F5 power amplifier

[jtktam]

just a newbie question

how much heat does the F5 generate?

I am currently building 4 channels to biamp my speakers and was going to use a 6" x 24" x 2" heatsink per side, with 2 channels on each side

-joe

 

[bear]

as previously discussed, ur likely much better off with 6" x 12" x 2" per pair of mosfets which equals one channel. Cut it in half... read back a few pages??


Unless of course (unlikely) with the fins vertical, the horizontal length is then 24" - which is fine.


_-_-

 

[jackinnj]

just a newbie question

how much heat does the F5 generate?

-joe

2 times 1.3 amps times 23 volts = 60 watts when it's resting. That's what you have to "dissipate".

 

[Nelson Pass]

and that would be per channel

 

[a.wayne]

2 times 1.3 amps times 23 volts = 60 watts when it's resting. That's what you have to "dissipate".

Jack is that for both channels running, for times 2 ?

 

[fork]

F5 Bridge Rectifier - tinkering

I have some friends in my audio club who swear by the improvements from upgrading the diodes or bridge rectifiers in their amps. I wonder if this is worth trying in the F5 or maybe the circuit design is such that a better part won't have much effect on the sound?

I can't seem to find a post on this, regarding the F5, but my electronics background is such that I might not be using the right search term. Can anyone direct me to a post they're aware of or provide feedback on your experiments?


Thanks

 

[acold7dusta]

Pass F5 pictures by acold7dusta - Photobucket

getting close!

 

[cviller]

Looks great!

 

[jackinnj]

Jack is that for both channels running, for times 2 ?

That's one channel as NP artfully demonstrates. I believe he said 62W in the AX article.

 

[samoloko]

0,0033 uF mains noise suppression question

Hi

there are too many classes x, x2, y, y2
Is there any preferable here - also I have seen some use bigger value here
I got 230VAC

 

[jtktam]

Pass F5 pictures by acold7dusta - Photobucket

getting close!

I see you got a "save 50c" coupon in the pics

-joe

 

[jackinnj]

Hi

there are too many classes x, x2, y, y2
Is there any preferable here - also I have seen some use bigger value here
I got 230VAC

Here's what you need to know about X and Y capacitors -- page 3 a "must read":

http://www.conis-bg.com/downloads_pdf/EMI and RFI filters/suppression capacitors.pdf

 

[bear]

I have some friends in my audio club who swear by the improvements from upgrading the diodes or bridge rectifiers in their amps. I wonder if this is worth trying in the F5 or maybe the circuit design is such that a better part won't have much effect on the sound?

I can't seem to find a post on this, regarding the F5, but my electronics background is such that I might not be using the right search term. Can anyone direct me to a post they're aware of or provide feedback on your experiments?
Thanks

It all depends on intangible things, like how things sound to you on your system now, and how things sound with "regular" parts in the amp...

but it's a safe bet to go with "soft recovery" rectifiers...
...my friend Rick who built up his F5 first using "ordinary" parts says that putting in "premium" parts improved the sound. I did hear the sound improve, but he also did other things that were more fundamental at the same time... the improvements were not subtle from the time he assembled it somewhat hodgepodge using random wire and layout to now where it is reasonably well done electrically, big improvement to the point where the amp is impressive to me...

I'd say buy extra boards (send me my commission check on this advice! ) and stuff one set to start with "regular" or "cheap" and see how it works. Then go for expensive premium parts either one at a time or all at once in the new boards and see 4 urself!

_-_-bear

 

[umut1001]

I removed Rifa 18000uf capacitors at the end and put 25v 47000uf kendeil caps.Voltage and sound increased.I describe that is the huge improvement

 

[bear]

When you increase the capacitance the voltage gets closer to the peak value... sound level ought to be the same. Perhaps you mean the sound was "better"? I think so.

_-_-bear

 

[umut1001]

When i increase the capacitance the voltage ripple decraesed,total voltage increased.And also sound became better(bass mid and treble) as you say

 

[acold7dusta]

I see you got a "save 50c" coupon in the pics

-joe

Ha good catch, I'm building this at my parent's house, and you can see my mom's a little thriftier than me

Looks great!

Thanks! wouldn't have been possible without your boards!

 

[jtktam]

that is very nice looking btw

-joe

 

[a.wayne]

I removed Rifa 18000uf capacitors at the end and put 25v 47000uf kendeil caps.Voltage and sound increased.I describe that is the huge improvement

explain better please ...

Are you saying it sounded better due to larger size or due to being a better cap?.. were you using the same value total or only 18 K for Rifa ?

 

[umut1001]

I am using two types of capacitor now.You know F5 power supply is CRC.I was using Rifa 18000uf 105C low esr caps.And it sounded good.DC value at output was +-19,6 volts.I removed the rifa caps at the end(First C rifa is still there)and replaced it with Kendeil 25v 47000uf(I think it is about 15 year old yellow cap but has about 14A ripple current.It is better than 8A ripple Rifa)And by the way the output voltage increased to 21 volts.
I will remove first Rifa and replace it with Kendeil too.If i have much money I would buy Mundorf Computer Grade capacitors.
Now i believe that Capacitor is one of the most important thing in amplifier.Better caps sounds better.In class A designs ripple current of capacitors is important.Use most quality cap as you can.If i were you i will buy there some computer grade screw type capacitors.Because there is USA and can find good things for cheaper!