F6 Illustrated Build Guide

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Very nice jjacek! I have the same case (2 of them) but without the custom etching. I really like this case but as you know first hand, it's not very wide. I was going to put a pair of Teabag's GB F6 in one (have M2 in the other) but the autoformers leave no room for the power transformer so I have an F5 in there for now instead.

How does it sound?
 
jjacek,
Very clean looking work! Love the case.



Have you measured temperature of heatsinks or mosfet pins?

I am curious how warm your amplifier is running. I have mine biased at around 470mv. Even with my large heatsinks, (5 units tall by 400mm long) I am running just under 140d f. on my middle mosfet pins.

Since i set the bias during mild weather, I felt this would leave a cushion for running my amp during warmer weather. Perhaps I am being too conservative and have could run my bias a little higher. I'm enjoying the amplifier so much, its hard to imagine there would be much room for improvement.
 
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Hook,

Good "soup to nuts" DIY build... ;) DIY chassis work needs patience and some work...


Thanks, the chassis took much longer to build than the all the actual electronics. Got tendonitis in my elbow from drilling and tapping many holes. But I enjoy that kink of work, my next project is speakers. Still, I would do it again if I found a bargain on heatsinks like I did this time. I found these at a store that sells scrap aluminum, they were selling the sinks for $11.95 each. They are quite heavy, the base is thick and the fins are rather thick too. Takes about two hours to get to full temperature. The whole thing weighs a lot, my wife thinks it absurd. :emoticon:
 
F6 was my very first solid-state class A amp that I ever built, I was pretty much a tube guy all along. I like the design using the interstage line trafo as a phase splitter, a lot of tube design in the '80s uses interstage line trafo too.

I built it as a dual monobloc with individual power supply, and it was dead quiet with no hums or hissing noise, something that tube set has a hard time achieving this kind of silence. And has been enjoying since to its tube-like sounding.

Then I chanced upon SLB power supply thread, with phenomenal ripple control, I decided to upgrade it for my F6, since one dual-rail SLB can handle both channels adequately. So I replaced the CRC ps.

Upon powering up with SLB, there was no thump, however hums and noises were pretty loud on both channels, my F6 was completely silenced previously. I troubleshoot all I can and at my wit's end, I seek help from Xrk, then he guided me thru with this diagram of his and I was able to get my F6 to be quiet at idle again.

Sharing his sketch here, so others may do the same without wasting time troubleshooting ground loop hums while building this amp. Pls, wire the primary according to your local AC line voltage.

 
Thanks Zen, not too much specific requirement for now, except I don't want to unnecessarily push F6 into 4ohm if it was not designed to. For reference I am using Klipsch R-160M's which are 96db 8ohm speakers. I also have 5000F's, just wanted to understand what differences can be heard on a 4ohm pair (if I parallel one of both).