[Arlekiin]

Hello,
 
So I have been thinking that there are not too many headphone amplifiers with remote controls it becomes especially important if they also work as pre-amplifiers.
Even having remote function for powerON/OFF would be a reason enough to have a remote.
This might seem like a novelty but my headphone amp isnt terribly close to me and its especially uncomfortable to switch it ON or OFF.
This got me thinking that it shouldnt be too hard to add the volume control using servos and IR/FM remote and the power switch. If one is using tubes could FM receiver influence tubes?
Has anybody else been looking into this?
It might be a real simple mod but I will take a trip to the local electronics store and see what I can find (servos, IR or FM reciever and switch capable of remote open/close circuit function (servo based again?).
Volume should be really simple I only need to attach the servo to the volume pot...simplest way of doing it would be via strings? Like old radio dials....
 
 
Any thoughts on that?

 

[ramenmeal]

I can definitely see this being a good feature for higher end headphone amps, but I really doubt it happening in the lower market

 

[Arlekiin]

Depends on the definition of higher end amps if we talk about 200+ USD amps then yes I agree that there is no point in trying to add such a feature to sub 200USD amplifiers.
Anything over 200 could have these features since the cost of parts could be pretty low if we are talking about commercial amps then I think it would make sense to have this feature as an option for extra 30-50USD.

 

[MrTom]

I was thinking about this today!
 
Are you thinking about implementing this on a full size amplifier?
 
In my simple mind, the circuit for servo/stepper control would be the easy part - the hard part would be setting up the linkage in an elegant way.
 
If you are thinking of doing this, remember that most (if not all) hobby servos can not turn continuously and will need to be modified in order to defeat the physical stops (in most cases this is a simple dremel job).
 
If you have a choice between IR and FM, I'd go IR as the hardware is arguably easier to implement. I also can't think of any interference issues you'd have with IR and your audio kit (although, I'm no expert).
 
If you do get anywhere with this, I'd love to hear how you get on!!

 

[Arlekiin]

Well Im thinking of implementing it on my DIY Morgan Jones Amp which is great for modding and later on maybe on something else aswell who knows if I ever finish it I might even set up a guide

. 
I will look into switches remote volume controls etc...there might be other solutions out there besides servos. Servos where the first solution to pop into my mind...motorized pots or electronic controllers maybe.
 

 

[MrTom]

Quote:

Well Im thinking of implementing it on my DIY Morgan Jones Amp which is great for modding and later on maybe on something else aswell who knows if I ever finish it I might even set up a guide

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I will look into switches remote volume controls etc...there might be other solutions out there besides servos. Servos where the first solution to pop into my mind...motorized pots or electronic controllers maybe.
 

 
I understand! I'm not familiar with the amp (new guy, sorry!). I was thinking that you have chosen or already like the volume pot you have, so changing it to a motorised one would be a bit of a quality downgrade? (or an expensive upgrade!!).
 
A servo would be a great way to go though, you'd only need a small one, the control circuit is very easy to drive and the resolution is pretty good, even on a cheap one. The servo mod for continuous rotation is very well documented on the web.
 
The system flow would be like this, as I see it
 
IR/FM send -> IR/FM receive -> Signal decode -> Drive motor
 
The remote control could easily be done with simple analogue circuitry (2x 555 IC's to drive the IR LED? Two different freq's), allowing the microcontroller to interpret and then drive your motor.
 
Another way would be to get rid of the pot and replace with a relay based attenuator

Using the microcontroller to also drive the resistor ladder selections. The downside would be that you'd lose the knob turning interface unless you got some rotary encoder and interfaced that with the microcontroller (not impossible, but how far do you want to go?!

)

 

[Arlekiin]

I think I prefer the servo route at least for the first mod.
However I think there are some clever tricks and guides on "hackaday.com" about making rotary encoders using andruino but using andruino would be overkill for such a project.

 

[MrTom]

Quote:

I think I prefer the servo route at least for the first mod.
However I think there are some clever tricks and guides on "hackaday.com" about making rotary encoders using andruino but using andruino would be overkill for such a project.

Yes there is, I remember the article I think - Grey code?
 
It would be massive overkill. Although you could use a mousewheel encoder

 
If you used a stepper, you could leave the volume knob in 'gear' and turn it, if you used a servo, you'd need a slip clutch or some other method so the servo gears didn't get mashed.
 
Hmm, I think I'm making this a lot harder than it should be - I'll step out and let you find a simpler solution