What am I doing wrong: bi-amping Nac150x

Sorry for the delay in the answer. I was in bed with the flu, but now I'm ok

I report that "pseudomonobloc" is working ok, without distortion.
Using the cables in bicabling configuration (2 to 4) I connected the right channel of amp 1 to speaker 1 and left channel of amp 2 to speaker 2.

One of the Nap150x was recaped a month ago and the other is around 13 years and never was repaired. I'm trying to notice any inbalance between channels... 

The way that I was pretending to use the amps in biamplification doesn't had this problem, because one amp was only for the trebles and the other for the mid/basses.

On the long run can this configuration damage the amplifiers? One of the channels on each amp is running without any load, so Can a couple of plugs with apropriate resistors on the unused terminals prevent damage?

Hope you are getting over the flu ok Naka. Glad to hear the mono blocked arrangement is working. You won't damage the amplifier(s) by using them in this configuration as they can run without a load. 

If you get a chance, with the speaker cables disconnected from the amplifier end of the crossover, can you measure the resistance between the two black terminals on the crossover- they shouldn't be connected internally as the treble and bass sections should be electrically separate (and this would concur with a circuit diagram i found of the darius crossover) but i just wanted to make sure your crossover is the same. The reason i ask is that if they are connected internally in the crossover for any reason, when you bi-amp in the configuration where each amp takes a pair of speaker drive units you could end up coupling the two amplifier negative terminals together which is not a good idea.

I'd look at getting your 13 years old 150 serviced but you may want to balance that cost with the possible improvement you have in your present configuration against just running a better single amplifier

James

Hi James

Today, listening to quiet music on normal level, I still detect a bit of low distortion using the pseudomonobloc configuration. In other words there I can hear some "static" on top of the music.

I have done the resistance measure with a DVM and the value showed was always 1

Just remember to do this: return the system to the simple configuration (one amp and biwiring) and check for distortion... and there it was, a small signal distortion one the treble!

In desperation, I then put the Odysseys away and set up the old Van Dammes, and voilá, no distortion at all.

Remember, I've always used the Van Damme cables, and the Chord Odysseys 4 entered the system for biamp proposes. When confronted with the distortion problems I started to test every configuration with the same cables - the Chords.

Now I need to test everything over again with just Van Damme cables...

naka posted:

On the long run can this configuration damage the amplifiers? One of the channels on each amp is running without any load, so Can a couple of plugs with apropriate resistors on the unused terminals prevent damage?

Errrrr.....???????.

What damage are you expecting? Resistors on the unused output terminals of the power amp? Really????

jon honeyball posted:

naka posted:

On the long run can this configuration damage the amplifiers? One of the channels on each amp is running without any load, so Can a couple of plugs with apropriate resistors on the unused terminals prevent damage?

Errrrr.....???????.

What damage are you expecting? Resistors on the unused output terminals of the power amp? Really????

I suspect that naka isn't sure what damage to expect, hence his perfectly reasonable question. No such thing as a stupid question in my book, there are however stupid replies, as you have neatly demonstrated.

Not having a current drawing load on one of the channels is the advantage of doing a pseudo-monoblock. That way all the energy reserves in the filter capacitors are dedicated to the one channel that provides current gain. There will also effectively be a dedicated transformer per channel too. Which is why this is described as pseudomonoblock. Loading the unused channel with a power resistor will negate pretty much all of the benefits of the pseudoMB configuration. 

Yes Tyranniux got it: not  knowing about what to expect I put the question on the table, and thank you all for your answers. 

I remember reading somewhere that power amplifiers don't like to work without any load... and I don't what to damage my precious gear.

Member Ron Toolsie presented a detailed answer