6L6 recommended a Murata part with the same specs. I'm sure each is as good as the other.
Another F6 lives! Powered up tonight for about one hour. Set the bias and offset with no problems. I've built DHT amps for about 15 years now so there a certain sound I'm accustomed to. What I'm hearing from the F6 even early in the break in period is very good sound driving some very high efficiency horns. More later. Thanks to you all you here who helped me and for the diystore for selling the parts to make the build easy.
Jim
Jim
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https://youtu.be/XQr1Sk4VXTw
Just finished new diy speakers. They are around 90-91 db. F6 is matched with them perfectly. Clear, wide, smooth sound. But i started to hear a little hum. What are your opinions?
Just finished new diy speakers. They are around 90-91 db. F6 is matched with them perfectly. Clear, wide, smooth sound. But i started to hear a little hum. What are your opinions?
Is it low pitched (50/60Hz), or more of a 100/120Hz buzz? Is the hum still there with shorted inputs?
By 2 psu, you mean two windings, separately rectified and filtered?
Can you post the psu schematic?
The hum was probably there before. Can you post the psu schematic and a photo of the wiring?
Mosfet F6 Illustrated Build Guide
Two things to note - 1) I didn’t know if the power transformer was going to magnetically couple with the input transformers, so I wanted it as far away as possible.
I'm using a shielded Antek transformer (AS-4218) for my F6 build. Do I need to take any other precautions to isolate the input transformers from the Antek? I was thinking about buying one of the steel transformer covers that Antek sells but because the AS series are magnetically shielded, is the transformer cover overkill? Won't the cover also make the transformer run hotter?
I used no such precautions, did use shielded interconnect cable for input runs, mine is stone quiet, even with highly efficient horns. I used an unshielded Antek 5218 transformer. Dead quiet.
Russellc
Hi Russellc,
I think that cause of hum is my not enough transformer. i hear stable level hum. it doesnt change by volume up or down.
Your transformer is 400VA, mine is 360VA and bias is 1,4A. how about your bias?
My transformer is 500VA, but Papa amps uses 300 VA if I remember correctly?
What type wire for inputs? As to bias, I don't remember off hand, I brought it up to where everybody said to have it,
Amp isn't that hot at all, others said they went higher with no improvement, so I left it as was.
Russellc
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