Just to be clear, the low performance silicon pads I measured did not come with the F5m kit, they were a purchase from ebay as a base line stock buy, but I didn't look into it further for improvements, so that is my fault entirely. I presume and hope that other proper branded soft pads and those with the kit are better. I hope I didn't cause any confusion.
I also bought lots of mica washers cheap, but didn't use them either. I'll stick to these ceramic pads and paste in future. Thanks again.
I also bought lots of mica washers cheap, but didn't use them either. I'll stick to these ceramic pads and paste in future. Thanks again.
Aluminum nitride ceramic interfaces and goop worked really well for me with the F7ish boards I got from another member.
Older post about aluminum nitride.
Older post about aluminum nitride.
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So I ordered some of the B57236S0479M000 and these are considerably smaller than what came in the kit, are these really the higher current part?
Its not the size of the package but how you use it…..
Your question is a bit confusing, which ones are the ones you ordered and which are the ones that are installed on the PSU?
Your question is a bit confusing, which ones are the ones you ordered and which are the ones that are installed on the PSU?
What's on the board now is what came with the kit. The writeup mentions an alternative part, B57236S0479M000, which I ordered and are on that cut tape, in case you were planning on running higher bias levels.
I went ahead and ordered a bunch, and they just seem kinda weenie. Maybe they sent me the wrong ones.
Also, I noticed in the write up, something to the effect of R3 and R4 could possibly be combined, but opting for a 5w part seemed excessive.
Well, I dunno about you guys, but on mine, R4 and R3 are cool as a cucumber, it's R6 and R7 that get smokin hot, so I decided to throw some 5w parts in there. They still get warm, but at least I can't smell them.
Well, I dunno about you guys, but on mine, R4 and R3 are cool as a cucumber, it's R6 and R7 that get smokin hot, so I decided to throw some 5w parts in there. They still get warm, but at least I can't smell them.
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I used the Epcos B57236S0479M000 for my build per Nelson's F5m article when I realized I wanted to run higher bias current and the 10ohm thermisters were not recommended to be used over 1A bias (I used a 4U/300 Deluxe chassis). Don't worry about size difference, the Epcos are still rated at 7.5A. The whole point is they get hot and resistance goes down after preventing inrush due to capacitors charging on power on.
https://www.diyaudio.com/community/threads/f5m-kit.408290/post-7637342
For clarity, the CL60 @Jacruzer787 posted above were intended for the @rhthatcher PSU/AC-In boards (or the store V3 PSU), not F5m PSU.
https://www.diyaudio.com/community/threads/f5m-kit.408290/post-7637342
For clarity, the CL60 @Jacruzer787 posted above were intended for the @rhthatcher PSU/AC-In boards (or the store V3 PSU), not F5m PSU.
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I too am peasant. I just followed the article for F5m (after someone pointed out I originally was not by setting the bias so high @1.6A)...and it sounds glorious. It "sparkles"!
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I've gotten into tube amps in the last couple years, because I've started to enjoy pushing them into a little bit of distortion, and I've been enjoying the f5m for a few days now with just over 1A of bias (0.50v) and it seems to be doing a lot of the same tricks that my tube amps do when you ride the edge.
Well, at least there I know for sure. According to Pa, in his 2023 Burning amp video, he did say that the F5M is tuned mostly for negative phase second harmonic, but that third starts creeping in when you push it.... "life is just tough".
Glad you are enjoying it!
Glad you are enjoying it!
Been using a Jolida EL-34 integrated since '96 with vintage tubes, thought I had my final amp, but I could no longer afford the high tube prices. Sound was excellent but the F5M shows how much grunge and noise was riding on the signal. It's a sleeper, initially sounded great but not involving. It's bloomed over the past two weeks and the lack of any extraneous character just makes it more endearing. I've noticed it sounds It's best after several hours when it reaches its max temperature and bias and is being pushed harder.
Do you think one power supply board with a 300va transformer would be Current enough to run four channels?
Mine is a bit bigger than 300 va and it gets pretty warm after a couple of hours, so.
The R3 and R4 combination gets hot with increase in output voltage level. If I'm not mistaken, at +/-20V output voltage (25W into 8 ohms) , its peak dissipation is over 2W.
lol, well I changed those for 5w parts, I might do the same for the other ones because why not.