[tremrej65]

I read somewhere in this forum few month ago that a F5M would be a good match for GR Research's speaker. So I built one. It's a 25 watts into 8 ohms, class A. This is a good amp. Even though the X-LS Encore are not very efficient (87 dB), the F5M can push them loud enough for a "smallish" room (15x11x8 feet).
I made my own chassis: two actually. I repurpose an the chassis of an old received for the power supply, and I made my own chassis for the amps.
It sound pretty good. And it is super silent. I didn't measure the noise floor but is not audible. Absolute silence.
I love it.







...yes I need to build new stand for the speaker. It'll be a project for this winter.
Regards.

[mkrawcz]

Having the power supply separate and dual mono like that really takes the F5M to another level.

[KTS]

That is a unique build, did you use the standard thermo resistors in the power supply or the heavier ones? Well done very clean build!

[tremrej65]

That is a unique build, did you use the standard thermo resistors in the power supply or the heavier ones? Well done very clean build!

I used the one in the kit. I think there's 10 ohms. In Nelson Pass's paper, he mention we could go 5 ohms if the bias is above 1 amps. I'm bias at 1.3 amps (0.613 volts on R6). I guess I should have gone for the 5 ohms one. I assume when you mention "heavier one" you refer to the 5 ohms version. Using the 10 ohms might explain the voltage drop I'm getting at the amps: unloaded, the voltage is above 26 volts. With the amps at 1.3 amp bias, the voltage drop at 22.5. I'll ask in the diyaudio forum. Good idea.

[KTS]

I used the one in the kit. I think there's 10 ohms. In Nelson Pass's paper, he mention we could go 5 ohms if the bias is above 1 amps. I'm bias at 1.3 amps (0.613 volts on R6). I guess I should have gone for the 5 ohms one. I assume when you mention "heavier one" you refer to the 5 ohms version. Using the 10 ohms might explain the voltage drop I'm getting at the amps: unloaded, the voltage is above 26 volts. With the amps at 1.3 amp bias, the voltage drop at 22.5. I'll ask in the diyaudio forum. Good idea.

Yes I was referring to the 5ohm thermistors.

[YEEEEGZ]

Looking sweet! The cabinets you made for the OB subs are so freaking cool too.