Removing Protection Circuitry From F5

[ttan98]

Hi,

I note the following:

1. Peter Daniel wrote somewhere on F5 thread that he noticed that the F5 sound much better with the Protection Circuitry Removed(PCR) i.e. the 2 transistors and associated resistors removed.

2. The F5 with PCR has the same topology as the Profet from France. Looks like the French amp does not worry about the reliability of their amp. Worst still their amp does not have source resistors on their mosfet.

my question has anyone use F5 with the PCR, how reliable or unreliable with this amp be? If I use a DC protection circuit board in front of the amp will it protect my speakers in case the amp fails.

Any comments are welcomed.

 

[Nelson Pass]

I have not found that the protection circuit affects the sound.

As to the rest, perhaps you would prefer to build the Profet circuit.

 

[flg]

Is not the ProFET circuit a class AB thingy? (low bias)
Also is there not some variability involved in the values and thresholds for the protection stuff of F5 that may be optimised for protection only and not to effect the "sound"?

 

[Zen Mod]

besides class/Iq , Profet is different in one tiny but also very important detail - feedback arrangement

regarding other one - I'm sure that F5 made on Al heatsink will sound different from same one , made on Bronze heatsink



best protection circuit for your speaker is ........ very fast nail , connected on output terminal , when needed

 

[generg]

I can say that the F5 driven without protection circuit on my Thiel SCS 2.4 (4R and lower/89dB/1W) sounded better to my ears……

that is all I can say…...

 

[labjr]

I can say that the F5 driven without protection circuit on my Thiel SCS 2.4 (4R and lower/89dB/1W) sounded better to my ears……

that is all I can say…...

Think you can hear a difference blindfolded?

 

[tinitus]

Think you can hear a difference blindfolded?

no, that would be like eating and holding your nose

 

[bear]

i am fairly confident that many have built the Eff Phyve without the protection circuitry.

 

[tinitus]

I think most here have built without
until now
but more and more appear to be buying pirate parts
they seem to be the ones building with protection curcuit

 

[Andersonix]

If I use a DC protection circuit board in front of the amp will it protect my speakers in case the amp fails.

You mean in front of the speakers?

 

[ttan98]

You mean in front of the speakers?

More precisely, the output of F5 connected to the input of DC detection circuitry.

 

[Nelson Pass]

Is not the ProFET circuit a class AB thingy? (low bias)

The 2X15 watt version is clearly Class A. Judging from the curves, I would
imagine that the 50W mono version leaves Class A at 10 or 15 watts rms
(twice that for a peak), which makes sense as a bridged version of the
stereo unit.

 

[Andersonix]

More precisely, the output of F5 connected to the input of DC detection circuitry.

Yes. Do you have something specific in mind?