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#1
Posted to rec.audio.tech
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X-Meridian opamp replacement
The Auzentech card is shipped with socketed dual opamps on the
outputs, S4580P The spec seems pretty average and subjectively a bit of top end seems missing compared to the X-Fi. Whether the X-Fi had too much to start with is another question... Anyway, suggested replacements, assuming replacements are necessary at all? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz Dirk |
#2
Posted to rec.audio.tech
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X-Meridian opamp replacement
In article . com, "Dirk Bruere at NeoPax" wrote:
The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average and subjectively a bit of top end seems missing compared to the X-Fi. Whether the X-Fi had too much to start with is another question... Anyway, suggested replacements, assuming replacements are necessary at all? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz I don't know if the package is the same, but you might take a look at LM4562 http://cache.national.com/ds/LM/LM4562.pdf greg |
#3
Posted to rec.audio.tech
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X-Meridian opamp replacement
On 5 Apr, 14:35, (GregS) wrote:
In article . com, "Dirk Bruere at NeoPax" wrote: The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average and subjectively a bit of top end seems missing compared to the X-Fi. Whether the X-Fi had too much to start with is another question... Anyway, suggested replacements, assuming replacements are necessary at all? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz I don't know if the package is the same, but you might take a look at LM4562http://cache.national.com/ds/LM/LM4562.pdf greg That looks well impressive. Thanks Dirk |
#4
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Dirk Bruere at NeoPax" wrote in
message ups.com The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average and subjectively a bit of top end seems missing compared to the X-Fi. Whether the X-Fi had too much to start with is another question... Anyway, suggested replacements, assuming replacements are necessary at all? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz Have you run the Audio Rightmark program on the card to see what areas of performance need improving? |
#5
Posted to rec.audio.tech
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X-Meridian opamp replacement
On 5 Apr, 15:48, "Arny Krueger" wrote:
"Dirk Bruere at NeoPax" wrote in oglegroups.com The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average and subjectively a bit of top end seems missing compared to the X-Fi. Whether the X-Fi had too much to start with is another question... Anyway, suggested replacements, assuming replacements are necessary at all? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz Have you run the Audio Rightmark program on the card to see what areas of performance need improving? No, due to the fact I've only just learned about it! However, a lot of this audio stuff and what people consider to be a 'good' sound is pretty subjective. See "valve amps":-) Dirk |
#6
Posted to rec.audio.tech
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X-Meridian opamp replacement
Dirk Bruere at NeoPax wrote: The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average Not at all. 4580s are a lot better than average. Where did you get your data from ? and subjectively a bit of top end seems missing compared to the X-Fi. It certainly won't be due to the 4580 ! Whether the X-Fi had too much to start with is another question... Anyway, suggested replacements, assuming replacements are necessary at all? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: Get the original JRC data for the NJM4580. You can see that the nV/sqrt Hz is well below that of a 5532. It's ~ 3nV/sqrt Hz. 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz The 4580 is easily the equal of the 5532. Better in fact. Notably distortion. Graham |
#7
Posted to rec.audio.tech
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X-Meridian opamp replacement
Dirk Bruere at NeoPax wrote: On 5 Apr, 15:48, "Arny Krueger" wrote: "Dirk Bruere at NeoPax" wrote in oglegroups.com The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average and subjectively a bit of top end seems missing compared to the X-Fi. Whether the X-Fi had too much to start with is another question... Anyway, suggested replacements, assuming replacements are necessary at all? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz Have you run the Audio Rightmark program on the card to see what areas of performance need improving? No, due to the fact I've only just learned about it! However, a lot of this audio stuff and what people consider to be a 'good' sound is pretty subjective. See "valve amps":-) In the case of valve amps ppl like the colouration they add. Graham |
#8
Posted to rec.audio.tech
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X-Meridian opamp replacement
Eeyore wrote:
Dirk Bruere at NeoPax wrote: On 5 Apr, 15:48, "Arny Krueger" wrote: "Dirk Bruere at NeoPax" wrote in oglegroups.com The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average and subjectively a bit of top end seems missing compared to the X-Fi. Whether the X-Fi had too much to start with is another question... Anyway, suggested replacements, assuming replacements are necessary at all? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz Have you run the Audio Rightmark program on the card to see what areas of performance need improving? No, due to the fact I've only just learned about it! However, a lot of this audio stuff and what people consider to be a 'good' sound is pretty subjective. See "valve amps":-) In the case of valve amps ppl like the colouration they add. Graham I know. I've played around with DSP progs feeding speakers and technically measured flat response is not the 'best' sound even though it might be the most accurate. -- Dirk http://www.onetribe.me.uk - the UK's only occult talk show Hosted by Dirk Bruere and Marc Power |
#9
Posted to rec.audio.tech
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X-Meridian opamp replacement
Eeyore wrote:
Dirk Bruere at NeoPax wrote: The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average Not at all. 4580s are a lot better than average. Where did you get your data from ? and subjectively a bit of top end seems missing compared to the X-Fi. It certainly won't be due to the 4580 ! Whether the X-Fi had too much to start with is another question... Anyway, suggested replacements, assuming replacements are necessary at all? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: Get the original JRC data for the NJM4580. You can see that the nV/sqrt Hz is well below that of a 5532. It's ~ 3nV/sqrt Hz. 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz The 4580 is easily the equal of the 5532. Better in fact. Notably distortion. What's the audible effects of slew rates? From a naive EE POV I would assume that (for a 1V o/p signal) anything better than 1 volt per 25 uS would be inaudible since that corresponds with a 40kHz response for a Nyquist 20kHz resolution -- Dirk http://www.onetribe.me.uk - the UK's only occult talk show Hosted by Dirk Bruere and Marc Power |
#10
Posted to rec.audio.tech
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X-Meridian opamp replacement
Dirk Bruere at NeoPax wrote: What's the audible effects of slew rates? With the numbers in question for audio ? NONE, zilch, nix. From a naive EE POV I would assume that (for a 1V o/p signal) anything better than 1 volt per 25 uS would be inaudible since that corresponds with a 40kHz response for a Nyquist 20kHz resolution As I'm sure you know, the peak dV/dt of a sinwave is 2.pi.f.Vpeak. I hope I remembered that right. so for 20kHz @ 25V pk-pk (typically clipping level) its .... 1.6 V/us. Graham |
#11
Posted to rec.audio.tech
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X-Meridian opamp replacement
Dirk Bruere at NeoPax wrote: Eeyore wrote: In the case of valve amps ppl like the colouration they add. I know. I've played around with DSP progs feeding speakers and technically measured flat response is not the 'best' sound even though it might be the most accurate. That's simply an opinion of course. ;~) Find some truly flat speakers first ! Graham |
#12
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Dirk Bruere at NeoPax" wrote in
message I've played around with DSP progs feeding speakers and technically measured flat response is not the 'best' sound even though it might be the most accurate. When you measure the response of a speaker, you are not measuring the *total* response of the speaker, you are just measuring the sound from the speaker that happens to fall on the microphone, weighted by the directional pattern and response curve of the mic. For example, if you measure a speaker in an anechoic chamber with a good instrumentation mic, all you are measuing is the on-axis reponse of the speaker. But, in a regular room, you hear a mixture of the on-axis response of the speaker weighted by your hearing, plus all of the off-axis responses of the speaker as modified by reflection around the room and back to your ears. It is very hard to measure a speaker and weight its response just like your ears do. Contrast that with a wire. A wire has just one input and one output. It's relatively easy to measure the loss in a wire because of that. It if far easier to figure out what a wire should do if it is nearly perfect. |
#13
Posted to rec.audio.tech
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X-Meridian opamp replacement
Eeyore wrote:
Dirk Bruere at NeoPax wrote: What's the audible effects of slew rates? With the numbers in question for audio ? NONE, zilch, nix. From a naive EE POV I would assume that (for a 1V o/p signal) anything better than 1 volt per 25 uS would be inaudible since that corresponds with a 40kHz response for a Nyquist 20kHz resolution As I'm sure you know, the peak dV/dt of a sinwave is 2.pi.f.Vpeak. I hope I remembered that right. so for 20kHz @ 25V pk-pk (typically clipping level) its .... 1.6 V/us. Graham Which is roughly what I stated for 1V p-p (chosen to make the sums simpler) give or take an omega -- Dirk http://www.onetribe.me.uk - The UK's only occult talk show Presented by Dirk Bruere and Marc Power on ResonanceFM 104.4 http://www.resonancefm.com |
#14
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Dirk Bruere at NeoPax" wrote in message ... I've played around with DSP progs feeding speakers and technically measured flat response is not the 'best' sound even though it might be the most accurate. Naturally, for YOU. It depends on YOUR auditory system and your listening experiences and desires. Many people do prefer accurate though, and simply adjust their perception to suit. MrT. |
#15
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Arny Krueger" wrote in message ... When you measure the response of a speaker, you are not measuring the *total* response of the speaker, you are just measuring the sound from the speaker that happens to fall on the microphone, weighted by the directional pattern and response curve of the mic. Surely you realise that measurement microphones are usually both omni-directional and are flat to the required degree, and/or have a known calibration curve. (In fact I know you do, so am puzzled why you wrote that?) For example, if you measure a speaker in an anechoic chamber with a good instrumentation mic, all you are measuing is the on-axis reponse of the speaker. But, in a regular room, you hear a mixture of the on-axis response of the speaker weighted by your hearing, plus all of the off-axis responses of the speaker as modified by reflection around the room and back to your ears. It is very hard to measure a speaker and weight its response just like your ears do. And very little point anyway since it changes both within the rooom, and from room to room. And your auditory system partly discriminates directional and time delayed signals anyway, thus making any simple integration further pointless IMO. MrT. |
#16
Posted to rec.audio.tech
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X-Meridian opamp replacement
Dirk Bruere at NeoPax wrote: Eeyore wrote: Dirk Bruere at NeoPax wrote: What's the audible effects of slew rates? With the numbers in question for audio ? NONE, zilch, nix. From a naive EE POV I would assume that (for a 1V o/p signal) anything better than 1 volt per 25 uS would be inaudible since that corresponds with a 40kHz response for a Nyquist 20kHz resolution As I'm sure you know, the peak dV/dt of a sinwave is 2.pi.f.Vpeak. I hope I remembered that right. so for 20kHz @ 25V pk-pk (typically clipping level) its .... 1.6 V/us. Which is roughly what I stated for 1V p-p (chosen to make the sums simpler) give or take an omega. Do bear in mind that in order to avoid slew induced distortion, it's wise to stay well clear of the limiting slew rate too. Graham |
#17
Posted to rec.audio.tech
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X-Meridian opamp replacement
Eeyore wrote:
Dirk Bruere at NeoPax wrote: Eeyore wrote: Dirk Bruere at NeoPax wrote: What's the audible effects of slew rates? With the numbers in question for audio ? NONE, zilch, nix. From a naive EE POV I would assume that (for a 1V o/p signal) anything better than 1 volt per 25 uS would be inaudible since that corresponds with a 40kHz response for a Nyquist 20kHz resolution As I'm sure you know, the peak dV/dt of a sinwave is 2.pi.f.Vpeak. I hope I remembered that right. so for 20kHz @ 25V pk-pk (typically clipping level) its .... 1.6 V/us. Which is roughly what I stated for 1V p-p (chosen to make the sums simpler) give or take an omega. Do bear in mind that in order to avoid slew induced distortion, it's wise to stay well clear of the limiting slew rate too. Graham Yes. However, I suppose my original question was whether there is any audible effects when the slew rate limit is well into the ultrasonics. But maybe that has more to do with ears than electronics. -- Dirk http://www.onetribe.me.uk - The UK's only occult talk show Presented by Dirk Bruere and Marc Power on ResonanceFM 104.4 http://www.resonancefm.com |
#18
Posted to rec.audio.tech
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X-Meridian opamp replacement
On Tue, 10 Apr 2007 12:54:07 +0100, Dirk Bruere at NeoPax
wrote: Eeyore wrote: Dirk Bruere at NeoPax wrote: Eeyore wrote: Dirk Bruere at NeoPax wrote: What's the audible effects of slew rates? With the numbers in question for audio ? NONE, zilch, nix. From a naive EE POV I would assume that (for a 1V o/p signal) anything better than 1 volt per 25 uS would be inaudible since that corresponds with a 40kHz response for a Nyquist 20kHz resolution As I'm sure you know, the peak dV/dt of a sinwave is 2.pi.f.Vpeak. I hope I remembered that right. so for 20kHz @ 25V pk-pk (typically clipping level) its .... 1.6 V/us. Which is roughly what I stated for 1V p-p (chosen to make the sums simpler) give or take an omega. Do bear in mind that in order to avoid slew induced distortion, it's wise to stay well clear of the limiting slew rate too. Graham Yes. However, I suppose my original question was whether there is any audible effects when the slew rate limit is well into the ultrasonics. But maybe that has more to do with ears than electronics. What matters is not whether slew rate limiting happens in the audible frequency range, but whether it happens at all. If there are ultrasonic signals big enough to cause slew rate limiting, there will be massive intermod effects on audible signals. Any amplifier should always roll its HF response off at a rate which guarantees that no signal will cause limiting. d -- Pearce Consulting http://www.pearce.uk.com |
#19
Posted to rec.audio.tech
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X-Meridian opamp replacement
On 2007-04-10, Don Pearce wrote:
On Tue, 10 Apr 2007 12:54:07 +0100, Dirk Bruere at NeoPax wrote: However, I suppose my original question was whether there is any audible effects when the slew rate limit is well into the ultrasonics. But maybe that has more to do with ears than electronics. What matters is not whether slew rate limiting happens in the audible frequency range, but whether it happens at all. If there are ultrasonic signals big enough to cause slew rate limiting, there will be massive intermod effects on audible signals. Any amplifier should always roll its HF response off at a rate which guarantees that no signal will cause limiting. Indeed that's exactly AIUI. I always thought a properly-specified single RC pole at the input of an amplifier was standard practice and was sufficient to stop the amplifier hitting its slew rate limits for any signal that would not cause clipping. I was puzzled many years ago to see lots of hot air in the audio press about slew-rate-induced distortion. Of course I was merely a student of semiconductor device physics at the time so what did I know of designing amplifiers. However it seemed that this was a non-problem then and remains a non-problem now. If I am wrong then I am sure someone will enlighten me. Perhaps good design practice has to be re-discovered from time to time. -- John Phillips |
#20
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Mr.T" MrT@home wrote in message
"Arny Krueger" wrote in message ... "Dirk Bruere at NeoPax" wrote in message I've played around with DSP progs feeding speakers and technically measured flat response is not the 'best' sound even though it might be the most accurate. When you measure the response of a speaker, you are not measuring the *total* response of the speaker, you are just measuring the sound from the speaker that happens to fall on the microphone, weighted by the directional pattern and response curve of the mic. Surely you realise that measurement microphones are usually both omni-directional and are flat to the required degree, and/or have a known calibration curve. (In fact I know you do, so am puzzled why you wrote that?) Key words: "sound from the speaker that happens to fall on the microphone". For example, if you measure a speaker in an anechoic chamber with a good instrumentation mic, all you are measuring is the on-axis reponse of the speaker. But, in a regular room, you hear a mixture of the on-axis response of the speaker weighted by your hearing, plus all of the off-axis responses of the speaker as modified by reflection around the room and back to your ears. It is very hard to measure a speaker and weight its response just like your ears do. And very little point anyway since it changes both within the rooom, and from room to room. Please see the post I was responding to. The author seemed to be a bit mystefied about why setting up a speaker for flat measured response did not always correspond to best sounding response. The point of my post is that with speakers, what we measure is not usually the same as what we hear. And your auditory system partly discriminates directional and time delayed signals anyway, thus making any simple integration further pointless IMO. MrT. |
#21
Posted to rec.audio.tech
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X-Meridian opamp replacement
"John Phillips" wrote
in message I always thought a properly-specified single RC pole at the input of an amplifier was standard practice and was sufficient to stop the amplifier hitting its slew rate limits for any signal that would not cause clipping. Hold that thought! ;-) I was puzzled many years ago to see lots of hot air in the audio press about slew-rate-induced distortion. Doing their part to increase global warming, methinks! Of course I was merely a student of semiconductor device physics at the time so what did I know of designing amplifiers. However it seemed that this was a non-problem then and remains a non-problem now. If I am wrong then I am sure someone will enlighten me. The signals coming into the line input of an audio interface should be pretty well tamed-down by the preceeding stages of amplification and processing. For example, a mic preamp seems to be far more likely to be encountering hard-to-follow signals. Interestingly enough, one of the places where highly-regarded mic preamps distinguish themselves from more ordinary products is their resistance to IM from broadband signals at their inputs. Perhaps good design practice has to be re-discovered from time to time. |
#22
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X-Meridian opamp replacement
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#23
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X-Meridian opamp replacement
On Tue, 10 Apr 2007 10:39:11 -0400, "Arny Krueger"
wrote: Interestingly enough, one of the places where highly-regarded mic preamps distinguish themselves from more ordinary products is their resistance to IM from broadband signals at their inputs. I have a GSM phone sitting right next to my Behringer mixer right now. Not a hint of induced noise. d -- Pearce Consulting http://www.pearce.uk.com |
#24
Posted to rec.audio.tech
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X-Meridian opamp replacement
On 2007-04-10, Arny Krueger wrote:
"John Phillips" wrote in message I always thought a properly-specified single RC pole at the input of an amplifier was standard practice and was sufficient to stop the amplifier hitting its slew rate limits for any signal that would not cause clipping. Hold that thought! ;-) I was puzzled many years ago to see lots of hot air in the audio press about slew-rate-induced distortion. Doing their part to increase global warming, methinks! Of course I was merely a student of semiconductor device physics at the time so what did I know of designing amplifiers. However it seemed that this was a non-problem then and remains a non-problem now. If I am wrong then I am sure someone will enlighten me. The signals coming into the line input of an audio interface should be pretty well tamed-down by the preceeding stages of amplification and processing. I am sure that's generally true, but as a designer I am equally sure I could not assume its truth in all circumstances. The only safe approach seems to be that of assuming a very wide bandwidth input and making sure the amplifier still behaves. For example, a mic preamp seems to be far more likely to be encountering hard-to-follow signals. Another place to make no unwarranted assumptions. Interestingly enough, one of the places where highly-regarded mic preamps distinguish themselves from more ordinary products is their resistance to IM from broadband signals at their inputs. A result of good design for the purpose. Assumptions seem to be the root of many a cock-up. -- John Phillips |
#25
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X-Meridian opamp replacement
"Don Pearce" wrote in message
On Tue, 10 Apr 2007 10:39:11 -0400, "Arny Krueger" wrote: Interestingly enough, one of the places where highly-regarded mic preamps distinguish themselves from more ordinary products is their resistance to IM from broadband signals at their inputs. I have a GSM phone sitting right next to my Behringer mixer right now. Not a hint of induced noise. Sometimes higher frequencies create less fuss. I notice that keying a FRS walkie-talkie in the sanctuary causes a click in the SR system at church, but no audio. |
#26
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X-Meridian opamp replacement
On Tue, 10 Apr 2007 12:11:27 -0400, "Arny Krueger"
wrote: "Don Pearce" wrote in message On Tue, 10 Apr 2007 10:39:11 -0400, "Arny Krueger" wrote: Interestingly enough, one of the places where highly-regarded mic preamps distinguish themselves from more ordinary products is their resistance to IM from broadband signals at their inputs. I have a GSM phone sitting right next to my Behringer mixer right now. Not a hint of induced noise. Sometimes higher frequencies create less fuss. I notice that keying a FRS walkie-talkie in the sanctuary causes a click in the SR system at church, but no audio. Yebbut GSM phones seem to have supernatural powers of penetration. There are plenty of professional installations that are as susceptible as hell to them. d -- Pearce Consulting http://www.pearce.uk.com |
#27
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X-Meridian opamp replacement
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#28
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X-Meridian opamp replacement
Dirk Bruere at NeoPax wrote:
However, I suppose my original question was whether there is any audible effects when the slew rate limit is well into the ultrasonics. Yes, I encountered one opamp sounding plain boring when under RF stress. Dirk Kind regards Peter Larsen |
#29
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X-Meridian opamp replacement
Eeyore wrote:
Dirk Bruere at NeoPax wrote: The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average Not at all. 4580s are a lot better than average. They don't do really bad things. I did find a circuit using them boring, and vastly improved after an opamp replacement. It certainly won't be due to the 4580 ! On the probabilities here we disagree. The 4580 is easily the equal of the 5532. It could go either way, I have heard thingies with 553x being harsh or being forward. I do not know why, but I recall that 553x comes in many brands, makes and flavors. Better in fact. Notably distortion. You may recall my modded DAT, Preben Friis's measurements suggested that distortion was lower before the opamp replacement, much to my surprise since it got so much cleaner by being modded, but it must be included that coupling cap issues also were addressed. Graham Kind regards Peter Larsen |
#30
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X-Meridian opamp replacement
Dirk Bruere at NeoPax wrote:
The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P socketed, that is nice, complete url to the manufacturer? The spec seems pretty average and subjectively a bit of top end seems missing compared to the X-Fi. Hmmm .... Whether the X-Fi had too much to start with is another question... I have not heard that specific product. Anyway, suggested replacements, assuming replacements are necessary at all? What is the context of the sound card? The 5532 has better slew rate, although I'm not sure about the noise because the data sheet for the S4580P simply says: 0.8 uV RMS, RIAA Rs=2k2, f=30kHz LPF Bandwidth = 15MHz Analog Devices OPA(?) 275 comes to mind as very well sounding and very well behaved. Burr Brown 2134 has a charming midrange and is also a nice upgrading tool to work with, but slmewhat more prone to turn-on(/turn off thumps. Burr Brown X604 seems to have superior extremes of the audio range, but can come across as bright. NOTE however that effects of unbiased couplling caps can cloud the issue and that very much audio has passed fantazillions of "industry standard" components prior to reaching your playback system. Which is to say that modding may be irrelevant, I would actively discourage it as an unsuitable risk vs. possible benefit if not for the socketing of the original IC's Industry standard components DO tend to be those that pass approval in tech deparment AND in finance department, the latter departments tend to do their dollar math in 0.000000000001 cent increments. All evaluations above are subjective and in one context where distortion measurement was made the meausured distortion of the modded apparatus increased by modding rather than decreasing, it also sounded very much better, but specs were against the mod and showed that the original component choice was very sane. Dirk Kind regards Peter Larsen |
#31
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X-Meridian opamp replacement
Peter Larsen wrote: Eeyore wrote: Dirk Bruere at NeoPax wrote: The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average Not at all. 4580s are a lot better than average. They don't do really bad things. I did find a circuit using them boring, and vastly improved after an opamp replacement. Using what kind of replacement ? It certainly won't be due to the 4580 ! On the probabilities here we disagree. Tell me more. The 4580 is easily the equal of the 5532. It could go either way, I have heard thingies with 553x being harsh or being forward. I do not know why, but I recall that 553x comes in many brands, makes and flavors. That is true. I recall such comments being made in the late 70s early 80s. The chip design may have altered ( only Philips/Signetics made it then and Philips no longer make it btw ) as may the circuits it's used in. Better in fact. Notably distortion. You may recall my modded DAT, I'm not familiar with that actually. Preben Friis's measurements suggested that distortion was lower before the opamp replacement, much to my surprise since it got so much cleaner by being modded, but it must be included that coupling cap issues also were addressed. The coupling cap. Was that a small value zero bias electrolytic ? That makes some sense. Graham |
#32
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X-Meridian opamp replacement
Arny Krueger wrote:
[Grahamps question] The coupling cap. Was that a small value zero bias electrolytic ? That makes some sense. The SV3800 uses _very_ large coupling caps that by design are unpolarized. BB 2604's were used as replacement opmaps leading to subjectively improved audio detail but also to a measureable increase in distortion as detected by Preben Friis. We made a couple of comparative recordings, I'll probably put them on my site if I care to re-do it some day. If its the mod that Peter posted info about here a few years back, It is about the SV3800 mod, where Preben Friis kindly provided his own SV3800 for comparison. The SV3800 PCB is not of a quality that is intended for repeat soldering, and traces run under the glue that keeps the opamps in place during solder. I'd rather advice against the mod due to the risk rather than reocmmend it for the obtained vastly improved audio quality. one salient feature was a rather dramatic change in FR below 100 Hz. That was _intentional_ since the machine was used for live location recording, the caps that could not be simply omitted where chosen as small as possible to avoid overly large lumps of polypropylene dangling inside a machine that would be frequently transported. Input and output coupling caps were bypassed rather than replaced. I don't see the point of having the preamp end with a coupling cap and the DAT begin with a new, one must be enough. Whether that is a suitable general practice for everybody is entirely a different issue, in this context of a minimalistic recording setup every omitted component helps. It is still in its modded state a very good machine - the equal of the Fostex FR2, albeit differently sounding, but DAT tapes tend to be less very good than they were, or the transport is flawed or both, and I got tired of losing recordings due to tape debris (from new tapes!) on the heads and now I use a less good sounding harddisk recorder that brings the recording home every time. Kind regards Peter Larsen |
#33
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Eeyore" wrote in
message Peter Larsen wrote: Eeyore wrote: Dirk Bruere at NeoPax wrote: The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P The spec seems pretty average Not at all. 4580s are a lot better than average. They don't do really bad things. I did find a circuit using them boring, and vastly improved after an opamp replacement. Using what kind of replacement ? It certainly won't be due to the 4580 ! On the probabilities here we disagree. Tell me more. The 4580 is easily the equal of the 5532. It could go either way, I have heard thingies with 553x being harsh or being forward. I do not know why, but I recall that 553x comes in many brands, makes and flavors. That is true. I recall such comments being made in the late 70s early 80s. The chip design may have altered ( only Philips/Signetics made it then and Philips no longer make it btw ) as may the circuits it's used in. Better in fact. Notably distortion. You may recall my modded DAT, I'm not familiar with that actually. Preben Friis's measurements suggested that distortion was lower before the opamp replacement, much to my surprise since it got so much cleaner by being modded, but it must be included that coupling cap issues also were addressed. The coupling cap. Was that a small value zero bias electrolytic ? That makes some sense. If its the mod that Peter posted info about here a few years back, one salient feature was a rather dramatic change in FR below 100 Hz. |
#34
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Peter Larsen" wrote...
Dirk Bruere at NeoPax wrote: The Auzentech card is shipped with socketed dual opamps on the outputs, S4580P socketed, that is nice, complete url to the manufacturer? www.auzentech.com |
#35
Posted to rec.audio.tech
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X-Meridian opamp replacement
Arny Krueger wrote: "Eeyore" wrote The coupling cap. Was that a small value zero bias electrolytic ? That makes some sense. If its the mod that Peter posted info about here a few years back, one salient feature was a rather dramatic change in FR below 100 Hz. In *frequency response* ! Do you have any details of this ? Graham- |
#36
Posted to rec.audio.tech
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X-Meridian opamp replacement
Eeyore wrote:
Arny Krueger wrote: "Eeyore" wrote The coupling cap. Was that a small value zero bias electrolytic ? That makes some sense. If its the mod that Peter posted info about here a few years back, one salient feature was a rather dramatic change in FR below 100 Hz. In *frequency response* ! Yes. Do you have any details of this ? I can re-measure it some day, it was the *AIM* of the coupling cap mod part of it to raise the -3 dB point to the vicinity of 20 Hz, and it was not a flaw of the total mod that an approximation to that spec was obtained, nor did that outcome have anything to do with the opamp swap. The shape of the roll-off did get kinda strange because of the peculiar circuit around the record level pots ... I just don't care much for recording ventilation noise, train subsonics and the strange rumble caused by people walking in the parts of a building that are adjacent to the concert hall in the New Carlsberg Glyptotek. Graham- Kind regards Peter Larsen |
#37
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Peter Larsen" wrote in
message Eeyore wrote: Arny Krueger wrote: "Eeyore" wrote The coupling cap. Was that a small value zero bias electrolytic ? That makes some sense. If its the mod that Peter posted info about here a few years back, one salient feature was a rather dramatic change in FR below 100 Hz. In *frequency response* ! Yes. Do you have any details of this ? I can re-measure it some day, it was the *AIM* of the coupling cap mod part of it to raise the -3 dB point to the vicinity of 20 Hz, and it was not a flaw of the total mod that an approximation to that spec was obtained, nor did that outcome have anything to do with the opamp swap. The shape of the roll-off did get kinda strange because of the peculiar circuit around the record level pots ... I just don't care much for recording ventilation noise, train subsonics and the strange rumble caused by people walking in the parts of a building that are adjacent to the concert hall in the New Carlsberg Glyptotek. I don't fault the strategy of limiting LF response to improve SQ of live recordings. I do it quite often. The usual consquences of limiting LF response within reason and good taste are a cleaner-sounding recording, particularly when reproduced on systems with limited dynamic range at very low frequencies, which includes the vast majority of consumer music listening systems. |
#38
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Peter Larsen" wrote in message ... Not at all. 4580s are a lot better than average. They don't do really bad things. I did find a circuit using them boring, and vastly improved after an opamp replacement. "Boring" a real technical term there :-) Maybe if you told us exactly what TECHNICAL parameter was "vastly improved" by the replacement? You DID do proper measurements to determine that you weren't just imagining things, right? MrT. |
#39
Posted to rec.audio.tech
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X-Meridian opamp replacement
"Mr.T" wrote:
"Peter Larsen" wrote in message ... Not at all. 4580s are a lot better than average. They don't do really bad things. I did find a circuit using them boring, and vastly improved after an opamp replacement. "Boring" a real technical term there :-) Yes. Maybe if you told us exactly what TECHNICAL parameter was "vastly improved" by the replacement? Detail, spatial definition and rendition, perspective - in short: stereo imaging - and intertransient silence. You DID do proper measurements to determine that you weren't just imagining things, right? I did not, and I specifically mentioned that measured distortion performance of the thingamajic in question was worse after the mod. If you want to think that it did not in fact sound better after the mod, then think so and be happy. I am happy with the many good recordings I got from it after the mod, and we can then both be happy and believe that each other is a fool as per your implicit suggestion. MrT. Kind regards Peter Larsen |
#40
Posted to rec.audio.tech
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X-Meridian opamp replacement
Arny Krueger wrote:
The usual consquences of limiting LF response within reason and good taste are a cleaner-sounding recording, Actually not, things like voice and instrument box sounds suffer, it is bad for guitars and the entire violoncel family as well as for concert grands and for perceived 3-dimensinality particularly when reproduced on systems with limited dynamic range at very low frequencies, which includes the vast majority of consumer music listening systems. But the outcome is that playback systems that do not have an extended lf response sound cleaner and also rooms with a system with extended LF response in them but with LF resonance issues sound a lot cleaner, and for these reasons I generally will use high pass filtering in post, often it appears to me to be the optimum trade-off in terms of midrange clarity. Kind regards Peter Larsen |
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