Running two sets of speakers off one output

[Papajoe 221]

Hi All,

My neighbor is going to use one channel of his TFM-25 to drive two sets of outdoor speakers.  He can't use both channels due to a physical problem. He only ran 1 set of wires from the amp position to the switch area when  wiring his house.  So, he will try to accomplish this by feeding one channel of the amp to a splitter switch that has some sort of amplifier built in . (I have not seen the unit.) Its one of those 'A', 'B' and 'A' plus 'B' ones. Will he need to use 16 ohm speakers outside,so that when he chooses 'both' he doesn't overload the amp? I seem to remember something about speakers in parallel.

Thanks,

Papajoe

Edited June 25, 2018 by Papajoe

[Daddyjt 9,645]

Is he running one pair or two pair of speakers?

 

if he’s just running one pair, and he doesn’t plan to push concert levels, I would think one channel of a TFM 25 would handle two 8 ohm speakers in parallel just fine.  If he’s running TWO pair, then run each pair in series, then parallel the two sets, to present an 8 ohm load to the amplifier. 

 

Mnd you, this would not be an ideal setup for critical listening, but for a mono outdoor background music duty, is completely acceptable. 

 

[zumbini 6,150]

3 hours ago, Papajoe said:

he will try to accomplish this by feeding one channel of the amp to a splitter switch that has some sort of amplifier built in . (I have not seen the unit.) Its one of those 'A', 'B' and 'A' plus 'B' ones.

I've never seen a speaker selector switch that was powered, but there are some that provide passive gain controls for matching levels.

 

Note that you don't need a selector switch to run 2 pairs of speakers in series parallel as Mark suggested.

[kve777 6,889]

We would need the make and model of this amplified switch device to fully understand the ramifications.

[Papajoe 221]

He is wanting to have each location running stereo.  I will find out about the switch.

Papajoe

[zumbini 6,150]

You lost me Joe. I thought you said he only had one channel available.

 

5 hours ago, Papajoe said:

He can't use both channels due to a physical problem. He only ran 1 set of wires from the amp position to the switch area when  wiring his house.

 

[Papajoe 221]

Sorry about all the confusion. I am confused myself and if I am confused that is not a good thing.  My neighbor and I talked about this during one of our 'after 5 PM meetings' and you know what that means 'wine' will be present.   More about this later. We need at least one more 'meeting' for clarification.

Papajoe       

 

Edited June 26, 2018 by Papajoe

[loner_t 2,568]

22 minutes ago, Papajoe said:

We need at least one more 'meeting' for clarification.

 

Hopefully, it will be 'before 5pm', sans wine. ?

[Papajoe 221]

Hey,

I'm a pure bred Italian, we do some of our best planning with a 'wine' catalyst.

Papajoe   

[Papajoe 221]

Well, I finally got the info on that 'switch'. It's an Audiosource AE100VC. It is an 'Impedance matching volume control'. It is used to allow you to run up to 16 '8' ohm speakers off of one channel of an amp without overloading the amp. It has a slide switch that allows you to choose 1x, 2x, 4x and 8x, depending on how many speakers you have. I believe that it presents a 4 ohm load to the amp. It also has a master volume control included.

He will be running 2 pairs of 8 ohm speakers. The A,B, A+B switch is just that.  He is using one channel of his TFM 15 amp to run these outdoor speakers. The other channel will be used to run a wireless speaker set  into his shop.  The whole thing will be controlled by the 'second zone' on his CT-17 preamp. Doesn't sound that confusing anymore.

Papajoe

[loner_t 2,568]

32 minutes ago, Papajoe said:

He is using one channel of his TFM 15 amp to run these outdoor speakers.

The 'stereo' imaging will suffer, depending on what is fed into the TFM-15.

Edited June 27, 2018 by loner_t

[Papajoe 221]

Maybe, I did not put that correctly. He will be using the 'A' speaker outputs on the amp to run his outdoor speakers. Saving the 'B' output for  a second pair of speakers, later.    

[zumbini 6,150]

21 minutes ago, Papajoe said:

Maybe, I did not put that correctly. He will be using the 'A' speaker outputs on the amp to run his outdoor speakers. Saving the 'B' output for  a second pair of speakers, later.    

Now it makes sense Joe. The amp is a TFM-15 with 4 pairs of speaker binding posts (like a receiver), not a TFM-25 as originally stated.

 

Note the caution which recommends a 16 ohm minimum when using both A and B speaker outputs:

 

[Papajoe 221]

Zumbini-

You are correct about the wrong amp. When I first went to his house and started talking to him about I thought was a possible conflict with his amp, he looked at me and said "I am going to use the TFM-15 not the TFM-25. Then I remembered that I had also sold him a TFM-15 to use just for this purpose.  Boy, did I feel 'dumb'. LOL

Papajoe