New NCDX(i) module from Lars Clausen

[marmatsouris]

Originally Posted by sopiblack

Hi marmatsouris Are the input ic still in a socket, i use ad8620 in my ncd1, it plays music in the right way.

Hi sopiblack.

I have not tried the ad8620 in my ncd1 modules, just the lm4562 which gave a tuby sound.
The new modules do not have a socket so you can not change ics easily.
I would go for the opa627 version since i like this opamp very much.

Regards,

Nikos

[Erlend Sæterdal]

Originally Posted by marmatsouris

Hi sopiblack.

I have not tried the ad8620 in my ncd1 modules, just the lm4562 which gave a tuby sound.
The new modules do not have a socket so you can not change ics easily.
I would go for the opa627 version since i like this opamp very much.

Regards,

Nikos

So do I but not in this amp. The treble live its own life.

[marmatsouris]

Originally Posted by Erlend Sæterdal

So do I but not in this amp. The treble live its own life.

Hi Erlend,

when you say the treble lives its own life, are you refering to the ncd1 modules and waht do you mean? Is it very revealing or very thin????

bye.

[Erlend Sæterdal]

Originally Posted by marmatsouris

Hi Erlend,

when you say the treble lives its own life, are you refering to the ncd1 modules and waht do you mean? Is it very revealing or very thin????

bye.

I mean 627 makes it sound both revealing and thin. It is not homogen. Too much treble.

[sopiblack]

Originally Posted by marmatsouris

Hi sopiblack.

I have not tried the ad8620 in my ncd1 modules, just the lm4562 which gave a tuby sound.
The new modules do not have a socket so you can not change ics easily.
I would go for the opa627 version since i like this opamp very much.

Regards,

Nikos

Hi marmatsouris i use ad8620 because it has very good data with 5 volt, i have tried with opa 627, but the sound vas to hard, but try, and let me hear what you think.

I use a squezzebox 3 and a heavy modified ezdac i use 4 ncd1 modules with ad8620, and seperat powersupply for every ncd1 module and i use a nas server.
Regards
Hans Nielsen

[Lars Clausen]

Knivies: I tested the modules with a constant load of 2 Ohms for days now, and it works nice and stable. But please use common sense. Don't get an overvolt transformer and load your amplifier with low impedance. That is asking for trouble. I suggest 2x33V AC for 2 Ohms load, it will give you something like 500 Watts RMS.

Merry Christmas and happy new year to everyone!

[Ltralus]

Originally Posted by Lars Clausen

Knivies: I tested the modules with a constant load of 2 Ohms for days now, and it works nice and stable. But please use common sense. Don't get an overvolt transformer and load your amplifier with low impedance. That is asking for trouble. I suggest 2x33V AC for 2 Ohms load, it will give you something like 500 Watts RMS.

Merry Christmas and happy new year to everyone!

A resistive load of even 2 ohms is an easy load. Why can't your module reliably operate at the rated voltage? Wasn't its short duration current capability one of its big sellers? Can it not reliably handle such events? Does it not have reliable current limiting?

What if my speakers are 4 ohms with dips to half an ohm, must I use 12 volt rails? It seems like it might not be so reliable off the bench.

Merry Christmas saint clausen

[Lars Clausen]

Hello James J.
I did not say it's not reliable, i just suggested to use common sense.
The load capability is not specified yet, however the MOSFET's are 38 Ampere types from IR/Vishay, so they are very rugged, and load capability should be similar to NCD1, however we may downgrade it a bit as part of our high reliability design strategy. Make some extra headroom.
The main selling point is not ½ ohm loading capability :-) We try to make the best sound in the world, that's all, and most people use 4-8 Ohm speakers anyway.

If you really want to run ½ ohm speakers, you should get a specially optimised amplifier for that, and the main concern is not the MOSFET's but rather the filter coil, which must have lower inductance, to keep up with frequency response. Both MOSFET and filter coil concerns of course lead to lower supply voltage.
If your speaker is only low impedance in some frequency areas, i can recommend using an active filter and two amplifiers, adapted to those impedances. This will give you 'best of both worlds' :-)

[Ltralus]

Most people's 4-8 ohms speaker impedance are nominally rated. Were you given reason to believe the values don't often stray from that, if so perhaps we could see that data? It may prove invaluable in facilitating projects based off your products.

Can you tell me again if they in fact have overcurrent protection, and if so what is the trip point? I didn't quite get that from your previous rhetoric.

It strikes me that a "high reliability design strategy" should likely have the specifications down on paper before they go into shipping, but here it seems to be more of an afterthought. Were there problems in testing? This provokes me to ask, high reliability compared to what? Were your previous versions unsound or have you clausen believe they're more reliable than everything else? Please help me make sense of this. Thanks.

[soongsc]

Why would anyone design speakers with such low impedance? There must be a very specific reason technically or mentally.

I have not hear any speaker with such low inpedance play well.