[Agrippa]

Yo!

Before I go ahead and set things up, I thought I'd better check to see if there's any hefty drawbacks to what I'm about to do.  Any feedback or advice would be most gratefully appreciated.

Basically, I want to use two preamps in my system - a tube pre for music and a solid state pre for the TV - since I can then (hopefully) leave the ss pre on 24/7, while preserving the tubes in the other amp for when I listen to music.

I thought I'd do this in the simplest manner possible, by using Y-adapters on the power-amps.  Am I correct in thinking that this is unproblematic, or am I about to blow my system to smithereens?

- A

[srb]

You would be in essence connecting the outputs of the two preamps to each other and trying to send voltages back through the output of the other, even if one were turned off.
 
It would also present a wonky load to the power amplifier.  I doubt you would have "smithereens", as in shrapnel, but I wouldn't be surprised if one or even all of the components were damaged in some way.
 
I think you need some sort of switching device.
 
Steve

[HAL]

Not a good idea.

Agree with Steve, you need a switching device that does not allow both preamps to be tied to the power amp at the same time.   If one of the preamps has a Home Theater mode, that would allow switching between the SS and Tube preamps.

[Agrippa]

Well bugger....  I hoped that the low voltage/current involved would mean it'd be a risk-less exercise, particularly as one preamp would always be off, but I guess not then.

Oh well, off to look for a good audio switch.

[rllrll]

I have a HT Processor and a SS two channel Pre-amp both connected to two Rythmik F15SE subs. I'm using the subs, line-in connections. I have had this set up for 6 months with no problems. However, I never turn both the Processor and Pre-amp on at the same time.

[srb]

I have a HT Processor and a SS two channel Pre-amp both connected to two Rythmik F15SE subs. I'm using the subs, line-in connections. I have had this set up for 6 months with no problems. However, I never turn both the Processor and Pre-amp on at the same time.

Are you using Y-cables or buffered isolated dual inputs on the subs?
 
Steve

[mix4fix]

Do not combine signals with a Y-cable...

Same concept - line signals:
http://mobileaudio.com/rac-faq/rac-faq_5.html#SEC106

The common thought is to use a Y-adapter to "combine" the left and right channels. However, by using a Y-adapter, you are actually summing the line voltages and directly shorting the left and right channels at the head unit, which could cause problems.

The correct way to create a mono signal is to cut off the ends of the RCA cables, combine the signal grounds (the outer shield), and then use a 1 kOhm (1/4 watt, 5% tolerance) resistor to each of the center conductors. Solder and insulate the resistors so that you don't short them prematurely, and then connect the two resistors together. Connect the summed signal ground to the shield of the new RCA plug, and the summed center conductor to the center pin of the RCA plug.

Back in my car audio days, I built a summing circuit using a radio shack project box, an 8 pin rca jack, two resisters, and some wire (so I didn't have to cut up cables).

I would build a nice little box to select/isolate pre-amps and amps/subs using a selectable switching device and have isolation/distribution so you don't have Y cables everywhere.

[rllrll]

"Are you using Y-cables or buffered isolated dual inputs on the subs?"


I'm using a y-cable out of the processor and pre-amp and that is all.