Cviller's F5c

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thor61

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Joined 2010
#1
Has anyone built a amp based on using these boards ? And if so could one post some construction details ? Thank-you !
f-5c_-_copy_1_1.jpg
 
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#3
I built a standard F5 using these pcb's.It was configured with a single power supply using a cvillers p/s board with 8x33,000uf 40V caps; schottky diodes powered from a 500VA Toroidy.pl transformer with dual 18V secondaries.The heatsinks are the PS385 from these guys;over sized for an F5 but will come in for something else in the future;
http://www.gdrectifiers.co.uk/uploads/Heatsinks_for_large_isolated_modules.pdf
I had difficulty getting the bias adjusted to start with but Zen Mod pointed me in the right direction and it has been making beautiful music for the past 2 years.Never did get round to trying the dual output;cascoded version and I now have a Turbo V2 under construction.
I will post a few pics later.
 
#5
thor61 said:
if so could one post some construction details ?
Click to expand...

I used those boards, will take some pics today and post them. I first used the standard first watt zen style crc psu, and ended up with 180mV of ripple, so I am reworking the psu now with more c and im trying choke input.

I did not cascode, used a xfmr with 20v secs, ended up with 27.5 volt rails with the crc. the construction is pretty standard for F5, just more parts to match. also if you want a high bias, get big sinks like the ones in Audiosans pic. those look like usa's 10.08 profile, looks like he has two per channel.

Even with f5t boards on the horizon, I think those boards are well worth the time to build into an amp.

cheers
 
#12
oneplustwo said:
With two power supplies, did you consider using two sets of rectifiers since you have enough secondaries to supply them?
Click to expand...

The channels are sharing the psu. At a glance it looks like two, it was a crc with 30uF/.1r/3uF per rail, with 27.5V rails and 180mV ripple in circuit on the F5c. Now it is 30uF/5mH/90uF clc. The rails from the first board are the inputs to the second. I don't have the chokes yet, so I don't know what the volt or ripple are.

The xfmr is AN-8420, 800va.
 
#14
Russellc said:
That's HeatsinkUSA 10.08" sink right? Were 4 pieces of this sink required for a one pair output F-5, or were you allowing for future two pairs per channel? Or just good old overkill?😀

Or do I just not see the double outputs?

Russellc
Click to expand...

it's a little overkill. but also 2 pairs of output. +/-23V rails and 1.7A bias, so that it runs a little higher in class A at 6ohm.
 
#15
I'm building mine today, Standard F5, but I'd like to cascode...

Not sure:

1. Cascode improve sound? if only using one pair of output devices
2. Anything to adjust (resistor values?)

Also is it ok to glue the thermistor on the output device with thermal epoxy. My thermistors are not rigid leaded.

Thanks !!!!
 
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