The diyAudio First Watt M2x

[dantwomey]

Good to hear. Hopefully, I'll be up and running sometime this coming weekend.

Regards,
Dan

[grataku]

Originally Posted by darrr

My measuring interface is a notebook soundcard, so not the best. The maximum I can give to input is 0.5Vrms. I didn't even connect the dummy load here. I just wanted to observe the noise.
Input board is still Mountain View.

Darr,
if I see correctly in the picture (post 5026), you have the speaker gnd blue wires going to the amp board, when I did that my amp exhibited a slight hum as well which I attributed to some type of gnd loop. That goes away completely when I connect the speaker gnd to the star gnd on the PS. I saw this point discussed somewhere around here before. Worth a try to rewire.

[darrr]

Thanks grataku
I have already done the combinations with wiring so this option has already been checked. With no result. However, having a transformer outside the chassis , I will also check it again.

[cubicincher]

Hello hayenc,


the dimbulbtester - phenomena is well known with the M2X:

If you switch the M2X on the dimbulbtester dims down/ or goes off (then everything is o.k. with your M2X) and after a few seconds the bulb comes back shining. It is the same on my M2X. Also other members reported about this behaviour.


Greets
Dirk

[thompsontechs]

hayenc, that behavior you had was normal for the M2.

here's how it goes, light comes in bright as the large caps charge, they reach charge and then dim down, it takes a bit to bias up the circuit.... it comes in slowly and the light will again get brighter. It depends on the wattage of the bulb, just how bright it will get.

[Mark Johnson]

Have a look at Official M2 Schematic post #3355







_

[hayenc]

Originally Posted by thompsontechs

hayenc, that behavior you had was normal for the M2.

here's how it goes, light comes in bright as the large caps charge, they reach charge and then dim down, it takes a bit to bias up the circuit.... it comes in slowly and the light will again get brighter. It depends on the wattage of the bulb, just how bright it will get.

Thanks much. Did not make it through all of the M2 posts and had limited my search to the M2x thread. After making the blasphemous heresy mods, the amp is settling in with offset.

Hoping for music this afternoon.

[darrr]

I pushed the transformer back really far. This is what the ARTA graphs look like. On the second, when the edcor output is shorted.
Attachment 944378

[darrr]

Next step
Power transformer setting and 50Hz noise. It is different for each channel. I have to find a common pointlewy%20kana%C5%82%20trafo%20na%20godzin%C4%99%2010.jpgprawy%20%20kana%C5%82%20trafo%20na%20godz%209.jpgJPEG_20210420_232047_4872055441746900396.jpg