Amp a/b switch

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Rettib2001
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Amp a/b switch

Unread post by Rettib2001 »

Hi,

I would ideally like to run my all NVA setup for stereo listening and add my AVR for TV/Movies as the room correction really helps for that type of content.

I have a simple amp A/B switch box made by Dynavox. It works well in this scenario with amps that aren't NVA as I can just use any speaker cable between the front L/R speakrs but given that I wouldn't dare use my NVA A80 mkII with any third party speaker cable, I'm scratching my head as to how to avoid disaster.

My current 'in theory' solution would be (when the NVA amp is selected) to use my LS5 speaker cable from the A80 MKii to the A/B switch input, then LS6 from the Switch output to the speakers. There would however been a short length (10CM) of non NVA cable insude the switch.

I've already upgraded this cable to some duelund speaker cable. If I replaced it again with either solid core high quality copper, or a short length of nva cable (which I can already anticipate being fiddly at best given all the cores) the path from the amp to the speakers would techinically be all NVA speaker cable.

Is this asking for trouble? Is there a better solution for dual amps via some sort of switching device?

Thanks in advance for any guidance.

Mark

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Re: Amp a/b switch

Unread post by savvypaul »

Can you draw and post a basic diagram of your system and connections, just so we are sure we are all talking about the same thing.
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Re: Amp a/b switch

Unread post by Ithilstone »

After some Google search for Dynavox - my main concern would be not the cables inside the box ( even if upgraded ) but the switch itself - it looks like a serous bottleneck. In my opinion you would loose all the benefits of LS5 or LS6 if the signal is routed through this kind of switch - not to mention that if it breaks it could "short" inside.
When I discussed with RD how to implement a switch to cut off speaker taps to use just the headphones on my AP70, His opinion was to buy the on-on copper or silver contact toggle switch 6A or higher and rout the signal through it - and that was on very short signal path inside the amp - for your scenario it would have to be something much better than 6A.
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Re: Amp a/b switch

Unread post by Fretless »

The advice from Tomasz is sound.

If it were me, I would split the output before the power amps and use the 'Tape Out' from the NVA preamp (with the volume pot then turned to zero) as the line input to the AVR.

This would require an extra pair of front L-R speakers, but it would save you from blowing up the NVA amps and possibly the speakers as well.

Another option is the same setup as above but then use the NVA to drive the front stereo pair and have the AVR driving the remaining surround speakers.
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Re: Amp a/b switch

Unread post by Geoff.R.G »

Fretless wrote: Tue Nov 09, 2021 10:55 am Another option is the same setup as above but then use the NVA to drive the front stereo pair and have the AVR driving the remaining surround speakers.
That would be my preference. I really don’t like switching speakers, much better to do it at the pre-amp.

Rettib2001
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Re: Amp a/b switch

Unread post by Rettib2001 »

Thanks a lot for all the replies and for drawing my attention to both further potential issues as well as possible solutions.

To be honest I think the safest (not cheapest) way to achieve what I would like to do is to replace my current AVR with one that has preouts for front L/R.

That way I can just use two inputs on the P50SA, one for the NVA A80s and one for the AVR preouts. I'll avoid any speaker cable issues and will retain the sound qulity benefits that the LS6 cable has to offer.

Now to find a reasonably priced AVR with at least stereo preouts.... the joys of wanting it all, ha.

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