do all pre-amps sound the same?

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

Re: do all pre-amps sound the same?

"Steve" <goldstarsteve@gmail,com > wrote in message
news:fso76701j74@news3.newsguy,com ...
> 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

Re: do all pre-amps sound the same?

On Sun, 30 Mar 2008 14:43:09 -0700, Serge Auckland wrote
(in article <fsp1hd02u4a@news3.newsguy,com >):

> "Steve" <goldstarsteve@gmail,com > wrote in message
> news:fso76701j74@news3.newsguy,com ...
>> 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.

Re: 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?

Re: do all pre-amps sound the same?

"Serge Auckland" <sergeauckland@btinternet,com > wrote in message
news:fsp1hd02u4a@news3.newsguy,com ...

>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".

Re: do all pre-amps sound the same?

"Harry Lavo" <hlavo@comcast,net > wrote in message
news:fsroub01t7k@news1.newsguy,com

> 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.

Re: do all pre-amps sound the same?

On Mar 30, 10:13 am, Steve <goldstarst...@gmail,com > 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

Re: do all pre-amps sound the same?

"Serge Auckland" <sergeauckland@btinternet,com > wrote in message
news:fsuj6801lg7@news5.newsguy,com ...
> "Harry Lavo" <hlavo@comcast,net > wrote in message
> news:fsroub01t7k@news1.newsguy,com ...
>> "Serge Auckland" <sergeauckland@btinternet,com > wrote in message
>> news:fsp1hd02u4a@news3.newsguy,com ...
>>
>>>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.

Re: do all pre-amps sound the same?

Harry Lavo <hlavo@comcast,net > wrote:
> "Serge Auckland" <sergeauckland@btinternet,com > wrote in message
> news:fsuj6801lg7@news5.newsguy,com ...
> > "Harry Lavo" <hlavo@comcast,net > wrote in message
> > news:fsroub01t7k@news1.newsguy,com ...
> >> "Serge Auckland" <sergeauckland@btinternet,com > wrote in message
> >> news:fsp1hd02u4a@news3.newsguy,com ...
> >>
> >>>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

Re: do all pre-amps sound the same?

"Steven Sullivan" <ssully@panix,com > wrote in message
news:ft11o30311@news3.newsguy,com ...
> Harry Lavo <hlavo@comcast,net > wrote:
>> "Serge Auckland" <sergeauckland@btinternet,com > wrote in message
>> news:fsuj6801lg7@news5.newsguy,com ...
>> > "Harry Lavo" <hlavo@comcast,net > wrote in message
>> > news:fsroub01t7k@news1.newsguy,com ...
>> >> "Serge Auckland" <sergeauckland@btinternet,com > wrote in message
>> >> news:fsp1hd02u4a@news3.newsguy,com ...
>> >>
>> >>>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.

Re: do all pre-amps sound the same?

Harry Lavo <hlavo@comcast,net > wrote:
> "Steven Sullivan" <ssully@panix,com > 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

Re: do all pre-amps sound the same?

"Steven Sullivan" <ssully@panix,com > wrote in message
news:ft3ke309su@news1.newsguy,com ...
> Harry Lavo <hlavo@comcast,net > wrote:
>> "Steven Sullivan" <ssully@panix,com > 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.

Re: do all pre-amps sound the same?

Harry Lavo <hlavo@comcast,net > wrote:
> "Steven Sullivan" <ssully@panix,com > wrote in message
> news:ft3ke309su@news1.newsguy,com ...
> > Harry Lavo <hlavo@comcast,net > wrote:
> >> "Steven Sullivan" <ssully@panix,com > 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?

Re: do all pre-amps sound the same?

"Steven Sullivan" <ssully@panix,com > wrote in message
news:ft7vkj01h0s@news5.newsguy,com ...
> Harry Lavo <hlavo@comcast,net > wrote:
>> "Steven Sullivan" <ssully@panix,com > wrote in message
>> news:ft3ke309su@news1.newsguy,com ...
>> > Harry Lavo <hlavo@comcast,net > wrote:
>> >> "Steven Sullivan" <ssully@panix,com > 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.

Re: do all pre-amps sound the same?

"Harry Lavo" <hlavo@comcast,net > wrote in message
news:ft14dv057r@news3.newsguy,com ...
> "Steven Sullivan" <ssully@panix,com > wrote in message
> news:ft11o30311@news3.newsguy,com ...
>> Harry Lavo <hlavo@comcast,net > wrote:
>>> "Serge Auckland" <sergeauckland@btinternet,com > wrote in message
>>> news:fsuj6801lg7@news5.newsguy,com ...
>>> > "Harry Lavo" <hlavo@comcast,net > wrote in message
>>> > news:fsroub01t7k@news1.newsguy,com ...
>>> >> "Serge Auckland" <sergeauckland@btinternet,com > wrote in message
>>> >> news:fsp1hd02u4a@news3.newsguy,com ...
>>> >>
>>> >>>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