F5 power amplifier

[a.wayne]

Hello Oscar ,

Were you able to get any bench testing done ?

regards.

[osscar]

Hi a.wayne,

I did the conclusions based on sounding performance of my F5. I have no signs of audiophile (im use only standard parts - 1% Metal film 0.6W all small resistors and power film 3w resistors and vishay transistors). but the measurements of the my F5 amplifier is well (square wave response, bandwidth etc..),also design is on top (thank you Mr.Pass for sharing it). So it is not sounding bad-its sound so great IMHO. Now I thinking of another DIY Pass amp construction for my brother - maybe Aleph J or F4.

regrads,

oskars

[jameshillj]

Try an F3 for something really quite different!

[osscar]

thanks for the advice now will read an article about f3, sorry for OT.

[bear]

prooptiki, I can't tell from the pix which way is up. But if the transformer is down, you might consider putting the F5 board and output devices closer to the bottom of the heatsink.

It may not matter because you have a very large heatsink - but see how hot it gets after about 6 hours of being on, after the heatsink reaches some sort of thermal equilibrium.

Wondering if you milled the backside of those heatsinks or if they came that way?

_-_-bear

[prooptiki]

Originally Posted by bear

prooptiki, I can't tell from the pix which way is up. But if the transformer is down, you might consider putting the F5 board and output devices closer to the bottom of the heatsink.

It may not matter because you have a very large heatsink - but see how hot it gets after about 6 hours of being on, after the heatsink reaches some sort of thermal equilibrium.

Wondering if you milled the backside of those heatsinks or if they came that way?

_-_-bear

Thanks, I am considering also to add two more channels f5 to the botom, but first I have to find out a good way to make my B1 buffer having two outputs!

I made some changes to the thermistors, now they are on the mosfets!
But still the heatsinks are too big, for about 36hours on power, the amplifier is colder than my cd player!!! I am going to try covering the heatsinks...
The heatsinks came as the are now, 40euros!!

[GKLTDKV]

40 euros? from where? i have search anywhere but the prices are..................very high

[alazira]

Originally Posted by osscar

Thanks for the information Alazira and Andrew. Currently I do not change anything - I am enjoying every day sound of F5 with the new(and and pretty cheap) lot's sensitive speakers. Very light sound of the amplifier in spite of its weight at this time I do not use any preamp - just a CD player line level adjustment from remote control, but the-20dB on sony CDP is not enough - f5 sounds too loud for me sometimes.

It seems that I've joined Papa`s DIY fan club

Hi osscar,

just a thought, but if it plays too loud you could increase R9 or even better reduce R10 (100K trimpot would be good here)

[AlanElsdon]

Hi - I have a pair of F5s built using Peter Daniels board - apart from the excellent sound I am getting a rather odd effect. If I touch (or just move my hand near) the heatsinks then the volume drops to nothing for about half a second and the fades back in rapidly.

Weird.

Even weirder is that once I have done this and then touch the amp again there is no effect.

[Melon Head]

Have you conected your chassis to earth?