hypex ncore

[deandob]

Great tips on earthing/grounding, thanks Bruno, I'll definitely re-check my grounding & layout as per the wiring diagram.

I'm looking forward to checking out the new modules when they are available.

[Bruno Putzeys]

@Shaman, Yes I think indeed we're go for the discrete buffers. And probably for the loop amplifier too while we're at it (Ncore isn't fully passive like UcD).
I'm still collecting votes on the power issue though. There's some who think 400W is already intimidating and others who can't get enough power... I was wondering though, suppose I make it 400 at 4 ohms but like the 1200, low impedance capable (so you get 600~700W into 2 ohms with a realistic PSU). Would that be a compromise? Power hungry folks just add woofers

For the output connectors I'm considering having custom gold plated screw tags made, a П-shaped bridge with a screw through the top that pulls a square nut upwards, so the wire goes between the nut and the top. The nice thing is I can connect the power stage on one leg and take the feedback off the other so you can screw in multiple sets of wire for bi-wiring and really have only 1.5 milliohms of common impedance between them.

The input and power connectors are another kettle o' fish because now there's also a +/-15V supply and I'm not that happy with the current Molex KK for the input. So there I still haven't found a decent alternative to using a high quality industrial type and including preconfectioned cables with the module.

@brubeck
I find it hard to describe the sound of something that essentially has no sound of its own. The music's just there. I suppose it's what people call "effortless", but in a manner that doesn't even try to impress. It just refuses to draw attention to itself.

[jmbulg]

I vote for the 400W + version as long as it is easy to implement (initimidation for me is rather the complexity of possible connections for beginners than the power itself). As for low impedance, probably it depends if there are a more speakers with low impedances (which would benefit from this approach) than low sensitivity (which would ask for even higher power) in the diy community ?

[Matsen]

Originally Posted by Bruno Putzeys

I'm still collecting votes on the power issue though. There's some who think 400W is already intimidating and others who can't get enough power... I was wondering though, suppose I make it 400 at 4 ohms but like the 1200, low impedance capable (so you get 600~700W into 2 ohms with a realistic PSU). Would that be a compromise? Power hungry folks just add woofers

If you have to choose only one power class, that seems to be a nice choice!

[sp502]

Originally Posted by TheShaman

I thought we had solved that. More power than the UcD400 (ideally at NC1200 levels), premium components (where it matters) and the best discrete input you can design (aka world class).

TheShaman talks to my heart
Being the owner of a dual mono UcD400HG - HxR for four years,
there are not much more to ask for than these!

I can't wait to be shocked again by the performance...

A quick question:
Is there in your plans a matching linear or regulated SMPS power supply?

[TheShaman]

Originally Posted by Bruno Putzeys

I'm still collecting votes on the power issue though. There's some who think 400W is already intimidating and others who can't get enough power... I was wondering though, suppose I make it 400 at 4 ohms but like the 1200, low impedance capable (so you get 600~700W into 2 ohms with a realistic PSU). Would that be a compromise? Power hungry folks just add woofers

A better compromise would, perhaps, be a 300@8/600@4 module.
I'm a bit "greedy" on this subject because of my past experience.
This is going to be a statement amplifier so it's very likely it'll be used on statement loudspeakers. I've heard UcD amps in various setups and whenever we had such a speaker, like a big B&W (and I'm not talking 800 but even 802N), a big Focal or a big ATC or even a good old Infinity, the UcD400s would start to "sweat" as soon as we turned the volume higher than normal (see: over 100dBs). 700s had no such issues, of course. Most people and esp. those who have big speakers want to hear LOUD every now and then - and even if they don't, they want to know they can and not that their amp is not up to the task.
And it's not like ClassD is really attractive to the high-sensitivity (horn etc.) loudspeaker crowd, to begin with.

I assume the existing UcD line of products will still be available for purchase so someone with lower-end speakers could opt for the soon-to-be-updated (half-way between the existing UcD and Ncore, if I get it right) lower powered UcDs. [Not that I believe there is such a thing as "too much power", but I can understand the "too expensive" term]

Just my 2c of course.

[UrSv]

As mentioned earlier as current design considerations I would also opt for easy access of standard industrial connectors that are easily obtainable across the globe.

Also mentioned I second that the mounting on heatsink could be much better than for the current UcD range. The UcD OEM range looks much better in that aspect IMHO.

Perhaps the On/Off control could be handled via a jumper on the module itself in case one does not want to use it for thump free operation in order to avoid using any cables for that?

Furthermore I can perhaps represent a small group of people in Sweden and request that the modules should be both low impedance capable but even more important they should be low frequency capable. On another forum we have serious problems finding amplifiers with a low enough bottom extension that are stable at low frequencies. For instance the ICE-Power 1000ASP fails and goes into weird clipping/cut-out behaviour when driven hard at low frequencies.

Regards
UrSv, who still misses the two single digit serial UcD180STs gone MIA on return to Hypex

[Bruno Putzeys]

@TheShaman
Actually I've always felt that the effect of UcD400's "sweating" had more to do with current than with voltage, which is why I set so much stall on 2 ohm performance. My hunch there would be that a 600W/2 ohm module would be preferable to 600W/4. Something to ponder. The UcD product range remains in place.

@UrSv: Yes let's open the mounting can. For EMC reasons I prefer plate mounting like the NC1200 and the current UcD OEM range. The only thing this can't answer is the question what to do if you want to fasten screws from the inside out. So:
@JMBulg: If we were to decide on the plate construction, I see two options. One is that the user makes a second plate that's bigger than the module (e.g. 1cm around) onto which the module mounts normally (screws through the bottom) and then that whole construction is bolted into the chassis from the module side. The other option would be a kind of mounting brackets to clamp the module down. Do you think you could live with either? Other suggestions welcome too btw.

@SP502, SMPS, but not regulated. The amplifier itself is a pretty capable regulator in its own right...

[UrSv]

Originally Posted by Bruno Putzeys

@UrSv: Yes let's open the mounting can. For EMC reasons I prefer plate mounting like the NC1200 and the current UcD OEM range. The only thing this can't answer is the question what to do if you want to fasten screws from the inside out.

A larger plate than module is fine with me. It really doesn't have to be much larger as 10 mm would probably be fine on two edges.

Would through PCB mounting be bad? I mean four holes that you reach through the PCB itself?

[jmbulg]

@JMBulg: If we were to decide on the plate construction, I see two options. One is that the user makes a second plate that's bigger than the module (e.g. 1cm around) onto which the module mounts normally (screws through the bottom) and then that whole construction is bolted into the chassis from the module side.

This is actually what I did and it is feasible. It demands however more mechanical work, not necessarily within reach for occasional DIY, and makes a possible source of problems (two contact surfaces instead of one for the hear transfer).

Suggestion: make your heatsink 10mm larger on two sides only (probably longer since the module is probably shorter than the SMPS. Making it higher is more susceptible to add further constraints on case heights) and make the adequate holes there.