Equaliser for Shure V15III
 

In article , Serge Auckland
wrote:

The cartridge is rather dull, not bright, and I know about the
recommended capacitative load, but that's not what I'm after. In the
mid '70s, somebody, and I think it was either Shure themselves, or
possibly SME, published a cartridge equaliser circuit which consisted
of one or two resistors and a capacitor, may have been two caps, and
which had the effect of lifting the lower treble suck-out, and the
extreme hf droop. It also had the effect of dropping the total output
by a couple of dB as I recall. It's that circuit I'm looking for and
sadly can't find.


My recollection is that Jim Sugden wrote a HFN article on that and gave the
circuit you have in mind. If I get a chance I'll have a look later today
and then report what I can find. I am pretty shure pun I have a copy of
the article. :-)

You can see the frequency response I'm getting
http://audiopages.googlepages.com/V1...full;init:.png

I would be quite wary of test LPs. I've been comparing some and the
responses they give are all over the place!

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Equaliser for Shure V15III
 

On 03 Oct, wrote:


My recollection is that Jim Sugden wrote a HFN article on that and gave
the circuit you have in mind. If I get a chance I'll have a look later
today and then report what I can find. I am pretty shure pun I have a
copy of the article. :-)

Found this quicker that I expected!

HFN April 1968 "Flatten your Head" by Jim Sugden.

The circuit he published uses a shunt of a 330pF and 3k3 in series.

He also used a *series* cap of 0.047microfarads to control the rise at LF,
but said this was optional. Also cautioned that some amps (e.g. his
Radford) didn't like this as the higher LF source impedance led to more
hum.

The above was for the V15/II, not III. I do recall that Shure did sell an
adaptor, but haven't found any details. I assume that most people - inc
myself - were quite happy with just a capacitance shunt with no extras.

FWIW He then reported +/-1dB from 30Hz to 16kHz, which doesn't seem to me
much different to a V15III and a plain cap shunt. However you may find that
fiddling slightly with the values will get flatter response. That said, we
may be in the territory where results will vary from one example to the
next! :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Equaliser for Shure V15III
 

In article , Don Pearce
wrote:


I did the simulation two years ago and the results are still he

http://81.174.169.10/odds/v15iii/cartridge.html

For some reason this page doesn't work well in IE (saved as HTML from
Mathcad), but use Firefox and it'll be fine. It shows how peaky the cart
gets with added capacitance. And of course a 3dB peak at 10kHz is going
to beat flat extension to 20kHz any day when it comes to sounding
bright.

I'd be interested to know how you did the simulation. In particular, if/how
you included the coupling between the mechanical resonance(s) and
electronic loading.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Equaliser for Shure V15III
 

Don Pearce wrote:

Phil Allison wrote:
"Don Pearce"
Woody wrote:

Shure cartridges were designed to work into a load of 47K resistance
(like all others) in parallel with something around 360pF capacitance.
The pickup arm cables and the interconnect to the amp would account for
about 120-150pF, which leaves the cartridge underloaded and thus rather
peaky and bright.

The way the impedances work out, you get more peakiness as the load goes
up, not down.


** Shure V15IIIs definitely sound brighter with less loading capacitance -
and or an increase in the load resistance above 47 kohms.


Adding an extra 200pF to the basic cartridge and wires will increase the
level at 10kHz by about 2.5dB.


** Don just plucked that figure out of his bum.

The real number is about 0.5dB at 8 to 10 kHz.

So barely audible.

What an extra 200pF * DOES * do is drop the response at 14 - 17 kHz by 3
or 4 dB - and THAT is what a person with good hearing notices as "
duller ".


This is all about the way the capacitance resonates with the inductance of
the cartridge.


** For anyone who cares to simulate the situation, a V15III has the
following :

L = 550 mH.

R = 1370 ohms

Fo = 42kHz ( equates to about 25 pF internal C )


I did the simulation two years ago and the results are still he

http://81.174.169.10/odds/v15iii/cartridge.html

For some reason this page doesn't work well in IE (saved as HTML from
Mathcad), but use Firefox and it'll be fine. It shows how peaky the cart
gets with added capacitance. And of course a 3dB peak at 10kHz is going
to beat flat extension to 20kHz any day when it comes to sounding bright.

And some nutcases think CD's crap !

Graham

Equaliser for Shure V15III
 

Jim Lesurf wrote:

On 03 Oct, wrote:

My recollection is that Jim Sugden wrote a HFN article on that and gave
the circuit you have in mind. If I get a chance I'll have a look later
today and then report what I can find. I am pretty shure pun I have a
copy of the article. :-)

Found this quicker that I expected!

HFN April 1968 "Flatten your Head" by Jim Sugden.

The circuit he published uses a shunt of a 330pF and 3k3 in series.

He also used a *series* cap of 0.047microfarads to control the rise at LF,
but said this was optional. Also cautioned that some amps (e.g. his
Radford) didn't like this as the higher LF source impedance led to more
hum.

The above was for the V15/II, not III. I do recall that Shure did sell an
adaptor, but haven't found any details. I assume that most people - inc
myself - were quite happy with just a capacitance shunt with no extras.

FWIW He then reported +/-1dB from 30Hz to 16kHz, which doesn't seem to me
much different to a V15III and a plain cap shunt. However you may find that
fiddling slightly with the values will get flatter response. That said, we
may be in the territory where results will vary from one example to the
next! :-)

What joy one no longer has to worry about such things.

I can still recall lining up the tape machines at Sound Developments. And of
course when a new batch of tape came in you had to be very careful.

Does EMI 815 sound familiar to anyone. It was their stock 'standard' tape there
IIRC. They had a couple of Studers and a fair few of Ampexes. I liked the
Ampexes, far more reliable. The MM1100 or was it 1200 ? impressed me
considerably.

Graham

Equaliser for Shure V15III
 

Eeyore wrote:

Don Pearce wrote:

Phil Allison wrote:
"Don Pearce"
Woody wrote:

Shure cartridges were designed to work into a load of 47K resistance
(like all others) in parallel with something around 360pF capacitance.
The pickup arm cables and the interconnect to the amp would account for
about 120-150pF, which leaves the cartridge underloaded and thus rather
peaky and bright.

The way the impedances work out, you get more peakiness as the load goes
up, not down.

** Shure V15IIIs definitely sound brighter with less loading capacitance -
and or an increase in the load resistance above 47 kohms.


Adding an extra 200pF to the basic cartridge and wires will increase the
level at 10kHz by about 2.5dB.

** Don just plucked that figure out of his bum.

The real number is about 0.5dB at 8 to 10 kHz.

So barely audible.

What an extra 200pF * DOES * do is drop the response at 14 - 17 kHz by 3
or 4 dB - and THAT is what a person with good hearing notices as "
duller ".


This is all about the way the capacitance resonates with the inductance of
the cartridge.

** For anyone who cares to simulate the situation, a V15III has the
following :

L = 550 mH.

R = 1370 ohms

Fo = 42kHz ( equates to about 25 pF internal C )

I did the simulation two years ago and the results are still he

http://81.174.169.10/odds/v15iii/cartridge.html

For some reason this page doesn't work well in IE (saved as HTML from
Mathcad), but use Firefox and it'll be fine. It shows how peaky the cart
gets with added capacitance. And of course a 3dB peak at 10kHz is going
to beat flat extension to 20kHz any day when it comes to sounding bright.

And some nutcases think CD's crap !


Yes, that's a bit harsh - I use the one in the car every so often, when
there's nothing on the radio. No point ruling them out altogether.

Rob

Equaliser for Shure V15III
 

"Don Pearce"
Phil Allison wrote:

The way the impedances work out, you get more peakiness as the load goes
up, not down.


** Shure V15IIIs definitely sound brighter with less loading
apacitance - and or an increase in the load resistance above 47 kohms.


Adding an extra 200pF to the basic cartridge and wires will increase the
level at 10kHz by about 2.5dB.


** Don just plucked that figure out of his bum.

The real number is about 0.5dB at 8 to 10 kHz.

So barely audible.

What an extra 200pF * DOES * do is drop the response at 14 - 17 kHz
by 3 or 4 dB - and THAT is what a person with good hearing notices as
" duller ".


This is all about the way the capacitance resonates with the inductance
of the cartridge.


** For anyone who cares to simulate the situation, a V15III has the
following :

L = 550 mH R = 1370 ohms Fo = 42kHz ( equates to about 25 pF
internal C )



I did the simulation two years ago and the results are still he

http://81.174.169.10/odds/v15iii/cartridge.html



** I tested using a ** REAL ** Shure V15III - owned one since 1978,
long out of use now.

No peak around 10kHz is created by adding 200 pF (or even 400pF ) to 150pF
with a 47kohms load.

Proves yet again the absolute folly of naive simualtions.

Fools like Jim Leserf and Don the drongo you are world champs at that fake
art.





...... Phil

Equaliser for Shure V15III
 

In article ,
Eeyore wrote:
Does EMI 815 sound familiar to anyone.

Yup. Best kept for tying up the roses. ;-)

It was their stock 'standard' tape there
IIRC. They had a couple of Studers and a fair few of Ampexes. I liked the
Ampexes, far more reliable. The MM1100 or was it 1200 ? impressed me
considerably.

Never had much to do with Ampex audio recorders but loved and hated Studer
in the same breath.

--
*Never kick a cow pat on a hot day *

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

Equaliser for Shure V15III
 

Jim Lesurf wrote:
In article , Don Pearce
wrote:


I did the simulation two years ago and the results are still he

http://81.174.169.10/odds/v15iii/cartridge.html

For some reason this page doesn't work well in IE (saved as HTML from
Mathcad), but use Firefox and it'll be fine. It shows how peaky the cart
gets with added capacitance. And of course a 3dB peak at 10kHz is going
to beat flat extension to 20kHz any day when it comes to sounding
bright.

I'd be interested to know how you did the simulation. In particular, if/how
you included the coupling between the mechanical resonance(s) and
electronic loading.

Slainte,

Jim


The maths you see is all of it. The intention wasn't to model how flat
the cartridge was, merely how its output changed in response to
differing capacitive loads.

d

Equaliser for Shure V15III
 

Phil Allison wrote:
"Don Pearce"
Phil Allison wrote:
The way the impedances work out, you get more peakiness as the load goes
up, not down.

** Shure V15IIIs definitely sound brighter with less loading
apacitance - and or an increase in the load resistance above 47 kohms.


Adding an extra 200pF to the basic cartridge and wires will increase the
level at 10kHz by about 2.5dB.

** Don just plucked that figure out of his bum.

The real number is about 0.5dB at 8 to 10 kHz.

So barely audible.

What an extra 200pF * DOES * do is drop the response at 14 - 17 kHz
by 3 or 4 dB - and THAT is what a person with good hearing notices as
" duller ".


This is all about the way the capacitance resonates with the inductance
of the cartridge.

** For anyone who cares to simulate the situation, a V15III has the
following :

L = 550 mH R = 1370 ohms Fo = 42kHz ( equates to about 25 pF
internal C )


I did the simulation two years ago and the results are still he

http://81.174.169.10/odds/v15iii/cartridge.html



** I tested using a ** REAL ** Shure V15III - owned one since 1978,
long out of use now.

No peak around 10kHz is created by adding 200 pF (or even 400pF ) to 150pF
with a 47kohms load.

Proves yet again the absolute folly of naive simualtions.

Fools like Jim Leserf and Don the drongo you are world champs at that fake
art.



You never made any such measurement. In fact you have never produced the
slightest shred of evidence that you have ever done anything in your life.

d