Switching Speakers between two amps

[dhherring]

Thinking about when I get my Sterermour online, I would like to come up with a fairly simple, easy method to swith my speakers between the Stereomour and my existing amp. 

I've taken a look at the Niles Audio DPS-1, and may still go that route.

But I was wondering is there may be a DIY solution to this issue, utilizing a couple of DPDT switches?

I'm also open to any suggestions anyone else has to offer.

What way ye all? Any and all comments/suggestions are welcome.

Don

[Grainger49]

Not the answer you seek, I use dual banana plugs.  All my amps have dual banana female receptacles. 

[Paully]

That was going to be my suggestion.   

[Grainger49]

You can do it with a four pole double throw switch.  That switches right hot and common, left hot and common for both amps to the two speakers.  Switching both commons will keep any chance for a ground loop out of the way.

[dhherring]

Thanks for the suggestions Grainger.  The 4PDT switch did catch my attention and I may give that a try.

But your comment about the dual banana plugs got me thinking about putting together a junction 'box' utilizing binding post and banana plugs.  While not as convenient as a single switch, I think the connection points would be superior.

Since I would be the one person doing the switching, I could live with that small bit of effort to switch the speakers between my amps.

Don

[Grainger49]

I've been using banana plugs and 5 way binding posts since some time in the 70s.  They have a large contact area and get cleaned every year or two.  You know, whenever I think about it.

The box with plugs for switching is good.  Just keep the amps wired to the box and swap the plugs from one to another.  Don't make it such that one amp could drive the other amp.  This is a bad thing, I have seen the results, smoke.

[rif]

I have a similar need and like the 4PDT (or 2 DPDT?) idea.  Any thoughts on specs for the switches?  I have no idea what type of voltage or current flows through a speaker wire.  Will any one do, or do I need something special to keep up the sound quality?

-david

[Paul Joppa]

Pretty much any switch will do. The voltages are low enough that arcing is unlikely, and current is under an amp even on peaks with SETs.

Whatever switch you use, someone somewhere will tell you it's inadequate. There's no point in a better switch, you'll get the same story.

My two cents.

[RPMac]

If switched "live", doesn't a tube amp always need a load on the output?

[Grainger49]

I thought that for a long time.  Paul Joppa set me straight.  It is amplifiers with feedback that must have a load on them.  All Bottlehead products are safe for switching.  From your signature it looks like you are fine.

[xcortes]

"Whatever switch you use, someone somewhere will tell you it's inadequate. There's no point in a better switch, you'll get the same story"

That's a classic!

[RPMac]

Grainger, just so I'm clear on this...if I put a switch between my Parabee and Paraglow to do the " infamous A-B testing", there would be no damage to my output tubes?
Also, the switch should be a 4 pole 'break before make' or double throw switch so as not to have the two amp outputs connect?

[rif]

Paul
So something like this? - the one in the pix not the PDF.
Except of course the other way round-2 amps input, 1 amp comes out to the speakers.


http://www.audiocircle.com/index.php?topic=112944.msg1173919#new

-david

[Grainger49]

Robert,

I have to admit that I don't know the Parabee or Paraglow.  If they are like current Bottlehead products, no feedback, and PJ has posted often about his feelings about feedback, you will be fine.  Maybe PJ will post back.

[Paul Birkeland]

Grainger, just so I'm clear on this...if I put a switch between my Parabee and Paraglow to do the " infamous A-B testing", there would be no damage to my output tubes?
Also, the switch should be a 4 pole 'break before make' or double throw switch so as not to have the two amp outputs connect?

There will be no damage, correct.

The switch may not have to be a 4 pole, if the amps both have the - speaker lead grounded, and they are plugged into the same outlet.  Having said that, a 4 pole switch seems safest.

Non-shorting (Break before make) seems like a good idea.