Hi, all,
I'm replacing the noisy pots in my Symetrix preamp with a rotary switch.
Most of the ones I find are break-before-make, but I'm wondering if it is
better to use that, or a make-before break unit?

George Reiswig
Song of the River Music

In article writes:

I'm replacing the noisy pots in my Symetrix preamp with a rotary switch.

I presume you're going to put some resistors on that switch, too. Or
are you looking at a switch-based volume control? There are a few
available, but they're pretty expensive. I used to have a link to a
well respected one that I recall was about $400 for a balanced stereo
control.

Most of the ones I find are break-before-make, but I'm wondering if it is
better to use that, or a make-before break unit?

I'd think you'd want to use a break-before-make. Otherwise your "pot"
would open at every step, causing at minimum an annoying click, and at
worst, a wide-open momentary blast.



--
I'm really Mike Rivers )
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 he double-m-eleven-double-zero at yahoo

Most of the ones I find are break-before-make, but I'm
wondering if it is better to use that, or a make-before
break unit?

"Mike Rivers" wrote ...
I'd think you'd want to use a break-before-make. Otherwise
your "pot" would open at every step, causing at minimum an
annoying click, and at worst, a wide-open momentary blast.

I think you've got it backwards, Mike. If you use a break-
before-make switch it WILL open between every step.
Agree that is undesirable in a stepped attenuator.

Okay...You're right, Richard. I think Mike got the terms mixed up and meant
to say make before break.

Mike was right, though, that this will be a resistor network in this. Zero
ohms is maximum gain, 2500 is minimum. So if you go from, say 1000 ohms to
infinity, will the gain go to zero? Is it better to have a shorting switch
(make before break) such that it instead goes from 1000 to whatever the
lower (parallel) resistance is next to it?

George Reiswig
Song of the River Music

"Richard Crowley" wrote in message
...
Most of the ones I find are break-before-make, but I'm
wondering if it is better to use that, or a make-before
break unit?

"Mike Rivers" wrote ...
I'd think you'd want to use a break-before-make. Otherwise
your "pot" would open at every step, causing at minimum an
annoying click, and at worst, a wide-open momentary blast.

I think you've got it backwards, Mike. If you use a break-
before-make switch it WILL open between every step.
Agree that is undesirable in a stepped attenuator.

In article writes:

"Mike Rivers" wrote ...
I'd think you'd want to use a break-before-make.

I think you've got it backwards, Mike.

You're right. I do. But they rhyme. I just saw what was written and
copied it. But the principle was correct.



--
I'm really Mike Rivers - )
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 he double-m-eleven-double-zero at yahoo

In article writes:

Mike was right, though, that this will be a resistor network in this. Zero
ohms is maximum gain, 2500 is minimum. So if you go from, say 1000 ohms to
infinity, will the gain go to zero? Is it better to have a shorting switch
(make before break) such that it instead goes from 1000 to whatever the
lower (parallel) resistance is next to it?

OK, let's back up a bit here. Exactly what circuit are you planning to
use? If it's a simple attenuator with a switched set of fixed
resistors:

---------/\/\/\/-----+----------------------------
|
+----+----+----+----+-----+---
| | | | | |




in | | | | | | out
o o o o o o

^
|
|
|
---------------------o-------------------------------


in this case you don't want to use a break-before-make switch. If you
do, then you'll momentarily have no attenuation (maximum level)
between each step, which could be annoying or disasterous. If you use
a make-before-break switch, you'll be momentarily be paralleling two
resistors which will drop the level between steps.



--
I'm really Mike Rivers )
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 he double-m-eleven-double-zero at yahoo

Like I said, Mike, 0 ohms is maximum gain (it's an SX-202), and 2500 ohms is
minimum. So an open (infinite R) would be very low gain if I understand
right.

George Reiswig
Song of the River Music

"Mike Rivers" wrote in message
news:znr1077236506k@trad...

In article
writes:

Mike was right, though, that this will be a resistor network in this.
Zero
ohms is maximum gain, 2500 is minimum. So if you go from, say 1000 ohms
to
infinity, will the gain go to zero? Is it better to have a shorting
switch
(make before break) such that it instead goes from 1000 to whatever the
lower (parallel) resistance is next to it?

OK, let's back up a bit here. Exactly what circuit are you planning to
use? If it's a simple attenuator with a switched set of fixed
resistors:

---------/\/\/\/-----+----------------------------
|
+----+----+----+----+-----+---
| | | | | |




in | | | | | | out
o o o o o o

^
|
|
|
---------------------o-------------------------------


in this case you don't want to use a break-before-make switch. If you
do, then you'll momentarily have no attenuation (maximum level)
between each step, which could be annoying or disasterous. If you use
a make-before-break switch, you'll be momentarily be paralleling two
resistors which will drop the level between steps.



--
I'm really Mike Rivers )
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 he double-m-eleven-double-zero at yahoo

"Mike Rivers" wrote ...
in this case you don't want to use a break-before-make switch. If you
do, then you'll momentarily have no attenuation (maximum level)
between each step, which could be annoying or disasterous. If you use
a make-before-break switch, you'll be momentarily be paralleling two
resistors which will drop the level between steps.

Hard to avoid switching artifacts in an inexpensive/homemade
stepped attenuator. That is why they are used mostly for gain-
setting and not level-riding.

Richard Crowley wrote:
"Mike Rivers" wrote ...
in this case you don't want to use a break-before-make switch. If you
do, then you'll momentarily have no attenuation (maximum level)
between each step, which could be annoying or disasterous. If you use
a make-before-break switch, you'll be momentarily be paralleling two
resistors which will drop the level between steps.

Hard to avoid switching artifacts in an inexpensive/homemade
stepped attenuator. That is why they are used mostly for gain-
setting and not level-riding.

Hint: use a make-before-break switch, and instead of using a series
of resistors like Mike drew, use a resistor ladder where each contact
on the switch has a resistor from it to the next contact up (and so
each resistor is sized for the _difference_ in value between the two
adjacent contacts). Doing this results in much quieter operation
with cheap switches.

The C&K 12-position rotary switches from Digi-Key are available in
make-before-break configuration, and if you can live with only 12
positions they are pretty good.

I find having only 12 positions pretty irritating myself.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"A. & G. Reiswig" wrote in message

Hi, all,
I'm replacing the noisy pots in my Symetrix preamp with a rotary
switch. Most of the ones I find are break-before-make, but I'm
wondering if it is better to use that, or a make-before break unit?

You might want to look at the audiophile stepped-attenuator market for
products of this kind, parts, kits, and assembled product.

In article writes:

Like I said, Mike, 0 ohms is maximum gain (it's an SX-202), and 2500 ohms is
minimum. So an open (infinite R) would be very low gain if I understand
right.

This sounds like a question for Monte or someone who knows the circuit
you're talking about, but hopefully you understand the principle.



--
I'm really Mike Rivers )
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 he double-m-eleven-double-zero at yahoo

A. & G. Reiswig wrote:
Hi, all,
I'm replacing the noisy pots in my Symetrix preamp with a rotary switch.
Most of the ones I find are break-before-make, but I'm wondering if it is
better to use that, or a make-before break unit?

Hmmm, make-before-break, or break-before-make? Never thought about this
issue. The first one would imply a momemtary surge and the other a
momentary mute, neither or which is good.

Are these the only choices?

If I were to design a stepped attenuator, I would have it so that at
full attenuation all contacts would be open. As the switch progressed
through the steps, each contact would close, and the ones before it
would remain closed.

The resistors be calculated to fit this scenario of paralleled values.

There would be no make or break problem, which is good if you have to
switch right in the midst of recording. The negative side is that
at minimum attenuation, your signal is running through 12 or so
paralleled resistors, perhaps compromising the quality.

Rob R.

Aha! That's it. Good advice, Scott. Makes a lot of sense.

George Reiswig
Song of the River Music

"Scott Dorsey" wrote in message
...
Richard Crowley wrote:
"Mike Rivers" wrote ...
in this case you don't want to use a break-before-make switch. If you
do, then you'll momentarily have no attenuation (maximum level)
between each step, which could be annoying or disasterous. If you use
a make-before-break switch, you'll be momentarily be paralleling two
resistors which will drop the level between steps.

Hard to avoid switching artifacts in an inexpensive/homemade
stepped attenuator. That is why they are used mostly for gain-
setting and not level-riding.

Hint: use a make-before-break switch, and instead of using a series
of resistors like Mike drew, use a resistor ladder where each contact
on the switch has a resistor from it to the next contact up (and so
each resistor is sized for the _difference_ in value between the two
adjacent contacts). Doing this results in much quieter operation
with cheap switches.

The C&K 12-position rotary switches from Digi-Key are available in
make-before-break configuration, and if you can live with only 12
positions they are pretty good.

I find having only 12 positions pretty irritating myself.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

....unfortunately, and this is why I originally asked the question, it looks
like all anybody actually carries are break-before-make (non-shorting)
switches. Naturally.

George Reiswig
Song of the River Music

"A. & G. Reiswig" wrote in message news:...
Aha! That's it. Good advice, Scott. Makes a lot of sense.

George Reiswig
Song of the River Music

"Scott Dorsey" wrote in message
...
Richard Crowley wrote:
"Mike Rivers" wrote ...
in this case you don't want to use a break-before-make switch. If you
do, then you'll momentarily have no attenuation (maximum level)
between each step, which could be annoying or disasterous. If you use
a make-before-break switch, you'll be momentarily be paralleling two
resistors which will drop the level between steps.

Hard to avoid switching artifacts in an inexpensive/homemade
stepped attenuator. That is why they are used mostly for gain-
setting and not level-riding.

Hint: use a make-before-break switch, and instead of using a series
of resistors like Mike drew, use a resistor ladder where each contact
on the switch has a resistor from it to the next contact up (and so
each resistor is sized for the _difference_ in value between the two
adjacent contacts). Doing this results in much quieter operation
with cheap switches.

The C&K 12-position rotary switches from Digi-Key are available in
make-before-break configuration, and if you can live with only 12
positions they are pretty good.

I find having only 12 positions pretty irritating myself.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

A. & G. Reiswig wrote:
...unfortunately, and this is why I originally asked the question, it looks
like all anybody actually carries are break-before-make (non-shorting)
switches. Naturally.

Digi-Key. C&K 12 position types. The same ones I used in my recent DIY EQ
article in Recording.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Sat, 21 Feb 2004 23:26:27 GMT, "A. & G. Reiswig"
wrote:

...unfortunately, and this is why I originally asked the question, it looks
like all anybody actually carries are break-before-make (non-shorting)
switches. Naturally.

Michael Percy Audio sells Shallco and Elma switches made for the
purpose, and kits with resistors, etc. As does Goldpoint, and
maybe others. Space limitations?

Chris Hornbeck

"I love cats because I enjoy my home; and
little by little, they become its visible soul."
-Jean Cocteau

Yup...there is an inherent space limitation. The pots being replaced are a
little over .5" diameter, and I can go as deep as .75" from the front panel.
But thanks for the tip...I'll see what the sources you mention have to
offer.

One company that comes up when I Google this topic is Otto Controls, and
they seem to have some nice miniatures with gold-plated contacts, but I have
no idea who sells them.

Thanks again!

George Reiswig
Song of the River Music

"Chris Hornbeck" wrote in message
...
On Sat, 21 Feb 2004 23:26:27 GMT, "A. & G. Reiswig"
wrote:

...unfortunately, and this is why I originally asked the question, it
looks
like all anybody actually carries are break-before-make (non-shorting)
switches. Naturally.

Michael Percy Audio sells Shallco and Elma switches made for the
purpose, and kits with resistors, etc. As does Goldpoint, and
maybe others. Space limitations?

Chris Hornbeck

"I love cats because I enjoy my home; and
little by little, they become its visible soul."
-Jean Cocteau

"A. & G. Reiswig" wrote in message

Yup...there is an inherent space limitation. The pots being replaced
are a little over .5" diameter, and I can go as deep as .75" from the
front panel. But thanks for the tip...I'll see what the sources you
mention have to offer.

One company that comes up when I Google this topic is Otto Controls,
and they seem to have some nice miniatures with gold-plated contacts,
but I have no idea who sells them.

http://www.electronet.com/search/mfg.asp?CoID=518

"A. & G. Reiswig" wrote:


One company that comes up when I Google this topic is Otto Controls, and
they seem to have some nice miniatures with gold-plated contacts, but I have
no idea who sells them.

Make sure you're sitting down when you get the price from Otto!
I've seen Otto toggles that'll cost you in excess of $100USD, let alone rotaries...
Otto make the toughest switches known to man, but that price tag....

Let me know if the price is amicable, but I've a terrible suspicion it won't be... Moqs can be a problem too.




----------
Sent via SPRACI - http://www.spraci.net/ - Parties,Raves,Clubs,Festivals

In article (THERMIONIC) writes:

Make sure you're sitting down when you get the price from Otto!
I've seen Otto toggles that'll cost you in excess of $100USD, let alone
rotaries...
Otto make the toughest switches known to man, but that price tag....

The kick in the pants is that he wants this to replace the noisy gain
control pots in a $250 mic preamp. I think he should replace the pots
with pots. If it was a $2500 preamp, this might be a cool modification
but for an SX-202? I wouldn't.

God bless hobbyists. They keep the rest of us sane.


--
I'm really Mike Rivers )
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 he double-m-eleven-double-zero at yahoo

My thinking, too, Mike. If I can get the switches for $9 like I thought I
could, then I think it might be worth it. If I have to spend a fair
fraction of the value of the preamp itself just for these switches...

George Reiswig
Song of the River Music

"Mike Rivers" wrote in message
news:znr1077473512k@trad...

In article (THERMIONIC) writes:

Make sure you're sitting down when you get the price from Otto!
I've seen Otto toggles that'll cost you in excess of $100USD, let alone
rotaries...
Otto make the toughest switches known to man, but that price tag....

The kick in the pants is that he wants this to replace the noisy gain
control pots in a $250 mic preamp. I think he should replace the pots
with pots. If it was a $2500 preamp, this might be a cool modification
but for an SX-202? I wouldn't.

God bless hobbyists. They keep the rest of us sane.


--
I'm really Mike Rivers )
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 he double-m-eleven-double-zero at yahoo