What's the best motorised volume control?

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planarboy

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Joined 2007
#1
I would like to have remote volume control installed in my Darkvoice 336SE, does anyone know what the best quality kit for this is?
If I made a remote control housing, would I be able to somehow just hookup another pot and knob instead of buttons, when I turn it up on the remote the amps knob just copies how much i turned it up. How cool would that be?
That sounds impossible, is it?
Thanks for anyone that wants to help,
dave
 
#9
If matching is important, use chip volume controls. The tolerance of circuits on a chip is much better than that of a mechanical control that wears with time.
Alternatively, use trimmers before or after the control to minimize the difference.
 
#10
Thankyou folks, a wealth of information for me, I havent gone through it all yet. I was interested to know if anything beat alps (except that big bloody gold thing). I guess I can set a 200AU budget and be very happy.
I say all this without even knowing how much room is in the amp.


Imagine if you could have just a wooden box with a knob on it as the remote, and as you turn the knob, so the knob turns on the amp accordingly. The knob in the remote wouldnt have to be super audio quality. I dont know if this is possible, Ive certainly never seen it before, except some old vcrs had a big knob on the remote as jog shuttle, but that wasnt exactly what I meant either.

Thanks again folks, in a couple hours I will have coffee and hit the links.
What to buy out of, for around the same price:

*Remote for my headphone amp, whic is also my preamp, my speakers volume control
*UWE cartridge body for my stock-as-a-rock denon dl103
*Cinemag stepups
*Get my supex SD900 super II retipped
*4 records
?????????????????????????????????????????????????????????????????????
I have 200 bucks to blow and cant decide which out of these 5 things to do.
 
#11
planarboy said:
Thankyou folks, a wealth of information for me, I havent gone through it all yet. I was interested to know if anything beat alps (except that big bloody gold thing). I guess I can set a 200AU budget and be very happy.
I say all this without even knowing how much room is in the amp.


Imagine if you could have just a wooden box with a knob on it as the remote, and as you turn the knob, so the knob turns on the amp accordingly. The knob in the remote wouldnt have to be super audio quality. I dont know if this is possible, Ive certainly never seen it before, except some old vcrs had a big knob on the remote as jog shuttle, but that wasnt exactly what I meant either.

Thanks again folks, in a couple hours I will have coffee and hit the links.
What to buy out of, for around the same price:

*Remote for my headphone amp, whic is also my preamp, my speakers volume control
*UWE cartridge body for my stock-as-a-rock denon dl103
*Cinemag stepups
*Get my supex SD900 super II retipped
*4 records
?????????????????????????????????????????????????????????????????????
I have 200 bucks to blow and cant decide which out of these 5 things to do.
Click to expand...
Probably best way to implement it is to use a servo motor with friction drive and external positional feedback. Then have a microcontroller read the position and set some volume control chips to match the position. And use a H bridge (a "MOSFET driver" chip is the simplest way to do it) to drive the servo motor. No need to implement feedback as that's the user's job. In other words, the motor stays off unless a remote command is changing the volume.
 
#12
makezine.com

a couple of issues ago makezine had a simple remote control project using a servo and pic. it looks dead easy and i plan to implement it myself. i am currently waiting on parts.

although you need a subscription to gain access to the article most of the necessary info is available on their site:

http://makezine.com/16/diycircuits_volume/

you can find sample code for the pic there as well as the circuit schematic. The pic he uses (08M)is available here: http://www.rev-ed.co.uk/picaxe/

all that is left to do is to mechanically couple your servo the volume control you already have. mcmaster.com has plenty of belts and timing gears to choose from.
 
#13
Typical pots (including the Alps Blue) have 20% tracking between channels. If you want better tracking, go for discrete switched resistors using relays. There are several projects out there that use IR or a mono linear pot to control the input to a microcontroller which then takes care of switching the relays. Then you can control the resistors to say Dale RN 1% series 😉
 
#14
Redshift187 said:
Typical pots (including the Alps Blue) have 20% tracking between channels. If you want better tracking, go for discrete switched resistors using relays. There are several projects out there that use IR or a mono linear pot to control the input to a microcontroller which then takes care of switching the relays. Then you can control the resistors to say Dale RN 1% series 😉
Click to expand...
Interesting approach but not very practical if you want a lot of steps. There are dedicated volume control chips that are better for this application. The very strict environment in which chips are made can get you better tolerance than discretes anyways.
 
#16
Brett said:
6 relays will do 64 steps. Seven gives you 128 and 0.5dB resolution. This is more than enough. In typical use, most VCs are used over a <20dB range except for up/down from mute.
Click to expand...
But why when there are chips designed just for that purpose with nice features like zero cross switching and make-before-break to avoid noise during switching?
 
#17
star882 said:

But why when there are chips designed just for that purpose with nice features like zero cross switching and make-before-break to avoid noise during switching?
Click to expand...
For me personally it's simply a preference for three reasons; the last lot of digital controls were awful, but I'd have to dig out the notebooks from the time to see why. Second, I have another project for something else that is similar and will adapt this to it. One variation I want to try later is the passive JFET bufferec xover and the constant output Z of this type will give minimal issues, and (fourth) I've designed everything discrete in the analogue path, and I'd rather it stay that way unless I need to do something different.

My comment before was that it's not hard to do with relays. Plus I already use them for signal routing.
 
#18
star882 said:

Interesting approach but not very practical if you want a lot of steps. There are dedicated volume control chips that are better for this application. The very strict environment in which chips are made can get you better tolerance than discretes anyways.
Click to expand...


You wouldnt happen to have the names of these chips?
The last one i managed to find had 0.1% thd. no thanks!!
 
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