F5 power amplifier

[pchw]

Originally posted by juluska
What do you think about that pcbs that sold on ebay?
I's worth a try to build that kits?

There are 2 F5 pcb group buys from 2 kind souls that are approved by Papa. Everything else is just pirate stolen IP goods. They are all no good, period.

[umut1001]

hi everybody ! i found new transistors for f5.. they are irfp150n and fairchild's sfh9154 .. they have more input capacitance but sounds very well.they are like complementary transistors.they have same gate voltage..bass and treble are also good

[rhing]

Originally posted by pchw

There are 2 F5 pcb group buys from 2 kind souls that are approved by Papa. Everything else is just pirate stolen IP goods. They are all no good, period.

Ditto. Buying through the approved group buys on this forum provides ready access to assistance from all the DIYers here including the Master himself. If you buy the pirated boards, you are on your own. Why waste your money?

[trishend]

Hi Cviller,

I want to order the F5 boards, but am a new member so cannot mail you directly. Can you mail me to initiate? Or what are the alternatives?

Trishend

[ichiban]

Originally posted by tms0425
I finished my F5 with CViller's power supply and amp pcb's to keep my pair of F4's company. It went together really easily and biased up with no problems at all. Thanks Christian and Papa for this little gem!

Antek toroid, TSHA 22k uf caps, PRP resistors, etc. Nothing fancy.

Tom

tms0425, I'm getting closer to an F5 build and I'm curious as to how you attached the wiring to CVillers boards. Wire gauge used.

I've yet to find a way to setup two F5s in balanced mode, and I'm hoping the Conrad MF35-151.5's will handle the heat.
The remaining parts from Digikey arrive Thursday, so maybe by this weekend I'll hear what everyone has been talking about.

[woodturner-fran]

Nice looking box there ichiban.

Tonight I made more progress... but first a step back. I took and then labelled a pic of what I did with the output resistors. Seems that its part of my penance to show it all but maybe it might save some other poor soul. Morgan Jones talks in his book about never working when you're tired or late at night... well its then or never around these here parts! The boards are messy, bits having been soldered in and out a good few times so excuse the looks ok?! So look, if it saves anyone else...





and here she is powered up in the workshop, front face on, lid in place. I ended up painting it a nice shade of metallic green. I have it inside now playing a disc but am about to head downstairs and have a listen before bedtime. thanks again to Nelson, Peter and all who helped out here. everyone.



Fran

[tms0425]

Originally posted by ichiban


tms0425, I'm getting closer to an F5 build and I'm curious as to how you attached the wiring to CVillers boards. Wire gauge used.

I've yet to find a way to setup two F5s in balanced mode, and I'm hoping the Conrad MF35-151.5's will handle the heat.
The remaining parts from Digikey arrive Thursday, so maybe by this weekend I'll hear what everyone has been talking about.

I used 16 gauge for V+/V-, power grounds, AC wiring, doubled 20g Cardas for the speaker outputs, and 1x22g Cardas for the signal input/grounds. You could go bigger as the holes are very oversized.

I wish I had some of those nice milled and drilled Conrads. Very nice

I'm not really sure you'll have enough dissapation to put 4 channels of those 2 sinks. If I recall it's 62w each, so might be tough with 4. Also, that layout of toroids will get one of them VERY close to the signal wires on the back panel. If you want to try it I would mock it up with the supply on the bench, handwired to 2 boards first, then try a 4 if all goes well. Instead of tapping the heatsinks for all of them right away, I would be inclined to use flat bar stock temporarily clamped over the pairs of Mosfets. If it won't work that way in free air, the closed case with toroids inside definitely wouldn't make it. With all that said, my pair does not run as hot as I though it would. The F4's run about 45 C biased up a little harder than Nelson recommended.

[Nelson Pass]

Originally posted by tms0425
I'm not really sure you'll have enough dissapation to put 4 channels of those 2 sinks.

Just adjust the bias until the sinks run 50-55 deg C, and there you are.

[tms0425]

Originally posted by Nelson Pass


Just adjust the bias until the sinks run 50-55 deg C, and there you are.

... comfortably warm by your usual standards

[Tea-Bag]

I was playing with the F5 and wondered why the V+ and - was around 22.5v

Then I looked at my parts. For R5-R8, I used INDUCTIVE wirewounds. I think this may be the reason. (This was purely a lack of looking at the obvious when ordering)

Is this a big problem?

Tea-Bag