F5 power amplifier

[Nelson Pass]

Originally Posted by Zen Mod

using shottky can't do any harm

fact is that Papa is using them in Pass Labs products

Actually we are using fast/soft recovery types

[samoloko]

Originally Posted by Lucas_G

Now that is a very good tip! Thank you!

Being a greedy Dutchman, I will write to them in English. I hope they will answer...

Has anyone ordered with them from abroad? How smooth went the transaction?

would you get a quote
I like to buy toroid for F5 as well Aleph XJ

[Lucas_G]

Originally Posted by samoloko

would you get a quote
I like to buy toroid for F5 as well Aleph XJ

I did not receive an answer yet (It's weekend in Poland) ,but I will let you know when I hear from them.

BTW, I have got some large an new toroids with 30V on the attick.
I bought them for some extra Alephs (I did build an Aleph5 - splendif amp!), but never found the time to built those extra pairs.
If anyone is interested in buying these, drop me a mail...

Regards,

Lucas

[Lucas_G]

Originally Posted by Nelson Pass

Actually we are using fast/soft recovery types

Nelson, did you have a preference for a certain type of diode?
Was the difference in sound quality obvious?

Regards,

Lucas

[tinitus]

I used this
Hyperfast and fast recovery, which I didnt know about back then

Appears to work ok though, since amp sounds nice, and beats many around

But now I wonder if I should try "soft recovery" types


https://www1.elfa.se/data1/wwwroot/w...A/07023393.pdf

Bridge is mounted on sides of heatsink
I would NOT do that with classA
Hope picture will change to F5 next time

[jackinnj]

I have used MUR860's and HexFred diodes...ashamed to admit I can't tell the difference.

[Lucas_G]

Originally Posted by jackinnj

I have used MUR860's and HexFred diodes...ashamed to admit I can't tell the difference.

Nothing to be ashamed of - maybe both are quite good at it.

I was wondering whether the MUR 860 (I have got bunches around) is up to the task for 2 channels of F5. They are specified with 8 A maximum. Is that enough safety margin for this application?

I have also got spare PCBs of the CarlosFM PSU here that uses these MUR 860s. I could use them together wit Civiller PSU boards in a CRCLC configuration, if they could stand the current draw. Can anyone advice on this?

The IR 30EPH06 used by Tinitus is of a totally different caliber. It is rated with 30 A. Has anyone else experience with these?

[Lucas_G]

Originally Posted by tinitus

I used this
Hyperfast and fast recovery, which I didnt know about back then

Appears to work ok though, since amp sounds nice, and beats many around

But now I wonder if I should try "soft recovery" types


https://www1.elfa.se/data1/wwwroot/w...A/07023393.pdf

Bridge is mounted on sides of heatsink
I would NOT do that with classA
Hope picture will change to F5 next time

Hi Tinitus,

In the PDF it says:

"State of the art Hyperfast recovery rectifiers designed with optimized performance of forward voltage drop,
Hyperfast recover time, and soft recovery."

So maybe you have made a better choice than you realize

BTW, do they get warm?

[tinitus]

Originally Posted by Lucas_G

Hi Tinitus,

BTW, do they get warm?

I didnt see the soft recovery, so you saved me there, thanks

No, they dont get hot
Or, as hot as the heatsink the outputs are mounted on

I have driven a 1ohm speaker, but it definately liked 2ohm better
Its a 50wat, so could ad up to considerably amount of current

I dont know, but F5 is not designed to deliver huge amounts of current
Might help if you use double bridge on each channel
May depend on the heatsink, or whatever you choose to mount them on
Maybe power-up is the worst possible situation

But really, I dont know how much current flows in each diode of a bridge
But basicly it shouldnt be much more than bias current, and use the original curcuit with limiters
And maybe save a bit an trafo size
And, depending on your speakers
But again, power-up could be the most critical situation

But personally, that may not be where I would save money

[ichiban]

Originally Posted by tinitus

I have driven a 1ohm speaker, but it definately liked 2ohm better
Its a 50wat, so could ad up to considerably amount of current

I'm wondering if the F5 would be up to the task of driving Strathearns
one half ohm resistance if the amp only high passed 300-500 Hz ?
First order input filter on F5.

Anybody?