Two amplifiers on one speaker pair

[corElement]

Hi, had a question

If I have a speaker pair with total of 8 bindings posts for woofer / tweeter and both are connected using 4 bridges, if I have 2 amplifiers, and both remain connected, but I alternate between amplifiers where one stays off while the other one plays, should I expect everything to go kaput?

 

[A K Bhattacharjee]

Hi, had a question

If I have a speaker pair with total of 8 bindings posts for woofer / tweeter and both are connected using 4 bridges, if I have 2 amplifiers, and both remain connected, but I alternate between amplifiers where one stays off while the other one plays, should I expect everything to go kaput?

My KEF speakers are attached with two amplifiers & I use alternately. No problem.

 

[corElement]

My KEF speakers are attached with two amplifiers & I use alternately. No problem.

can you elaborate on the chain? do the speakers have bridged binding posts?

 

[Subbu68]

I think it depends on the amp type.

Just electrical engineering sense. If valve (tube) amp with output transformers, the switched off amp would load the other amp. The output transformer primary would develop a high voltage when the secondary side is loaded on the other amp.

With the low impedance of the inactive amp connected parallel to the speaker, the overall impedance presented to the active amp will be too low IMO and overloading it.

I would use a speaker switch or physically change the wires on the speaker. (I had been doing it before I built a OB).

Hi, had a question

If I have a speaker pair with total of 8 bindings posts for woofer / tweeter and both are connected using 4 bridges, if I have 2 amplifiers, and both remain connected, but I alternate between amplifiers where one stays off while the other one plays, should I expect everything to go kaput?

Usually there are two pairs of binding posts on higher end speaker to bi-wire the speakers. Can you elaborate how there are 8 on yours? Must be an interesting design.

 

[mbhangui]

I would avoid such a connection. The amp that is passively connected is also a load. Some amps when switched off may not be conducting eue to various reasons like amp has an internal speaker protection circuit that switches on only when powered. Also some amps (the transistor powered ones), the transistor conducts only when voltage is provided to the emitter. So in such cases where the un-powered amp doesn't have a low impendance of the output you will be ok. But some cases it may be fatal for one or the both amp though the speaker may enjoy some sparks and bangs witnessing the death of an amp. What @Subbu68 has put a scenario is also possibe when one of the amp is a tube powered amp and the output transformer will act as a step up transformer.

Either put a speaker switch or have the other amp have pair of speaker cables that you make sure to disconnect if not using. I'm personally using a DIY speaker switch to switch two amps with two pairs of speakers

 

[MaSh]

Hi, had a question

If I have a speaker pair with total of 8 bindings posts for woofer / tweeter and both are connected using 4 bridges, if I have 2 amplifiers, and both remain connected, but I alternate between amplifiers where one stays off while the other one plays, should I expect everything to go kaput?

Yes an accident that could happen. Why do you want to try them alternatively? Rather try to Bi Amp your speakers or even Tri Amp your speakers.

MaSh

 

[corElement]

I think it depends on the amp type.

Just electrical engineering sense. If valve (tube) amp with output transformers, the switched off amp would load the other amp. The output transformer primary would develop a high voltage when the secondary side is loaded on the other amp.

With the low impedance of the inactive amp connected parallel to the speaker, the overall impedance presented to the active amp will be too low IMO and overloading it.

I would use a speaker switch or physically change the wires on the speaker. (I had been doing it before I built a OB).



Usually there are two pairs of binding posts on higher end speaker to bi-wire the speakers. Can you elaborate how there are 8 on yours? Must be an interesting design.

4 on each speaker, you make a good point

Thanks for the input guys. I've decided to manually switch rather than have them connected all the time in bridged mode.

 

[Anshul_J]

@corElement, good decision to avoid connecting 2 amps at the same time. I have personal experience with it. It is likely to cause major damage to the amps and the speaker. @Subbu68 is absolutely right, it will not happen with every amp, but it's an accident waiting to happen.

 

[surfatwork]

What's the problem if the speakers have bi-wire terminals? From the description, I am led to believe that's the situation. 8 posts suggests 4 on each speaker, 2 for the woofer and 2 for the tweeter. If the terminal bridges are removed, I don't see a problem at all.

 

[Subbu68]

What's the problem if the speakers have bi-wire terminals? From the description, I am led to believe that's the situation. 8 posts suggests 4 on each speaker, 2 for the woofer and 2 for the tweeter. If the terminal bridges are removed, I don't see a problem at all.

OP has corrected it. It has two sets for biwiring LF and HF. Biwiring posts split the HF and LF, isn't it?

If his speaker has 8 posts (4 sets), there'd be two sets of woofers and mid/tweeters . you remove the bridges and wire them to separate amps, yes no issues. But would someone design such speaker? The woofer that is not working would be acting as a passive radiator and all that modelling would make it a Uber expensive kit.

 

[A K Bhattacharjee]

can you elaborate on the chain? do the speakers have bridged binding posts?

Yes, the speakers have bridged binding posts. KEF has screw system to bridge/unbridge. I have unbridged & connected the amplifiers. In this way you cannot biwire the amplifiers.

 

[Subbu68]

Yes, the speakers have bridged binding posts. KEF has screw system to bridge/unbridge. I have unbridged & connected the amplifiers. In this way you cannot biwire the amplifiers.

How do you feed the amps?The same signal or HF to one and LF to the other throu a DSP sort of thing?

The two sets of posts when bridged lets you connect to a single amp outputting the full range. Disconnect the bridge and connect LF to one amp and HF to another or Biamp.

My present Heresy III also have and earlier Jamo too had bridged binding posts. Don't have a DSP nor two identical amps. So cannot Biamp them

 

[surfatwork]

This discussion needs a photo of the back of the speakers.

 

[surfatwork]

OP has corrected it. It has two sets for biwiring LF and HF. Biwiring posts split the HF and LF, isn't it?

If his speaker has 8 posts (4 sets), there'd be two sets of woofers and mid/tweeters . you remove the bridges and wire them to separate amps, yes no issues. But would someone design such speaker? The woofer that is not working would be acting as a passive radiator and all that modelling would make it a Uber expensive kit.

I understood it to be 8 terminals in total. So 4 per speaker. Which works out to 2 for the woofer and 2 for the tweeter. Which is normal in bi-wire speakers. Like I said, a pic would help.

 

[Subbu68]

I understood it to be 8 terminals in total. So 4 per speaker. Which works out to 2 for the woofer and 2 for the tweeter. Which is normal in bi-wire speakers. Like I said, a pic would help.

What @corElement was asking is as below, I believe so that he can avoid the hassle of disconnecting the wire from Amp 1 to speaker and connect Amp 2 if he wanted to use Amp 2 OR avoid a speaker changeover switch as @mbhangui made.
Sketch is only for one channel.


Doing so can damage the amp and speaker if the amp terminals are not isolated from speaker when switched off. That's what some of us were trying to convey.

If bi-amping, the bridge between HF and LF terminals are removed and connected to two amps one driving HF and the other LF as well as split the input signal to amps with an electronic crossover or the like.

If Bi-wiring from same amp also the bridge links to be removed, HF and LF wired separately to the same amp terminals but if that has any benefit? Electrically it only doubles the area of wire but for short connections at these current levels is it necessary? I didn't find any difference. Only difference, double the amount on the wire was swiped off my credit card and have a redundant set of wires in my junk box.

 

[Subbu68]

There was a similar thread last year

Connecting one set of speakers to two amplifiers

Hi friends. Recently I started having some problems with my AVR. It was at the service center for a quite a while, and when it came back, it again started giving issues. So I had to send it back to the service center. In the mean time, I bought a used Fosi Amp so that I could at least use my...

www.hifivision.com

 

[Shammi Dang]

Hi, had a question

If I have a speaker pair with total of 8 bindings posts for woofer / tweeter and both are connected using 4 bridges, if I have 2 amplifiers, and both remain connected, but I alternate between amplifiers where one stays off while the other one plays, should I expect everything to go kaput?

As discussed in this thread and various opinions put up by different members. I have spoiled one of my amplifier by this exercise around a year back. It was pure ignorance on my part. I connected two integrated amps to speaker having HF and LF binding posts. I used to keep one amplifier on and the other totally off that means I was using only one amp at a time. Somehow one of the amplifier developed some problems with this experiment. So please don't do this, Instead Option 1 - Buy 8 sets of Banana plugs and run two separate set of speaker wires, one from each amp. Connect only to the speaker side when playing that particular amp or Option 2 - a speaker selector switch (amazon pricing is ridiculous) or Option 3 - Run only one set of speaker cable and change on the amp side (if convenient) whenever you are playing that amp. I am currently following option 1 as it is hard for me to change on the amp side.

 

[surfatwork]

What @corElement was asking is as below, I believe so that he can avoid the hassle of disconnecting the wire from Amp 1 to speaker and connect Amp 2 if he wanted to use Amp 2 OR avoid a speaker changeover switch as @mbhangui made.
Sketch is only for one channel.

View attachment 76761
Doing so can damage the amp and speaker if the amp terminals are not isolated from speaker when switched off. That's what some of us were trying to convey.

If bi-amping, the bridge between HF and LF terminals are removed and connected to two amps one driving HF and the other LF as well as split the input signal to amps with an electronic crossover or the like.

If Bi-wiring from same amp also the bridge links to be removed, HF and LF wired separately to the same amp terminals but if that has any benefit? Electrically it only doubles the area of wire but for short connections at these current levels is it necessary? I didn't find any difference. Only difference, double the amount on the wire was swiped off my credit card and have a redundant set of wires in my junk box.

Yeah, that wouldn't be a good idea.