Outdoor Volume Control Affecting Both A & B Channels.

[mauritzr]

Hi all,

I have been lurking on this forum for a while now and it has helped me in numerous ways so a big thank you to everyone on here!

I am currently experiencing a problem that I have not been able to find a solution for. I have an older pioneer receiver that I have set up to power 4 outdoor speakers, two on channel A and another pair on B. I have installed outdoor volume controls on both channels.

The problem that I am having is that the outdoor volume controls are not working properly. If you try to adjust the volume on one channel (A) then it also affects channel (B). Does anyone know if this is a receiver problem or could it be an issue with the volume controls? Any help provided will be greatly appreciated!

Thanks,

M

 

[adk highlander]

Hello mauritzr and welcome to the forum.

Could you give us a bit more info as to how the controls are wired to the receiver. (parallel, series, etc.) Do you have the model of volume control you are using?

Thanks.

 

[mauritzr]

Thanks for the quick reply adk.

I am not certain about the type of control that I am using as it is 150 miles from where I am right now. I do know that it is rated for 80 watts a channel and that each controller has a left and right input and output and that I am using one volume control for A, and one for B.

Channel A has a L & R speaker outputs which are wired into the volume control inputs and then on to the speakers through the outputs of the volume control. Same with channel B. So basically the volume controls and then the speakers are wired directly into their respective outputs on the receiver, no parallel or series wiring needed (I think) as each speaker has a dedicated output on the receiver.

 

[MDS]

The A and B speaker outputs on a receiver are generally wired in parallel internally and the main volume control of the receiver will affect both sets of speakers at the same time.

You cannot use two separate external volume controls if the desire is to control the volume of each pair of speakers independently. You'd need to drive each pair of speakers from different speaker outputs of the receiver.

Alternatively you could use a speaker selector and just connect it to the A terminals and the volume controls and speakers to its outputs.

 

[mauritzr]

I understand that the main volume control on the receiver will control both A & B channels. My hope was to set the main volume at a certain level and then use the separate volume controls to adjust as needed.

Each speaker is driven from a separate channel on the receiver.

Receiver Channel A has a L & R output. Each one of these outputs is wired directly into it's separate input on the volume control (L&R inputs). Then it continues on through the volume control outputs (separate L&R) to the speakers. Channel B is wired the same.

Here is a simple diagram. Each line represents the (+) and (-) of the L & R speakers.

 

[TLS Guy]

I understand that the main volume control on the receiver will control both A & B channels. My hope was to set the main volume at a certain level and then use the separate volume controls to adjust as needed.

Each speaker is driven from a separate channel on the receiver.

Receiver Channel A has a L & R output. Each one of these outputs is wired directly into it's separate input on the volume control (L&R inputs). Then it continues on through the volume control outputs (separate L&R) to the speakers. Channel B is wired the same.

Here is a simple diagram. Each line represents the (+) and (-) of the L & R speakers.

Speakers A & B are using the same amps, and are not intended to be run concurrently.

If you plan on running all speakers together then the speakers should be 16 ohm if your receiver is 8 ohm rated or 8 ohm if it can handle 4 ohms.

I also suspect your volume controls are not impedance matching, which will put your receiver at risk.

What I would do is parallel two left speaker and two right speakers. Use two impedance matching volume controls, one for each channel and connect the volume controls to the A or B speaker terminals but not both.

 

[mauritzr]

Ok, I don't understand why the A and B are not to be run concurrently. Before I installed the volume controls I had both channels running with no problem.

My problem appeared with the volume controls (and the problem disappears when both are set to max). I understand that both channels (A&B) are prob running off of the same amp. My question is; Is it possible to install a volume control and not have it affect the other channel?

I currently have this volume control
http://www.amazon.com/Proficient-Audio-Systems-VC60AW-60-Watt/dp/B001JT16X6

There is no indication that it is impedance matching but I don't see how that can be an issue considering that each 8 ohm speaker is running off of it's own channel. I never had any impedance issues before the volume controls, so why would that be an issue now? The problem I am having is when I adjust the control on channel A, it is affecting channel B and vice versa.

 

[MDS]

Ok, I don't understand why the A and B are not to be run concurrently. Before I installed the volume controls I had both channels running with no problem.

But the master volume control on the receiver affected both sets of speakers at the same time. They are being run concurrently from a single amp with two sets of outputs wired in parallel.

TLS Guy is talking about the fact that when wired in parallel the impedance halves. The receiver can usually handle two sets of stereo speakers in this fashion but it's a strain on the amp at higher volume levels. Hence the recommendation to use 16 ohm speakers or impedance matching volume controls to keep a steady 8 ohm impedance. If the receiver is handling both sets without difficulty then no worries but that doesn't change the fact that you cannot do what you want to do and independently set the volume of each set of speakers with volume controls that are wired to a single output.

 

[TLS Guy]

Ok, I don't understand why the A and B are not to be run concurrently. Before I installed the volume controls I had both channels running with no problem.

My problem appeared with the volume controls (and the problem disappears when both are set to max). I understand that both channels (A&B) are prob running off of the same amp. My question is; Is it possible to install a volume control and not have it affect the other channel?

I currently have this volume control
http://www.amazon.com/Proficient-Audio-Systems-VC60AW-60-Watt/dp/B001JT16X6

There is no indication that it is impedance matching but I don't see how that can be an issue considering that each 8 ohm speaker is running off of it's own channel. I never had any impedance issues before the volume controls, so why would that be an issue now? The problem I am having is when I adjust the control on channel A, it is affecting channel B and vice versa.

The problem is that A & B speakers use the same amplifiers. So there is no difference between connecting all speakers to either A or B or connecting the two sets to A & B independently and selecting A & B speakers concurrently.

Now I don't know what the impedance of your speakers are, and I don't know if your receiver is rated at four or 8 ohms. If your receiver is rated for four ohms you will be fine if you take the next steps.

You have the wrong volume controls. You need the impedance matching controls.

Now you need to know the impedance of your speakers. Then connect each speaker to the impedance tap on the impedance matching controls that is the same value as the impedance of that speaker.

Now the speakers that are connected to that control will make the amplifier see an impedance of 8 ohms.

Now whether you connect the two controls to A or B or both, the amplifier will see an impedance of four ohms if all speakers are playing.

So if you connect one set of speakers to A and the other to B, the amplifier will see an 8 ohm load when playing A or B alone, but if you play all sets it will see four ohms. Unless your receiver is four ohm rated I do not recommend using both sets of speakers at the same time, unless this is always a low volume background music situation.

 

[XEagleDriver]

Because the volume controls are variable resistors

Ok, I don't understand why the A and B are not to be run concurrently. Before I installed the volume controls I had both channels running with no problem.

My problem appeared with the volume controls (and the problem disappears when both are set to max). I understand that both channels (A&B) are prob running off of the same amp. My question is; Is it possible to install a volume control and not have it affect the other channel?

I currently have this volume control
http://www.amazon.com/Proficient-Audio-Systems-VC60AW-60-Watt/dp/B001JT16X6

There is no indication that it is impedance matching but I don't see how that can be an issue considering that each 8 ohm speaker is running off of it's own channel. I never had any impedance issues before the volume controls, so why would that be an issue now? The problem I am having is when I adjust the control on channel A, it is affecting channel B and vice versa.

Mauritzr,

FWIW: The reason a change to Volume Control #1 (VC1) causes a change on Volume Control #2's (VC2) speakers is that the two volume controls are in fact connected in parallel at the receiver's A/B speaker posts.

Therefore, a change to the volume setting on VC1 (which changes it's resistance/impedance) causes a change in the current going to VC2 (or visa versa). This is what is causing the phenomenom you are experiencing.

A simple way to view this is. Electrons are lazy little SOBs, and if the impedance in one VC is increased more of the lazy little SOBs will go to the other VC since it is "easier" to pass through.

The reason this does not happen at full max volume on the VC, is then the VC is at it's least resistance setting and is acting like a piece of wire (aka what you had before adding the VCs).

Options:

1) An impedance matching volume control should fix this, by presenting a consistent impedance to the receiver's amplifiers independent of VC setting or speaker impedance. So the little lazy SOBs will go in equal amounts to each speaker set, independent of the volume setting on the VC.

2) If your receiver supports it, you can "assign" a second set of amplifiers to output the audio signal and then connect VC2 to these other speaker posts instead of the Speaker "B" posts. These are normally either the surround or rear surrounds speaker posts. This option, if available will be found in the "bi-amp" section of your manual.

FWIW: Thanks for the link, I did not see any indication the VC's you are using are impedance matching.

Cheers,
XEagleDriver

 

[WaynePflughaupt]

The problem that I am having is that the outdoor volume controls are not working properly. If you try to adjust the volume on one channel (A) then it also affects channel (B). Does anyone know if this is a receiver problem or could it be an issue with the volume controls? Any help provided will be greatly appreciated!

Congratulations! It looks like you have that rare-bird receive that does the A/B speakers in series. I’ve only seen it once before, and perhaps not coincidentally, it was also a Pioneer. If the A and B speaker connections are internally wired in series, you would indeed have the problem you’re experiencing with L-pad connected between the amp and speakers.

I'd suggest getting a different amp with parallel connections, but as Eagle indicated, even that may not fully solve the problem.

Regards,
Wayne A. Pflughaupt

 

[TLS Guy]

Congratulations! It looks like you have that rare-bird receive that does the A/B speakers in series. I’ve only seen it once before, and perhaps not coincidentally, it was also a Pioneer. If the A and B speaker connections are internally wired in series, you would indeed have the problem you’re experiencing with L-pad connected between the amp and speakers.

I'd suggest getting a different amp with parallel connections, but as Eagle indicated, even that may not fully solve the problem.

Regards,
Wayne A. Pflughaupt

I have never seen a series A & B speaker switch. He can test that possibility, as if he selects A & B with only a speaker connected to A or B but not both he should have no sound at all, as the speakers will be open circuit.

 

[M Code]

A/B speaker switching is frequently done in a Series Connections configuration. Since the amplifier's output stage cannot handle low impedance loads < 6 Ohms especially in lower cost AVRs..

Note that (2) 8 Ohm speakers in parallel would be 4 Ohms..

Just my $0.02....

 

[TLS Guy]

A/B speaker switching is frequently done in a Series Connections configuration. Since the amplifier's output stage cannot handle low impedance loads < 6 Ohms especially in lower cost AVRs..

Note that (2) 8 Ohm speakers in parallel would be 4 Ohms..

Just my $0.02....

We have been through the impedance issue.

The OP had better find out pretty quickly if his A/B selector switch is a series connection. If so, it means that receiver can not handle four ohm loads and he will not be able to use speaker volume controls. He will need another receiver that can handle four ohm loads.

 

[M Code]

We have been through the impedance issue.

The OP had better find out pretty quickly if his A/B selector switch is a series connection. If so, it means that receiver can not handle four ohm loads and he will not be able to use speaker volume controls. He will need another receiver that can handle four ohm loads.

EZ to check Series connections..
1. Switch both speakers A & B ON
2. Disconnect 1 lead of the left speaker A
What happened?
A. If the left speaker B stopped playing then it is Series connections
B. If the left speaker B kept playing then it is Parallel connections

Next question..

Just my $0.02...

 

[TLS Guy]

EZ to check Series connections..
1. Switch both speakers A & B ON
2. Disconnect 1 lead of the left speaker A
What happened?
A. If the left speaker B stopped playing then it is Series connections
B. If the left speaker B kept playing then it is Parallel connections

Next question..

Just my $0.02...

Please read the tread. We have been there.