you trust your ears?
/Peter
This is a little bit of threadjacking but Peter has a point, and not.
Many opinions are just only that. You must filter everything (even what I says, some thinks I'm talking tjurbajs..) but it's always a feeling involved, hard to argue about. I don't like HD600 but I like my HD545....
I'm a true believer of double blind tests, which almost never takes place.
I notice that in many cases the hifi freaks are listening to mp3 without blushing...and.. at same time judging hifi gear.
Many opinions are just only that. You must filter everything (even what I says, some thinks I'm talking tjurbajs..) but it's always a feeling involved, hard to argue about. I don't like HD600 but I like my HD545....
I'm a true believer of double blind tests, which almost never takes place.
I notice that in many cases the hifi freaks are listening to mp3 without blushing...and.. at same time judging hifi gear.
MurrayP, the circuit you have used is rather classical. The opamps (the lower ones) serves as simulated inductors. The cause rather much distortion and it's important that the opamps are rather fast otherwise the "inductor effect" gets reduced. But since the frequency is only around 100 Hz, I think the application isn't so demanding.
Rod Elliott has made the simpliest form a gyrator (simulated inductor).
You could make it bootstrapped and/or buffered. See application note from National.
AN-435
Rod Elliott has made the simpliest form a gyrator (simulated inductor).
You could make it bootstrapped and/or buffered. See application note from National.
AN-435
Attachments
peranders,
I´m also a believer in blind tests, it´s just that sometimes it´s not necessary becasue the difference are so obvious. But if there is a difference to me, I use to pass the blind test with my friends.
BTW FWIW, I made a BUF634 driver with batteries and VG driver. This driving my HD600 from an outboard ECHoaudio dac (gina 20bit). This set up listening to MP3´s was among the better sound I have heard 🙂
Biasing both the signal BUF634 and VG BUF634 into full class A made a clear difference.
This sound was "better" than using the NON upgraded SCD-XB940 in my big rig.
Now with some upgrades in the big rig, the table has turned a couple of rounds.
/Peter
I´m also a believer in blind tests, it´s just that sometimes it´s not necessary becasue the difference are so obvious. But if there is a difference to me, I use to pass the blind test with my friends.
BTW FWIW, I made a BUF634 driver with batteries and VG driver. This driving my HD600 from an outboard ECHoaudio dac (gina 20bit). This set up listening to MP3´s was among the better sound I have heard 🙂
Biasing both the signal BUF634 and VG BUF634 into full class A made a clear difference.
This sound was "better" than using the NON upgraded SCD-XB940 in my big rig.
Now with some upgrades in the big rig, the table has turned a couple of rounds.
/Peter
peranders said:
There was a major difference. I have used 2134 in headphone driver and my SACD player, both were totally uninvolving and hifi/synthetic sounding. After jumping to class A BUF634 for the HD600, and Zapfilter in the SACD player, I have state of the art quality, so much better it is ridicolous to discuss the differences.
Stax top of the line and Orpheus is "better" then HD600, but not in the same way. HD600 is so good it satisifes a discerning ear, even if Orpheus would do that to a slightly higher degree.
But somewhere the performance get so low its not enjoyable, thats what I´m talking about.
In the end these kind of discussions may be about what each and everyone of us are able to hear. And if one person can not hear a difference, then he assumes that the one that say he can
is fantasizing. We are all different with different skills and abbilitys in many areas of life, that goes for hearing and processing sounds as well.
I enjoy highend sound more then a friend of mine who is kinda more "hifi´ish". When I can differentiate two components in a hartbeat, he needs more time to "zoom" in to that. But most often he get it. This is interesting and I found out that I (the audiophile with expensive gear) have a hearing that reaches about 10dB further down than the average Swede. That means when mr Svensson does not hear a sine tone anymore in the hearing test, I can attenuate the signal -10dB and still hear it.
Maybe this is one of the reasons I enjoy high end so much more then the everage guy. For me there is a major difference between all electronics I have tried and I often hear the difference in interconnects and speakercables as well.
Ok, I´lll stop here 🙂
Have a nice day all of you!
/Peter
peranders said:
peranders,
no I haven´t. Do you suggest it could improve upon the BUF634?
In such case I really must try it 🙂 I mean, half the fun with audio is to take things a step further... right?
Btw, is that what they call "audiophilia-nevrosa"... he he!
/Peter
Datawice the 634 is better but I would like the TO220 model (which not ELFA has). The DIL08 can't beliver som much power before it gets too hot.
Nevertheless, a buffer makes wonders very often but it's rather rare.
Nevertheless, a buffer makes wonders very often but it's rather rare.
The BUF-634 and the LT-1010 are each fine Parts. thay sound different and have a sound similar to Op Amps made by the same manufacture so the BUF-634 sounds it best with BB and some of the newer Analog Devices Op Amps AD-8610. the LT-1010CT is a wounderfull match to the LT-1122. use rbias on the LT-1010 of 20 Ohms. connect the BW pin on the BUF-634 to V- for the best out of each of these parts. You also might consider the HA-5002. But this device has no Output current limit. this Buffer is fast and Agressive sounding while still being cleen.
Back on track the simulated inductors Do work better with High speed Op Amps i use Video grade devices by default for these at all frequencies in the Audio range. Also current sourcing the Output is also a good thing with this circuit.
Back on track the simulated inductors Do work better with High speed Op Amps i use Video grade devices by default for these at all frequencies in the Audio range. Also current sourcing the Output is also a good thing with this circuit.
ppl
hi, nice to see you drop in.
I use to visit Headwize but only once in a while now. I must say I really learned a lot from your posts over there and you were one of the persons I was refering to in my earlier post in this thread.
The AD8610, is it "better" than AD825 IYO?
hi, nice to see you drop in.
I use to visit Headwize but only once in a while now. I must say I really learned a lot from your posts over there and you were one of the persons I was refering to in my earlier post in this thread.
The AD8610, is it "better" than AD825 IYO?
peranders said:
I´m really interested in trying the TO220 also. Since biasing the DIL full class A (shorting the pin to V-) improves the sound driving HD600, I would like to try a TO220 with higher voltage and max bias to see if it improves the sound further.
Maybe we can go together and buy a bunch from somewhere?
I wonder have anyone made a preamp or "buffered attenuator" with the BUF634? In such case I wonder about the sound compared to a passive and an active with discrete follower???
I know it depends on many variables but still...
/Peter
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