F5 power amplifier

Put all neg RCA and neg binding post to 'center' of dual rail supply. Then connect the CL60 from that point to chassis ground and Power Earth ground.

Do not put the input shielding to star ground but to the board only.
Just in case.

Thanks for your instructions, I did what you said, everthing to the center of dual rail supply and the input only to the board!

Dead quite, using B1 buffer, its the first time i turn the pot to maximun with out any noise!

By the way the highs are here and they are fantastic... it was a ground problem!!!
Pictures coming!

What a balanced and clean sound! Thanks Mr Pass
 
Is there any method to know that i already overdrive the F5 more than 20watts? because i scare that i kill the amp when i crank up the volume too much:t_ache:

If you massively clip the amp, it is more likely that you will kill the tweeters than the amp...

Not much to worry about. To my ears the amp starts to sound slightly "compressed" when peaks push it into clipping... not much else seems to happen.

If you need more power, try making a bridged pair per channel??

There are several schemes that have already been posted about this... also the cascode trick too.

_-_-bear

Andrew, have you found the time to build one yet? :scratch:
 
Dumb construction questions: (pics attached)

How do I wire the IEC, fuse, and switch?

Also, is the earth common for the AC, line level and speaker level connections?

Thanks,
 

Attachments

  • IMG_2483.JPG
    IMG_2483.JPG
    92.6 KB · Views: 680
  • IMG_2484.JPG
    IMG_2484.JPG
    146.3 KB · Views: 681
How do I risk the short to heatsink? I have extra insulators if they are required.

That heatsink is from Papa...

Maybe you can keep the insulators oriented with the outputs so the metal underside of the transistor can't touch the heatsink by accident. And maybe move the amplifier board closer to the center of the heatsink.
 
Last edited:
what tinitus said...

you can peel the heatpads and turn them so that they are square below the Mosfets...

The mosfets get very hot, they should be most of the way down that heatsink, lower is better.

The diodes don't get so hot... you can move them so they are in a square pattern, not a long pattern as they now are...
face their leads at each other too...

That will let you have shorter wires. Shorter is usually good.

_-_-
 
Last edited:
Nothing is wired up yet. The holes were already tapped in the sink and that was the only way I could get the fets to line up with the holes. I will turn the pads...

Regarding my initial question "How do I wire the IEC, fuse, and switch?"...

Positive from the IEC -> one terminal on the fuse. The next terminal on the fuse is wired to one terminal on the switch and the next terminal on the switch to the hot lead on the primaries of the power transformer.

Thanks Gentleman,
 
Member
Joined 2003
Paid Member
Positive from the IEC -> one terminal on the fuse. The next terminal on the fuse is wired to one terminal on the switch and the next terminal on the switch to the hot lead on the primaries of the power transformer.

Correct! With the exception that it's AC, there's no positive as in DC. Make sure L1 connects to fuse>>switch. AC ground>>directly to chassis. Speaker and signal (line level) connects to PS ground or to a star ground. PS/star ground connects to chassis ground via thermistor or bridge rectifier. Take a look at the ZenV4 article, specifically Figure 6 - unregulated power supply example.

-john
 

Attachments

  • plugs USA.jpeg
    plugs USA.jpeg
    24.6 KB · Views: 840
Last edited:
Curse you DIY AUDIO!!! (kidding...sort of...)

Well, before I had my aleph mini complete I had ordered Peter D's F5 boards and universal PSU...For some reason I can not stop building amplifiers!!!

The aleph mini is a great little amp but I am looking forwards to a little more power. I am currently driving a pair of Fostex FE127E's in the planet 10 Fonken cabinet.

So far I have collected all of the resistors and caps for the amp boards and PSU. Still need misc enclosure bits - rca's speaker terminals etc. and a transformer.

I am not sure If I go with an 18V 20V or 22V unit. Most likely to be a 400VA unit from Antek. I am using a 12V 200VA unit for the mini and am only getting 14V +/-.

And the Pièce de résistance - A hifi2000 4U with heatsinks
 
High power F5X

Today I started to populate my high power F5X PC boards .
I need to ad the 3 pair (Toshiba) MOSFETs /PC board and JFets .
Also I will have to buy some 5K trim pot .
I hope soon I can set up for testing .:)
Some pictures
Greets
 

Attachments

  • IMG_0002_2.JPG
    IMG_0002_2.JPG
    72.5 KB · Views: 766
  • IMG_0002.JPG
    IMG_0002.JPG
    69.1 KB · Views: 756