M2X experience
Hello M2X-builders,
I reported about my problems with the TUCSON - board (offset at loudspeaker-output drifting away).
On this lazy sunday morning I inspected everything around my switcher-board.
Putting out the boards, measuring,.....
Then I inspected the TUCSON board. All solder joints, measuring,....
Then I put out the OPAmp - OPA1611 (SOIC8) on a DIP8 socket with adapter-
pcb. Nothing to see under the magnifier glasses. Measuring - 1 pin suspicious.
And then I had suddenly 2 parts in my hands.
I disassembled all and soldered it again. And I cleaned so much. Especially
the flux between the legs of the OPAmp.
It works!!!!
I put the TUCSON boards in. Switching on (I was alittle bit nervous) and all
worked flawless.
I am happy!
Dirk
Hello M2X-builders,
I reported about my problems with the TUCSON - board (offset at loudspeaker-output drifting away).
On this lazy sunday morning I inspected everything around my switcher-board.
Putting out the boards, measuring,.....
Then I inspected the TUCSON board. All solder joints, measuring,....

Then I put out the OPAmp - OPA1611 (SOIC8) on a DIP8 socket with adapter-
pcb. Nothing to see under the magnifier glasses. Measuring - 1 pin suspicious.
And then I had suddenly 2 parts in my hands.

I disassembled all and soldered it again. And I cleaned so much. Especially
the flux between the legs of the OPAmp.
It works!!!!
I put the TUCSON boards in. Switching on (I was alittle bit nervous) and all
worked flawless.
I am happy!
Dirk
Attachments
M2X experience
Hello MEPER,
I also reworked the NORWOOD boards. I couldn't measure anything wrong.
I followed the hints of Mark Johnson where to search first. Measured through
the complete board. All solderjoints have been reworked. It looks better now. Haven't tryed the NORWOODs yet.
Listening to TUCSON.
I can say it sounds very detailed. I think I have a tendency to prefer TUCSON
when listening to ELECTRONIC music and some POP. (music from KRAFTWERK, LCD-Soundsystem,...). But these are first impressions.
I have to drink a glass of red wine on this little success and my dumbness
Listen to the music...
Dirk
Hello MEPER,
I also reworked the NORWOOD boards. I couldn't measure anything wrong.
I followed the hints of Mark Johnson where to search first. Measured through
the complete board. All solderjoints have been reworked. It looks better now. Haven't tryed the NORWOODs yet.
Listening to TUCSON.
I can say it sounds very detailed. I think I have a tendency to prefer TUCSON
when listening to ELECTRONIC music and some POP. (music from KRAFTWERK, LCD-Soundsystem,...). But these are first impressions.
I have to drink a glass of red wine on this little success and my dumbness

Listen to the music...
Dirk
A good Amarone is good for the brain…….or do you prefer a Spätburgunder?
A good Riesling Auslese from Mosel is not bad either…….
A good Riesling Auslese from Mosel is not bad either…….
Darn flux. It has jinxed more than one build. I used to have an ultrasonic cleaner which worked wonders, now I just soak any boards in alcohol (along with the brain while waiting) and then use a toothbrush to scrub the life out of them.
Glad you found the problem.
I too like the Tucson, but have not yet tried the Norwood.
.. dB
Glad you found the problem.
I too like the Tucson, but have not yet tried the Norwood.
.. dB
answer to MEPER
Do you think the Amarone will rescue my damaged brain?
O.k., I look for a bottle....
Do you think the Amarone will rescue my damaged brain?

O.k., I look for a bottle....
M2X experience
What I can say yet:
The TUCSONs are very silent - it is very difficult to hear any hum or noise!
Dirk
What I can say yet:
The TUCSONs are very silent - it is very difficult to hear any hum or noise!
Dirk
I expect hum to be so low that even if you have our ear in the speaker it should be silent. Maybe mu-tape around the Edcor's can make it more silent?
Yes, the extra bottom with the 10 x 10 mm holes is very nice and is mandatory if a big power supply is built. The special connector kit I will get from the DiyStore. Will see what I find out regarding external or internal PSU for the M2X. I want to avoid hum pick up from the PSU. Seems the Edcor's is a little sensitive regarding this.
The SissySIT is not "that" sissy…..if it requires a 5U ? 🙂
I think Zenmod stated the 4 was sufficient, but get the 400 mm depth. Not sure if you can get pre drilled UMS pattern heat sinks. Why not just get Deluxe 5U like you say...I love mine. I have used a few deluxe 4 chassis with success in F6, Aleph J and M2....but not dual mono, just single transformer versions.
A while back someone inquired about Deluxe 4 with 400 mm UMS pattern heat sinks, and someone piped up it could be done if 5 people wanted one. 4 more spoke up and it was done. I don't know if that was a one time shot, or if a group of 5 is required, or now they are tooled up and it is an option....
.....anybody know? Otherwise I will go for another Deluxe 5U.
Russellc
The SissySIT is not "that" sissy…..if it requires a 5U ? 🙂
I expect a 4U/400 to be absolutely fine for a SissySIT for us here in Northern / Middle Europe. I base my estimate on my experience with my Aleph J and M2 in a case that has heatsinks similar to the 4U/400 (160 mm high x 400 mm deep x 40 mm fins, but no wavy profile on fins). Aleph J with single pair of outputs ran on 19V / 2.2A or 24V / 2.0A, M2 is running on 24V / 1.82A. I can leave my hands on the heatsinks indefinitely.
I'm looking to build a universal case with a universal dual-mono power supply. Don't know what other interesting amps will come down the pike, and I want to have some heatsinking capability in reserve ... 😛
Best regards,
Claas
M2 must be double up as it is a PP so both output transistors burn 24 x 1.82 in heat?
Just below 90W pr. side?
Just below 90W pr. side?
The manual for the First Watt M2 amplifier, which is available for download on First Watt’s website, says it draws 160 watts from the mains. That includes both channels. Remember that not all of the heat goes into the two heat sinks. Some heat is dissipated in the bridge rectifiers. Some is dissipated in the CL60 inrush current limiters. Some is dissipated in the toroidal power transformer, which is not 100.0% efficient after all. And some heat is dissipated in the CRC filters of the power supply.
If really Really worried , you might ask someone who has a complete and working M2x to measure it with a home appliance watt meter. Here in US the dominant cheap brand is KillAWatt from Amazon.
If really Really worried , you might ask someone who has a complete and working M2x to measure it with a home appliance watt meter. Here in US the dominant cheap brand is KillAWatt from Amazon.
I got my Norwoods boards today. Thanks a lot. They looks great! …..will take a while until I am ready to test them as I need to build rest from scratch.
M2X experience
Hello M2X-builders,
today I mounted my overhauled NORWOOD - boards into the amp.
All is working! Fantastic!
I think responsible were my solderjoints at the OPAmps. I am not sure.
I resoldered the complete boards. I think I will never use Pb-free-solder
anymore for SMD-devices?!
I cleaned the NORWOODS from the flux (with Isopropyl-alcohol and an
unused toothbrush 😀).
Offset at loudspeakeroutput was measured 20 seconds after turn on.
(without any adjustments). 7 mV and 0mV seems pretty good?
I am running them in. Music is playing. Success!
Sorry to everybody I was confusing! I apologize!
Special thanks to Mark Johnson, 6L6 and MEPER!
Cheers
Dirk
Hello M2X-builders,
today I mounted my overhauled NORWOOD - boards into the amp.
All is working! Fantastic!
I think responsible were my solderjoints at the OPAmps. I am not sure.
I resoldered the complete boards. I think I will never use Pb-free-solder
anymore for SMD-devices?!
I cleaned the NORWOODS from the flux (with Isopropyl-alcohol and an
unused toothbrush 😀).
Offset at loudspeakeroutput was measured 20 seconds after turn on.
(without any adjustments). 7 mV and 0mV seems pretty good?
I am running them in. Music is playing. Success!
Sorry to everybody I was confusing! I apologize!
Special thanks to Mark Johnson, 6L6 and MEPER!
Cheers
Dirk

Attachments
Congrats with the success!
I have red Norwoods!! ...the sound should be a bit "warmer" than the blue Norwoods.
I have red Norwoods!! ...the sound should be a bit "warmer" than the blue Norwoods.
The manual for the First Watt M2 amplifier, which is available for download on First Watt’s website, says it draws 160 watts from the mains. That includes both channels. Remember that not all of the heat goes into the two heat sinks. Some heat is dissipated in the bridge rectifiers. Some is dissipated in the CL60 inrush current limiters. Some is dissipated in the toroidal power transformer, which is not 100.0% efficient after all. And some heat is dissipated in the CRC filters of the power supply.
If really Really worried , you might ask someone who has a complete and working M2x to measure it with a home appliance watt meter. Here in US the dominant cheap brand is KillAWatt from Amazon.
To Mark's point, here's measurements from my M2x using a Kill-A-Watt-EZ Electricity Usage Monitor:
AC input Voltage = 123.2 V
Frequency = 60 Hz
Current = 1.65 Amp
Watts = 145 Watt
Volt Amps = 201 VA
Power Factor = 0.71
My build is a fairly standard build, using diyAudio Store amp and PS boards with AnTek 300 VA toroid.
Before building a couple of First Watt amps, I expected these things to be space heaters that could warm our cold Wisconsin winter nights. Turns out they give off less heat than an old 3-way incandescent light bulb!
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