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Upgrading Op Amps?

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Anonymous
July 20, 2005 7:48:15 PM

Archived from groups: rec.audio.pro (More info?)

I have a Rolls RM203x mixer that recently took a power surge and lost
the left channel. Opening the box, I saw that it was full of BA4560 op
amps - 2 for the mic preamp, 1 for each of the 9 stereo channels, 2 for
the preamp output, and a couple other for things like the effects loop,
etc. I swapped some of the op amps and was able to get the left
channel working (though it then took out the channel from which I
swapped the op amp).

While searching online to buy some replacemet BA450s, I came across
people saying the NE5532s performed much better in various other
devices (mostly mic preamps) and that it was an easy swap.

Does anyone know if it truly is easy, ie. I can just put the new chips
in the DIP sockets? Should I do it for every BA450, or only in the
output stage? For the cheap cost of the NE5532s, I'm willing to
experiment.

Thanks for the advice!

Mark

More about : upgrading amps

July 20, 2005 8:29:26 PM

Archived from groups: rec.audio.pro (More info?)

MarkF786 wrote:
> I have a Rolls RM203x mixer that recently took a power surge and lost
> the left channel. Opening the box, I saw that it was full of BA4560 op
> amps - 2 for the mic preamp, 1 for each of the 9 stereo channels, 2 for
> the preamp output, and a couple other for things like the effects loop,
> etc. I swapped some of the op amps and was able to get the left
> channel working (though it then took out the channel from which I
> swapped the op amp).
>
> While searching online to buy some replacemet BA450s, I came across
> people saying the NE5532s performed much better in various other
> devices (mostly mic preamps) and that it was an easy swap.
>
> Does anyone know if it truly is easy, ie. I can just put the new chips
> in the DIP sockets? Should I do it for every BA450, or only in the
> output stage? For the cheap cost of the NE5532s, I'm willing to
> experiment.

Short answer, yes, they're pin-for-pin compatible, and one will often
'work' where the other was, *but*

the 5532 has protection diodes across the differential inputs, which
limits the input to ~0.6 V (before clip); fine for typical mic pre
stage use, but not for higher input voltage situations, i.e. a unity
gain inverter stage driving an active balanced line output.

It's safe to say no harm will come if you install them, but listen to
the board driven hard and see how it handles 'overload'...

FWIW other dual channel op amps that are also pin-for-pin, i.e. LF412,
MC33078, do not have the input voltage limitation. Heck a NJM2068 will
beat a 4560 on spec too (but how does it sound? ;-)

HTH,
-Robert
QTS
http://www.Braught.com
Anonymous
July 21, 2005 4:21:01 AM

Archived from groups: rec.audio.pro (More info?)

> Does anyone know if it truly is easy, ie. I can just put the new chips
> in the DIP sockets? Should I do it for every BA450, or only in the
> output stage? For the cheap cost of the NE5532s, I'm willing to
> experiment.

A _long_ time ago I had a mixer that used 741 op-amps. These were
swapped out for LF351 op-amps (which I had handy) and the improvement
was remarkable. As long as your pin-outs are the same and the voltages
are in spec' I can't see any reason not to make the change if you happen to
have something lying about, or within easy access and price.

Rv!
Related resources
Anonymous
July 21, 2005 7:08:53 AM

Archived from groups: rec.audio.pro (More info?)

On Thu, 21 Jul 2005 12:28:15 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

> Under ALL normal (ie non distorting ) operating conditions, the two
>inputs of an op-amp are at the SAME voltage ( +/- a few mV/ at very most )
>
>An op-amp useds as a unity gain inverter has BOTH inputs at virtual ground
>all the time !!

Perzactly. And we should demand non-overload conditions these
days, or not use op-amps.


>> It's safe to say no harm will come if you install them, but listen to
>> the board driven hard and see how it handles 'overload'...

Some applications, without input bandwidth limiting, like
mic preamps, phono equalizers, D/A I/V summing junctions,
and the like, are significantly defined by their ability
to deal with out-of-band overload signals.


>> FWIW other dual channel op amps that are also pin-for-pin, i.e. LF412,
>> MC33078, do not have the input voltage limitation.

> ** There is no such input voltage limitation !!!!!

Right. In this framework, clipping is clipping. If one has
given one's soul into the hands of op-amps, one must pray to
the Gods of Slew-Rate. Blessed be the survivors' next of
kin...

Thanks,

Chris Hornbeck
"All engineers are Scots, and all Scots are engineers."
-Scotty
July 21, 2005 8:34:42 AM

Archived from groups: rec.audio.pro (More info?)

Chris Hornbeck wrote:
> On Thu, 21 Jul 2005 12:28:15 +1000, "Phil Allison"
> <philallison@tpg.com.au> wrote:
>
> > Under ALL normal (ie non distorting ) operating conditions, the two
> >inputs of an op-amp are at the SAME voltage ( +/- a few mV/ at very most )
> >
> >An op-amp useds as a unity gain inverter has BOTH inputs at virtual ground
> >all the time !!
>
> Perzactly. And we should demand non-overload conditions these
> days, or not use op-amps.
>
>
> >> It's safe to say no harm will come if you install them, but listen to
> >> the board driven hard and see how it handles 'overload'...
>
> Some applications, without input bandwidth limiting, like
> mic preamps, phono equalizers, D/A I/V summing junctions,
> and the like, are significantly defined by their ability
> to deal with out-of-band overload signals.
>
>
> >> FWIW other dual channel op amps that are also pin-for-pin, i.e. LF412,
> >> MC33078, do not have the input voltage limitation.
>
> > ** There is no such input voltage limitation !!!!!
>
> Right. In this framework, clipping is clipping. If one has
> given one's soul into the hands of op-amps, one must pray to
> the Gods of Slew-Rate. Blessed be the survivors' next of
> kin...
>
> Thanks,
>
> Chris Hornbeck
> "All engineers are Scots, and all Scots are engineers."
> -Scotty

Thanks Chris, my bad; the differential input voltage limitation I was
referring to (for 5532's) obviously wouldn't apply to a unity gain hook
up.

Cheers,
-Robert
'Glad to see Phil is still the same, kind old net entity he was on
AGA.'
Anonymous
July 21, 2005 10:50:30 AM

Archived from groups: rec.audio.pro (More info?)

In article <42dedc6d@nntp.onyx.net> Rv@no.way.invalid writes:

> A _long_ time ago I had a mixer that used 741 op-amps. These were
> swapped out for LF351 op-amps (which I had handy) and the improvement
> was remarkable. As long as your pin-outs are the same and the voltages
> are in spec' I can't see any reason not to make the change if you happen to
> have something lying about, or within easy access and price.

You have to be careful not to substitute op amps that are too good. I
tried replacing the 4558 op amps in my TASCAM Model 5 mixer with
something that had a wider bandwidth (can't remember what, maybe
LF353s) and it oscillated when I had the cables connected from the
insert outputs to my patchbay - the cable capacitance was enough to
set it off. I changed them to something else, maybe TL072s, and all
was well and stable, and a little better sounding than with the
original op amps.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
July 21, 2005 10:50:31 AM

Archived from groups: rec.audio.pro (More info?)

> You have to be careful not to substitute op amps that are too good. I
> tried replacing the 4558 op amps in my TASCAM Model 5 mixer with
> something that had a wider bandwidth (can't remember what, maybe
> LF353s) and it oscillated when I had the cables connected from the
> insert outputs to my patchbay - the cable capacitance was enough to
> set it off. I changed them to something else, maybe TL072s, and all
> was well and stable, and a little better sounding than with the
> original op amps.

If the amp allows for external compensation, this should be fixable. A
properly compensated op amp, whether the compensation is internal or
external, should not oscillate.
Anonymous
July 21, 2005 12:00:41 PM

Archived from groups: rec.audio.pro (More info?)

"William Sommerwerck" <williams@nwlink.com> wrote in message
news:11dv184953upl5a@corp.supernews.com


>> You have to be careful not to substitute op amps that are
too
>> good. I tried replacing the 4558 op amps in my TASCAM
Model 5
>> mixer with something that had a wider bandwidth (can't
>> remember what, maybe LF353s) and it oscillated when I had
the
>> cables connected from the insert outputs to my patchbay -
the
>> cable capacitance was enough to set it off. I changed
them to
>> something else, maybe TL072s, and all was well and
stable,
>> and a little better sounding than with the original op
amps.
>
> If the amp allows for external compensation, this should
be
> fixable. A properly compensated op amp, whether the
> compensation is internal or external, should not
oscillate.

The hidden agenda is the load on the op amp.

Every op amp has an inherent output impedance. Attach a big
enough capacitive load directly to the op amp and the
combination of the capacitance and the output impedance can
create another frequency response pole that may destabilize
the op amp. Faster op amps are often more susceptible to
this problem.

Some slower op amps, or other opamps with really beefy
output stages are very stable or even unconditionally stable
in this regard.

The usual solution is to put what is known as a building-out
resistor on the equipment's ouput. Usually a relatively
small resistor like 68 ohms is enough, though sometimes 120
or even 300 ohms may be required. Often, there's a wire
jumper from the circuit board to the output jack that can be
replaced with an appropriate resistor to bring this
situation under control.

IME, the LF353 dual FET op amp was especially susceptible to
becoming unstable with directly-connected capacitive loads.
If you paid attention to this situation, avoided some
applications, and added building-out resistors in other
cases, it worked pretty well.

The point is that its a myth that there are op amps that are
better in *every* regard, and that these superior parts can
be slathered all over the place willy-nilly, and that
superior sound quality will naturally result.

I've seen a modest number of op amps failed subtly in use.
Therefore replacing them vastly improved the sound quality
of the equipment they were in. I think we've found a few
cases where op-amps with marginal gain-bandwidth have been
used in high-gain applications to cut costs. Therefore,
frequency response in the audible band, at maximum gain
settings, might be improved with better op amps. OTOH, in
well-designed equipment, its hard to improve sound quality
with many of these so-called upgrades.

There is a well-known effect called the McGurk Effect where
visual evidence overcomes audible evidence for most people.
This is demonstrated quite effectively at
http://www.media.uio.no/personer/arntm/McGurk_english.h... .
I think a fair amount of audio equipment is McGurked. In
audio McGurking the changed visual appearance of the
equipment overcomes the audible evidence that there was
really no change.
Anonymous
July 21, 2005 2:33:50 PM

Archived from groups: rec.audio.pro (More info?)

William Sommerwerck <williams@nwlink.com> wrote:
>> You have to be careful not to substitute op amps that are too good. I
>> tried replacing the 4558 op amps in my TASCAM Model 5 mixer with
>> something that had a wider bandwidth (can't remember what, maybe
>> LF353s) and it oscillated when I had the cables connected from the
>> insert outputs to my patchbay - the cable capacitance was enough to
>> set it off. I changed them to something else, maybe TL072s, and all
>> was well and stable, and a little better sounding than with the
>> original op amps.
>
>If the amp allows for external compensation, this should be fixable. A
>properly compensated op amp, whether the compensation is internal or
>external, should not oscillate.

It should not.

But parasitics should also be low, PC board layouts should be careful to
minimize them, and grounds should all be solid and low impedance.

None of these things are the case in the Tascam Model 5. You'll find
these same things are major issues in a lot of gear from that era.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
July 21, 2005 8:27:48 PM

Archived from groups: rec.audio.pro (More info?)

> Every op amp has an inherent output impedance. Attach a big
> enough capacitive load directly to the op amp and the
> combination of the capacitance and the output impedance can
> create another frequency response pole that may destabilize
> the op amp. Faster op amps are often more susceptible to
> this problem.

National Semiconductor makes an op amp that takes this into account. I
believe that the amp's corner automatically moves down as the capactive load
increases. I forget the model number.

> I've seen a modest number of op amps failed subtly in use.
> Therefore replacing them vastly improved the sound quality
> of the equipment they were in. I think we've found a few
> cases where op-amps with marginal gain-bandwidth have been
> used in high-gain applications to cut costs. Therefore,
> frequency response in the audible band, at maximum gain
> settings, might be improved with better op amps. OTOH, in
> well-designed equipment, its hard to improve sound quality
> with many of these so-called upgrades.

But even high-quality op-amps aren't sonically perfect. I have no doubts
about my ability to hear the difference in a double-blind test.
Anonymous
July 21, 2005 10:25:09 PM

Archived from groups: rec.audio.pro (More info?)

In article <11dv184953upl5a@corp.supernews.com> williams@nwlink.com writes:

> If the amp allows for external compensation, this should be fixable.

Sure, nearly anything is fixable. I assumed he was looking for a
plug-in replacement. If the replacement allows for external
compensation and the original didn't (or it wasn't used) chances are
that even if the power, inputs, and output pinouts are the same on the
original and replacement devices, compensation capacitors will have to
be tacked on to the board without real traces or pads. Sure, it's done
all the time, but when someone asks what sounds to me like an innocent
question, I look for a simple answer first.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
July 22, 2005 2:43:06 AM

Archived from groups: rec.audio.pro (More info?)

"William Sommerwerck" <williams@nwlink.com> wrote in message
news:11e0btcr55lgpb1@corp.supernews.com

> But even high-quality op-amps aren't sonically perfect.

Sure they are. I've been thoroughly humiliated by trying to
distinguish music that went through upwards of 20 stages of
TL074, and that isn't even a particularly good op amp.

>I have no doubts about my ability to hear the difference
in a
> double-blind test.

I do, mostly because I tried long and hard.
Anonymous
July 22, 2005 8:49:43 AM

Archived from groups: rec.audio.pro (More info?)

>> But even high-quality op-amps aren't sonically perfect.

> Sure they are. I've been thoroughly humiliated by trying to
> distinguish music that went through upwards of 20 stages of
> TL074, and that isn't even a particularly good op amp.

>> I have no doubts about my ability to hear the difference
>> in a double-blind test.

> I do, mostly because I tried long and hard.


Let me be specific...

In sighted bypass tests, the difference I hear is a slight darkening and
"sweetening" of the sound. It's not huge, but it is audible, especially on
really good playback equipment. Both JC and JGH hear exactly the same thing,
though that isn't hard and fast proof, of course.

By the way, if you can ever get your hands on the Lexicon CP-1, their first
consumer surround processor, I'd like to know what results you get in blind
AB bypass test. I only note that due to complaints from me and other
reviewers about its sound quality, Lexicon redesigned the circuitry for the
CP-2.
July 22, 2005 11:01:04 AM

Archived from groups: rec.audio.pro (More info?)

>
> Let me be specific...
>
> In sighted bypass tests, the difference I hear is a slight darkening and
> "sweetening" of the sound. It's not huge, but it is audible, especially on
> really good playback equipment. Both JC and JGH hear exactly the same thing,
> though that isn't hard and fast proof, of course.
>
>
I find it amusing that you describe "a slight darkening and
sweetening of the sound" as "being specific".

Mark
Anonymous
July 22, 2005 12:44:06 PM

Archived from groups: rec.audio.pro (More info?)

>>I have no doubts about my ability to hear the difference
in a
>> double-blind test.


>I do, mostly because I tried long and hard.

Arny and I have argued this before, but I assure anyone who reads this
that I could easily hear the difference between the various high end
opamps I tested in my console several years ago when I had it modded. I
compared level matched stereo program material through pairs of
channels fitted with several different Burr-Brown amps to the stock
chips and the Linear Technologies video grade chips that had been
originally installed by Jim Williams (Audio Upgrades), who did the
mods. They were all distinctly different sounding, and one, the Burr
Brown 2604, had the best combination of warmth, soundstage depth and
clarity, and became my choice. My original posts on the testing should
still be in Google's NG archives.

Ted Spencer, NYC
www.tedspencerrecording.com
July 22, 2005 5:32:54 PM

Archived from groups: rec.audio.pro (More info?)

In article <F5GdnXYwYaanwH3fRVn-hA@comcast.com>, "Arny Krueger" <arnyk@hotpop.com> wrote:
>"William Sommerwerck" <williams@nwlink.com> wrote in message
>news:11e0btcr55lgpb1@corp.supernews.com
>
>> But even high-quality op-amps aren't sonically perfect.
>
>Sure they are. I've been thoroughly humiliated by trying to
>distinguish music that went through upwards of 20 stages of
>TL074, and that isn't even a particularly good op amp.
>
>>I have no doubts about my ability to hear the difference
>in a
>> double-blind test.
>
>I do, mostly because I tried long and hard.

Was that 20 stages of inverting or noninverting design??

greg
Anonymous
July 22, 2005 5:32:55 PM

Archived from groups: rec.audio.pro (More info?)

"GregS" <szekeres@pitt.edu> wrote in message
news:D bqsj4$h8k$1@usenet01.srv.cis.pitt.edu

> In article <F5GdnXYwYaanwH3fRVn-hA@comcast.com>, "Arny
> Krueger" <arnyk@hotpop.com> wrote:

>> "William Sommerwerck" <williams@nwlink.com> wrote in
message
>> news:11e0btcr55lgpb1@corp.supernews.com

>>> But even high-quality op-amps aren't sonically perfect.

>> Sure they are. I've been thoroughly humiliated by trying
to
>> distinguish music that went through upwards of 20 stages
of
>> TL074, and that isn't even a particularly good op amp.

>>> I have no doubts about my ability to hear the
difference in a
>>> double-blind test.

>> I do, mostly because I tried long and hard.

> Was that 20 stages of inverting or noninverting design??

Non-inverting, I think. If I recall right, the stage gain
was something like 10 dB. There were passive attenuators
between the stages to equalize the gain.

I think I know how to make TL074s have a characteristic
sound - jack up the stage gain, make 'em latch, drive a low
Z, etc.

Sorry but this was about 20 years ago. I am still living
more in the present than the past. ;-)
Anonymous
July 22, 2005 7:56:15 PM

Archived from groups: rec.audio.pro (More info?)

>> In sighted bypass tests, the difference I hear is a slight darkening and
>> "sweetening" of the sound. It's not huge, but it is audible, especially
on
>> really good playback equipment. Both JC and JGH hear exactly the
>> same thing, though that isn't hard and fast proof, of course.

> I find it amusing that you describe "a slight darkening and
> sweetening of the sound" as "being specific".

How much more specific do you want? Because that's what it sounds like. Am I
to spend 10 pages in excruciating detail, a la Stereophile?
Anonymous
July 22, 2005 7:58:00 PM

Archived from groups: rec.audio.pro (More info?)

> Arny and I have argued this before, but I assure anyone who reads this
> that I could easily hear the difference between the various high end
> opamps I tested in my console several years ago when I had it modded. I
> compared level matched stereo program material through pairs of
> channels fitted with several different Burr-Brown amps to the stock
> chips and the Linear Technologies video grade chips that had been
> originally installed by Jim Williams (Audio Upgrades), who did the
> mods. They were all distinctly different sounding, and one, the Burr
> Brown 2604, had the best combination of warmth, soundstage depth and
> clarity, and became my choice. My original posts on the testing should
> still be in Google's NG archives.

I am /not/ taking Arny's side, but I'm curious about the lengths of time you
listened, listening conditions, attempts at control, etc.
July 22, 2005 9:51:25 PM

Archived from groups: rec.audio.pro (More info?)

In article <1122047046.841600.28520@g14g2000cwa.googlegroups.com>, prestokid@aol.com wrote:
>>>I have no doubts about my ability to hear the difference
>in a
>>> double-blind test.
>
>
>>I do, mostly because I tried long and hard.
>
>Arny and I have argued this before, but I assure anyone who reads this
>that I could easily hear the difference between the various high end
>opamps I tested in my console several years ago when I had it modded. I
>compared level matched stereo program material through pairs of
>channels fitted with several different Burr-Brown amps to the stock
>chips and the Linear Technologies video grade chips that had been
>originally installed by Jim Williams (Audio Upgrades), who did the
>mods. They were all distinctly different sounding, and one, the Burr
>Brown 2604, had the best combination of warmth, soundstage depth and
>clarity, and became my choice. My original posts on the testing should
>still be in Google's NG archives.
>
>Ted Spencer, NYC
>www.tedspencerrecording.com

Do you come about these conclusions from listening in any
paticular time frame. I'm trying to find out more on how the listening
is done exactly. as far as time frame, length, etc.
From my own experiance, it usually takes some time to
really get a good listen, in fact when I fine tune speakers,
it sometimes takes me weeks to decide what to do.

greg
Anonymous
July 23, 2005 12:25:53 AM

Archived from groups: rec.audio.pro (More info?)

In article <dbrbnt$kvg$1@usenet01.srv.cis.pitt.edu> szekeres@pitt.edu writes:

> Do you come about these conclusions from listening in any
> paticular time frame. I'm trying to find out more on how the listening
> is done exactly. as far as time frame, length, etc.
> From my own experiance, it usually takes some time to
> really get a good listen, in fact when I fine tune speakers,
> it sometimes takes me weeks to decide what to do.

Take as much time as you need. It's your console to experiment with.
It probably doesn't take too much time if you do something that
doesn't work well. But it takes far too much time if you have two or
three things all that sound pretty pretty good, and are improvements
over what you started with, and then you try to decide which one is
best. That might change from day to day as the air changes, your
hearing changes, and you listen to different material.

At some point, you have to make a decision. I know how hard that is
for some people.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
July 23, 2005 3:23:08 AM

Archived from groups: rec.audio.pro (More info?)

On Fri, 22 Jul 2005 15:58:00 -0700, "William Sommerwerck"
<williams@nwlink.com> wrote:

>I am /not/ taking Arny's side, but I'm curious about the lengths of time you
>listened, listening conditions, attempts at control, etc.

If we ever got everybody in the newsgroup together at
one time and did a listening test with mutually
agreeable parameters, it'd be the end of the newsgroup.

The only remaining topics would be questions from
new folks or the permanent and entrenched BBQ/beer/politics/
religion/otherfunstuff.

Just kidding; we could obviously argue about the
testing conditions at the big shoot-out indefinitely.

Arf!, and Thanks, as always,

Chris Hornbeck
"Said 'Hey Baby, did you get that letter?
If you take me back, I'll treat you better.'
Nobody's business but my own,
But my own." -John Hurt
Anonymous
July 23, 2005 4:27:22 AM

Archived from groups: rec.audio.pro (More info?)

William Sommerwerck wrote:

> > You have to be careful not to substitute op amps that are too good. I
> > tried replacing the 4558 op amps in my TASCAM Model 5 mixer with
> > something that had a wider bandwidth (can't remember what, maybe
> > LF353s) and it oscillated when I had the cables connected from the
> > insert outputs to my patchbay - the cable capacitance was enough to
> > set it off. I changed them to something else, maybe TL072s, and all
> > was well and stable, and a little better sounding than with the
> > original op amps.
>
> If the amp allows for external compensation, this should be fixable. A
> properly compensated op amp, whether the compensation is internal or
> external, should not oscillate.

Dual and quad op-amps never have external compensation IME.

Graham
Anonymous
July 23, 2005 4:27:23 AM

Archived from groups: rec.audio.pro (More info?)

> Dual and quad op-amps never have external compensation IME.

No, not if you're going to cram them into 8- or 14-pin packages.
Anonymous
July 23, 2005 4:29:18 AM

Archived from groups: rec.audio.pro (More info?)

Mike Rivers wrote:

> In article <42dedc6d@nntp.onyx.net> Rv@no.way.invalid writes:
>
> > A _long_ time ago I had a mixer that used 741 op-amps. These were
> > swapped out for LF351 op-amps (which I had handy) and the improvement
> > was remarkable. As long as your pin-outs are the same and the voltages
> > are in spec' I can't see any reason not to make the change if you happen to
> > have something lying about, or within easy access and price.
>
> You have to be careful not to substitute op amps that are too good. I
> tried replacing the 4558 op amps in my TASCAM Model 5 mixer with
> something that had a wider bandwidth (can't remember what, maybe
> LF353s) and it oscillated when I had the cables connected from the
> insert outputs to my patchbay - the cable capacitance was enough to
> set it off. I changed them to something else, maybe TL072s, and all
> was well and stable, and a little better sounding than with the
> original op amps.

Bi-fet op-amps are relatively notorious for stability issues compared to bipolar
types. I don't think it's anything inherent to the technology just the specific
aprts that made it into volume production.

The TL07x series will oscillate quite happily too esp when connected as a voltage
follower.

Graham
Anonymous
July 23, 2005 4:32:13 AM

Archived from groups: rec.audio.pro (More info?)

"electron@grapevine.net" wrote:

> MarkF786 wrote:
> > I have a Rolls RM203x mixer that recently took a power surge and lost
> > the left channel. Opening the box, I saw that it was full of BA4560 op
> > amps - 2 for the mic preamp, 1 for each of the 9 stereo channels, 2 for
> > the preamp output, and a couple other for things like the effects loop,
> > etc. I swapped some of the op amps and was able to get the left
> > channel working (though it then took out the channel from which I
> > swapped the op amp).
> >
> > While searching online to buy some replacemet BA450s, I came across
> > people saying the NE5532s performed much better in various other
> > devices (mostly mic preamps) and that it was an easy swap.
> >
> > Does anyone know if it truly is easy, ie. I can just put the new chips
> > in the DIP sockets? Should I do it for every BA450, or only in the
> > output stage? For the cheap cost of the NE5532s, I'm willing to
> > experiment.
>
> Short answer, yes, they're pin-for-pin compatible, and one will often
> 'work' where the other was, *but*
>
> the 5532 has protection diodes across the differential inputs, which
> limits the input to ~0.6 V (before clip); fine for typical mic pre
> stage use, but not for higher input voltage situations, i.e. a unity
> gain inverter stage driving an active balanced line output.

Rubbish ! An op-amp in linear operation has no +input to -input differential
at all other than the offset voltage and output signal / Avol ( at the
frequency in question).

The 5532 does draw slightly more current han a 4560 though, so if the PSU
design is marginal you might have problems substituting them all.

Graham
Anonymous
July 23, 2005 4:35:51 AM

Archived from groups: rec.audio.pro (More info?)

prestokid@aol.com wrote:

> >>I have no doubts about my ability to hear the difference
> in a
> >> double-blind test.
>
> >I do, mostly because I tried long and hard.
>
> Arny and I have argued this before, but I assure anyone who reads this
> that I could easily hear the difference between the various high end
> opamps I tested in my console several years ago when I had it modded. I
> compared level matched stereo program material through pairs of
> channels fitted with several different Burr-Brown amps to the stock
> chips and the Linear Technologies video grade chips that had been
> originally installed by Jim Williams (Audio Upgrades), who did the
> mods. They were all distinctly different sounding, and one, the Burr
> Brown 2604, had the best combination of warmth, soundstage depth and
> clarity, and became my choice. My original posts on the testing should
> still be in Google's NG archives.

One thing for sure - you can certainly *measure* the difference.

Graham
Anonymous
July 23, 2005 4:47:59 AM

Archived from groups: rec.audio.pro (More info?)

On 21 Jul 2005 04:34:42 -0700, "electron@grapevine.net"
<electron@grapevine.net> wrote:

> the differential input voltage limitation I was
>referring to (for 5532's) obviously wouldn't apply to a unity gain hook
>up.

Maybe the more relevant consideration is the differential
input voltage as a complex mix of input signal slew rate
and the device's delay in passing the feedback signal
back around to the differential input.

>'Glad to see Phil is still the same, kind old net entity he was on
>AGA.'

We're all just our same old selves. None of us is immune;
none is "right". We're all working towards a truth that
exists beyond our lifetme; and possibly never.

Chris Hornbeck
"Said 'Hey Baby, did you get that letter?
If you take me back, I'll treat you better.'
Nobody's business but my own,
But my own." -John Hurt
Anonymous
July 23, 2005 6:25:53 AM

Archived from groups: rec.audio.pro (More info?)

William Sommerwerck wrote:

> > Dual and quad op-amps never have external compensation IME.
>
> No, not if you're going to cram them into 8- or 14-pin packages.

It's the 8 and 14 pin packages that make them so popular !

Graham
July 23, 2005 8:37:24 AM

Archived from groups: rec.audio.pro (More info?)

Pooh Bear wrote:
> "electron@grapevine.net" wrote:
>
> > MarkF786 wrote:
> > > I have a Rolls RM203x mixer that recently took a power surge and lost
> > > the left channel. Opening the box, I saw that it was full of BA4560 op
> > > amps - 2 for the mic preamp, 1 for each of the 9 stereo channels, 2 for
> > > the preamp output, and a couple other for things like the effects loop,
> > > etc. I swapped some of the op amps and was able to get the left
> > > channel working (though it then took out the channel from which I
> > > swapped the op amp).
> > >
> > > While searching online to buy some replacemet BA450s, I came across
> > > people saying the NE5532s performed much better in various other
> > > devices (mostly mic preamps) and that it was an easy swap.
> > >
> > > Does anyone know if it truly is easy, ie. I can just put the new chips
> > > in the DIP sockets? Should I do it for every BA450, or only in the
> > > output stage? For the cheap cost of the NE5532s, I'm willing to
> > > experiment.
> >
> > Short answer, yes, they're pin-for-pin compatible, and one will often
> > 'work' where the other was, *but*
> >
> > the 5532 has protection diodes across the differential inputs, which
> > limits the input to ~0.6 V (before clip); fine for typical mic pre
> > stage use, but not for higher input voltage situations, i.e. a unity
> > gain inverter stage driving an active balanced line output.
>
> Rubbish ! An op-amp in linear operation has no +input to -input differential
> at all other than the offset voltage and output signal / Avol ( at the
> frequency in question).
>
> The 5532 does draw slightly more current han a 4560 though, so if the PSU
> design is marginal you might have problems substituting them all.
>
> Graham

Right- sorry, you're late to the party, Phil A. already enjoyed himself
cussin' me to point that out in his special way (rather than state fact
and kindly correct my mis-information like you have.)

AFA the back to back diodes across the differential inputs of a 5532
causing trouble (in circuits that previously used an op amp that
doesn't have them), I'd like to apologize to the group for my error; a
gross assumption on my part, after seeing 5532's retrofited in various
pieces over the years (with poor results), and after looking at
internal (op amp) schematic diagrams, I've been walking around with
this 'assumptive mis-truth' for a long time!

-Robert
Anonymous
July 23, 2005 8:41:31 PM

Archived from groups: rec.audio.pro (More info?)

"electron@grapevine.net" wrote:

> Pooh Bear wrote:
> > "electron@grapevine.net" wrote:
> >
> > > MarkF786 wrote:
> > > > I have a Rolls RM203x mixer that recently took a power surge and lost
> > > > the left channel. Opening the box, I saw that it was full of BA4560 op
> > > > amps - 2 for the mic preamp, 1 for each of the 9 stereo channels, 2 for
> > > > the preamp output, and a couple other for things like the effects loop,
> > > > etc. I swapped some of the op amps and was able to get the left
> > > > channel working (though it then took out the channel from which I
> > > > swapped the op amp).
> > > >
> > > > While searching online to buy some replacemet BA450s, I came across
> > > > people saying the NE5532s performed much better in various other
> > > > devices (mostly mic preamps) and that it was an easy swap.
> > > >
> > > > Does anyone know if it truly is easy, ie. I can just put the new chips
> > > > in the DIP sockets? Should I do it for every BA450, or only in the
> > > > output stage? For the cheap cost of the NE5532s, I'm willing to
> > > > experiment.
> > >
> > > Short answer, yes, they're pin-for-pin compatible, and one will often
> > > 'work' where the other was, *but*
> > >
> > > the 5532 has protection diodes across the differential inputs, which
> > > limits the input to ~0.6 V (before clip); fine for typical mic pre
> > > stage use, but not for higher input voltage situations, i.e. a unity
> > > gain inverter stage driving an active balanced line output.
> >
> > Rubbish ! An op-amp in linear operation has no +input to -input differential
> > at all other than the offset voltage and output signal / Avol ( at the
> > frequency in question).
> >
> > The 5532 does draw slightly more current han a 4560 though, so if the PSU
> > design is marginal you might have problems substituting them all.
> >
> > Graham
>
> Right- sorry, you're late to the party, Phil A. already enjoyed himself
> cussin' me to point that out in his special way (rather than state fact
> and kindly correct my mis-information like you have.)
>
> AFA the back to back diodes across the differential inputs of a 5532
> causing trouble (in circuits that previously used an op amp that
> doesn't have them), I'd like to apologize to the group for my error; a
> gross assumption on my part, after seeing 5532's retrofited in various
> pieces over the years (with poor results), and after looking at
> internal (op amp) schematic diagrams, I've been walking around with
> this 'assumptive mis-truth' for a long time!

No problem. Well now you know !

The back to back diodes are there to prevent reverse bias damage to the input
transistors that would likely degrade the noise figure IIRC.

I'm curious about the unsatisfactory replacements you mention. Could you elaborate
?

Graham
Anonymous
July 23, 2005 11:56:35 PM

Archived from groups: rec.audio.pro (More info?)

Wow, thanks everyone for the replies. BTW, I received the NE5532s
today, put them in, and everything is working like a charm. Though I
was formerly an "audiophile" who believed in such gimmickry as painting
the edges of my CDs green, now a days I tend to be much more skeptical
about audio voodoo. With that said, I do think the new op amps sound
slightly cleaner (though it could be my imagintion), but certainly they
have higher output since I find myself lowering the volume less that
the standard levels I used before.

Now if I had some money to piss away, I'd buy 15 Brown Burr ops amps to
upgrade to ;-)

Who'd thought it'd be so easy ;-)

Mark
Anonymous
July 24, 2005 8:39:57 AM

Archived from groups: rec.audio.pro (More info?)

"MarkF786" <MarkF_786@yahoo.com> wrote in message
news:1122173795.854278.261630@g43g2000cwa.googlegroups.com
> Wow, thanks everyone for the replies. BTW, I received
> the NE5532s today, put them in, and everything is working
> like a charm. Though I was formerly an "audiophile" who
> believed in such gimmickry as painting the edges of my
> CDs green, now a days I tend to be much more skeptical
> about audio voodoo. With that said, I do think the new
> op amps sound slightly cleaner (though it could be my
> imagintion), but certainly they have higher output since
> I find myself lowering the volume less that the standard
> levels I used before.


The irony is that in modern audio circuits, the one change
that absolutely can't happen due to an op amp swap is a
change in level, given of course that the settings on the
console are the same. Reason why: circuit gain is all set by
inverse feedback loops, and changing the op amps doesn't
change the inverse feedback loops.

IOW if your main console output amp has 6.00 dB gain with a
LM301, it has no choice but to have 6.00 dB gain with a
5532. This is because the amp's gain is set by some
resistors controlling the feedback around the op amp, not
the op amp itself.
Anonymous
July 24, 2005 7:18:49 PM

Archived from groups: rec.audio.pro (More info?)

MarkF786 wrote:

> Wow, thanks everyone for the replies. BTW, I received the NE5532s
> today, put them in, and everything is working like a charm. Though I
> was formerly an "audiophile" who believed in such gimmickry as painting
> the edges of my CDs green, now a days I tend to be much more skeptical
> about audio voodoo. With that said, I do think the new op amps sound
> slightly cleaner (though it could be my imagintion), but certainly they
> have higher output since I find myself lowering the volume less that
> the standard levels I used before.

Now, I hate to disappoint you but the op-amp won't affect the volume level
! The signal levels are set by the circuit ( action of negative feedback )
and aren't influenced by your choice of device.

A classic case of 'user bias' perhaps ? I.e. hearing what you want to hear.



> Now if I had some money to piss away, I'd buy 15 Brown Burr ops amps to
> upgrade to ;-)

Now that's probably entirely unnecessary.

> Who'd thought it'd be so easy ;-)

Me ! ;-)

Graham
Anonymous
July 25, 2005 1:10:15 AM

Archived from groups: rec.audio.pro (More info?)

Arny Krueger wrote:

> "MarkF786" <MarkF_786@yahoo.com> wrote in message
> news:1122173795.854278.261630@g43g2000cwa.googlegroups.com
> > Wow, thanks everyone for the replies. BTW, I received
> > the NE5532s today, put them in, and everything is working
> > like a charm. Though I was formerly an "audiophile" who
> > believed in such gimmickry as painting the edges of my
> > CDs green, now a days I tend to be much more skeptical
> > about audio voodoo. With that said, I do think the new
> > op amps sound slightly cleaner (though it could be my
> > imagintion), but certainly they have higher output since
> > I find myself lowering the volume less that the standard
> > levels I used before.
>
> The irony is that in modern audio circuits, the one change
> that absolutely can't happen due to an op amp swap is a
> change in level, given of course that the settings on the
> console are the same. Reason why: circuit gain is all set by
> inverse feedback loops, and changing the op amps doesn't
> change the inverse feedback loops.
>
> IOW if your main console output amp has 6.00 dB gain with a
> LM301, it has no choice but to have 6.00 dB gain with a
> 5532. This is because the amp's gain is set by some
> resistors controlling the feedback around the op amp, not
> the op amp itself.

What's this 'inverse feedback' Arny ? I think you mean negative
feedback.

Seemingly my own reply to the previous post seems to have got lost in
the news server, so I'll post it again.

You're right about the gain of course.

Graham
Anonymous
July 25, 2005 1:11:47 AM

Archived from groups: rec.audio.pro (More info?)

MarkF786 wrote:

> Wow, thanks everyone for the replies. BTW, I received the NE5532s
> today, put them in, and everything is working like a charm. Though I
> was formerly an "audiophile" who believed in such gimmickry as painting
> the edges of my CDs green, now a days I tend to be much more skeptical
> about audio voodoo. With that said, I do think the new op amps sound
> slightly cleaner (though it could be my imagintion), but certainly they
> have higher output since I find myself lowering the volume less that
> the standard levels I used before.

Now, I hate to disappoint you but the op-amp won't affect the volume level
! The signal levels are set by the circuit ( action of negative feedback )
and aren't influenced by your choice of device.

A classic case of 'user bias' perhaps ? I.e. hearing what you want to hear.



> Now if I had some money to piss away, I'd buy 15 Brown Burr ops amps to
> upgrade to ;-)

Now that's probably entirely unnecessary.

> Who'd thought it'd be so easy ;-)

Me ! ;-)

Graham
Anonymous
September 25, 2005 3:19:11 AM

Archived from groups: rec.audio.pro (More info?)

Arny Krueger <arnyk@hotpop.com> wrote:

> There is a well-known effect called the McGurk Effect where
> visual evidence overcomes audible evidence for most people.
> This is demonstrated quite effectively at
> http://www.media.uio.no/personer/arntm/McGurk_english.h... .
> I think a fair amount of audio equipment is McGurked. In
> audio McGurking the changed visual appearance of the
> equipment overcomes the audible evidence that there was
> really no change.

I'm not sure a purely linguistic phenomenon has any bearing on the
question of economic and aesthetic visual cues, but I noticed something
interesting about the listening experience at this link that I thought
warranted resurrecting this months-old thread.

Watch the video at that link and listen. Just like they say, you think
you're hearing something you're not. When you close your eyes, you're
supposed to hear something different - you're supposed to hear what's
really being said. Except I didn't. Not at first, anyway. I listened
to it several times and still heard what I thought I heard with my eyes
open. I listened to it several more times and it gradually began to
change. Finally, after about 6 or 8 repeats, it sounded like it was
supposed to sound. Very interesting.

I thought this might shed some interesting light on the way we do
comparative listening. Exactly what it says, I'm not entirely sure.

ulysses
Anonymous
September 25, 2005 10:08:42 AM

Archived from groups: rec.audio.pro (More info?)

"Justin Ulysses Morse" <ulyssesnospam@rollmusic.com> wrote
in message
news:1127621952.c398b3efa4327809e9575bd76ab59fbc@teranews
> Arny Krueger <arnyk@hotpop.com> wrote:
>
>> There is a well-known effect called the McGurk Effect
>> where visual evidence overcomes audible evidence for
>> most people. This is demonstrated quite effectively at
>> http://www.media.uio.no/personer/arntm/McGurk_english.h...
>> . I think a fair amount of audio equipment is McGurked.
>> In audio McGurking the changed visual appearance of the
>> equipment overcomes the audible evidence that there was
>> really no change.
>
> I'm not sure a purely linguistic phenomenon has any
> bearing on the question of economic and aesthetic visual
> cues, but I noticed something interesting about the
> listening experience at this link that I thought
> warranted resurrecting this months-old thread.
>
> Watch the video at that link and listen. Just like they
> say, you think you're hearing something you're not. When
> you close your eyes, you're supposed to hear something
> different - you're supposed to hear what's really being
> said. Except I didn't. Not at first, anyway. I
> listened to it several times and still heard what I
> thought I heard with my eyes open. I listened to it
> several more times and it gradually began to change.
> Finally, after about 6 or 8 repeats, it sounded like it
> was supposed to sound. Very interesting.
>
> I thought this might shed some interesting light on the
> way we do comparative listening. Exactly what it says,
> I'm not entirely sure.

The usual explanation is that the McGurk effect is about
learned behavior, which extends to perceptions.

There does seem to be some natural variation in how the
demos of the McGurk effect is perceived.

I've had others report that they simply did not perceive the
effect at all.

It is known that people perceive speech with a mixture of
hearing and lip reading. IOW body language as compared to
spoken language The lip reading aspect of perception of
speech may be stronger among people who are somewhat
hearing-impaired.
Anonymous
September 25, 2005 4:48:59 PM

Archived from groups: rec.audio.pro (More info?)

That's why i think some sort of media needs to record the evidence so
minimize the " real time " distraction . Have someone else punch in , or
do
edits and then see if you can tell .

there was an interesting speaker cable shoot out some time ago , that looked
at the a/b/y blind test and found most people about 50% correct , no better
than guessing then going back to the stats found they were actually 80 %
correct
but only in the first couple of tries , after that falling back to the 50 %

Don't forget where there is money involved as well to influence ones choice


"Justin Ulysses Morse" <ulyssesnospam@rollmusic.com> wrote in message
news:1127621952.c398b3efa4327809e9575bd76ab59fbc@teranews...
> Arny Krueger <arnyk@hotpop.com> wrote:
>
> > There is a well-known effect called the McGurk Effect where
> > visual evidence overcomes audible evidence for most people.
> > This is demonstrated quite effectively at
> > http://www.media.uio.no/personer/arntm/McGurk_english.h... .
> > I think a fair amount of audio equipment is McGurked. In
> > audio McGurking the changed visual appearance of the
> > equipment overcomes the audible evidence that there was
> > really no change.
>
> I'm not sure a purely linguistic phenomenon has any bearing on the
> question of economic and aesthetic visual cues, but I noticed something
> interesting about the listening experience at this link that I thought
> warranted resurrecting this months-old thread.
>
> Watch the video at that link and listen. Just like they say, you think
> you're hearing something you're not. When you close your eyes, you're
> supposed to hear something different - you're supposed to hear what's
> really being said. Except I didn't. Not at first, anyway. I listened
> to it several times and still heard what I thought I heard with my eyes
> open. I listened to it several more times and it gradually began to
> change. Finally, after about 6 or 8 repeats, it sounded like it was
> supposed to sound. Very interesting.
>
> I thought this might shed some interesting light on the way we do
> comparative listening. Exactly what it says, I'm not entirely sure.
>
> ulysses
Anonymous
September 25, 2005 4:49:00 PM

Archived from groups: rec.audio.pro (More info?)

"GKB" <gboboski@shaw.ca> wrote in message
news:%0xZe.548866$5V4.344081@pd7tw3no
> That's why i think some sort of media needs to record the
> evidence so minimize the " real time " distraction .
> Have someone else punch in , or do
> edits and then see if you can tell .
>
> there was an interesting speaker cable shoot out some
> time ago , that looked at the a/b/y blind test and found
> most people about 50% correct , no better than guessing
> then going back to the stats found they were actually 80
> % correct
> but only in the first couple of tries , after that
> falling back to the 50 %
>
> Don't forget where there is money involved as well to
> influence ones choice

In the case of digital recording mixed analog or digital,
it's all a slam dunk.

Just edit up two digital recordings made by different means,
so that they have identical digital format, level, start and
stop times.

Compare them with one of the pieces of audio file comparison
software you can find at www.pcabx.com or via the Hydrogen
Audio forums. You don't need anybody else to help you.

If you're even semi-competent with a DAW, you can have your
answer later on today. ;-)
!