I had a strange experience when making the final DC offset adjustments on M2X mono blocks. The L-channel was easy to adjust and was very stable. The R-channel fluctuated and jumped suddenly 20-30 mV and never got really stable. I had scope on power supply and output to see if voltage was ok and if I had an oscillation at output. Then I worked the spade connectors to the M2X PCB and after that R-channel was as stable as L-channel. Strange......maybe this also was the reason why I had more 50 Hz noise on R-channel than L-channel in above measurements. Maybe I check later but first I think I will see if the amps can play some music.......but as I use high quality connectors I don't like this.......
They were crimped on using a prof. Knipex crimper tool.
I think the bad connection was not in the crimping but in the connection.
I pulled connectors half off and on again which seems to work. I don't know which was bad. I think very little contact resistance can cause unstable DC offset. The resistance will probably not be stable but change a bit all the time. I will keep an eye on it and measure DC offset regularly.
I heard some music and they played extremely well. It was hard to switch off for the night....... .....very crisp and detailed with good bas control....and no noise.....
I think the bad connection was not in the crimping but in the connection.
I pulled connectors half off and on again which seems to work. I don't know which was bad. I think very little contact resistance can cause unstable DC offset. The resistance will probably not be stable but change a bit all the time. I will keep an eye on it and measure DC offset regularly.
I heard some music and they played extremely well. It was hard to switch off for the night....... .....very crisp and detailed with good bas control....and no noise.....
I also have a couple of those which are good if you need more DMMs for e.g. combined bias/offset adjust. I got my in Lidl. 0.1 mV resolution is quite normal if you pay around 100 - 150 USD
I have considered a bench model which goes lower......but they are more expensive.
I used to have HP with 5 zeros precision, alas that's no more.
I ordered a bunch of those connectors, from Germany, as well. I guess more people did than talk here. It took them several weeks to “source” them. The thingees are roughly 1 euro a piece. Shipping was about $15 Germany-Alabama.
I will probably stick with the nuts (switching to bolt on top shortly) until I make a few more daughter cards, and decide which ones I will want swap in from time to time. Keep in mind, each set of daughter cards will use 8 euro of connectors.
I will probably stick with the nuts (switching to bolt on top shortly) until I make a few more daughter cards, and decide which ones I will want swap in from time to time. Keep in mind, each set of daughter cards will use 8 euro of connectors.
131A12049X CONEC | Mouser
Pins are a little harder to find than the sockets.
Spendy, but worth it to me and that is all that matters
Pins are a little harder to find than the sockets.
Spendy, but worth it to me and that is all that matters
I also have a couple of those which are good if you need more DMMs for e.g. combined bias/offset adjust. I got my in Lidl. 0.1 mV resolution is quite normal if you pay around 100 - 150 USD
I have considered a bench model which goes lower......but they are more expensive.
A compact Fluke 101 is about $70 and is pretty good for ascertaining if your amp output is low enough noise. I noticed that 0.1mV ms reading is usually pretty quiet and 0.0mV is basically inaudible with my ear pressed to the speaker cone. Meaning you can use it for a headphone amp. A headphone amp should not measure higher than 0.0mV on the Fluke or you will hear noise with typical 96dB/mW 32ohm cans.
The route I have chosen to go.
If it saves me one dropped nut, it will be worth it.
what do you have going on here?
It looks like an great way to hot swap the input boards. I want to do it too!
So the code 706-131A12049X you linked is for the 3.18mm diameter. Does it fit fine in the M3 holes on the board?
From the pic one of the sides is gold plated but I can tell about the other. Can both sides be soldered? Is it sold as a male-female unit, right? It is a little pricy but whatever.
thanks
I prefer Mouser in the US.
If others are interested the numbers are:
706-132C12049X socket 3.18mm class 1 $3.2 each
706-131A12049X pin 3.18mm class 3 $1.7 each
The class 1 is rated at 500 cycles of plug/unplug vs 50 for class 3. Class 1 pin is special order.
Given the cost, I will put to the sockets on the main boards and the pins on the daughter boards.
If others are interested the numbers are:
706-132C12049X socket 3.18mm class 1 $3.2 each
706-131A12049X pin 3.18mm class 3 $1.7 each
The class 1 is rated at 500 cycles of plug/unplug vs 50 for class 3. Class 1 pin is special order.
Given the cost, I will put to the sockets on the main boards and the pins on the daughter boards.
- Home
- Amplifiers
- Pass Labs
- The diyAudio First Watt M2x