Speaker protecion for F5

Tyimo · 2013-02-12 11:05 am

Hi!
What should be the ideal speaker protecion for the F5 or any direct coupled relatives?
Is there any "official" solution?

Greets:
Tyimo

KatieandDad · 2013-02-12 11:13 am

In a word, there is no official solution. I believe the original design relies upon the sturdy design to protect itself.

ianc13 · 2013-02-12 12:18 pm

While there isn't an official line on this if you are concerned then have a look in the diyaudio store. There is a PCB set for soft start + speaker protection (2 boards as a set) that will do the job. And you are supporting the forums if you do decide to buy.

Dzius · 2013-02-12 12:49 pm

According to F5 manual there should be no more than 25mV at the speaker output, so isn't dangerous unless there is any fault.

ianc13 · 2013-02-12 12:59 pm

Alas I had one channel of my F5 go pop and trigger one of my speaker protection boards. It was during normal operation so, while rare, these things can happen!

willamp · 2013-02-12 1:24 pm

Early in my F5's life it was accidentally left on for a couple of days. When I had been using it the heatsinks had never gotten over 48 C but somehow during this couple of days something happened and the fuse blew. I found both output mosfets on the failed channel were now burned out. I had no speaker protection on it at the time but fortunately my speakers were switched to a different amp via a switchbox and weren't connected to the F5. After this I added the store's speaker protection board and lowered the bias from 1.3 to 1A after replacing the mosfets and source resisters. I haven't had any trouble with it since but definitely wouldn't go without the speaker protection again. And also, of course I'm much more careful that it doesn't get left on.

Dzius · 2013-02-12 3:36 pm

Guess it had something to do with P1 and P2 potentiometers quality.

Tyimo · 2013-02-12 3:58 pm

While there isn't an official line on this if you are concerned then have a look in the diyaudio store. There is a PCB set for soft start + speaker protection (2 boards as a set) that will do the job. And you are supporting the forums if you do decide to buy.

Thanks!

willamp · 2013-02-12 6:03 pm

Dzius said:
Guess it had something to do with P1 and P2 potentiometers quality.

Not sure what you mean about the pots. If you're referring to me lowering the bias, I only did that to be safer, and run a little cooler.

Bksabath · 2013-02-13 1:04 am

Gogle up NTE 7100 I am using those and Amplimo relay on my F5

Speaker protecion for F5

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