What F5 amp is this?

[thomassannes]

Greetings from Norway!

I have been building electronics for some time and just found a very nice DYI Class A amp that i got for cheap. It sounds amazing and it got plenty of punch.

I cannot figure out what kit it is, i see that it is one of the F5 kits, but it apears to be some kind of balanced dual mono configuration. Do anyone know what it is? What is the output power? It draws about 280-300 watts continous from the mains. There are two large transformers each outputing 24x2 volts.

I do have about 500mv of LF hum noise on the left channel and 180mv on the right channel. Is this due to the BIAS setting beeing off? Or is it bad grounding? any tips to fix this issue?

Cheers! 😎

 

[Itsmee]

It looks like an F5 Turbo, couldn't tell from the photo which version.

 

[rayma]

I do have about 500mv of LF hum noise on the left channel and 180mv on the right channel.
Is this due to the BIAS setting beeing off? Or is it bad grounding?

Looks like it is dual mono, so probably this is a grounding related issue. Leave the bias settings
as-is for now, they're probably ok. Closer, clearer photos of the interior are needed.

Seems like you got a really good deal.

 

[Itsmee]

Didn't see that bit, grounding issue +1

 

[AudioSan]

That is a dual mono F5 turbo V2.

 

[JeffYoung]

50Wpc (assuming standard bias). It has a push-pull output stage, though, so it will deliver more (in class AB) into less-than-8-ohm loads.