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#1
Posted to rec.audio.high-end
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do all pre-amps sound the same?
Hi
It occurs to me that all the arguments here about amps sounding the same refer to power amps not pre amps, come to think of it all the articles I have seen on this topic refer to power amps too. I am interested has anyone tried this on pre-amps? Or on integrated amps which combine the two? Steve |
#2
Posted to rec.audio.high-end
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do all pre-amps sound the same?
"Steve" wrote in message
... Hi It occurs to me that all the arguments here about amps sounding the same refer to power amps not pre amps, come to think of it all the articles I have seen on this topic refer to power amps too. I am interested has anyone tried this on pre-amps? Or on integrated amps which combine the two? Steve The issue of all amplifiers sounding the same is one of thresholds of hearing. All modern electronics, unless specifically designed to be so, will have an essentially flat frequency response, low distortion in all its forms and low noise. As these are well below the threshold of audibility, it follows that all electronics will sound the same once level matched and used within their design parameters. This will apply even more to pre-amps which by their very nature have an easier task than power amps. The sole proviso to the above is the RIAA equalisation and cartridge loading that some pre-amps still provide if they have phono inputs. The RIAA accuracy will determine the overall phono frequency response, and the cartridge loading will determine how the cartridge performs. Consequently, I would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. S. -- http://audiopages.googlepages.com |
#3
Posted to rec.audio.high-end
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do all pre-amps sound the same?
On Sun, 30 Mar 2008 14:43:09 -0700, Serge Auckland wrote
(in article ): "Steve" wrote in message ... Hi It occurs to me that all the arguments here about amps sounding the same refer to power amps not pre amps, come to think of it all the articles I have seen on this topic refer to power amps too. I am interested has anyone tried this on pre-amps? Or on integrated amps which combine the two? Steve The issue of all amplifiers sounding the same is one of thresholds of hearing. All modern electronics, unless specifically designed to be so, will have an essentially flat frequency response, low distortion in all its forms and low noise. As these are well below the threshold of audibility, it follows that all electronics will sound the same once level matched and used within their design parameters. This will apply even more to pre-amps which by their very nature have an easier task than power amps. The sole proviso to the above is the RIAA equalisation and cartridge loading that some pre-amps still provide if they have phono inputs. The RIAA accuracy will determine the overall phono frequency response, and the cartridge loading will determine how the cartridge performs. Consequently, I would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. S. That's a reasonable assumption. |
#4
Posted to rec.audio.high-end
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do all pre-amps sound the same?
Consequently, I
would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. S. That's a reasonable assumption.- Hide quoted text - - Show quoted text - I forgot about the phono input but leaving that aside are there no differences likely in a well designed pre? And if so presumably no lilely differences between a pre/power combo and an integrated combo providing they have the same specs? |
#5
Posted to rec.audio.high-end
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do all pre-amps sound the same?
"Serge Auckland" wrote in message
... snip The issue of all amplifiers sounding the same is one of thresholds of hearing. All modern electronics, unless specifically designed to be so, will have an essentially flat frequency response, low distortion in all its forms and low noise. As these are well below the threshold of audibility, it follows that all electronics will sound the same once level matched and used within their design parameters. This will apply even more to pre-amps which by their very nature have an easier task than power amps. The sole proviso to the above is the RIAA equalisation and cartridge loading that some pre-amps still provide if they have phono inputs. The RIAA accuracy will determine the overall phono frequency response, and the cartridge loading will determine how the cartridge performs. Consequently, I would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. Don't forget the interface.....output impedances of preamps can vary widely with frequency response and vary greatly from model to model. This makes matching up with the input impedances of power amps iffy in some cases. I have Onkyo preamps, for example, that work fine with most power amps but roll off noticeably when mated with Outlaw monoblocks. Yet the preamps rated output impedance (at 1000 ohms) is the standard "100 ohms" and the input impedance of the amps is the standard "10k ohms". |
#6
Posted to rec.audio.high-end
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do all pre-amps sound the same?
On Mar 30, 10:13*am, Steve wrote:
Hi It occurs to me that all the arguments here about amps sounding the same refer to power amps not pre amps, come to think of it all the articles I have seen on this topic refer to power amps too. I am interested has anyone tried this on pre-amps? Or on integrated amps which combine the two? Steve Hmmm... I would state that pre-amps are much more subject to component condition, circuit design and quality. A prime example of this might be the venerable PAT-5 (Dynaco) vs. the PAT-5 BiFET. The latter sounded pretty flat pretty universally. The former could sound anything from flat to glass-in-a-blender depending on the specific quality of a couple of transistors in the driver circuit - the FET mod cured this variance. I have cleaned up any number of tube pre-amps and made remarkable differences to their sound simply by careful capacitor replacement, component cleaning, tube replacement (if required) and so forth. But all of the above really does not answer your question directly. I keep at present a total of six pre-amps - the solid-state units pretty much sound of-a-piece. The tube units also pretty much sound of- a-piece. But there is a difference that I (believe I) can pick out 100% of the time between them (tube & SS) but not hardly that accurately within them. Which is better? Mpffff.... I like 'em both. Neither does that as I won't say a flat "yes". But I do not subscribe the every-component-is-sonically-different position either. Peter Wieck Melrose Park, PA |
#7
Posted to rec.audio.high-end
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do all pre-amps sound the same?
"Harry Lavo" wrote in message
... "Serge Auckland" wrote in message ... snip The issue of all amplifiers sounding the same is one of thresholds of hearing. All modern electronics, unless specifically designed to be so, will have an essentially flat frequency response, low distortion in all its forms and low noise. As these are well below the threshold of audibility, it follows that all electronics will sound the same once level matched and used within their design parameters. This will apply even more to pre-amps which by their very nature have an easier task than power amps. The sole proviso to the above is the RIAA equalisation and cartridge loading that some pre-amps still provide if they have phono inputs. The RIAA accuracy will determine the overall phono frequency response, and the cartridge loading will determine how the cartridge performs. Consequently, I would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. Don't forget the interface.....output impedances of preamps can vary widely with frequency response and vary greatly from model to model. This makes matching up with the input impedances of power amps iffy in some cases. I have Onkyo preamps, for example, that work fine with most power amps but roll off noticeably when mated with Outlaw monoblocks. Yet the preamps rated output impedance (at 1000 ohms) is the standard "100 ohms" and the input impedance of the amps is the standard "10k ohms". If there is roll-off with the Outlaw monoblocks, then there are several possibilities:- 1) The roll-off is a subjective impression which is not there when measured. By the way, I assume you meant (at 1000 Hz) not 1000 ohms. 2) You are using a very long length of cable between your preamp and Outlaw power amp ;-) With an output impedance of 100 ohms into 10k, there should be no roll off in the audio band unless the capacitance is pretty high. I calculate a 3dB drop at 20kHz needs a capacitance of 79nF. With typical 100-150pF/metre capacitance, that's 527-790 metres of cable! 3) The output impedance of the preamp is not 100 ohms, but a great deal higher. 4) The input of the Outlaw power amp has a very high capacitance. Normally it would be a few pF, but if Outlaw for whatever reason put, for example, 100nF, then there would indeed be a noticeable roll-off even with short cables. If 1) above is not the case, then there's ALWAYS a measurable reason for any effect. S. -- http://audiopages.googlepages.com |
#8
Posted to rec.audio.high-end
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do all pre-amps sound the same?
"Serge Auckland" wrote in message
... "Harry Lavo" wrote in message ... "Serge Auckland" wrote in message ... snip The issue of all amplifiers sounding the same is one of thresholds of hearing. All modern electronics, unless specifically designed to be so, will have an essentially flat frequency response, low distortion in all its forms and low noise. As these are well below the threshold of audibility, it follows that all electronics will sound the same once level matched and used within their design parameters. This will apply even more to pre-amps which by their very nature have an easier task than power amps. The sole proviso to the above is the RIAA equalisation and cartridge loading that some pre-amps still provide if they have phono inputs. The RIAA accuracy will determine the overall phono frequency response, and the cartridge loading will determine how the cartridge performs. Consequently, I would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. Don't forget the interface.....output impedances of preamps can vary widely with frequency response and vary greatly from model to model. This makes matching up with the input impedances of power amps iffy in some cases. I have Onkyo preamps, for example, that work fine with most power amps but roll off noticeably when mated with Outlaw monoblocks. Yet the preamps rated output impedance (at 1000 ohms) is the standard "100 ohms" and the input impedance of the amps is the standard "10k ohms". If there is roll-off with the Outlaw monoblocks, then there are several possibilities:- 1) The roll-off is a subjective impression which is not there when measured. By the way, I assume you meant (at 1000 Hz) not 1000 ohms. 2) You are using a very long length of cable between your preamp and Outlaw power amp ;-) With an output impedance of 100 ohms into 10k, there should be no roll off in the audio band unless the capacitance is pretty high. I calculate a 3dB drop at 20kHz needs a capacitance of 79nF. With typical 100-150pF/metre capacitance, that's 527-790 metres of cable! 3) The output impedance of the preamp is not 100 ohms, but a great deal higher. 4) The input of the Outlaw power amp has a very high capacitance. Normally it would be a few pF, but if Outlaw for whatever reason put, for example, 100nF, then there would indeed be a noticeable roll-off even with short cables. If 1) above is not the case, then there's ALWAYS a measurable reason for any effect. It's either 3 or 4. Cables are short, and the monoblocks sound fine with my ARC and Audionics preamps. It may be a combination of both. The Onkyo preamps are their AV models from the early 90's (I tried three with remote as a poor man's multichannel amp...works well except for the rolloff). I doubt that they use a buffered output, and suspect that impedance rises with frequency. The outlaw monoblocks are a hybrid class A/AB up to 60 watts, then a digital amp above that. Their stated input impedance is a bit low at 10k at 1000hz (yep!) and may drop further at high frequencies. Nonetheless, I think while most preamp/amp mismatches are more subtle than mine, some variance can sometimes be found which can influence system matching. That was my point. |
#9
Posted to rec.audio.high-end
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do all pre-amps sound the same?
Harry Lavo wrote:
"Serge Auckland" wrote in message ... "Harry Lavo" wrote in message ... "Serge Auckland" wrote in message ... snip The issue of all amplifiers sounding the same is one of thresholds of hearing. All modern electronics, unless specifically designed to be so, will have an essentially flat frequency response, low distortion in all its forms and low noise. As these are well below the threshold of audibility, it follows that all electronics will sound the same once level matched and used within their design parameters. This will apply even more to pre-amps which by their very nature have an easier task than power amps. The sole proviso to the above is the RIAA equalisation and cartridge loading that some pre-amps still provide if they have phono inputs. The RIAA accuracy will determine the overall phono frequency response, and the cartridge loading will determine how the cartridge performs. Consequently, I would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. Don't forget the interface.....output impedances of preamps can vary widely with frequency response and vary greatly from model to model. This makes matching up with the input impedances of power amps iffy in some cases. I have Onkyo preamps, for example, that work fine with most power amps but roll off noticeably when mated with Outlaw monoblocks. Yet the preamps rated output impedance (at 1000 ohms) is the standard "100 ohms" and the input impedance of the amps is the standard "10k ohms". If there is roll-off with the Outlaw monoblocks, then there are several possibilities:- 1) The roll-off is a subjective impression which is not there when measured. By the way, I assume you meant (at 1000 Hz) not 1000 ohms. 2) You are using a very long length of cable between your preamp and Outlaw power amp ;-) With an output impedance of 100 ohms into 10k, there should be no roll off in the audio band unless the capacitance is pretty high. I calculate a 3dB drop at 20kHz needs a capacitance of 79nF. With typical 100-150pF/metre capacitance, that's 527-790 metres of cable! 3) The output impedance of the preamp is not 100 ohms, but a great deal higher. 4) The input of the Outlaw power amp has a very high capacitance. Normally it would be a few pF, but if Outlaw for whatever reason put, for example, 100nF, then there would indeed be a noticeable roll-off even with short cables. If 1) above is not the case, then there's ALWAYS a measurable reason for any effect. It's either 3 or 4. Cables are short, and the monoblocks sound fine with my ARC and Audionics preamps. It may be a combination of both. The Onkyo preamps are their AV models from the early 90's (I tried three with remote as a poor man's multichannel amp...works well except for the rolloff). I doubt that they use a buffered output, and suspect that impedance rises with frequency. The outlaw monoblocks are a hybrid class A/AB up to 60 watts, then a digital amp above that. Their stated input impedance is a bit low at 10k at 1000hz (yep!) and may drop further at high frequencies. Nonetheless, I think while most preamp/amp mismatches are more subtle than mine, some variance can sometimes be found which can influence system matching. That was my point. I'm not seeing strong evidence for 'rolloff' here. Possibility #1 has by no means been discounted. ___ -S http://en.wikipedia.org/wiki/List_of_fictional_sheep |
#10
Posted to rec.audio.high-end
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do all pre-amps sound the same?
On Tue, 1 Apr 2008 19:08:40 -0700, Harry Lavo wrote
(in article ): "Serge Auckland" wrote in message ... "Harry Lavo" wrote in message ... "Serge Auckland" wrote in message ... snip The issue of all amplifiers sounding the same is one of thresholds of hearing. All modern electronics, unless specifically designed to be so, will have an essentially flat frequency response, low distortion in all its forms and low noise. As these are well below the threshold of audibility, it follows that all electronics will sound the same once level matched and used within their design parameters. This will apply even more to pre-amps which by their very nature have an easier task than power amps. The sole proviso to the above is the RIAA equalisation and cartridge loading that some pre-amps still provide if they have phono inputs. The RIAA accuracy will determine the overall phono frequency response, and the cartridge loading will determine how the cartridge performs. Consequently, I would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. Don't forget the interface.....output impedances of preamps can vary widely with frequency response and vary greatly from model to model. This makes matching up with the input impedances of power amps iffy in some cases. I have Onkyo preamps, for example, that work fine with most power amps but roll off noticeably when mated with Outlaw monoblocks. Yet the preamps rated output impedance (at 1000 ohms) is the standard "100 ohms" and the input impedance of the amps is the standard "10k ohms". If there is roll-off with the Outlaw monoblocks, then there are several possibilities:- 1) The roll-off is a subjective impression which is not there when measured. By the way, I assume you meant (at 1000 Hz) not 1000 ohms. 2) You are using a very long length of cable between your preamp and Outlaw power amp ;-) With an output impedance of 100 ohms into 10k, there should be no roll off in the audio band unless the capacitance is pretty high. I calculate a 3dB drop at 20kHz needs a capacitance of 79nF. With typical 100-150pF/metre capacitance, that's 527-790 metres of cable! 3) The output impedance of the preamp is not 100 ohms, but a great deal higher. 4) The input of the Outlaw power amp has a very high capacitance. Normally it would be a few pF, but if Outlaw for whatever reason put, for example, 100nF, then there would indeed be a noticeable roll-off even with short cables. If 1) above is not the case, then there's ALWAYS a measurable reason for any effect. It's either 3 or 4. Cables are short, and the monoblocks sound fine with my ARC and Audionics preamps. It may be a combination of both. The Onkyo preamps are their AV models from the early 90's (I tried three with remote as a poor man's multichannel amp...works well except for the rolloff). I doubt that they use a buffered output, and suspect that impedance rises with frequency. The outlaw monoblocks are a hybrid class A/AB up to 60 watts, then a digital amp above that. Their stated input impedance is a bit low at 10k at 1000hz (yep!) and may drop further at high frequencies. By digital, do you mean "class D"? So, this amp changes from class A and A/B above 60 Watts to class D? I'd love to see how they accomplish THAT! Nonetheless, I think while most preamp/amp mismatches are more subtle than mine, some variance can sometimes be found which can influence system matching. That was my point. Well, I think that it would have to be SOME roll-off for anyone to actually hear any attenuation above about 10KHz. |
#11
Posted to rec.audio.high-end
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do all pre-amps sound the same?
"Steven Sullivan" wrote in message
... Harry Lavo wrote: "Serge Auckland" wrote in message ... "Harry Lavo" wrote in message ... "Serge Auckland" wrote in message ... snip The issue of all amplifiers sounding the same is one of thresholds of hearing. All modern electronics, unless specifically designed to be so, will have an essentially flat frequency response, low distortion in all its forms and low noise. As these are well below the threshold of audibility, it follows that all electronics will sound the same once level matched and used within their design parameters. This will apply even more to pre-amps which by their very nature have an easier task than power amps. The sole proviso to the above is the RIAA equalisation and cartridge loading that some pre-amps still provide if they have phono inputs. The RIAA accuracy will determine the overall phono frequency response, and the cartridge loading will determine how the cartridge performs. Consequently, I would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. Don't forget the interface.....output impedances of preamps can vary widely with frequency response and vary greatly from model to model. This makes matching up with the input impedances of power amps iffy in some cases. I have Onkyo preamps, for example, that work fine with most power amps but roll off noticeably when mated with Outlaw monoblocks. Yet the preamps rated output impedance (at 1000 ohms) is the standard "100 ohms" and the input impedance of the amps is the standard "10k ohms". If there is roll-off with the Outlaw monoblocks, then there are several possibilities:- 1) The roll-off is a subjective impression which is not there when measured. By the way, I assume you meant (at 1000 Hz) not 1000 ohms. 2) You are using a very long length of cable between your preamp and Outlaw power amp ;-) With an output impedance of 100 ohms into 10k, there should be no roll off in the audio band unless the capacitance is pretty high. I calculate a 3dB drop at 20kHz needs a capacitance of 79nF. With typical 100-150pF/metre capacitance, that's 527-790 metres of cable! 3) The output impedance of the preamp is not 100 ohms, but a great deal higher. 4) The input of the Outlaw power amp has a very high capacitance. Normally it would be a few pF, but if Outlaw for whatever reason put, for example, 100nF, then there would indeed be a noticeable roll-off even with short cables. If 1) above is not the case, then there's ALWAYS a measurable reason for any effect. It's either 3 or 4. Cables are short, and the monoblocks sound fine with my ARC and Audionics preamps. It may be a combination of both. The Onkyo preamps are their AV models from the early 90's (I tried three with remote as a poor man's multichannel amp...works well except for the rolloff). I doubt that they use a buffered output, and suspect that impedance rises with frequency. The outlaw monoblocks are a hybrid class A/AB up to 60 watts, then a digital amp above that. Their stated input impedance is a bit low at 10k at 1000hz (yep!) and may drop further at high frequencies. Nonetheless, I think while most preamp/amp mismatches are more subtle than mine, some variance can sometimes be found which can influence system matching. That was my point. I'm not seeing strong evidence for 'rolloff' here. Possibility #1 has by no means been discounted. Measurement, no. But in a system I know and has always sounded "one way" with much other equipment, and suddenly it is dull and lifeless when these preamps are inserted....careful listening was used to determine that I wasn't just imagining it involving lots of swapping (yes, Steven, I am objective enough that the thought occurred to me....I often start where you leave off). There is a HF rolloff that is pretty severe and sonically very degrading. And it is a design parameter, not a flaw...since it exists no matter which of the three preamps are used with the Outlaws, and it doesn't exist with any one of three other power amps or with other preamps used with the same power amps. And it is infinitely repeatable. |
#12
Posted to rec.audio.high-end
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do all pre-amps sound the same?
Harry Lavo wrote:
"Steven Sullivan" wrote in message I'm not seeing strong evidence for 'rolloff' here. Possibility #1 has by no means been discounted. Measurement, no. But in a system I know and has always sounded "one way" with much other equipment, and suddenly it is dull and lifeless when these preamps are inserted....careful listening was used to determine that I wasn't just imagining it involving lots of swapping (yes, Steven, I am objective enough that the thought occurred to me....I often start where you leave off). There is a HF rolloff that is pretty severe and sonically very degrading. And it is a design parameter, not a flaw...since it exists no matter which of the three preamps are used with the Outlaws, and it doesn't exist with any one of three other power amps or with other preamps used with the same power amps. And it is infinitely repeatable. and again...possibility #1 has by no means been discounted. Let's assume the 'pretty severe' rolloff is real, though... have you considered writing to Outlaw Audio? They could confirm whether your claim that it's a 'design paramenter' is true. If it's not not, maybe they'll fix your broken Outlaw for you. ___ -S http://en.wikipedia.org/wiki/List_of_fictional_sheep |
#13
Posted to rec.audio.high-end
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do all pre-amps sound the same?
"Harry Lavo" wrote in message
... "Steven Sullivan" wrote in message ... Harry Lavo wrote: "Serge Auckland" wrote in message ... "Harry Lavo" wrote in message ... "Serge Auckland" wrote in message ... snip The issue of all amplifiers sounding the same is one of thresholds of hearing. All modern electronics, unless specifically designed to be so, will have an essentially flat frequency response, low distortion in all its forms and low noise. As these are well below the threshold of audibility, it follows that all electronics will sound the same once level matched and used within their design parameters. This will apply even more to pre-amps which by their very nature have an easier task than power amps. The sole proviso to the above is the RIAA equalisation and cartridge loading that some pre-amps still provide if they have phono inputs. The RIAA accuracy will determine the overall phono frequency response, and the cartridge loading will determine how the cartridge performs. Consequently, I would expect that if there are any differences when levels are accurately matched and under suitably blind conditions, then it is most likely due to the RIAA eq or cartridge. Don't forget the interface.....output impedances of preamps can vary widely with frequency response and vary greatly from model to model. This makes matching up with the input impedances of power amps iffy in some cases. I have Onkyo preamps, for example, that work fine with most power amps but roll off noticeably when mated with Outlaw monoblocks. Yet the preamps rated output impedance (at 1000 ohms) is the standard "100 ohms" and the input impedance of the amps is the standard "10k ohms". If there is roll-off with the Outlaw monoblocks, then there are several possibilities:- 1) The roll-off is a subjective impression which is not there when measured. By the way, I assume you meant (at 1000 Hz) not 1000 ohms. 2) You are using a very long length of cable between your preamp and Outlaw power amp ;-) With an output impedance of 100 ohms into 10k, there should be no roll off in the audio band unless the capacitance is pretty high. I calculate a 3dB drop at 20kHz needs a capacitance of 79nF. With typical 100-150pF/metre capacitance, that's 527-790 metres of cable! 3) The output impedance of the preamp is not 100 ohms, but a great deal higher. 4) The input of the Outlaw power amp has a very high capacitance. Normally it would be a few pF, but if Outlaw for whatever reason put, for example, 100nF, then there would indeed be a noticeable roll-off even with short cables. If 1) above is not the case, then there's ALWAYS a measurable reason for any effect. It's either 3 or 4. Cables are short, and the monoblocks sound fine with my ARC and Audionics preamps. It may be a combination of both. The Onkyo preamps are their AV models from the early 90's (I tried three with remote as a poor man's multichannel amp...works well except for the rolloff). I doubt that they use a buffered output, and suspect that impedance rises with frequency. The outlaw monoblocks are a hybrid class A/AB up to 60 watts, then a digital amp above that. Their stated input impedance is a bit low at 10k at 1000hz (yep!) and may drop further at high frequencies. Nonetheless, I think while most preamp/amp mismatches are more subtle than mine, some variance can sometimes be found which can influence system matching. That was my point. I'm not seeing strong evidence for 'rolloff' here. Possibility #1 has by no means been discounted. Measurement, no. But in a system I know and has always sounded "one way" with much other equipment, and suddenly it is dull and lifeless when these preamps are inserted....careful listening was used to determine that I wasn't just imagining it involving lots of swapping (yes, Steven, I am objective enough that the thought occurred to me....I often start where you leave off). There is a HF rolloff that is pretty severe and sonically very degrading. And it is a design parameter, not a flaw...since it exists no matter which of the three preamps are used with the Outlaws, and it doesn't exist with any one of three other power amps or with other preamps used with the same power amps. And it is infinitely repeatable. So measure it and tells us what it is. If you can hear a roll-off, then you can measure it. It's not that difficult, any half-decent sound card, an attenuator and any of the free audio analysis programs will do it. You could also ask Outlaw what the input capacitance of their amp is. If it's very high, then it would give you a roll-off with almost any pre-amp. S. -- http://audiopages.googlepages.com |
#14
Posted to rec.audio.high-end
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do all pre-amps sound the same?
Sonnova writes:
The outlaw monoblocks are a hybrid class A/AB up to 60 watts, then a digital amp above that. Their stated input impedance is a bit low at 10k at 1000hz (yep!) and may drop further at high frequencies. By digital, do you mean "class D"? So, this amp changes from class A and A/B above 60 Watts to class D? I'd love to see how they accomplish THAT! Apparently it is Class G: http://www.outlawaudio.com/support/faq_200.html |
#15
Posted to rec.audio.high-end
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do all pre-amps sound the same?
"Steven Sullivan" wrote in message
... Harry Lavo wrote: "Steven Sullivan" wrote in message I'm not seeing strong evidence for 'rolloff' here. Possibility #1 has by no means been discounted. Measurement, no. But in a system I know and has always sounded "one way" with much other equipment, and suddenly it is dull and lifeless when these preamps are inserted....careful listening was used to determine that I wasn't just imagining it involving lots of swapping (yes, Steven, I am objective enough that the thought occurred to me....I often start where you leave off). There is a HF rolloff that is pretty severe and sonically very degrading. And it is a design parameter, not a flaw...since it exists no matter which of the three preamps are used with the Outlaws, and it doesn't exist with any one of three other power amps or with other preamps used with the same power amps. And it is infinitely repeatable. and again...possibility #1 has by no means been discounted. Let's assume the 'pretty severe' rolloff is real, though... have you considered writing to Outlaw Audio? They could confirm whether your claim that it's a 'design paramenter' is true. If it's not not, maybe they'll fix your broken Outlaw for you. ___ -S http://en.wikipedia.org/wiki/List_of_fictional_sheep Again, Steven....I'm ahead of you. That was one of the first things I did. They did not come right out and say it, but they did acknowledge that the input impedance was lower than normal and that some preamps with a rising high end impedance might affect frquency response. |
#16
Posted to rec.audio.high-end
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do all pre-amps sound the same?
"Steve" wrote in message ...
Hi It occurs to me that all the arguments here about amps sounding the same refer to power amps not pre amps, come to think of it all the articles I have seen on this topic refer to power amps too. I am interested has anyone tried this on pre-amps? Or on integrated amps which combine the two? Steve The question of preamps sounding the same has to be qualified. Apparently not all are built with sensible input and output specs. I remember a Tascam mixing board that caused a HF rolloff when driven from a Tascam 4-channel tape deck. It turned out that there were capacitors, soldered physically right across the input jacks of the board. Go figure. Maybe they were added at the last minute. Or maybe the guy who sold it to me had done it it (I don't recall if the caps were in the schematic -- this was in the 70s -- but I kind of think they were). Another issue is the argument that the rise in source (output) impedance of some power amps at high frequencies can cause response changes as a function of the differing HF driver loads of various speakers. Since amplifiers have an extremely low source impedance, relative to the load impedance (4 Ohms, 8 Ohms, whatever), it would seem negligible, unless it rises a whole lot, and this might be just another imagined problem, rampant in these circles. None the less, there can be problems interfacing sources with preamps, preamps with power amps, as well as power amps with speakers. In a world of sensibly designed equipment, it wouldn't happen, but occasionally does. A competent technician should be aware of the potential problems, and check for them. Similarly, a competent technician will check the output impedance of any source that's going to be driving a long cable, calculate it's capacitance, and ensure that the resulting HF rolloff will be well above the audio range. For plug-n-play people, these are potential situations, and in the final analysis, the components can indeed sound different. Properly interfaced, I believe they won't. Serge gave the details of that well in his first follow-up. -- Regards from Virginia Beach, Earl Kiosterud |
#17
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do all pre-amps sound the same?
Harry Lavo wrote:
"Steven Sullivan" wrote in message ... Harry Lavo wrote: "Steven Sullivan" wrote in message I'm not seeing strong evidence for 'rolloff' here. Possibility #1 has by no means been discounted. Measurement, no. But in a system I know and has always sounded "one way" with much other equipment, and suddenly it is dull and lifeless when these preamps are inserted....careful listening was used to determine that I wasn't just imagining it involving lots of swapping (yes, Steven, I am objective enough that the thought occurred to me....I often start where you leave off). There is a HF rolloff that is pretty severe and sonically very degrading. And it is a design parameter, not a flaw...since it exists no matter which of the three preamps are used with the Outlaws, and it doesn't exist with any one of three other power amps or with other preamps used with the same power amps. And it is infinitely repeatable. and again...possibility #1 has by no means been discounted. Let's assume the 'pretty severe' rolloff is real, though... have you considered writing to Outlaw Audio? They could confirm whether your claim that it's a 'design paramenter' is true. If it's not not, maybe they'll fix your broken Outlaw for you. ___ -S http://en.wikipedia.org/wiki/List_of_fictional_sheep Again, Steven....I'm ahead of you. That was one of the first things I did. They did not come right out and say it, but they did acknowledge that the input impedance was lower than normal and that some preamps with a rising high end impedance might affect frquency response. How about you reprint what Outlaw actually wrote? |
#18
Posted to rec.audio.high-end
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do all pre-amps sound the same?
"Steven Sullivan" wrote in message
... Harry Lavo wrote: "Steven Sullivan" wrote in message ... Harry Lavo wrote: "Steven Sullivan" wrote in message I'm not seeing strong evidence for 'rolloff' here. Possibility #1 has by no means been discounted. Measurement, no. But in a system I know and has always sounded "one way" with much other equipment, and suddenly it is dull and lifeless when these preamps are inserted....careful listening was used to determine that I wasn't just imagining it involving lots of swapping (yes, Steven, I am objective enough that the thought occurred to me....I often start where you leave off). There is a HF rolloff that is pretty severe and sonically very degrading. And it is a design parameter, not a flaw...since it exists no matter which of the three preamps are used with the Outlaws, and it doesn't exist with any one of three other power amps or with other preamps used with the same power amps. And it is infinitely repeatable. and again...possibility #1 has by no means been discounted. Let's assume the 'pretty severe' rolloff is real, though... have you considered writing to Outlaw Audio? They could confirm whether your claim that it's a 'design paramenter' is true. If it's not not, maybe they'll fix your broken Outlaw for you. ___ -S http://en.wikipedia.org/wiki/List_of_fictional_sheep Again, Steven....I'm ahead of you. That was one of the first things I did. They did not come right out and say it, but they did acknowledge that the input impedance was lower than normal and that some preamps with a rising high end impedance might affect frquency response. How about you reprint what Outlaw actually wrote? Because I talked to them on the phone. Hard to "reprint" a phone conversation. |
#19
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do all pre-amps sound the same?
"Harry Lavo" wrote in message
Don't forget the interface.....output impedances of preamps can vary widely with frequency response and vary greatly from model to model. Yes and no. There are two relevant specs, the output impedance of the preamp, and the range of impedances that the preamp is designed to drive. These are two different things. The output impedance of preamp exists mostly to predict the high frequency losses due to capacitive loading. To a lesser degree, it predicts over-all losses of gain due to resistive loading. The range of impedances that the preamp is designed to drive helps predict the low frequency response of the preamp, and its ability to deliver large signals. For example, consider a preamp that has an output impedance of 1000 ohms, but is designed to drive loads of 100,000 ohms or above. The 1000 ohm output impedance suggests that loads of as little as 10,000 ohms will be driven with something like a fairly minimal 1 dB loss, and that a wide range of cable capacitances can be driven with few high frequency losses. But 1000 ohms is not low enough for driving exceptionally long cables, such as 100 feet. 100 ohms would be better. The fact that the preamp is designed drive loads of 100,000 ohms or above suggests that a load with 10,000 ohm input impedance may cause significant low frequency losses, and that the preamp may be unable to deliver its full rated output. This makes matching up with the input impedances of power amps iffy in some cases. I have Onkyo preamps, for example, that work fine with most power amps but roll off noticeably when mated with Outlaw monoblocks. That would be surprising if the Onkyo are reasonably modern SS designs. I would expect that they would drive a 10,000 ohm load with full bandwidth down to 20 Hz and below. Yet the preamps rated output impedance (at 1000 ohms) is the standard "100 ohms" No, 1000 ohms is not 100 ohms. and the input impedance of the amps is the standard "10k ohms". Agreed. It is not unusual to find power amps with input impedances as low as 5,000 ohms, but not many below that. |
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