FS: 6-channel volume--discrete, balanced (APOX) - diyAudio
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Old 24th February 2005, 05:10 PM   #1
tiroth is offline tiroth  United States
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Join Date: Dec 2001
Location: Pittsburgh, PA, USA
Default FS: 6-channel volume--discrete, balanced (APOX)

This is a complete 6-channel "passive preamp" (attenuator) based on the APOX boards. It would be great for either multichannel or for an active DCX2496 setup.

It is currently setup for balanced operation, but will also function fine as a unbalanced attenuator. You would just need to mount the input/output RCA jacks.

Features
  • All discrete (relays and resistors, no VCAs or pots!)
  • 255 attenuation steps
  • Bright blue LED display
  • Dale 1/2W resistors
  • Instant-on 12V / 1.5A trigger
  • Time delay 12V / 1.5A trigger
  • Three chassis construction
  • Remote controllable with any universal remote
  • No ground path between chassis; external transformers (wall warts) for signal chassis
  • Switches to control signal ground path
  • No earth grounding of signal chassis
  • Signal wiring only 0.5-4 inches maximum

I built this in multiple boxes to eliminate contamination due to noise from the PSU or control circuitry. It is quite silent. The volume control works fine at least 20' away from the signal boxes; it probably will work even farther away.

There are three boxes because I was using 4 channels to control front, center, sub and 2 channels to control the surrounds. The third box allowed me to run signal instead of amp wiring to the back. The third box also offers optional balanced-to-unbalanced conversion and a summed center channel output with level adjust.

The controller will also accomadate source selection; however, I do not have any of the input boards, and APOX is no longer selling to the public. They may sell some of their old stock if you are interested, I do not know.

If you are interested, please email me with an offer or any questions. I am quite open to any offer, however, to set the stage the original costs were: APOX boards ~$350, the resistors ~$40, plus metalwork, connectors, etc. I will not charge for blood and sweat.

The pics below are rather old; I will get some detail shots of the signal wiring ASAP.

Click the image to open in full size.

Click the image to open in full size.

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Old 24th February 2005, 09:25 PM   #2
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Join Date: Jan 2001
Location: Scandinavia
Default Wow - that looks impressive!

Well done - excellent work!

What are the impedances of the volume section?

I am impressed.

Petter
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Old 25th February 2005, 01:36 AM   #3
tiroth is offline tiroth  United States
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Join Date: Dec 2001
Location: Pittsburgh, PA, USA
Thanks! It is not up to Peter's standards, but maybe some day... The main shunt resistor is 50K, the minimum impedance is 5K.

Here are some more pictures:
Click the image to open in full size.
Large version: http://www.anidian.com/imgs/3q_large.jpg

Teflon shielded solid core wiring
Click the image to open in full size.
Large version: http://www.anidian.com/imgs/in_left.jpg
Large right side: http://www.anidian.com/imgs/in_right.jpg

Exterior: http://www.anidian.com/imgs/ext.jpg
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Old 25th February 2005, 02:03 AM   #4
bowdown is offline bowdown  Australia
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Join Date: Feb 2004
Location: Perth
yeah im interested but what do you want for it in total?? If you wish to discuss it with on email you can contact me at gurujabbal@telstra.com

cheers

Bowdown
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Old 25th February 2005, 01:14 PM   #5
tiroth is offline tiroth  United States
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Join Date: Dec 2001
Location: Pittsburgh, PA, USA
I've sent replies to those who requested more information.

Here is some additional technical info from the APOX site:
http://www.apoxcontrols.com/apox1.htm
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Old 26th February 2005, 03:04 AM   #6
Illusus is offline Illusus  Canada
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Location: Prairie Wasteland, Canada
Default Re: FS: 6-channel volume--discrete, balanced (APOX)

" I will not charge for blood and sweat. " - ewww, there's blood and sweat in there?! JK.

Anyway, nice work on the chassis, very simple and very stylish.
__________________
Fighting the program since 1976.
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Old 28th February 2005, 01:27 PM   #7
tiroth is offline tiroth  United States
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Location: Pittsburgh, PA, USA
$450?
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Old 8th March 2005, 04:32 AM   #8
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Tiroth,

Have you received any of my e-mails? If not I am fritz@inreach.

Fritz
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Old 8th March 2005, 03:42 PM   #9
tiroth is offline tiroth  United States
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Join Date: Dec 2001
Location: Pittsburgh, PA, USA
SOLD - thanks.

Fritz, reply off to you -- sorry you missed it.
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