[pstrisik]

Here's a bit of a technical question....   If I set up two amps with the high quality DECWare switch (https://www.decware.com/newsite/ZSB.html), is there any downside or, worse, harm that could come from having two sets of speaker wire going to the Omegas?  That would be one pair from each amp.  Only one amp would be active at any given time though.  Interested more in technical knowledge rather than "better to be careful", or "it's not a pure approach", and the like  .

It would be a good way to let the tube amp stay idle and not rack up mucho hours on prized tubes when music is more background than active listening. 

I should probably shoot Louis an email, too.

Thanks.......Pete

[Zachik]

Pete - did you ever get any responses?
I have similar situation where I am debating feeding 1 set of speakers with 2 amps, only 1 amp active at a time...

[pstrisik]

Pete - did you ever get any responses?
I have similar situation where I am debating feeding 1 set of speakers with 2 amps, only 1 amp active at a time...

Funny, I was just thinking about this again today.  I have the components, I guess I should just try it.  Stay tuned.

[SET Man]

Here's a bit of a technical question....   If I set up two amps with the high quality DECWare switch (https://www.decware.com/newsite/ZSB.html), is there any downside or, worse, harm that could come from having two sets of speaker wire going to the Omegas?  That would be one pair from each amp.  Only one amp would be active at any given time though.  Interested more in technical knowledge rather than "better to be careful", or "it's not a pure approach", and the like  .

It would be a good way to let the tube amp stay idle and not rack up mucho hours on prized tubes when music is more background than active listening. 

I should probably shoot Louis an email, too.

Thanks.......Pete

Hey!

  Wait, I'm trying to understand what are you trying to do here. So, you have two amps and you want to use them with your speaker?

   That box is a selector that can be configured as passive pre with volume control with two output. So, you want to feed both of your amps with that box and switch between the two amps you have with that box?

   OK, if you are going to use that box as your passive pre then that's fine. But if you already have a preamp then adding that box and extra cables will likely have some effect on the sound, how much degradation you can hear is depend on your amp and speaker. But that would solve the problem feeding and select between two amps.

....is there any downside or, worse, harm that could come from having two sets of speaker wire going to the Omegas?  That would be one pair from each amp.  Only one amp would be active at any given time though. 

....

  OK, let me get this straight, you want to run speaker cables from both amps to your speaker and leave them connected to your speakers even when one amp is not on?

  Am I understand this right? If so, DO NOT do it! You can damage your amps by doing this!

  Like you I have two amps. Both are SET amps. And when I want to switch between the two , I have to disconnect the RCA and speaker cables from one amp and move them to the other amps. Luckily it is not that hard for me since both of my amps are easily accessible.

   I hope this help and maybe other with more expertise can comment on this.

Buddy

 

[borism]

I also have two amplifiers one of which is an integrated and one set of speakers. The preamp has a tape out which I use to connect to an integrated amp (Bottlehead Stereomour) and the regular pre out drives my Atma-Sphere amplifier. The two sets of speaker outs (from the 2 amps) are connected (through short speaker wire runs) to a speaker switch box that I built myself, with one set of speaker outs connecting (one set of speaker cables) to one pair of speakers. Hope this is not too confusing.

At any point only one amplifier is connected to the speakers.

This is what the speaker switch box looks like:







It has worked without problems in my system.   

[pstrisik]

I also have two amplifiers one of which is an integrated and one set of speakers. The preamp has a tape out which I use to connect to an integrated amp (Bottlehead Stereomour) and the regular pre out drives my Atma-Sphere amplifier. The two sets of speaker outs (from the 2 amps) are connected (through short speaker wire runs) to a speaker switch box that I built myself, with one set of speaker outs connecting (one set of speaker cables) to one pair of speakers. Hope this is not too confusing.

At any point only one amplifier is connected to the speakers.

This is what the speaker switch box looks like:







It has worked without problems in my system.

Very nice!  That is the way to do it, though with one concern.  While using a switch with low level signals, there should be very minor quality loss if using good cables and a good switch (I have a decware switch that uses silver wire, etc.).  My understanding is that the potential for quality loss with a speaker level switch could be greater.  Proof of the pudding is in the eating however, so do you notice any difference with speakers connected to the switch vs. to the amp directly (comparing with one amp, obviously)?

That's an easy project to try.  I have a box, binding posts, and wire.  Just need a quality switch.

......Pete

[pstrisik]

Hey!

  Wait, I'm trying to understand what are you trying to do here. So, you have two amps and you want to use them with your speaker?

   That box is a selector that can be configured as passive pre with volume control with two output. So, you want to feed both of your amps with that box and switch between the two amps you have with that box?

   OK, if you are going to use that box as your passive pre then that's fine. But if you already have a preamp then adding that box and extra cables will likely have some effect on the sound, how much degradation you can hear is depend on your amp and speaker. But that would solve the problem feeding and select between two amps.

Just a switch, no volume control.  I control volume with the pre function of my DAC.

  OK, let me get this straight, you want to run speaker cables from both amps to your speaker and leave them connected to your speakers even when one amp is not on?

  Am I understand this right? If so, DO NOT do it! You can damage your amps by doing this!

  Like you I have two amps. Both are SET amps. And when I want to switch between the two , I have to disconnect the RCA and speaker cables from one amp and move them to the other amps. Luckily it is not that hard for me since both of my amps are easily accessible.

   I hope this help and maybe other with more expertise can comment on this.

Buddy

What is your basis for arguing this is dangerous to the amps?  If only one amp is switched on at a time, how does the speaker connection to the powered off amp pose a risk?    Thanks.

......Pete

[borism]

Very nice!  That is the way to do it, though with one concern.  While using a switch with low level signals, there should be very minor quality loss if using good cables and a good switch (I have a decware switch that uses silver wire, etc.).  My understanding is that the potential for quality loss with a speaker level switch could be greater.  Proof of the pudding is in the eating however, so do you notice any difference with speakers connected to the switch vs. to the amp directly (comparing with one amp, obviously)?

That's an easy project to try.  I have a box, binding posts, and wire.  Just need a quality switch.

......Pete

Hi Pete,

I got a high quality switch with silver contact and the short wire runs within the box are 14 ga, multi-stranded silver plated, teflon coated mil-spec wire. That's probably not the best speaker cable but I haven't noticed any degradation in sound. For any serious listening one can always connect the speaker wire directly to one amplifier.

Boris

[pstrisik]

Good to hear.  I just ordered a basic 2 amp/1 pr speakers switch for $60 to get started.  If the arrangement works out, I will build one as you did.  The difficulty might be finding the best quality switch part.  Did you mean to say the the switch itself has silver contacts?  That would mean it is higher quality overall.  Where did you source it?

Thx....Pete

[SET Man]

I also have two amplifiers one of which is an integrated and one set of speakers. The preamp has a tape out which I use to connect to an integrated amp (Bottlehead Stereomour) and the regular pre out drives my Atma-Sphere amplifier. The two sets of speaker outs (from the 2 amps) are connected (through short speaker wire runs) to a speaker switch box that I built myself, with one set of speaker outs connecting (one set of speaker cables) to one pair of speakers. Hope this is not too confusing.

At any point only one amplifier is connected to the speakers.

This is what the speaker switch box looks like:







It has worked without problems in my system.

Hey!

   Boris, that's pretty slick! Is that a cigar box?

Buddy
   

[SET Man]

Just a switch, no volume control.  I control volume with the pre function of my DAC.

What is your basis for arguing this is dangerous to the amps?  If only one amp is switched on at a time, how does the speaker connection to the powered off amp pose a risk?    Thanks.

......Pete

Hey!

   Of all the years I've been in audio I've never seen anyone do that. And I've never done that, since there will likely have effect on the amp, worst, that could short the amp out. You are basically putting a connection across the speaker terminals.

   OK, I'm not an electrical engineer so I'm no expert on this. But feel free to try it at your "own risk" if you want to find out and please let me know how things turn out.

    For me is only take 5mins to disconnect the cables and swap between my two SET amps. And I don't want to put more connectors, switches and cables between in my system, because I'm sure I can hear them small or big. I like to keep things simple.

    If it is so hard to access behind your amps to disconnect all the cables to swap between the two amps. Just build the switch box like the one Boris built.

Buddy

[richidoo]

What is your basis for arguing this is dangerous to the amps?  If only one amp is switched on at a time, how does the speaker connection to the powered off amp pose a risk?    Thanks.

Wiring the amps in parallel with the speakers will make a very low impedance load for the driving amp, and will damage the amp that is being driven backwards, because voltage source amps have low output impedance, external voltage applied to the amp output will draw lots of current and burn things up. The output impedance of a voltage amp is lower than any speaker, so most of the driving current will go to driving the other amplifier, not the speaker. The low impedance load may damage the driving amplifier also or cause protection.

Bridged amplifiers are designed to work in parallel but it's tricky business to make them cooperate and not fry each other, which is what often happens. Typically the load must be halved when the amps are bridged.

The correct tool for this job is a speaker selector switch.

This would work too. Apply some grease to the contacts to keep them from arcing. Both amps should be shut off before you switch. Speakers connected to the middle posts and the amps connected to the ends.

https://www.gearslutz.com/board/high-end/958082-hi-end-speaker-selector-do-they-exist.html

[avahifi]

If there is a possibility that your switch setup could allow two amplifiers to be connected to the same set of speakers at the same time, then you probably will damage both amplifiers.  Each amp will look like a very low impedance load for the other amp, not recommended.

Stay well, stay safe, stay healthy, stay sane.

Frank

[opnly bafld]

For me is only take 5mins to disconnect the cables and swap between my two SET amps.

I used to swap speaker cables between different amps all the time, but 5 mins, what did you do take a nap? 

[SET Man]

I used to swap speaker cables between different amps all the time, but 5 mins, what did you do take a nap? 

Hey!

    Thanks I needed that laugh, after being pretty much stuck in my apt in NYC for a while. Maybe I over guesstimate the time a bit.

     But! In my defense, I also have to swap a pair of RCA cables too! 

Buddy

[pstrisik]

Frank and richidoo,

I would think the lowering of impedance/parallel amps situation would only occur if both amps are powered on.  Is it also true if the non-selected amp is powered off?

......Pete

BTW, I am going with the speaker level switch approach as described above.  First with a ready made unit of basic quality.  If it all works logistically for me, I will build a higher quality one.

[pstrisik]

Hey!

   Boris, that's pretty slick! Is that a cigar box?

Buddy
   

I agree on the slick.  I think he used a file card box though.  Boris?

[borism]

Hi Pete and Buddy,

Thanks! Yes, that's an inexpensive file card box. The switch is from Mouser (I believe part # 633-S42) and it's an NKK 4PDT. The toggle has only 2 positions each connecting one set of inputs to the output. The contact as stated before is silver. Binding posts are from Madisound.

Boris

[pstrisik]

Thanks Boris.  Looks like I need some short speaker cables for the two amp runs.  I think I've got enough leftover Vintage WE wire for that and have some nice locking bananas.

[borism]

I used Duelund DCA12 wire for the short runs and the longer run to the speakers, also with some banana connectors.