Post your Solid State pics here.

[jacco vermeulen]

Originally Posted by martinbls

Another thing is that many diy'ers use discrete diodes on small pcb's even for much larger power amps with no added extra cooling than the backside of the TO220 or TO247 cases.

Martin,

TO220 diodes already have their own (small) heatsink, thermal resistance from case to ambient for a TO220 is 60C/W.
Plus an Rjc of 2C/W makes 62C/W thermal resistance from junction to ambient.
The popular MUR860 diode can deliver it's rated average forward current of 8A up to 155C case temperature.
Four MUR860 in a Graetz bridge handle 5A average current, in free standing position on a pcb.

Block bridge rectifiers such as an GPBC15 handle 15A only up to 55C and 8A at ~75C, which requires a 1 C/W heatsink according to the datasheet.
Without a heatsink, the average forward current number of a block bridge rectifier would drop like a fly (on a turd), way less than 4 bridge wired TO220 diodes.

There are other differences between diodes as the MUR860 and prewired bridge rectifiers that disables a direct comparison, such as reverse recovery times of 70ns versus 500.
For an example of heat problems with free-air MUR full bridges, check the Aleph-J thread at Holger's Analog Forum.

As i indicated, if you say it works, then it works.
Just appears a bit odd on a otherwise sublime laid out amp, if you can have a bulletproof PS rectifier at zero extra cost.

[martinbls]

Hmmm...

Perhaps you guys are right. I mean, I checked it, and even after about half an hour with a bit above moderate listening levels neither the bridge itself nor the ground plate of the pcb got noticably warm, but I'm seriously thinking about making that ps "bulletproof" and change the bridge for a 35A type, eventually with a small heatsink underneath. I will find a solution for that, I promise! Reliability even under extreme circumstances is always very important to me.

Thank you all for your remarks!

Martin

[martinbls]

Ok, what about this solution:

(Although this is quite difficult to describe in english...)

On pic 1 you can see the "kit", consisting of a small heatsink with 6,8k/W, the rectifier bridge (a new, unused one from my parts bin, but the very same type was used for the amp), two washers and a, well, sort of plastic washer. You get one of these when you buy a spindle of compact discs. On pic 2 and 3 you see how nicely the bridge fits in between the side walls of the heatsink.

The washers are all needed to ensure enough space between the bottom of the heatsink and the pcb to avoid shortcutting the traces and to accomplish some space for the soldering dots of the pins from the caps, with a nonconductive material of quite large diameter to spread the pressure from the centre bolt.

[martinbls]

On pic 4, 5 and 6 you see how precise the two washers match with the inner diameter of the plastic washer, and how precise the two washers match the exact hight of the plastic washer!

So, what do you guys think?

[martinbls]

This is how it would be installed on top of the pcb. Of course the hole for the centre bolt in the heatsink isn't drilled yet...

And: I could also double the hight if necessary. I have two of those plastic washers and of course many of those steel washers!

[syn08]

The YAP 2.1 controller is ready. DAC channels calibrated, YAP specific constants (power supply voltages, tolerances, temperature windows, max. offset, etc...) updated. Works like a charm 8)

Schematics, Gerbers, software .hex and source code will be available on my web site soon...

Now I can finish the YAP 2.1 construction

[lgreen]

Here are the pics from my thread Krill is Complete! which you can read if you want to know what the heck this is (also can search "Krill" here and check my web page).

Since this is a pics thread and I've posted the pics elsewhere, I hope this does not violate any double posting rules? If so I'm sorry.

[lanchile]

Hello, I finally got the input caps in. I love the sound of these small tanks!

[blueskynis]

Originally Posted by syn08

The YAP 2.1 controller is ready. DAC channels calibrated, YAP specific constants (power supply voltages, tolerances, temperature windows, max. offset, etc...) updated. Works like a charm 8)

Schematics, Gerbers, software .hex and source code will be available on my web site soon...

Now I can finish the YAP 2.1 construction

Looks very nice Syn08!

Cheers,
Nesa

[shaan]

My dirty work on dot boards. DoZ Preamp+Pavel's Class-A Follower. These are the simplest circuits I made in the last 10 years. BUT they sound the best.
These will be driving the mid+high in my soon-to-be born bi-amped system. cheers.

Link to this project's webpage-> Project 83 - MOSFET Power Follower(Updated)