Folded sheet metal heat sinks - efficiency?

[KEW]

This is the new Denon AVR-3400:

These have been becoming more and more common. Obviously much cheaper than machining or casting solid aluminum, but how effective are they. Certainly there is more airflow, but does anyone know how the sheet metal is thermally coupled/attached to the "base plate" of the heat sink?
Heat is an obvious concern with all that gets crammed in a modern AVR, and it would be good if this is actually a better cooling technique than the solid aluminum of the past.

 

[TheWarrior]

This is the new Denon AVR-3400:

These have been becoming more and more common. Obviously much cheaper than machining or casting solid aluminum, but how effective are they. Certainly there is more airflow, but does anyone know how the sheet metal is thermally coupled/attached to the "base plate" of the heat sink?
Heat is an obvious concern with all that gets crammed in a modern AVR, and it would be good if this is actually a better cooling technique than the solid aluminum of the past.

More than that, it looks like the may have switched to a Class D/G/H amplifier which should also be running cooler than AB. I would't doubt the thin cooling fins are plenty effective.

 

[M Code]

Corrugated sheet metal heat sinks in either aluminium or copper increases surface area, and subsequently, the volumetric performance. This type of heat sinks have been used in AVRs for >10 years, not really new a result of the SRP cost compression process of AVRs. Also the corrugated heat sink was significantly less expensive compared to extruded aluminum type, plus being much lighter in weight saving freight costs..

Just my $0.02...

 

[KEW]

I get the surface area part, but I believe the main reason solid Al was used in the past (and still is on high end gear?) is how do you get a high level of thermal transfer from the "base plate" to the "fins" since they are separate pieces. I'm sure they have figured it out, but wonder of they have a glue with a high level of transfer or if they physically weld the pieces together, etc.

@M Code
What is SRP Cost Compression?

 

[M Code]

I get the surface area part, but I believe the main reason solid Al was used in the past (and still is on high end gear?) is how do you get a high level of thermal transfer from the "base plate" to the "fins" since they are separate pieces. I'm sure they have figured it out, but wonder of they have a glue with a high level of transfer or if they physically weld the pieces together, etc.

Pieces are welded together.

@M Code
What is SRP Cost Compression?

Suggested Retail Price cost compression is the basic economic process AVRs (and other CE products) have undergone the last several years. As the internet and e-commerce increased their penetration there was high pressure on the brands to reduce prices, they responded by:

• Decreasing component overdesign
• Decreasing warranty
• Using more plastic than metal
• More integrated circuits
• Less expensive parts

The end-result was cheaper products but shortened product life, products were made to become obsolete rather than being repaired..

Just my $0.02...

 

[Verdinut]

Corrugated sheet metal heat sinks in either aluminium or copper increases surface area, and subsequently, the volumetric performance. This type of heat sinks have been used in AVRs for >10 years, not really new a result of the SRP cost compression process of AVRs. Also the corrugated heat sink was significantly less expensive compared to extruded aluminum type, plus being much lighter in weight saving freight costs..

Just my $0.02...

That might explain why recent D & M AVRs and those of some other manufacturers heat more and benefit from external fan cooling.

 

[tom67]

This is the new Denon AVR-3400:

These have been becoming more and more common. Obviously much cheaper than machining or casting solid aluminum, but how effective are they. Certainly there is more airflow, but does anyone know how the sheet metal is thermally coupled/attached to the "base plate" of the heat sink?
Heat is an obvious concern with all that gets crammed in a modern AVR, and it would be good if this is actually a better cooling technique than the solid aluminum of the past.

I'm sure a reputable company like Denon has determined that the new sinks are adequate...and they keep down the cost of the products which is a good thing. As a bonus, you can heat your frozen entrees on their newer product lines.

 

[Pogre]

Yeah, my SR6011 gets almost hot just idling.