Bi-amp and RCA Y Cable

Bubo

Super Member
Any danger to the amplifier if you use a Y cable to split the signal coming from a surround pre-amp, so you can bi-amp the center channel speaker?

I want to try it out to see if there is any difference in sound, but don't want to risk damage to my Yamaha amp.


Thanks!!
 
Careful.. and consider

Just a thought that you might want to look at the component spec or data sheets and estimate what this hookup will do "electrically".

Although it sounds straight forward and harmless, it may cause damage to the preamp stages of your main or the output stage of the surround amp.

Recently, I ruined a perfectly well operating surround sound receiver splitting signals at the output... :nono:was not a good idea!
 
Using a Y cord to hook 2 power amps up to the same preamp output should not cause any damage. If it did or does either it was a very poorly designed preamp to start with or there was an undiagnosed problem with the preamp.

Electrically, all the preamp will see with that arrangement is the 2 input impedances in parallel. Assuming that the two amp channels are 2 channels of the same power amp, it will cut the impedance the preamp sees in half. This will double the current required to drive the arrangement. This sounds bad but please consider these realities that equipment manufacturers deal with all the time: They never know what the preamp will be hooked to. The power amp in question could have input impedance as low as 10K ohms or as high as several hundred thousand ohms. What they try to do is make the output impedance of their own device as low as possible, often less then 100 ohms. If they achieve that, then the preamp will be fine if it is working into anything over 1 to 2 thousand ohms. To get that low an input impedance, the power amp must have an input impedance of less the 5K ohms. Very few power amps run that low.

Shelly_D
 
I tried this once. One of the amps was a SE-OTL amp and the other (if I recall) was a solid state.

Long story short, I sometimes switched between amps turning one off and the other on (and maybe back/forth) I never had them both on at same time. I used an A/B switch and they were wired to same speaker.

Discovered that if I turned the SS amp off and the OTL on, all was fine. If however, I had the OTL amp on and switched over to the SS amp, the SS amp would go into protection mode and reset.

Turns out the OTL amp discharged a tiny tiny amount of DC current. This current typically went from the RCA inputs, back to the preamp where nothing happened.

Since it was being "shared" electronically with the other amp via the "Y" cord, the DC current went to the SS amp and pushed it into protection mode.

This subject is beyond my technical expertise, I'm simply relating a story of what happened to me under a similar circumstance.
 
I tried this once. One of the amps was a SE-OTL amp and the other (if I recall) was a solid state.

Long story short, I sometimes switched between amps turning one off and the other on (and maybe back/forth) I never had them both on at same time. I used an A/B switch and they were wired to same speaker.

Discovered that if I turned the SS amp off and the OTL on, all was fine. If however, I had the OTL amp on and switched over to the SS amp, the SS amp would go into protection mode and reset.

Turns out the OTL amp discharged a tiny tiny amount of DC current. This current typically went from the RCA inputs, back to the preamp where nothing happened.

Since it was being "shared" electronically with the other amp via the "Y" cord, the DC current went to the SS amp and pushed it into protection mode.

This subject is beyond my technical expertise, I'm simply relating a story of what happened to me under a similar circumstance.

OK:

Just learned something interesting. I would contend however, that DC appearing on the input jacks of a power amp is a condition that is either defective and in need of repair or a design flaw in need of modification to correct. The condition described could pose a potential problem for the output devices of the preamp. It could be just an increase in distortion or cause a device failure.

So add to my caveats above that the 2 power amps should be in proper working condition.
 
I've been running two ss power amps from a single ss pre since Spring with no problems. Two sets of speakers on one amp and one set on the other. 4 input sources.
 
Pre amp Surround Receiver: Pioneer Elite VSX TX 21, record out
300mv / 2.2k ohm

Amp: Yamaha MX 800, main in.
1.32V / 60K ohms

Shelly,

I'm not sure I understand the math on this one, and don't want to get it wrong since I don't know how much current is enough even at a 15 to 1 ratio.

The pre amp is going to see Y cable with 30K ohms?

help!!!
 
The record out isn't what matters, it's the pre out. But, regardless, it would be an exception to an exception for it to not work properly. And, even if this were an exception to an exception case, nothing will be damaged.

Just do it and enjoy...
 
Interesting.. dilemma?

:dunno:I agree, the Y cables should not generate any "unforeseen" anomolies.

"Back in the day", this method was used to Bi-amp (the rigged version), hi powered bass reflex and mid-range horn speakers... I believe these clone speakers were called "Kick A_ _"... probably some wannabe Cerwin Vega clones?

They were huge, none the less! Sometimes as large as 18inch in fridge sized cabinets?

If you could not afford a sizable power amp to drive them, at least 200W or more, the split Y signal method was used to cheat two moderate integrated amps into behaving like dedicated low-range or high-range power amps.

The method actually worked most times and produced a steady and undisturbed power path.... So go for it!

But do read your specs first.... I'm just sayin :scratch2:
 
Pre amp Surround Receiver: Pioneer Elite VSX TX 21, record out
300mv / 2.2k ohm

Amp: Yamaha MX 800, main in.
1.32V / 60K ohms

Shelly,

I'm not sure I understand the math on this one, and don't want to get it wrong since I don't know how much current is enough even at a 15 to 1 ratio.

The pre amp is going to see Y cable with 30K ohms?

help!!!

If its the 2 channels of the Yamaha that the preamp is hooked to, then yes the preamp will see a 30K impedance. That should be fine. There are any number of amps out there that actually dip lower then that. Assuming that there are no undiagnosed issues with any of the equipment, you should be fine.

Shelly_D
 
Any danger to the amplifier if you use a Y cable to split the signal coming from a surround pre-amp, so you can bi-amp the center channel speaker?

I want to try it out to see if there is any difference in sound, but don't want to risk damage to my Yamaha amp.


Thanks!!

It should not be a problem. I drive two subs from a single LFE output of my HT system AVR using a Y-adapter.
 
Another project for the Holiday.

My Y Cable arrived yesterday in the mail.

I am working on casters for my LaScalas, when they are installed, this is next.

Thank you to everyone for the encouragement and info!!
 
Finally hooked up the Y cable.

Have been running it for three hours, no smoke or flames.

My EE friend would be happy that I don't have an amp running with no load on it.

Thanks to everyone for the input.
 
Unless it's a tube amp there's no trouble with no load. I've used a number of different SS amps using just one channel for some years...no problem.
 
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