Volume pots

[rollo]

  Looking for the quietest one made. There are variable resistor types and stepped as well as Autoformers. The use will be for an amp.


charles

[tmazz]

I'm not sure I understand what you mean by quiet. As a passive device a volume pot should not make any noise at all, except when you are moving it. And I am not sure why having the pot make a little noise while you are moving it would be a big deal. It's not like you would be doing any critical listening during the second or two it takes to make a volume change.  What am I missing?

[P.I.]

Resistive elements have a parameter that is called the “temperature coefficient of resistance”. It is quantified in parts per million (ppm).  These numbers can run any where from 0.01 to over 1200 with lower being better.  Most commercial pots run in the 750 - 1000 range.  This directly correlates to “self noise” generated in the resistive element.  At very low voltages, where TCR noise is most prevalent,  this can be a big deal.  Take a low output moving coil and we are talking about possible serious consequences.

So here is my take:

VHQ stepped attenuators can utilize resistors like the bulk foil one made by this company-

http://www.texascomponents.com/store/VishayFoilResistors.asp

They are a great company and make and quickly ship small order products.  Using all TCC resistors in a stepped attenuators can get very, very, VERY expensive.  I once built a 47 step, stereo attenuator for a customer and the cost for resistors alone was over $1500.00.  Made me nervous during the build due to the 380+ solder joints with an extremely difficult to work solder.  Done with that!

There are some great attenuators available here:

https://www.hificollective.co.uk/attenuator/glasshouse-elma-a47-jumbo-stepped-attenuator-mono.html

When it comes to pots I am a fan of the plastic element TKD products:

https://www.partsconnexion.com/tkd-potentiomters.html

They ‘sound’ very good which is to say they don’t sound at all. 

DACT is another great option.  This is the best “bang” I know of:

https://www.ebay.com/itm/283538214885

I’m not a fan of Alps. I had too many fail in studio applications.  They are, however, a good source for motorized pots.

For autoformers, Dave Slagle is THE Man! :  http://www.intactaudio.com/atten.html

There are so many options.  Pick a price point and do a search.

[Folsom]

The eBay DACTs are crazy good for the money. I'm not hesitant to use one at any price point except the fact that it has a limited number of positions.

[rollo]

  Was leaning towards the TDK plastic. Good reviews. Thanks Guys.

charles

[Response Audio]

Hey Charles. Just curious why you are installing a volume control in or prior to an amplifier?

[rollo]

  The Alan Eaton design uses one. I really would prefer my preamp. I am experimenting either by bypassing gain control and using preamp OR using a better gain control without preamp.



charles

[rollo]

  The Alan Eaton design uses one. I really would prefer my preamp. I am experimenting either by bypassing gain control and using preamp OR using a better gain control without preamp.



charles

  OK bypassed the volume pot and put Lamm Ref Preamp back in. No contest. More body, slam and bigger stage. I appreciate the K.I.S.S. theory simpler not as good. So enamored with the 45 tube now considering a Tektron mono blocks.

charles

[Nick B]

Doug,

Your Melos preamp tale is sad to read, but I’m amazed you actually got it back after all that time…. and am glad that you’re going to install the Tortuga ldr pot and put in better caps. When you get that done, maybe you’ll consider letting us know how it turned out and compares to the Coda??

Nick

hi charles,

just curious - did you ever try the lamm pre with the amp's pot in place, and simply set the amp's volume pot to max gain? most pots are pretty-much bypassed simply by max'ing them out.

now, on another tangent, that low life pos mark porzilli totally eff'd me over, taking 3 years to "repair" the ma333r's volume-balance control issue that was never fixed during the (admittedly fabulous) sonic upgrade he did.  instead of properly repairing the custom tube volume pot mod i paid $500 for, 15 years ago, plus shipping e/w; mark simply ripped it out and replaced it w/a cheap $15 pos chinese pot.  boy, was i ever bummed.  i can only imagine how good it would sound if it were properly repaired.

but it's something i'm going to do myself - heh! i've scoped it out, and it will be a relatively easy mod to swap out the pos pot for for an ldr pot, which i'm expecting will be a significant improvement.  and <$250 total.
https://tortugaaudio.com/products/diy-preamp-components/electronic-stepped-attenuator-epot-v3-mini/

and while i'm at it, what the hey - go nuts!  i also purchased 12 of obbligato's top ultra-premium caps to replace the ancient mid-grade solens, and 10 polystyrene bypass caps for the lesser caps.  while the ma333r has always been a fine sounding preamp, this should really improve things.  when all's said-n-done, it will be shoot-out time between it and my coda 07x which got purchased quite a while back when i thought it unlikely i'd ever see my melos again.  it's a fantastic preamp in its own right - and i never thought i'd ever be able to say that about a s/s preamp in my system.

doug s.

  OK bypassed the volume pot and put Lamm Ref Preamp back in. No contest. More body, slam and bigger stage. I appreciate the K.I.S.S. theory simpler not as good. So enamored with the 45 tube now considering a Tektron mono blocks.

charles

[rollo]

hi charles,

just curious - did you ever try the lamm pre with the amp's pot in place, and simply set the amp's volume pot to max gain? most pots are pretty-much bypassed simply by max'ing them out.

now, on another tangent, that low life pos mark porzilli totally eff'd me over, taking 3 years to "repair" the ma333r's volume-balance control issue that was never fixed during the (admittedly fabulous) sonic upgrade he did.  instead of properly repairing the custom tube volume pot mod i paid $500 for, 15 years ago, plus shipping e/w; mark simply ripped it out and replaced it w/a cheap $15 pos chinese pot.  boy, was i ever bummed.  i can only imagine how good it would sound if it were properly repaired.

but it's something i'm going to do myself - heh! i've scoped it out, and it will be a relatively easy mod to swap out the pos pot for for an ldr pot, which i'm expecting will be a significant improvement.  and <$250 total.
https://tortugaaudio.com/products/diy-preamp-components/electronic-stepped-attenuator-epot-v3-mini/

and while i'm at it, what the hey - go nuts!  i also purchased 12 of obbligato's top ultra-premium caps to replace the ancient mid-grade solens, and 10 polystyrene bypass caps for the lesser caps.  while the ma333r has always been a fine sounding preamp, this should really improve things.  when all's said-n-done, it will be shoot-out time between it and my coda 07x which got purchased quite a while back when i thought it unlikely i'd ever see my melos again.  it's a fantastic preamp in its own right - and i never thought i'd ever be able to say that about a s/s preamp in my system.

doug s.

  OK bypassed the volume pot and put Lamm Ref Preamp back in. No contest. More body, slam and bigger stage. I appreciate the K.I.S.S. theory simpler not as good. So enamored with the 45 tube now considering a Tektron mono blocks.

charles

  Yes I did. However the idea was to eliminate the active Pre and use a passive. In my case the Lamm conquered.

charles