Need recommendations for impedance matching volume controls that aren't too bulky - AVS Forum
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post #1 of 9 Old 12-02-2011, 03:25 PM - Thread Starter
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I had purchased a couple of rotary style impedance matching volume controls from Monoprice but as I was putting them in, the transformers are simply too bulky to fit properly into the gang box I have. The problem is at each volume control area, it is above some kind of light switch. So I've got some electrical work that is just getting in the way of it fitting properly.

The second issue is my wife thinks the rotary style volume controls look ugly. The best I can think of (aside from dropping $1000+ on some kind of integrated system like from Nuvo (preferable) or HTD) is to get a slider type. She seems ok with that. I've looked at many slider type volume controls but I don't want to start ordering items without knowing if they will be bulky. I realize my question is a little vague without providing dimensions but I'm just looking for any recommendations for a slider controls that are good quality, look nice, don't feel "cheap" and aren't bulky.

The speakers that the volume control will be controlling can handle up to 100+ watts but I doubt the receiver will be putting out that much. I'll be hooking up 3 pairs of speakers in parallel (hence the need for the impedance matching controls) to a zone B on a Pioneer VSX-1021-K.

I guess for more background, I had looked into the Lutron Chopin controls. Those actually looked pretty good for what I wanted to do, however you need an entire controller per zone, and I have 3 zones... it just seemed weird the way it worked.

The mid-level system from HTD looked pretty good, but for $1100... it's just too much for me to spend at the moment. Same with the Nuvo Essentia (that would be my dream pick though simply because the controls look pretty slick).
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post #2 of 9 Old 12-02-2011, 11:49 PM
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I'm not an expert on this stuff, but I don't believe impedance matching controls allow you to use multiple speakers off one amplifier channel like you are proposing. I think it is one speaker per channel only.

Take a look at the Leviton system matching module and their non-matching volume control sliders.

SG-AMP

SG-VST Volume Control


I've done the exact same setup - used the Zone 2 of a Yamaha receiver to power three pairs of speakers in bedrooms throughout a house. The receiver speaker connections connect to the SG-AMP module, then each volume control connects to each output on the SG-AMP.
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post #3 of 9 Old 12-03-2011, 05:41 AM
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The statement made by sebberry is incorrect.

To my knowledge all impedence matching volume controls are bulky. The non-impedence matching are smaller.

what is you setup? maybe you can use non impedence matching volume controls by adding a multi-channel amp.
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post #4 of 9 Old 12-03-2011, 11:03 AM
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Quote:
Originally Posted by canuck_fr View Post

The statement made by sebberry is incorrect.

It's ok, I'm learning here too.

So it is OK to daisy chain multiple impedance matching controls on one amp channel and they'll work to maintain a safe impedance?


Would the controls have to be in series or could you run them in parallel too?


I still think if you have the wires from all three rooms it will be cleaner and safer to patch it all in to the Leviton matching module. The controls are a bit smaller too since there is no transformer on them.
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post #5 of 9 Old 12-03-2011, 11:05 AM
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Quote:
Originally Posted by canuck_fr View Post

what is you setup? maybe you can use non impedence matching volume controls by adding a multi-channel amp.

He wants to run three rooms off the Zone B of the receiver. It would be cheaper to use the Leviton unit to distribute the speaker wires into the various rooms than to add a multi-ch amp.

He'd still have to run impedance matching controls if he had a multi-ch amp, no?



This stuff makes me
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post #6 of 9 Old 12-03-2011, 01:46 PM
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Quote:
Originally Posted by sebberry View Post

So it is OK to daisy chain multiple impedance matching controls on one amp channel and they'll work to maintain a safe impedance?

He's not daisy chaining them, he's running them in parallel, and that is exactly what the impedance-matching device is for - to compensate for multiple pairs in parallel.

Quote:


He wants to run three rooms off the Zone B of the receiver. It would be cheaper to use the Leviton unit to distribute the speaker wires into the various rooms than to add a multi-ch amp.

True, but the multichannel amp approach allows for upgrades to a multi-source system in the future...

Quote:


He'd still have to run impedance matching controls if he had a multi-ch amp, no?

No. With one pair of speakers per channel pair, there's nothing to "match"...

Jeff


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post #7 of 9 Old 12-03-2011, 02:01 PM
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Quote:
Originally Posted by jautor View Post

No. With one pair of speakers per channel pair, there's nothing to "match"...

Interesting. The way I always understood it was that if you were adding a volume control, adjusting the volume would alter the impedance of the load. My understanding was that the impedance matching control was to ensure a consistent load regardless of the volume setting.

So what happens to the impedance presented to the amplifier when you use a non-matching volume control? Surely it doesn't stay at 8 ohms, does it?




Another question - if you run two speakers in parallel, the impedance drops by one half. If you add more, the impedance continues to drop. If you have 4 8 ohm speakers for example, the impedance would rop down to 2 ohms, right?

So if impedance matching controls maintain each speaker at the 8ohm load regardless of volume setting, why would having 4 volume controls not cause the system impedance to drop?
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post #8 of 9 Old 12-03-2011, 05:26 PM
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Quote:
Originally Posted by sebberry View Post

Interesting. The way I always understood it was that if you were adding a volume control, adjusting the volume would alter the impedance of the load. My understanding was that the impedance matching control was to ensure a consistent load regardless of the volume setting.

No, that's not correct. Impedance matching is to "match" the expected impedance at the amplifier - which is an 8 ohm speaker per channel.

Quote:


So what happens to the impedance presented to the amplifier when you use a non-matching volume control? Surely it doesn't stay at 8 ohms, does it?

See "potentiometer" - it's a voltage divider...

Quote:


Another question - if you run two speakers in parallel, the impedance drops by one half. If you add more, the impedance continues to drop. If you have 4 8 ohm speakers for example, the impedance would rop down to 2 ohms, right?

So if impedance matching controls maintain each speaker at the 8ohm load regardless of volume setting, why would having 4 volume controls not cause the system impedance to drop?

Again, volume isn't the issue - it's the nominal impedance of the load. The "matching" is compensating for the 1/n change when speakers are connected in parallel.

Jeff


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post #9 of 9 Old 12-05-2011, 08:45 AM - Thread Starter
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I ended up getting the SGAMP and the volume controls suggested by sebberry. Hopefully this gets me what I need.

I'll definitely move to a multichannel amp in the future but I need something relatively cheap right away. Thanks for the help guys.
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