Yamaha M-80 Amplifier Connection Options

Harold,
My guess is that you are making the amp work harder by matching the impedance between the 2 halves of your speakers. I don't know your amp but know the Yamaha very well. The Yamaha makes some HUGE compromises when adding pairs of speakers, especially the C pair. A&B are Parallel which is halving the impedance. A,B&C are using a combination of parallel & series to keep the impedance reasonable. I don't know why they ever made this option available since the amp is so nice and the feature is so junky?

I also have a question on a bi-wiring set-up. My speakers are JMlab 8 ohm speakers capable of 50-150 watts and bi-wireable and my amp is a Luxman L-430 (105(?) w rms/channel. The amp has an A (L+R) and B (L+R) speaker inputs. It accepts 4-ohm - 16 ohm speakers if only the A-output is engaged and 8ohm-16 ohms if A+B speaker outputs are used.

The crux of my question:

I can bi-wire either to A speaker output on the amp alone or separate out the BASS/mids to A and the tweeters to the B speaker outputs on my amp. In fact I did this for a while with great sonic results.

However, I noticed that the amp was getting very hot and so I wondered if by this setup, the nominal 8-ohm resistance of my speakers had been reduced to 4 ohms which is below what the amp specifies for A+B speaker outputs being used simultaneously. When I limit the bi-wiring to the A-speaker output, less heat is generated, but the sound isn't as nice (better separation, depth, etc.)

If I am reducing the ohms to 4 with the A+B bi-wiring setup, is there ant conceivable way to get the same advantages by hooking up the 2 speakers in series. My mind blows a fuse when I try to think about this.

Any advice would be appreciated.

Harold

Good advice all; the specifications list 250 watts at 8 ohms but what it actually will push is anybody's guess. After reading the connections page in the manual for the 10th time I'm going to try wiring using the B & C channels. This set up will be in series and logically should give me a 16 ohm resistance???

The M-80 is in a class by itself when compared to anything Yamaha ever made. I don't think it is 250 watts per channel (can't recall)? However, the first 10 or so watts are class "A" which makes it so nice.
By using a pair of output, ie A & B, you are forcing the unit to use its internal impedance matching hardware. I wonder if this will impede the sound?
Personally, I would bi-wire using only the A jacks with Y splitters and see how that sounds. It may be slightly easier on the amp to use A&B or B&C but you may loose some dynamics??? Your speakers should be quite an easy load on any amp, so don't worry.
By the way, when playing softly, the amp will run extremely hot. That is the class A circuitry. Don't worry. It will only run cooler if you are blasting music and with 93db speakers, I doubt you will need more than 10 watts ever!

Not sure if this helps you, but I am doing something similar currently.

I have the Mirage OM9 speakers, rated for 50-150w 8ohm, bi-wire/bi-amp capable. I am driving them bi-wire using a Yamaha MX-460 amp, which is 80 wpc rms, and has A and B outputs.

On the amp, Outputs A run to the Highs, and B runs to the lows. To clarify, if I go to my amp and toggle B outputs off, you hear only the highs, and vice versa.

This was simply the most logical setup to me and also the simplest.

The difference in sound was noticeable. This setup works well, but when my 2nd new (to me) MX-460 amp comes in the mail I will be bi-amping.

Hope this helps.

Understanding bi-wiring isn't the challenge. I want to talk about using different channel outputs i.e. A OR B OR C (in what combination to be determined). The idea is to send the cleanest power to each pair of inputs on each of the speakers.

For example; my inclination is to use the (L) on Channel A with the (L) on channel B to bi-wire my left side. Then use the (R) side of channel B and C to the other. This is bordering on bi-amping but I think folks get the drift.

Do I stand to gain sonically or I am taking risks with the yamaha on in parallel vs. in series hook-ups?

Bi-wire is not the same as running two pair of speakers. You can hook one set of cables to speaker A posts, the other pair to speaker B posts....no problem.

Dave