• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

SIMPLE remote volume control with alps motorized pot

Jump to Latest
ChopperCharles

ChopperCharles

Member
Joined 2008
choppercharles.com
#1
I want to build a remote-controlled volume control into my tube amp, using a motorized pot. The Alps pot is +3v for up, -3v for down... I want to build my own IR remote and my own receiver that will operate the rotary switch.

RF is really out of the question, as the tube amp is aluminum and steel and is so shielded i'm unlikely to get a signal through. The project box I found for the remote control is also aluminum.

Does anyone sell a super-simple kit that will do this? I don't want it to work with an existing remote, I want to build it myself, and the simpler the circuit the better.

Thanks!

Charles.
 
#4
I picked up a passive preamp from Veteran that uses an Alps remote control pot and I am very happy with it. You can find the thread in the Analog Line Level section. Perhaps you can find a way to work with his setup without the preamp section. Well made with gold plated through holes.
 
#5
Mackin the box. I have the very kit you on Ebay you linked to. Have had it for years. It works well and is easy to use. Mine has a 100K pot, don't know if anything else is available.

There is some crosstalk, tho. Mostly on the relay board, but also in the volume section. I did everything I could think of to kill it, with no luck. Could never get it better than about 60dB. Just a word of warning of that's something that would bother you.
 
#6
It doesn't look like the daintamix kit actually comes with a remote control though.... I don't care about the mute or the power relay, I probably won't use those, but the crosstalk is an issue for me...

The 4-channel kit on eBay is just too much. I don't need all that, and I don't have the space for it. I shouldn't need a huge control board to give a pot +/-3v.

Any other ideas?

Charles.
 
#9
If your at all savy with any dialect of C programming, why not proto it with an arduino and burn the final project to a simple Atmega328 chip? Obviously you'd need a few logic steps in there for +3 and -3, but you could easily build your own IR receiver and have all the functions you want, how you want to control your pots. You'd even have pins left over for an LCD/VFD.
 
#10
I implemented remote control on my preamp. I was originally planning to mill my own remote control out of a billet of aluminum and use a home-made circuit, but then I came across the Apple Remote. It transmits in NEC IR format using a 38 kHz carrier. These buggers handle the demodulation and give you TTL pulses out. I then use those pulses to trigger an interrupt on an Atmel AVR micro controller that handles the decoding (and controls display and a PGA2320 volume control chip).

The new aluminum version of the Apple Remote is real sleek and only $20... You can't build your own for that never mind come anywhere close to their industrial design.

Another option is to use Philips RC-5. There's plenty of code examples (including an Atmel app note) out there for that. Note, however, that RC-5 uses a 36 kHz carrier so you'll need the RPM7136 receiver.

The PGA2320 is rather noisy -- about 10 dB above the noise floor of a low-noise op-amp (such as LME49710). The PGA2311 should be better...

~Tom
 
#11
Im using this one in my new preamp build - with an Alps POT (the cheap pot supplied with the kit has serious channel to channel tracking problems).
Altronics - Your One Stop Audio Visual & Electronics Supplier
Works with any "Universal" remote control

I'm also using the companion input/selector preamp board so I can do remote channel selection as well. Just leaving off the OpAmps etc and using tubes for the active elements.

Not a really cheap solution but it works.

Cheers,
Ian
 
#15
Attached is a cut down schematic of my remote selector/volume control box. I have removed the circuitry that is used for source identification, I used a hex display for A-AUX, D-DVD, C-CD etc.
The main purpose of putting this schematic up was to show how I drive the ALPS control, simple but very dirty but hell it works! All inputs are from a Darlington Driver chip, active Low outputs driven from a commercially made infra-red receiver module.
I take all unused inputs to ground via 100 ohm resistors and that kills any cross talk. Also I have a dedicated command to engage the Tape out sockets onto the audio Bus only when I need them.
A lot of designs leave the tape output cables hanging on the audio bus all the time 🙁
Les
 

Attachments

  • circuit diagram minimised.JPG
    circuit diagram minimised.JPG
    163.3 KB · Views: 2,802
#17
Well, a hole in the chassis and silicone. First I did a smallish one (like the one you will do for a big LED) but from extreme angles the remote didn't work so I made a bigger one and now works great. Experiment.
 
#19
RevMen said:
What about something like this?

Velleman Inc.

You can control it with pretty much any IR remote, and it has 2 output channels. You'd have to build some simple logic to translate that into +3 or -3 at the pot input.
Click to expand...

If I get it right one feeds 24V AC/DC 1A max to both channels. If for instance channel one in activated then the current starts to flow through this channel into a simple circuit that translates it into +3 Vdc. If channel two is activated then the circuit translates it into -3 Vdc.
This I understand, but as a n00b I do not understand how the circuit works that translates it into +3 or -3.
 
You must log in or register to reply here.
Top Bottom