hypex ncore

[Bruno Putzeys]

The plate is not insulated. Even if it were it'd have to be connected to the circuit ground by largish caps at every screw hole (for EMC).

There is no problem bolting them together onto one chassis though. So long as you stick to the cabling guidelines in the datasheet there's no problem interconnecting the grounds (the reason being that the signal never uses ground as a reference).

The plates on the SMPS are capacitively coupled to avoid accidents when someone touches the one on the primary side (or both). Having said that, you must treat everything on the primary side as dangerous live. No part of the primary side is "safe" in the spirit of safety standards. This means that if part of the chassis comes close to the primary side of the SMPS, you must install insulation.

[Julf]

Originally Posted by Bruno Putzeys

The plates on the SMPS are capacitively coupled to avoid accidents when someone touches the one on the primary side (or both). Having said that, you must treat everything on the primary side as dangerous live. No part of the primary side is "safe" in the spirit of safety standards. This means that if part of the chassis comes close to the primary side of the SMPS, you must install insulation.

Thanks! Will make sure there is enough of an air gap or insulation - my plan is to mount 4 nCores along the outer
side panels of the enclosure, with the 2 SMPS's standing on their side in the middle, bolted to a centre separator bulkhead. Only concern is cooling of the SMPS's in an enclosed space shared by 4 nCores (the nCores, being bolted to outward-facing side, should be OK), and that is why I was wondering aboout "extending" the cooling plates of the SMPS's to the chassis.

I also noticed one of the spacers for mounting the SMPS is metal, so I assume that spacer *should* be connected to the chassis?

[Bruno Putzeys]

Originally Posted by Julf

I was wondering aboout "extending" the cooling plates of the SMPS's to the chassis.

It doesn't get very hot (the hottest part is the transformer), but if you really wanted to do this you could use "gap pad" material.

Originally Posted by Julf

I also noticed one of the spacers for mounting the SMPS is metal, so I assume that spacer *should* be connected to the chassis?

Indeed. It's not awfully important but it improves EMC slightly.

[Julf]

Originally Posted by Bruno Putzeys

It doesn't get very hot (the hottest part is the transformer), but if you really wanted to do this you could use "gap pad" material.

Great! Thanks! Guess I will start without any extra cooling, and see how it works out.

[mr_push_pull]

so... all this wasted time just to find out that class D s not mature enough because it uses feedback when in fact shouldn't. I'm off guys, you'll find me bashing class D in some SET thread...

[OllBoll]

Bruno, does dc on the mains affect the SMPS in a negative way? You said before that the SMPS had a filter but I might as well ask specifically since I know my mains has lots of dc making my trafos humm.

[Bruno Putzeys]

Originally Posted by OllBoll

Bruno, does dc on the mains affect the SMPS in a negative way? You said before that the SMPS had a filter but I might as well ask specifically since I know my mains has lots of dc making my trafos humm.

DC doesn't affect the supply in any significant way. Certainly not in the way it affects transformers. Off topic, AC coupling the mains through a pair of big electrolytics in antiseries (and some form of overvoltage protection across that) works wonders against humming transformers. I've even seen amps that have those built in.

[johnrtd]

Compliments for Bruno. A marvellous article and an examplary approximation to look at the way feed back works.
IMHO Otala never implied that tubed circuits suffer (or not) from TIM. Otala concentrated his thoughts exclusively towards semiconductor circuits.
One of the nicest examples of feedback outside the audio community is the job of Matti at Bosch designing a new type of telephone. Huge amounts of feedback there.

John

[Bruno Putzeys]

Thanks!

Originally Posted by johnrtd

IMHO Otala never implied that tubed circuits suffer (or not) from TIM. Otala concentrated his thoughts exclusively towards semiconductor circuits.

Of course he didn't The reason why I stressed this point in the article is that you can't throw a brick into a gaggle of audio fans without hitting someone willing to claim that "Otala proved tube amps are better" (or one actually doing so until he was unexpectedly interrupted by an oncoming brick).

[matjans]

thhgttg-esque remark

PS: turns out EUR 4 balanced cable beats EUR 40 single ended (coaxial) cable btw.