In article ,
Arny Krueger wrote:
Isn't 600 ohms the standard source impedance for audio production?

Not for a long time - unless possibly using a balancing transformer,
which is rare these days.

Electronically balanced outputs are more likely 50 ohms.

Of course if you were driving into several miles of twisted pair, 600
ohms in and out still holds good.

--
*He who laughs last, thinks slowest.

Dave Plowman London SW
To e-mail, change noise into sound.

"Nick Gorham" wrote in message
...
Keith G wrote:


All well and good Trevor, but like Andy says: 'why'...???

Don't see the point of buying a perfectly adequate budget player in the
first place and then spending *more* money on it.....???


No, I just don't see the sense in that at all, if it makes it perform
better then why not spend more money on it?


OK, how about 'If you wanted something that sounded *better*, why buy it in
the first place?' then...??? :-)



I think even the most sceptical here would agree that cheap electrolytic
caps leave a lot to be desired, and replacing them in the output stage
with caps that have measurably better performance.


Only if the cheap caps are poor quality and don't do the job properly. I'm
not sure that, even building down to a budget, Pioneer would actually use
*crappy* caps....???


Using that logic Keith, do you want to swap the cerafine in your amp for a
standard RS cap? I will even offer you a tenner for your trouble swaping
it over.


A *whole* tenner? (To myself? - I wouldn't have to share it with anybody?
:-)

Of course the question is would a 'standard' cap really make any
difference??



I have heard a standard 575 and one with the sort of mods Trevor has
mentioned and I would suggest its £40 well spent.


Well, OK. AFAIAC the jury's out on 'audiophile upgrades' - I've not been in
a position to make comparisons myself so I just don't know. If you say those
mods made a positive difference then that's good enough for me. Whether I
could tell myself though, I've no idea...

I suppose it comes down to the money - if you *can* make one sound 'better'
for that little money I guess it would be worth the effort and expense. My
argument is that they sound plenty good enough to me straight out of the
box. Asitappens, I don't use mine (ours) for music anyway- we use it to
watch movies and it's excellent!! The sound is brilliant, picture quality is
superb (again, 'plenty good enough') and it does well with 'iffy' discs!!

What more could you want for so little money (in real terms)...???

"Trevor Wilson" wrote in message
...

"andy" wrote in message
oups.com...
As yet another owner of a Pioneer DV-575A I am curious about what the
above modifications will achieve and why?

**Output muting, via the use of BJTs has always been a sonic disaster,
IME. A relay contributes no distortion, whilst in the O/C mode.

A BJT contributes no significant distortion when switched off.

The output
IC used, whilst adequate, is hardly state of the art.

You don't need state of the art ICs for a signal with a guaranteed max
output of a couple of volts, and a guaranteed max bandwidth of 22kHz.
The Pioneer of course has better opamps than this, as it can happily
cope with 100kHz bandwidth for 24/192 - at 0.002% THD - and over six
channels, so plain old CD audio isn't going to be a problem.

Output ICs in 1983
(ie: First generation) CD players were superior.

Utter nonsense!

In Philips derived
machines, that usually meant an NE5532/5534 chip. A fine chip, back then
and still a fine chip today.

Indeed so, as are the perfectly adequate modern chips inside the
Pioneer, which have gain-bandwidth and distortion levels that a 5534
can only dream of!

There are two, 220 Ohm resistors in series
with each O/P IC. These should be shorted (after replacing the ICs with a
more suitable device, of course). A 440 Ohm output impedance is pitifully
high.

No higher than that of many well-regarded ultra-expensive passive
'preamps', and not a problem in most systems anyway. At worst, you
might get a treble rolloff as low as 100kHz in a system with long,
high-capacitance cabling. Hardly a disaster.........................

Additionally, it would be nice to organise a spilt rail power
supply, for the output IC. At present, it is powered by a single rail
supply, thus a large electrolytic coupling cap is required.

So what? Can you hear the difference?

I suggest anyone who is interested, to compare the 575A to a decent,
contemporary CD (only) player, such as a Rotel RCD951 and report on any
differences.

I already compared it to an *excellent* modern CD player, arguably the
very best, and found no audible differences.

Patrick, you're advocating expensive 'audiophile' tweaks of no proven
*audible* worth for a low-cost universal player. That is just plain
*bad* engineering - you should be ashamed of yourself! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Wed, 30 Mar 2005 12:35:02 +0100, Rob
wrote:

All looks quite bizarre to me ... but ... for anyone interested HFW (Jan
2005, pp.34-7) has some details: change output capacitors to Black Gate
- "really helped the Pioneer achieve its true potential"; overblown bass
"tamed"; high frequency "astounding"; "life-like ... sound blossomed"
etc. - you get the picture.

Indeed we do - more 'audiophile' tweaks with no actual *evidence* that
they make any audible difference whatever!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Wed, 30 Mar 2005 19:25:57 +1000, "Trevor Wilson"
wrote:


"Stewart Pinkerton" wrote in message
.. .
On Wed, 30 Mar 2005 07:44:29 +1000, "Trevor Wilson"
wrote:

* Dump the muting transistors. Use nothing, or relays.
* Dump the output ICs and use something decent.
* Dump the series resistors after the output ICs.

Those actions will bring your Pie-in-ear up the level of a Rotel RCD951.

How about dumping your idiotic opinions? Indeed, how about actually
*listening*, instead of just banging on?

**No need. The output stage of the Pie-in-ear is the same as that used in a
thousand other cheap DVD players.

Yup, and it gives 100dB dynamic range and less than 0.002% distortion
in most of them...............

They all benefit from rudimentary mods.

Bull****, this is old-fashioned audiophile tweakery with no proven
*audible* improvement.

And, to answer your next question, I have done the obligatory blind tests.
The results were a very convincing 100%. Not subtle at all.

Not on a Pioneer 575, or any equivelent modern player, you haven't.

You're the kind of guy who thinks that a 'well-engineered' amplifier
is some 300-watt tubed monobloc monster. Oh, wait a minute....... :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Wed, 30 Mar 2005 17:04:40 +0000 (UTC), Stewart Pinkerton
wrote:

On Wed, 30 Mar 2005 19:25:57 +1000, "Trevor Wilson"
wrote:


"Stewart Pinkerton" wrote in message
. ..
On Wed, 30 Mar 2005 07:44:29 +1000, "Trevor Wilson"
wrote:

* Dump the muting transistors. Use nothing, or relays.
* Dump the output ICs and use something decent.
* Dump the series resistors after the output ICs.

Those actions will bring your Pie-in-ear up the level of a Rotel RCD951.

How about dumping your idiotic opinions? Indeed, how about actually
*listening*, instead of just banging on?

**No need. The output stage of the Pie-in-ear is the same as that used in a
thousand other cheap DVD players.

Yup, and it gives 100dB dynamic range and less than 0.002% distortion
in most of them...............

They all benefit from rudimentary mods.

Bull****, this is old-fashioned audiophile tweakery with no proven
*audible* improvement.

And, to answer your next question, I have done the obligatory blind tests.
The results were a very convincing 100%. Not subtle at all.

Not on a Pioneer 575, or any equivelent modern player, you haven't.

You're the kind of guy who thinks that a 'well-engineered' amplifier
is some 300-watt tubed monobloc monster. Oh, wait a minute....... :-)

Wait a minute indeed, that's Pat Turner. Oh well, one 'tweako freako'
weird Ozzie is much like another............. :-)

--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:

I already compared it to an *excellent* modern CD player, arguably the
very best, and found no audible differences.

So what's the difference between the Pioneer DV-575, DV-575A and
the DV-575A-S? Do they all play SACD and DVDA?

--
Eiron.

"Stewart Pinkerton" wrote in message
...
On Wed, 30 Mar 2005 19:25:57 +1000, "Trevor Wilson"
wrote:


"Stewart Pinkerton" wrote in message
. ..
On Wed, 30 Mar 2005 07:44:29 +1000, "Trevor Wilson"
wrote:

* Dump the muting transistors. Use nothing, or relays.
* Dump the output ICs and use something decent.
* Dump the series resistors after the output ICs.

Those actions will bring your Pie-in-ear up the level of a Rotel RCD951.

How about dumping your idiotic opinions? Indeed, how about actually
*listening*, instead of just banging on?

**No need. The output stage of the Pie-in-ear is the same as that used in
a
thousand other cheap DVD players.

Yup, and it gives 100dB dynamic range and less than 0.002% distortion
in most of them...............

They all benefit from rudimentary mods.

Bull****, this is old-fashioned audiophile tweakery with no proven
*audible* improvement.

**After you perform the mods, let me know.


And, to answer your next question, I have done the obligatory blind tests.
The results were a very convincing 100%. Not subtle at all.

Not on a Pioneer 575, or any equivelent modern player, you haven't.

**Yes, I have.


You're the kind of guy who thinks that a 'well-engineered' amplifier
is some 300-watt tubed monobloc monster. Oh, wait a minute....... :-)

**Nope. Not even close. I prefer my amps with the following specs (at a
minimum):

Frequency response - DC - 100kHz. +/- 0.1dB
THD - 0.05% 20Hz - 20kHz
IMD - 0.05%
Damping factor - 100 (20Hz - 20kHz)
Etc


--
Trevor Wilson
www.rageaudio.com.au

"Arny Krueger" wrote in message
...
"Trevor Wilson" wrote in message

"andy" wrote in message
oups.com...
As yet another owner of a Pioneer DV-575A I am curious about what
the
above modifications will achieve and why?

**Output muting, via the use of BJTs has always been a sonic
disaster, IME.

Musta never seen it done right.

**Perhaps.


A relay contributes no distortion,

As long as the contacts are good.

**Relays (and BJTs) when used in muting circuits, are usually shunt devices.


whilst in the O/C mode.

In which case there is no signal at all.

**See above. O/C, means the signals is not shunted to ground.


The output IC used, whilst adequate, is hardly state of the
art. Output ICs in 1983 (ie: First generation) CD players were
superior. In Philips derived machines, that usually meant an
NE5532/5534 chip. A fine chip, back then and still a fine chip
today.

Right, but just because it aint' a 5532 doesn't mean it sounds bad or
contributes any audible flaws at all.

**I never said otherwise. The 5534/5532 has other benefits. As do other,
more contemporary devices.


There are two, 220 Ohm resistors in series with each O/P IC. These
should be shorted (after replacing the ICs with a more suitable
device, of course).

Why? Aren't building-out resistors good practice?

**Artificialy raising output impedances simply makes no sense at all.


A 440 Ohm output impedance is pitifully high.

Isn't 600 ohms the standard source impedance for audio production?


**Nope. 10 Ohms would be closer to reality.


Additionally, it would be nice to organise a spilt rail power
supply,
for the output IC. At present, it is powered by a single rail
supply,
thus a large electrolytic coupling cap is required.

What's wrong with a well-biased electrolytic?

**In a properly engineered circuit, it is not necessary. No capacitor is
ALWAYS better than ANY capacitor. Ever wondered why amplifier manufacturers
began elminating them from their products back in the mid 1960s? Hint: It
was not a cost cutting exercise.


I suggest anyone who is interested, to compare the 575A to a decent,
contemporary CD (only) player, such as a Rotel RCD951 and report on
any differences.

I suggest that Trevor quit pontificating and do some bias-controlled
listening tests of his own.

**Done. In fact, I did so, earlier this week.


--
Trevor Wilson
www.rageaudio.com.au

On Wed, 30 Mar 2005 19:15:46 +0100, Eiron wrote:

Stewart Pinkerton wrote:

I already compared it to an *excellent* modern CD player, arguably the
very best, and found no audible differences.

So what's the difference between the Pioneer DV-575, DV-575A and
the DV-575A-S? Do they all play SACD and DVDA?

Colour, mostly, and yes.

--

Stewart Pinkerton | Music is Art - Audio is Engineering