What am I doing wrong: bi-amping Nac150x

Your setup sounds like you have it wired correctly. I'm sure you must have, but have you removed the wire links between the bi-wire terminals (I take it these are later Darius, not early Darius speakers ?)

I'd also go back to the single amp configuration and just test both amplifiers in single amp mode to ensure they are working or you don't have a problem with one of the Snaic cables. 

James

Hi James

there are no links between the speakers terminals because these are indeed the original Darius. I love them to bits.

I will try testing the individual amps according to your advice. 

My doubt is about the Flacap2x hability to juice both amps... and the manual don't say much about the signal out B and C. After all what are they for?

Hi - Ok good about the bi-wire links. Just needed to ask the obvious first - Just one more silly question - You are still using the passive crossover though rather than connecting straight to the connectors on the back of the speaker ?

The Flatcap is not doing anything actively to the signal - it effectively passes the signal straight through from the far left 5 pin socket (connected to the 122) to the sockets labelled A-C - all 3 output sockets are identical. The 122X should be able to drive both power amplifiers without any issues. It might be worth checking with Naim if you still run into problems after checking both amps and Snaics. 

Let us know how you get on.

James

PS - you'll have to post some pictures when you get it all setup - the original Darius speakers were rather unique - great to see someone still using them 

First of all thank you for all the help

yes I'm using the Darius's external crossovers. And all was working great in biwire confuguration. I was using a pair of 7 meters Van Damme Pro L-OFC  speaker cables,  that are remarkable for the cost.

YRight now I am resetting the Chord's to biwire to test both amps and snaics separately.

I will post some pictures of all the gear. This Darius are the last generation ever build with highend crossover and Isolda cables.

No problem - hope you find the issue. I have one more idea if you don't find the problem but i'll let you test out the amps and cables first.

James

Something to get you going if both amps and Snaics check out ok in single amp configuration...

To check that your 122 can drive both amps ok try 'mono blocking' the 150 amps. Connect to the Flatcap as before but just use one channel from each amp to drive each speaker. So amp A use for left channel only and amp B use right channel only. Put links back in at speaker crossover end. You have just one channel of each amp driving one speaker.

Does this work Ok?

If so, do you have a continuity meter or DVM you can use to check something i'm wondering about with the Darius crossover which may explain what is happening when you bi-amp in this split (one amp does both speakers) configuration you are having problems with (in your original post)

I am already in bicable configuration using the same Nap150x and the same Snaic4 and all is ok.

Next steps:

1 - try the other Snaic4

2 - try the other Nap150X

Notes:

- the Darius crossover have 2 pairs of terminals that (like the Naim amps) only accept bananas, and they are very close together. I don't have the material to do a "shunted" connection right now.

- I do have a DVM.

How are you getting on ?

The problem you describe may be down to the SNAICs. The pre+flatcap may be struggling to drive all those SNAICs. You should try a pair of Naim active leads instead - effectively they are the same cable as the DIN-XLRs used on the big amps but with a DIN 4 in place of the XLR/Cannon connector.

I had already read something about Naim active leads, but how do I know if my two units of Snaic4 are active or passive?

They both look the same: black, with 4 pin locking plugs on both ends...

SNAICs are thicker, should have the Naim logo on the cable, whereas the active leads are thinner.  The active leads are rare secondhand but available to buy from your Naim dealer by special order.

But then, if the cable is the same, what is indeed the difference?

The 4-pin SNAIC has 4 conductors ch-1, ch-2, -ve & 24v ... right? And what about the Active Lead type?

The Active Lead does not carry 24v and is not shielded AFAIK.

Yep - lower capacitance cables. Before going down this route, have you checked both amps and Snaics are working ok ?

Understood. So in a regular Snaic4 connection between the Flatcap2X and the Nac150x the 24v is not used?

I wonder why does the Flatcap not accept 2 regular Snaics without problems... and the manual doesn't mention nothing about the need for Active Leads?

Hello James, I have checked both amps with the same cable, and they are ok.

So I'm going to check the other cable, and I will get back with results

Passive bi-amping was never Naim's intention, hence there would be no need for using a pair of SNAICs here.  

Thanks Richard.

Resuming: only a pair of Active Leads will work is that it? And why is this cables are not shielded, as JFritzen commented?

Why do you want them to be shielded?

I dont know... are the stock snaics shielded?

My second Snaic4 is also working ok with just one power amp -just tested it.

Instead of using Active Leads can I use a snaic4 cable with a "y" configuration to feed both amps? This will use only output A on the Flatcap.

Can this work?

Looks like you've checked out the Snaics and both power amps and all is working correctly so not many options left. Richards point about the ability of the 122x to drive a pair of Snaics makes sense. You could rule this out by making a pair of flat cap to 150 cables yourself (3 core 3A/5A mains cable ideal for this with couple of 4 Pin DIN plugs) if you can't get hold of the Active Snaic cables easily. We're straying into a forum no-go area here with the cables so i'll let you work the rest out for yourself 

On another note - the Darius speakers really deserve the best amplification so perhaps a better quality single amplifier may get you where you want to be rather than heading down the bi amp route ?

James

Yesterday, and once again, the oficial Naim technician stated that two Snaic4 from Flatcap2x to Nap150x should work. Plus, he said, I can connect to the power supply my CD5x also!

I deduct that maybe something is wrong with the Flatcap, maybe it needs a recap. I will open it today to see if I find anything wrong.

yes the Darius deserve something better and I pretend to get a Nap250.2 in the future, mas now this is all I got, and I'm a bit frustrated, specially because it should work in the simpliest way.

One way to surpass all my questions is to buy some diferent types of interconnect cables to see the results, but this is damm costly. And it is a bit nonsense because I don' understande the logic behind it. For exemple: I still don't understand the need for Active Leads and how they work.

I want to thank all of you that put you time and interest to followed this thread and give you expertise

Very strange - i doubt the flatcap needs a recap as you'd have the problem all the time - how old is it ?.

The 'active' leads are called as such as they are used in the naim active systems (with amps below the 250 range) but they can be used in normal passive systems where the amplifier does not need to supply 24v to the pre-amp - ie when you have a flatcap/ hicap etc to power the preamp and are connected between the power supply and power amp. They are just un-screened, low capacitance interconnects and give the active crossover an easier time as it can be driving a number of Snaic cables. As i said it would be very easy to make these cables yourself (or get a technician to do it) to minimise cost.

 I would suggest again, just making up some links for the darius crossover terminals and using the amps in mono block form (one channel on each amp) just to test that this works. 

To check your 122 can drive both amps ok try 'mono blocking' the 150 amps. Connect to the Flatcap as before but just use one channel from each amp to drive each speaker. So amp A use for left channel only and amp B use right channel only. Put links back in at speaker crossover end. You have just one channel of each amp driving one speaker

^^^

The pseudomonoblock configuration as above is the one I feel would work the best anyway.