F5 Turbo Circuit Boards

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UKToecutter

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lhquam said:
The F5 is relatively insensitive to ripple on the rails, as long as it is the same on the rail ends of the MOSFET source resistor (R18) and the JFET drain resistor (R5). This is why case must be taken to minimize AC currents in the path between the rails on output board and the input board. You might allow for caps on both boards and people can experiment to see what works best.
Click to expand...

Ihquam

I've added capacitor positions on the output boards.

Andy
 
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lhquam

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UKToecutter said:
Gentlemen,

I present the V3 Balanced input stage board.
I'm sure I can get it a bit smaller. It's currently 120mm x 64mm so smaller than 2 x SE Input stage boards.

V3BalancedInput.jpg


Andy
Click to expand...

The trace for the balanced connection R3, R4, P3, r29, R20, P6 also needs a terminal post or solder pad for grounding to disable the balanced mode and run each side independently. This is also needed for initial adjustment to set the bias currents, output offset, and 2nd harmonic. I would vote spst switch.
 
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UKToecutter

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lhquam said:
The trace for the balanced connection R3, R4, P3, r29, R20, P6 also needs a terminal post or solder pad for grounding to disable the balanced mode and run each side independently. This is also needed for initial adjustment to set the bias currents, output offset, and 2nd harmonic. I would vote spst switch.
Click to expand...
Ihquam
I hadn't planned on people using this board for SE.
There is already a board for that
 
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rdk845

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Joined 2006
Rush said:
Thanks Andy,

My order is correct as shown on your list.

By the way, I got a quote from Galco.com for Heatsink-KL-285(P)/180-SEKG for $73.37 each, $440.22 for all 6 needed. Pricey!

Rush
Click to expand...
I got quote of $52.04 each for 16 of them. ( just came up with maximum number that I would ever want for balanced > 100W class A F5T) Apparently quantity discount does work with seller. Since this sink seems to be very attractive option for F5T, it could to be a good candidate for a group buy. Unforuately I'm not in position to do a group buy, but if someone can lead that I would be interested in participating... :)
 
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Geofd

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Joined 2011
UKToecutter said:
MASantos

I'm going to call a moratorium on board development for now.
It's time to get some samples produced and test builds done.

Andy
Click to expand...

I could not agree more - we have so many options now - to many for my little mind to keep track.

The boards look great (but I also suspect the spacing will be a bit small, so I have ordered the individual FET boards as well)

PS for the V3 what are people going to use as a case - the MODU 5U 400 mm deep unit is good for 295W of disipation with 4 transistors/FETs per side. having 2 such huge cases seems a bit much. Does anyone else have any ideas ( for an off the shelf solution ?)
 
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UKToecutter

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Horio said:
Andy even when using the board for a balanced amp, I think it's supposed to be very helpful to balance/bias each side independently (single ended) prior to adjusting the balanced circuit.
Click to expand...

Ah...

I see it now.
We need to break the link between the wiper of P3 & P6 to set up. Is that right?

If so, my apologies to you Iqhuam.

I'll find a suitable switch

Andy
 
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