F5 Turbo Circuit Boards

[Variac]

I was asked whether the new boards will fit the UMS, which is the drilled and tapped hole standard as used in the diyAudio chassis. The answer is YES! that's the point.

To see the standard, go to t he store here:
http://www.diyaudio.com/store/ or select it at t he top of this page,
then look for this link:

PCB Summary (all amplifier PCBs are UMS compliant)

the 400mm deep chassis has more holes , as listed in the Standard so will accommodate 2 boards on each side, with MOSFETS and diodes. Four MOSFETS and DIODE per side in other words. the 300mm deep chassis will accommodate one board per side, ie 2 MOSFETS and 2 DIODES per side

Alex has laid these out for us per Toecutter's design. He's amazing!

We hope that board makers for all projects will use this standard when possible to make building up amps a lot easier!

[AudioSan]

Originally Posted by beetle

Bias is not summing up when bridged, as far as I understand. Disipation will be this per channel: 2 F5t*2A Bias*24V*8 Output devices = 384W or 576W with 3A Bias.

I am thinking about using one Modushop 5U 500 case per channel. They tell one sink can handle 0.2C°/W. There are 4 of them per chassis. 2 output devices per sink. Makes 96W to 144W disipation for each sink. 19.2 to 28.8°C above ambient in best case.

I think 100W per sink should conservatively spoken be possible. Then let's see if the sink can handle more heat.

What do you think?


Maybe my GF will be off to the moon when I tell her about the consumption. She is allready suspicious about my gear. Maybe I get rid of the power-on LEDs soon. She thinks there are to many of them. No LED, no consumption. solved.

they can handle a lot of heat those beasts. but at 2A bias. there is not much class A power when the amps sees 2ohm.

[AudioSan]

variac. you got my mail?

[6L6]

Originally Posted by beetle

...She is allready suspicious about my gear. Maybe I get rid of the power-on LEDs soon. She thinks there are to many of them. No LED, no consumption. solved.

Ah, yes. The lack of a LED light will completely disguise the fact that you will have a 500W space heater in the room...

[a.wayne]

Depends on the time of year ....

[beetle]

One? I am considering having two of them.

@AudioSan

How to calculate the power at 2Ohm Class A?

[AudioSan]

beetle. (bias x2) x (bias x2) x impedance /2.
so say 2A bias. it is 4 x 4 x 2 / 2 = 16W class A at 2ohm

[AndrewT]

pmax = i^2 * rload / 2

For 4Apk you get 16W. In a ClassA push pull output stage , you would need an output bias of >2A in each half of the balanced amplifier.

[beetle]

So ~3A bias 24V rails then. I would assume that Modushop 5U 500 has not the right sinks for 576W per channel. Or does it?

1kva 18V toroid will be costly. Any good source in Europe?

I would expect a total power of up to 200W in 4 ohm Class B and 36W class A. Right?

[Zen Mod]

4U/400 is enough for 100W/heatsink

so , say that 5U/500 is enough for maxmaxmax 150W/heatsink ....... no more