Another APOX volume control project

[tiroth]

Here is my completed APOX project. This is the control module.

 

[tiroth]

Insides of control.

 

[tiroth]

Closeup. I like to use a double-insulated transformer for the always-active part.

 

[tiroth]

Here is the satellite module that controls the front, center, and sub channels.

 

[tiroth]

This one controls the rear channels, and also matrix decodes the center-rear channel.

 

[dhaen]

”ü‚µ‚¢ ‚Å‚·‚Ë�B🙂

 

[Rarkov]

Hi,
Simply beautiful cause work...
So much so, that I'm going to steal it for the two or three chassis I have to build! Thanks for the inspiration! 🙂

Gaz

 

[Rarkov]

Hi,
I forgot to ask a couple of questions...

Where did you get the knobs?

What is the main case resting on?

How did you cut the window for the LCD? This is my nemisis!

Thanks,
Gaz

 

[tiroth]

”ü‚µ‚_‚È‚¢‚¯‚Ç�A‚_‚肪‚Æ‚¤‚²‚´‚¢‚Ü‚·�B

Thanks for the compliments. I must admit I was inspired myself by the Levinson equipment with the "tower" sides.

The knobs are from Kilo International...they are carried by Digikey and are only $6.
http://www.kilointernational.com/knobs/knobs.html

In the back there are two rubber feet. No need to get fancy with cones here. 😉 As far as the window, I effectively cheated with the design...the copper plate is thin enough that I could use a nibbling tool to get a nice rectangular opening.

 

[macboy]

How did you perform the matrix decode for the surround-back channel?

 

[tiroth]

Perhaps "decode" is too fancy a word...I simply summed L+R with a level adjustment, and 1st order LP at 7kHz to avoid destroying the stereo image. I tend to localize surround effects to one side when I am sharing the couch with my wife, so I hope this helps center the sound stage a bit better...no comments yet.

I forgot to note that the core components of this project are for sale here:

http://www.apoxcontrols.com/apox.htm?

Question: I've noticed that others seem to have better contrast on their LCD...I haven't been able to adjust mine much at all. Changing the brightness doesn't change the ratio of bleedthrough to character saturation, and the contrast adjustment itself is useless: one click is barely readable, 2-3 clicks and the text completely disappears. The refresh rate is very slow too, as if the contrast is too high...any suggestions? I'd like to be able to read the screen from 6' away...

 

[speaker]

This one controls the rear channels, and also matrix decodes the center-rear channel.

Which case is this, a Hammond?

speaker

 

[bigparsnip]

If you want to change the contrast of the screen try putting some different colour filters in front of it (you can experiment with different colour sweet wrappers from something like a box of quality street, and then you get to eat the chocolate too) as this will change the contrast of the display when you are looking at it through the filter.

 

[tiroth]

Thanks for the suggestion bigparsnip.

speaker, the case is a Hammond 1455N2201.

 

[roger-k]

Hi Tiroth!

Very nice work!!!

I can see you have used DIL-relays In the controller which controls the rear channels. Is these relays for the volume-control?

If it is, how is the sound quality?
Can you hear any click when you adjust the volume?

 

[moving_electron]

Perhaps "decode" is too fancy a word...I simply summed L+R with a level adjustment, and 1st order LP at 7kHz to avoid destroying the stereo image.

This article indicates that although L+R is proposed for center channel, the difference between L and R (L-R?) is what should be sent to the rears.

This makes sense since speach and other things that are associated with characters in the center of the stereo image are kept to the front. It also means that that low base probably never gets sent much to the rears, therefore the reliance on good main speakers or a room filling sub.

http://sound.westhost.com/project18.htm

 

[Cobra2]

How did you get all those boards to work together?

My Apox (IR1) will not even let me connect 4 input-boards...(for 8-inputs).
And I do not get any replies from Apox-support or Dale anymore...
Have anybody heard from them lately?

Arne K

 

[tiroth]

This article indicates that although L+R is proposed for center channel, the difference between L and R (L-R?) is what should be sent to the rears.

Sorry to be unclear. I have discrete rear channels so no need to decode the antiphase signal. The center-rear is the sum of the discrete rear channels.

My Apox (IR1) will not even let me connect 4 input-boards...(for 8-inputs).

I'm afraid I cannot help you as I do not have any input boards at all. I did find a bug though..."last volume" doesn't work if the "standby" mode is used. Arg. 😡 Hopefully this is an easy fix.