Gabor,
You seem to be anxious to start building a new amp. The good news is that I have shipped ALL boards. Those in the US will be receiving them today and tomorrow. Other members should be receiving them shortly.
I am curious as to how long it takes for Air Mail to reach other countries. It would be nice if people could report when they receive their boards.
You are welcome. I hope you have fun building the M2 clone.
I just remembered that I need to post the diagram to cut and fold the input transformer shield. I have it hand drawn but will try to find some simple software to sketch it.
Where can we find the shield for the edcor? I checked their website but couldn't find any.
Mike,
I organized the Group Buy for my version of the boards relying on the information in the post linked below.
http://www.diyaudio.com/forums/pass-labs/76482-first-watt-f1.html#post1694823
Nelson visited this thread after I posted the Group Buy announcement and did not express any concern, so I trust that his view on this matter has not changed.
When I said "cut and fold" it meant that we have to fabricate the shield. You can buy Mu-metal from McMaster Carr or other vendor, then mark it, cut it and bend it. The boards have two small holes to hold the shield in place.
Thank you for your answer
For a while I did not read anything about the GB so that was the reason I did asked for. (Someone mentioned a new GB on the forum)
I can wait that is not a problem! You just shipped out last week I will get it these week or next . 🙂
Greetings
Hi Grimberg,
Boards arrived in the mail today., thanks. Also heard from Edcor that the trafos have shipped, time to get busy ordering the rest of the parts.
PJN
Boards arrived in the mail today., thanks. Also heard from Edcor that the trafos have shipped, time to get busy ordering the rest of the parts.
PJN
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I also got my board today, thanks a bunch to Grimberg. I just need to find the latest BOM with mouser link which I think includes the parts for the led.
I am sorry if this is a trivial question but why no led with Toshibas? Bias problem?
They are discussing a possible modification to the circuit which includes the use of an LED.
The optional LED and associated resistor I added to the PCBs can be used regardless of your choice of output devices.
Got mine as well. Hoping I can start my build this weekend since this promises to be a busy week.
it would be sacrilege changing automatic bias circuit (optocoupler) to anything which demands setting
The LED I use in series with R6 to remedy a problem that arises if the MOSFETs have large differences in absolute Vgs and the mains voltage is shaky.
If you don't have these problems, you don't nee to think about such LED (it doesn't even shine, only veeeeery faintly).
The Toshibas come with very similar Vgs right from the spec. The Fairchild FQA, I have in addition, have larger differences in Vgs already by spec. In my pairs, however, the variation is even bigger than spec, almost 2V.
Btw, if you use a LED to compensate for different Vgs, think about paralleling a 1n4148 in reverse polarity or ugly things will happen when you switch off the amp.