Looking to add a motorized Volume Control to my TC-7520 need some advice

Anybody toy with the idea of a motorized pot? I'd really like to integrate something like this into my TC-7520 even if it means popping it into another case or a separate case for the pot.

Any ideas or suggestions? Can someone tell me how the pinout on the TC-7520 compares to this:

http://www.hificollective.co.uk/pdf/alps_layout1.pdf

And would it be easy enough to wire this board in?

http://www.hificollective.co.uk/pdf/gh_remote.pdf

I am not too astute in electronics but can follow instructions on point to point wiring.

As these pots come in 10k, 50k and 100k log as well as 10k and 100k linear taper, which would be most suitable?

You'll find the POT value somewhere in this thread http://theartofsound.net/forum/showthread.php?t=4933

Quote:

---

Originally Posted by Stratmangler

You'll find the POT value somewhere in this thread http://theartofsound.net/forum/showthread.php?t=4933

---

I sent the Op a PM.....no values listed there.

Great idea on the case though. Maybe I will try to add a few other things while I am at it like remote controlled input selection.

A few kits on Ebay may do just the trick:

http://cgi.ebay.com/IR-Remote-Contro...-/320524563918
http://cgi.ebay.com/Remote-Volume-Co...-/260455171082

http://cgi.ebay.com/IR-Remote-Contro...-/220620288227

http://cgi.ebay.com/Panasonic-motori...-/320512195805

Looks like I can build one fairly easy as well.

http://www.siliconchip.com.au/cms/A_30559/article.html

http://www.siliconchip.com.au/cms/ga...=0&a=30559&i=4

Pinouts for the Alps pot

http://cgi.ebay.com/ALPS-dual-motori...item519338cded

What is the correct type, linear or logarithmac?

It was this post in the thread linked to http://theartofsound.net/forum/showp...1&postcount=47

Quote:

---

Originally Posted by Stratmangler

It was this post in the thread linked to http://theartofsound.net/forum/showp...1&postcount=47

---

Thank you....

What is the difference between a linear and logarithmic pot?

On a linear scale, a change between two values is perceived on the basis of the difference between the values. Thus, for example, a change from 1 to 2 would be perceived as the same amount of increase as from 4 to 5.
On a logarithmic scale, a change between two values is perceived on the basis of the ratio of the two values. That is, a change from 1 to 2 (ratio of 1:2) would be perceived as the same amount of increase as a change from 4 to 8 (also a ratio of 1:2).

So a linear pot increases the volume evenly over its entire range of travel.

A log pot increases the volume to a lesser and lesser extent over it's range. So towards the top of it's range, turning the knob up a little only makes a very small increase to the volume, thus giving you finer control at louder volumes. For this reason log pots are often chosen for volume controls.

So I'd recommend you get a log version. The Alps Blue Velvets are reasonably priced and I think they're available from HiFi Collective and familygate on ebay. You'll also need a controller board and they're not cheap.

Excellent explanation. Thank you.

I'd love to find a source stateside for this stuff. Looks like I can get the Alps pot rather cheap/easily, still in search of a controller.

Quote:

---

Originally Posted by Stratmangler

It was this post in the thread linked to http://theartofsound.net/forum/showp...1&postcount=47

---

As the existing volume control is 20K, can I utilize a 10K, 50K or 100K? I don't see that there is a motorized 20K

http://cgi.ebay.com/ALPS-Potentiomet...-/350267364986

I did find this however, looks like the shaft size is different:

http://www.mouser.com/ProductDetail/...85DQt5lqqCI%3d

http://www.rapidonline.com/1/1/1707-...ntiometer.html

:popcorn:

Man this is a great idea. I think there might be room for something like this in my amp. I'll be following this thread closely.

Be sure to post lots of detailed info and pics! Thanks!

Could anyone offer advice as to how to wire this up to the 7520:
http://cgi.ebay.com/IR-Remote-Contro...-/220630057277

This looks like a real easy DIY:

http://www.flickr.com/photos/linux-works/3875427675/

Anyone care to offer some help? I am going to tackle this design:

http://www.flickr.com/photos/linux-works/3875427675/

The chip in this design "L293" http://www.st.com/stonline/products/...1330/l293d.pdf looks to be the device that would go between the TC-7520 existing volume control and the motorized volume control, correct?

The motorized volume control I will be using is this alps pot http://www.mouser.com/ProductDetail/...85DQt5lqqCI%3d

How exactly would I wire the tc-7520 to the L293? My techie friend is on vacation until Monday, I am sure he can tell me but I thought I'd get this going

You could always try the LDR type.
I spotted this t'other day http://www.tnt-audio.com/accessories...control_e.html

problem is all the cool design are in the UK! Shipping to the states gets ridiculous.

What I posted above will cost less than $20 including the motorized volume control

Quote:

---

Originally Posted by Stratmangler

You could always try the LDR type.
I spotted this t'other day http://www.tnt-audio.com/accessories...control_e.html

---

That's cool, Chris, cheers. I've got all the bits for a LS clone but never thought of adding remote control. :)

Quote:

---

Originally Posted by fmzip

Anyone care to offer some help? I am going to tackle this design:

http://www.flickr.com/photos/linux-works/3875427675/

The chip in this design "L293" http://www.st.com/stonline/products/...1330/l293d.pdf looks to be the device that would go between the TC-7520 existing volume control and the motorized volume control, correct?

The motorized volume control I will be using is this alps pot http://www.mouser.com/ProductDetail/...85DQt5lqqCI%3d

How exactly would I wire the tc-7520 to the L293? My techie friend is on vacation until Monday, I am sure he can tell me but I thought I'd get this going

---

Does it take specialized equipment or software to program the EEPROM?

Is that ALPS motorized pot linear? I think the pot in my amp might be linear because I can hardly turn it without big volume changes. I have to be really careful so if it was remote controlled it would probably be hard to dial in the perfect volume level.

Quote:

---

Originally Posted by James G

Does it take specialized equipment or software to program the EEPROM?

Is that ALPS motorized pot linear? I think the pot in my amp might be linear because I can hardly turn it without big volume changes. I have to be really careful so if it was remote controlled it would probably be hard to dial in the perfect volume level.

---

It's logarthmic. Either will work from what I have read.


You can order the chip from this guy and he said he'd load the firmware free of charge:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=250649137554

Firmware is here:

http://www.netstuff.org/mvc-master/firmware/arduino/

I have an email into the guy who developed it to ask him what is the difference between the two firmwares. Looks like he based the software to use a sony dvd remote using the transport arrow keys and the center button for volume up and down and slow volume up and down using the left and right keys, center button being mute.....

I have all the parts ordered from Digikey for the PCB assembly, two sets of parts cost me $15, and the motorized volume controller were $7 a piece. Pretty cost effective approach if this works

Quote:

---

Originally Posted by fmzip

<snip>
You can order the chip from this guy and he said he'd load the firmware free of charge:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=250649137554
</snip>

---

That guy only ships to the US. :(

Drat! :steam:

http://cgi.ebay.com/New-ATMega328P-A...-/250659877878

http://cgi.ebay.com/ATMEL-ATmega328-...-/220607156582

http://cgi.ebay.com/ATMEGA328P-PU-Ar...-/110537828578

A couple of these guys are in China so they certainly will ship to you.

Just ask them if you give them a firmware file if they will load it for you.

Also there are a ton of them on Ebay UK:

http://shop.ebay.co.uk/?_from=R40&_t...All-Categories

Thanks for the lookups Fran. I may wait to see how you get along with it before making any moves. My experience doesn't extend to breadboarding, so...

This is a worthwhile project I think though, with many possible applications. Walk us through it please! :)

Quote:

---

Originally Posted by James G

Thanks for the lookups Fran. I may wait to see how you get along with it before making any moves. My experience doesn't extend to breadboarding, so...

This is a worthwhile project I think though, with many possible applications. Walk us through it please! :)

---

+1

I suspect I'm not the only one - Caiman with remote volume would be a very attractive proposition straight into a power amp...

:popcorn:

Quote:

---

Originally Posted by Alex_UK

+1

I suspect I'm not the only one - Caiman with remote volume would be a very attractive proposition straight into a power amp...

:popcorn:

---

Not only the Caiman, that thing looks small enough to fit into a lot of tight places. You can find some pretty snazzy looking IR receivers that would blend right in with the rest of your gear and not look out of place! :eyebrows:

Quote:

---

Originally Posted by fmzip

Anyone care to offer some help? I am going to tackle this design:

http://www.flickr.com/photos/linux-works/3875427675/

The chip in this design "L293" http://www.st.com/stonline/products/...1330/l293d.pdf looks to be the device that would go between the TC-7520 existing volume control and the motorized volume control, correct?

The motorized volume control I will be using is this alps pot http://www.mouser.com/ProductDetail/...85DQt5lqqCI%3d

How exactly would I wire the tc-7520 to the L293? My techie friend is on vacation until Monday, I am sure he can tell me but I thought I'd get this going

---

Anyone care to look at this? I have all the parts, i really need someone to draw me up a schematic so i can put it together. I have no idea as to how this L293 chip fits into the design or how I would tie this into the TC-7520.

An engineer, I am not. :)