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Derwin Derwin is offline
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Default is it worth it to replace caps in old equalizer??


Hello, I have an old 70s-era 5-band equalizer made by Realistic (radio shack),
which I like to use in my guitar effects chain, and I opened it up the other
day just to see what it looked like inside, and I noticed that there are two
large electrolytic capacitors. They look fine, and the unit sounds OK, but
given that it is probably at least 30 years old now, and may have sat around
for many years not being used before I got my hands on it, could I expect
improved performance if I were to replace those two big electrolytics with new
ones?

Thanks for any advice!

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Arfa Daily Arfa Daily is offline
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Default is it worth it to replace caps in old equalizer??


"Derwin" wrote in message
news:yl6Nh.5912$6z3.687@edtnps82...

Hello, I have an old 70s-era 5-band equalizer made by Realistic (radio
shack),
which I like to use in my guitar effects chain, and I opened it up the
other
day just to see what it looked like inside, and I noticed that there are
two
large electrolytic capacitors. They look fine, and the unit sounds OK,
but
given that it is probably at least 30 years old now, and may have sat
around
for many years not being used before I got my hands on it, could I expect
improved performance if I were to replace those two big electrolytics with
new
ones?

Thanks for any advice!

Probably not. If it sounds OK with no signs of hum, then it's likely that
the caps are still working up to spec. If you have access to an ESR meter,
you could check them, or if not a meter, you could look at the ripple across
them with a scope. I'm a great advocate of " if it ain't broke, don't fix it
" - a philosophy that has served me well for 35 years in the business.
Shotgun replacement of components, or replacing just for the " might be "
hell of it, often results in problems that weren't there in the first place,
in my experience. If they are really easy to get at, and you can get
replacements with similar or better specs, and are determined to put your
stamp on it, as it were, then go ahead and replace them. It won't do any
harm.

Arfa


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William Sommerwerck William Sommerwerck is offline
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Default is it worth it to replace caps in old equalizer??

It's not uncommon for electrolytic caps to last 40 years or longer. I have
KLH table radios that are 45 years old, and still work with their original
electrolytics.

Electrolytic caps are odd -- they aren't anywhere nearly as unreliable as
you'd expect them to be.


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[email protected] meow2222@care2.com is offline
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Default is it worth it to replace caps in old equalizer??

On 24 Mar, 09:39, (Derwin) wrote:

Hello, I have an old 70s-era 5-band equalizer made by Realistic (radio shack),
which I like to use in my guitar effects chain, and I opened it up the other
day just to see what it looked like inside, and I noticed that there are two
large electrolytic capacitors. They look fine, and the unit sounds OK, but
given that it is probably at least 30 years old now, and may have sat around
for many years not being used before I got my hands on it, could I expect
improved performance if I were to replace those two big electrolytics with new
ones?

Thanks for any advice!


No. If youre considering doing jobs that dont need doing it may be
time to reevaluate ones life.


NT



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Jack[_2_] Jack[_2_] is offline
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Default is it worth it to replace caps in old equalizer??

wrote:
On 24 Mar, 09:39, (Derwin) wrote:

Hello, I have an old 70s-era 5-band equalizer made by Realistic (radio shack),
which I like to use in my guitar effects chain, and I opened it up the other
day just to see what it looked like inside, and I noticed that there are two
large electrolytic capacitors. They look fine, and the unit sounds OK, but
given that it is probably at least 30 years old now, and may have sat around
for many years not being used before I got my hands on it, could I expect
improved performance if I were to replace those two big electrolytics with new
ones?

Thanks for any advice!


No. If youre considering doing jobs that dont need doing it may be
time to reevaluate ones life.


NT

Don't replace them till they need it. The old high voltage ones can
last a long time, but if you've got a few spare minutes, some spare
dollars, do it by all means.
Dont worry about re evaluating your life. Life is full of cynics. You
do right, its wrong you do wrong its still right etc . Its how you
feel its your life......
PS Fixing things that dont need fixing is not good, only if youre
there. Priority says fix things that you need that need fixing, or as
a preventative.
Most likely you'll drop the equipment of a truck first...or similar.
Lifes like that....
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Scott Dorsey Scott Dorsey is offline
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Default is it worth it to replace caps in old equalizer??

In article yl6Nh.5912$6z3.687@edtnps82, Derwin wrote:

Hello, I have an old 70s-era 5-band equalizer made by Realistic (radio shack),
which I like to use in my guitar effects chain, and I opened it up the other
day just to see what it looked like inside, and I noticed that there are two
large electrolytic capacitors. They look fine, and the unit sounds OK, but
given that it is probably at least 30 years old now, and may have sat around
for many years not being used before I got my hands on it, could I expect
improved performance if I were to replace those two big electrolytics with new
ones?


Probably not, since all the electrolytic coupling caps in there are bad too.
And even if you do, you're stuck with 1970s Radio-Shack grade op-amp design.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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[email protected] ZZactly@aol.com is offline
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Default is it worth it to replace caps in old equalizer??

I am an expert on audio, certain areas, and this is one of them.

I totally agree with those who say if it ain't broke don't fix it,
but, some things are built broke.

To get the best quality integrated audio, which is the type of signal
for which this EQ was designed, they chose the wrong frequncies.

Now replacing the power supply filters is probably useless because of
the low current drain of the unit, there is simply almost no ripple
current to "wear out" the capacitor. However there are other things
one can do.

I have modified a couple of these, but then that was for integrated
program material, if you use it on a guitar you might want to go a
different direction. I don't remember the component values, but once
you understand how it works you can do things, many things.

A buddy of mine had his speakers in the corners, which made them very
boomy. They have bass, but it is ****ty.

At the wiper of the 60Hz control there is a cap, a coil and a
resistor. What I did was to take and change that control to about 35Hz
and made it shelving, that is to extend the control's range all the
way down, instead of that peaked response it originally had. I did
this by taking the resistor value down to less than ½ the original and
installing a capacitor about ten times the capacity of the original.

The 250Hz control was lowered to about 100Hz by cutting the resistor's
value in about ½ and installing a capacitor about three times the
original value.

The 1 Khz control was left alone. The 3.5 Khz control had it's range
extended slightly downward by increasing the value of it's capacitor.

Finally the 10 Khz control was modified to be shelving, and it's range
shifted upward. This brings out the timbre, rather than the tinny
treble. This was accomplished by actually lowering the capacitor value
as well as the resistor value, and shunting the coil with a low value
resistor, about ¼ the resistance of the new resistance value in the
tuned circuit for that band.

Actually if you know how to futz with it, you could have a nice setup.
run the channels in tandem but change some of the frequencies. Lower
the low ones on the left and raise the high ones on the right. And if
you tandem the channels you also can use a Y adapter to pick off the
signal for another amp, between stages.

Tell you what, if you get a chance to play a guitar on two amps at
once, enjoy. Set one clean and one fuzzed out. With a little adjusting
and practice you can make it sound like you are playing two guitars.

JURB

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Eeyore Eeyore is offline
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Default is it worth it to replace caps in old equalizer??



Derwin wrote:

Hello, I have an old 70s-era 5-band equalizer made by Realistic (radio shack),
which I like to use in my guitar effects chain, and I opened it up the other
day just to see what it looked like inside, and I noticed that there are two
large electrolytic capacitors. They look fine, and the unit sounds OK, but
given that it is probably at least 30 years old now, and may have sat around
for many years not being used before I got my hands on it, could I expect
improved performance if I were to replace those two big electrolytics with new
ones?


As suggested elsewhere, the PSU caps seem to be ok. You might want to consider
replalcing any electrolytics in the signal path though.

Graham



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Eeyore Eeyore is offline
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Default is it worth it to replace caps in old equalizer??



Jack wrote:

Most likely you'll drop the equipment of a truck first...or similar.


*After* replacing the caps !


Lifes like that....


Yes.

Graham


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Default is it worth it to replace caps in old equalizer??

On 24 Mar, 17:19, wrote:
I am an expert on audio, certain areas, and this is one of them.

I totally agree with those who say if it ain't broke don't fix it,
but, some things are built broke.

To get the best quality integrated audio, which is the type of signal
for which this EQ was designed, they chose the wrong frequncies.

Now replacing the power supply filters is probably useless because of
the low current drain of the unit, there is simply almost no ripple
current to "wear out" the capacitor. However there are other things
one can do.

I have modified a couple of these, but then that was for integrated
program material, if you use it on a guitar you might want to go a
different direction. I don't remember the component values, but once
you understand how it works you can do things, many things.

A buddy of mine had his speakers in the corners, which made them very
boomy. They have bass, but it is ****ty.

At the wiper of the 60Hz control there is a cap, a coil and a
resistor. What I did was to take and change that control to about 35Hz
and made it shelving, that is to extend the control's range all the
way down, instead of that peaked response it originally had. I did
this by taking the resistor value down to less than ½ the original and
installing a capacitor about ten times the capacity of the original.

The 250Hz control was lowered to about 100Hz by cutting the resistor's
value in about ½ and installing a capacitor about three times the
original value.

The 1 Khz control was left alone. The 3.5 Khz control had it's range
extended slightly downward by increasing the value of it's capacitor.

Finally the 10 Khz control was modified to be shelving, and it's range
shifted upward. This brings out the timbre, rather than the tinny
treble. This was accomplished by actually lowering the capacitor value
as well as the resistor value, and shunting the coil with a low value
resistor, about ¼ the resistance of the new resistance value in the
tuned circuit for that band.

Actually if you know how to futz with it, you could have a nice setup.
run the channels in tandem but change some of the frequencies. Lower
the low ones on the left and raise the high ones on the right. And if
you tandem the channels you also can use a Y adapter to pick off the
signal for another amp, between stages.

Tell you what, if you get a chance to play a guitar on two amps at
once, enjoy. Set one clean and one fuzzed out. With a little adjusting
and practice you can make it sound like you are playing two guitars.

JURB


If youre going to muck with it then start with a 10 band or more,
pointless to play with something as very limited as a 5 band.

If you wanted to adapt it for guitar use only, I'd make each side
different freqs and you can feed the signal thru both sides to get a
10 bander. And refrequency the 1kHz slider, which is the least useful
of them all.

But... its not worth bothering, might have been 25 yrs ago.


NT

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James Sweet James Sweet is offline
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Default is it worth it to replace caps in old equalizer??

Derwin wrote:
Hello, I have an old 70s-era 5-band equalizer made by Realistic (radio shack),
which I like to use in my guitar effects chain, and I opened it up the other
day just to see what it looked like inside, and I noticed that there are two
large electrolytic capacitors. They look fine, and the unit sounds OK, but
given that it is probably at least 30 years old now, and may have sat around
for many years not being used before I got my hands on it, could I expect
improved performance if I were to replace those two big electrolytics with new
ones?

Thanks for any advice!



If it sounds fine I wouldn't worry about it. On the other hand caps are
cheap and replacement is easy.
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Mogens V. Mogens V. is offline
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Default is it worth it to replace caps in old equalizer??

wrote:
On 24 Mar, 17:19, wrote:

I am an expert on audio, certain areas, and this is one of them.

I totally agree with those who say if it ain't broke don't fix it,
but, some things are built broke.

To get the best quality integrated audio, which is the type of signal
for which this EQ was designed, they chose the wrong frequncies.

Now replacing the power supply filters is probably useless because of
the low current drain of the unit, there is simply almost no ripple
current to "wear out" the capacitor. However there are other things
one can do.

I have modified a couple of these, but then that was for integrated
program material, if you use it on a guitar you might want to go a
different direction. I don't remember the component values, but once
you understand how it works you can do things, many things.

A buddy of mine had his speakers in the corners, which made them very
boomy. They have bass, but it is ****ty.

At the wiper of the 60Hz control there is a cap, a coil and a
resistor. What I did was to take and change that control to about 35Hz
and made it shelving, that is to extend the control's range all the
way down, instead of that peaked response it originally had. I did
this by taking the resistor value down to less than ½ the original and
installing a capacitor about ten times the capacity of the original.

The 250Hz control was lowered to about 100Hz by cutting the resistor's
value in about ½ and installing a capacitor about three times the
original value.

The 1 Khz control was left alone. The 3.5 Khz control had it's range
extended slightly downward by increasing the value of it's capacitor.

Finally the 10 Khz control was modified to be shelving, and it's range
shifted upward. This brings out the timbre, rather than the tinny
treble. This was accomplished by actually lowering the capacitor value
as well as the resistor value, and shunting the coil with a low value
resistor, about ¼ the resistance of the new resistance value in the
tuned circuit for that band.

Actually if you know how to futz with it, you could have a nice setup.
run the channels in tandem but change some of the frequencies. Lower
the low ones on the left and raise the high ones on the right. And if
you tandem the channels you also can use a Y adapter to pick off the
signal for another amp, between stages.

Tell you what, if you get a chance to play a guitar on two amps at
once, enjoy. Set one clean and one fuzzed out. With a little adjusting
and practice you can make it sound like you are playing two guitars.

JURB



If youre going to muck with it then start with a 10 band or more,
pointless to play with something as very limited as a 5 band.

If you wanted to adapt it for guitar use only, I'd make each side
different freqs and you can feed the signal thru both sides to get a
10 bander. And refrequency the 1kHz slider, which is the least useful
of them all.

But... its not worth bothering, might have been 25 yrs ago.


Plus many/most inexpensive EQ's arent phase liniar anyways...
Mostly useless for high quality audio. Besides, problems with a hifi
setup is better addressed actually fixing those problems at the source,
not trying to EQ them out.

--
Kind regards,
Mogens V.

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Default is it worth it to replace caps in old equalizer??

Eeyore wrote:

Derwin wrote:


Hello, I have an old 70s-era 5-band equalizer made by Realistic (radio shack),
which I like to use in my guitar effects chain, and I opened it up the other
day just to see what it looked like inside, and I noticed that there are two
large electrolytic capacitors. They look fine, and the unit sounds OK, but
given that it is probably at least 30 years old now, and may have sat around
for many years not being used before I got my hands on it, could I expect
improved performance if I were to replace those two big electrolytics with new
ones?



As suggested elsewhere, the PSU caps seem to be ok. You might want to consider
replalcing any electrolytics in the signal path though.


And as Scott mentioned, it's based on quite old opamps.
Not worth the efforts, not even if tone is under par. Then better go get
a better one. Unless the OP prefers that killer vintage tone.

--
Kind regards,
Mogens V.



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Derwin Derwin is offline
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Default is it worth it to replace caps in old equalizer??

Great ideas, thanks for the response, Zzactly!

In article . com,
says...

I am an expert on audio, certain areas, and this is one of them.

I totally agree with those who say if it ain't broke don't fix it,
but, some things are built broke.

To get the best quality integrated audio, which is the type of signal
for which this EQ was designed, they chose the wrong frequncies.

Now replacing the power supply filters is probably useless because of
the low current drain of the unit, there is simply almost no ripple
current to "wear out" the capacitor. However there are other things
one can do.

I have modified a couple of these, but then that was for integrated
program material, if you use it on a guitar you might want to go a
different direction. I don't remember the component values, but once
you understand how it works you can do things, many things.

A buddy of mine had his speakers in the corners, which made them very
boomy. They have bass, but it is ****ty.

At the wiper of the 60Hz control there is a cap, a coil and a
resistor. What I did was to take and change that control to about 35Hz
and made it shelving, that is to extend the control's range all the
way down, instead of that peaked response it originally had. I did
this by taking the resistor value down to less than =BD the original and
installing a capacitor about ten times the capacity of the original.

The 250Hz control was lowered to about 100Hz by cutting the resistor's
value in about =BD and installing a capacitor about three times the
original value.

The 1 Khz control was left alone. The 3.5 Khz control had it's range
extended slightly downward by increasing the value of it's capacitor.

Finally the 10 Khz control was modified to be shelving, and it's range
shifted upward. This brings out the timbre, rather than the tinny
treble. This was accomplished by actually lowering the capacitor value
as well as the resistor value, and shunting the coil with a low value
resistor, about =BC the resistance of the new resistance value in the
tuned circuit for that band.

Actually if you know how to futz with it, you could have a nice setup.
run the channels in tandem but change some of the frequencies. Lower
the low ones on the left and raise the high ones on the right. And if
you tandem the channels you also can use a Y adapter to pick off the
signal for another amp, between stages.

Tell you what, if you get a chance to play a guitar on two amps at
once, enjoy. Set one clean and one fuzzed out. With a little adjusting
and practice you can make it sound like you are playing two guitars.

JURB


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Derwin Derwin is offline
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Default is it worth it to replace caps in old equalizer??

In article . com,
says...

On 24 Mar, 09:39, (Derwin) wrote:

Hello, I have an old 70s-era 5-band equalizer made by Realistic (radio

shack),
which I like to use in my guitar effects chain, and I opened it up the other
day just to see what it looked like inside, and I noticed that there are two
large electrolytic capacitors. They look fine, and the unit sounds OK, but
given that it is probably at least 30 years old now, and may have sat around
for many years not being used before I got my hands on it, could I expect
improved performance if I were to replace those two big electrolytics with

new
ones?

Thanks for any advice!


No. If youre considering doing jobs that dont need doing it may be
time to reevaluate ones life.


I appreciate your response as well, but the cirumstances are that I have some
free time while I wait for some parts to arrive before I can get back to
recording, and for the past few weeks I've been doing a lot of soldering.
Since I've got all the tools laid out from the previous work, and can't get
back to recording, I figured I'd open up anything I have around that is
essentially worthless but still potentially useful (in my opinion) and see if I
could do any worthwhile modifications (I was hoping I'd be able to replace an
op amp in the equalizer, but there aren't any in it). However it does seem
like my rudimentary self-learned knowledge of electronics has already caused me
to do some useless things, such as replacing the op amps in an Alesis
Microlimiter with ones with lower noise specs, hoping to get a lower noise
floor, which did not happen because I didn't understand the circuit well enough
to realize that swapping op amps wouldn't result in a quieter unit.

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Derwin Derwin is offline
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Default is it worth it to replace caps in old equalizer??

In article x_pNh.9897$__3.9716@edtnps90, says...

Great ideas, thanks for the response, Zzactly!


But unfortunately it appears I won't be able to try them. The plastic ends on
the sliders don't come off the sliders, they're either glued on or were
manufactured that way, so it is impossible to take off the front panel to get
behind it where the circuit board is. Oh well.



In article . com,
says...

I am an expert on audio, certain areas, and this is one of them.

I totally agree with those who say if it ain't broke don't fix it,
but, some things are built broke.

To get the best quality integrated audio, which is the type of signal
for which this EQ was designed, they chose the wrong frequncies.

Now replacing the power supply filters is probably useless because of
the low current drain of the unit, there is simply almost no ripple
current to "wear out" the capacitor. However there are other things
one can do.

I have modified a couple of these, but then that was for integrated
program material, if you use it on a guitar you might want to go a
different direction. I don't remember the component values, but once
you understand how it works you can do things, many things.

A buddy of mine had his speakers in the corners, which made them very
boomy. They have bass, but it is ****ty.

At the wiper of the 60Hz control there is a cap, a coil and a
resistor. What I did was to take and change that control to about 35Hz
and made it shelving, that is to extend the control's range all the
way down, instead of that peaked response it originally had. I did
this by taking the resistor value down to less than =BD the original and
installing a capacitor about ten times the capacity of the original.

The 250Hz control was lowered to about 100Hz by cutting the resistor's
value in about =BD and installing a capacitor about three times the
original value.

The 1 Khz control was left alone. The 3.5 Khz control had it's range
extended slightly downward by increasing the value of it's capacitor.

Finally the 10 Khz control was modified to be shelving, and it's range
shifted upward. This brings out the timbre, rather than the tinny
treble. This was accomplished by actually lowering the capacitor value
as well as the resistor value, and shunting the coil with a low value
resistor, about =BC the resistance of the new resistance value in the
tuned circuit for that band.

Actually if you know how to futz with it, you could have a nice setup.
run the channels in tandem but change some of the frequencies. Lower
the low ones on the left and raise the high ones on the right. And if
you tandem the channels you also can use a Y adapter to pick off the
signal for another amp, between stages.

Tell you what, if you get a chance to play a guitar on two amps at
once, enjoy. Set one clean and one fuzzed out. With a little adjusting
and practice you can make it sound like you are playing two guitars.

JURB



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William Sommerwerck William Sommerwerck is offline
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Default is it worth it to replace caps in old equalizer??

Plus many/most inexpensive EQ's arent phase liniar anyways...
Mostly useless for high-quality audio.


Linear, not liniar.

This has been discussed ad-nauseum. If you are correcting for errors (as
opposed to introducing them), you don't want constant group delay. You want
the phase shift the equalizer introduces, because it offsets the phase shift
of the error.


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Mike Rivers Mike Rivers is offline
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On Mar 25, 4:25 am, (Derwin) wrote:

I use the
equalizer in a guitar effects chain, not to EQ a 'hifi setup'. I'm quite sure
the quality is no worse than a typical cheap equalizer guitar pedal.


It's possible, however, that it doesn't have sufficient headroom for
that application. This may not matter (everything about a guitar sound
is about distortion) but it's worth considering. That equalizer was
probably intended to go either between a preamp and power amplifier or
(effectively the same point in the circuit) in the "tape out/in" loop
of a receiver or integrated amplifier. The signal level at that point
is 10 to 20 dB lower than a guitar played hard. Guitar pedals know
this, but the equalizer may not.

But if it sounds OK to you, I'd leave it alone. About the only thing
that replacing the power supply electrolytics would do is reduce hum.
If that's not a problem, don't mess with it.

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Scott Dorsey Scott Dorsey is offline
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Default is it worth it to replace caps in old equalizer??

Derwin wrote:

But unfortunately it appears I won't be able to try them. The plastic ends on
the sliders don't come off the sliders, they're either glued on or were
manufactured that way, so it is impossible to take off the front panel to get
behind it where the circuit board is. Oh well.


They are glued. Remember, this is the worst grade of mass-market trash
available at the time; it's not designed to be actually repaired. Pry
them off with a screwdriver.

I suspect you will find that there is a bunch of stuff on the board that
you haven't seen yet.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Default is it worth it to replace caps in old equalizer??

They are not glued, but about a decade or so ago when I was mucking
around in one they were very difficult to get off. At this age the
attempt may break the posts off the pots. It would still be useable
but you'd need a key or a screwdriver or something to adjust it.

It may just be better to be glad the thing works. I know two people
with that model, the one modified and the other stock.

But now that you got me started, that EQ is poor for music. IIRC those
were actually discrete component OPAMPS and on the 60 HZ, which I
would've liked to extend the response of down to DC, it simply isn't
possible. That's OK, when they use like a 33uF and I replace it with a
470, it is close enough.

I have this old Soundcraftsman that I would really like to get a power
transformer for. Now that's an EQ !. And it uses coils in the tuned
circuit. Now that you got me started, the design of the old unity gain
except for shunting either source or degeneration with passive tuned
circuits has an advantage. The is when you use two adjacent controls
in the same direction (boost or cut) the tuned circuits begin to act
as if they are in paralell, giving less of a double hump in the
response curve.

This is going to get deep, get your waders on. Decades ago there was a
very accurate method of measuring frequency response. It fed a speaker
a single tick, and through fast fourier transform it was able to plot
the entire frequency response curve of a speaker. It was abandoned
because it was too accurate.

For a couple of decades cheap speakers were being passed off as high
fidelity and how they did it is simple. To make the response curve
look better they began using bands of pink noise, and a wide spectrum
mike. The problem was the bass, an FFT would accurately show the
possible +-10db variations in the lower ranges.

Now remember that the cone is still moving, being an inductive load
fed by a constant voltage, the problem is cancellation, and
nonlinearity of the magnetic field and/or compliance or the woofer's
suspension. This means that tons of THD are produced at the
frequencies reproduced less efficiently by the system.

Now, abandoning the FFT method and going with the pink noise, they are
checking for say 60Hz, but appearing in the output with this method
are the distortion components, 120Hz, 180Hz, 240Hz and so forth. This
all added up makes the curve look flatter, but it is not. I don't know
about anybody else, but for a 60Hz input, for a frequency response
curve, I would only want the 60Hz output to count in the results.

So anyway, back to the price of beans in Chile. This sparked my
curiousity and I promptly got out the square wave generator and the
oscilloscope. After some experimentation seeing what the controls did
to a 1Khz square wave I understood how the FFT works. Not the complex
math involved, but at least the concept. The FFT method was touted as
having the great advantage of not requiring an anechoic chamber to
take the test, true, a speaker would read pretty much the same in an
open field or in a phone booth. That is an exageration though, the
mike had to be a certain distance away.

Over the years I came to realize the one should just get good speaker
if one can afford them, and that is what I did. I got the Boston
A150s. This was over ten years ago and after all the abuse people with
their own stereos still come to hear things on MY stereo. And I just
found out recently that the midrange has the biggest magnet in the
system, not the woofer. At $400 for the pair used, which was MSRP I
whipped out the money after hearing them.And they were ten years old
almost at the time !. Go ahead and think that I got fleeced, but come
and listen to them first. We are talking 20-20,000 within 3db and 0.7%
THD at one watt. Remember, one watt is pretty loud for most people.

Some purists shun tone controls altogether, but not me. In fact I
designed but never built perhaps the best set of tone controls ever.
Bass turnover continuously varible from 44-480 Hz and +- 18db range.
Yes it is dangerous ! Midrange was pretty much standard but the treble
was just as gnarly. Went from about 2Khz to 9Khz, and had the same
range. No, you do not crank these up.

It was designed in response to the industry's propensity for not
giving us the outer octaves. But I simply do not need it anymore.

At this point, even though I do use a boosted bass, when I run out of
power it doesn't clip just the bass, all frequecies pretty much clip
at the same point.

Now to the guitar. If you play an electric with distortion, with solid
state you generally can't play G type or C type chords. The problem is
that the second note in the chord is only 4 frets (½ steps) away from
the base, rather than 7. But it can sound good on tubes, or specially
designed circuitry.

That old sweet sound was also due to interaction of the soft output
stage with the output transformer as well as the speaker. They built
power soaks for people who wanted that sound but wanted to practice at
a lower level, but the results were not quite the same thing. Would've
been better to regulate the B+ to the output stage.

I don't know if FETs would react the same, but they might, or at least
be very close.

The best thing I did though, was to start using two amps. One clean
and one all fuzzed out. You can just about make one guitar sound like
two. If you place the amps across the room from each other, you
actually get a sort of stereo image out of it.

Time marches on. I got ripped off and did not have a guitar for a
while. Then I got so dismayed by the media that I not only stopped
watching TV, I actually stopped listening to music for years. That's
right, it is hard to fathom, but I did.

That had a very interesting result. I do not play copies or covers
anymore. Period. I've written three songs, well one and two almost
songs. I have switched to the acoustic, and use chordography that
would never fly on an electric, even clean. It just sounds better on
an acoustic. Mine even has a pickup, but I prefer to mike it.

My next step is to buy one of those newer ones with the advanced
internal pickups. You can play it on a stereo and it sounds like an
acoustic. I was very impressed the first time I heard one.

Good luck grinding the ax (a term we used to use for playing with
distortion, heavy metal).

Ummm, BTW, something just cropped up in my memory. You got that old EQ
which allows seperate adjustments for each channel, get two amps and
set them inversely. Don't run them tandem, feed both via a splitter,
then each out to it's own amp. Then you set, say the left 60, 1K and
10K down, the others up. On the right set the 250 and 3.5K down, and
the others up. You might like the effect.

I am not too crazy about these new amps with all the digital effects.
It is all taken out of my hands. I don't think that'll ever change.

Also sometimes I'll play on the old Fender amp and a bass amp at the
same time. That sounds pretty good too.

Have fun with it.

JURB



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On 25 Mar, 06:02, (Derwin) wrote:
In article , says...


And even if you do, you're stuck with 1970s Radio-Shack grade op-amp design.


Actually I opened it hoping I could replace an op amp but there are no ICs in
it at all. But I did eventually realize that the two big electrolytics are
probably part of the power supply.


youre probably not looking at quality then. The 70s was awash with
grotty discrete kit.


NT

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wrote:

youre probably not looking at quality then.


He did say it was Radio Shack !

Graham

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"Eeyore" wrote in
message
wrote:

youre probably not looking at quality then.


He did say it was Radio Shack !


Right. The performance of cheap equalizers actually went uphill when cheap
ICs became available for implementing them.


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William Sommerwerck William Sommerwerck is offline
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And even if you do, you're stuck with 1970's
Radio-Shack grade op-amp design.


Actually I opened it hoping I could replace an op amp
but there are no ICs in it at all.


You're probably not looking at quality, then. The 70s
was [sic] awash with grotty discrete kit.


To the best of my knowledge, this equalizer was not an RS design. It came
from a little company called Metrotech, and appeared as a Popular
Electronics construction project. The same circuit was later used by BSR for
a 12-band equalizer.

It should be noted that, even in the '70s, IC designers were still "finding
their way" with respect to op amps. And there are plenty of current
designers who would not agree that ICs are inherently superior to discrete.


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Scott Dorsey Scott Dorsey is offline
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Default is it worth it to replace caps in old equalizer??

William Sommerwerck wrote:
And even if you do, you're stuck with 1970's
Radio-Shack grade op-amp design.


Actually I opened it hoping I could replace an op amp
but there are no ICs in it at all.


You're probably not looking at quality, then. The 70s
was [sic] awash with grotty discrete kit.


To the best of my knowledge, this equalizer was not an RS design. It came
from a little company called Metrotech, and appeared as a Popular
Electronics construction project. The same circuit was later used by BSR for
a 12-band equalizer.

It should be noted that, even in the '70s, IC designers were still "finding
their way" with respect to op amps. And there are plenty of current
designers who would not agree that ICs are inherently superior to discrete.


The problem is that active filters built on op-amps require lots and
lots of gain.... as a consequence, discrete op-amps in active circuits
tend to be problematic because really high-gain discretes are difficult
to build and keep stable.

It's the one application where monolithic op-amps really _were_ a huge
win, even back in the seventies when monolithic op-amps were... well...
kind of nasty.

Then again, you will still find people who are huge fans of the old ITI
equalizers, which are the typical four-op-amp parametric configuration
built with video-amplifier-style discrete op-amps. Neutral they aren't.
But some people like the interesting weirdness.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."


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William Sommerwerck wrote:

And there are plenty of current designers who would not agree that ICs are
inherently superior to discrete.


In certain specific instances ICs are clearly inferior. Mic amps for example.

Graham


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Eeyore wrote:
William Sommerwerck wrote:

And there are plenty of current designers who would not agree that ICs are
inherently superior to discrete.


In certain specific instances ICs are clearly inferior. Mic amps for example.


Depends. What is discrete and what is an IC?

Are large area transistor arrays discrete or ICs? They make great mike
preamp front ends.

Hybrids aren't monolithic... but they aren't discrete either....
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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The problem is that active filters built on op-amps require
lots and lots of gain... as a consequence, discrete op-amps
in active circuits tend to be problematic because really
high-gain discretes are difficult to build and keep stable.


The Metrotech's amplification was not op-amp based.


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