On the universal PSU PCB from DIY store there is layout for a cap across the bridge/diodes and also layout for a RC snupper. Do you use that for noise suppression?
The single cap is easy but the RC snupper circuit is a bit more complicated to design. Do you have a recommended RC value that is better than "nothing" for the M2X PSU using 2x18 VAC transformers?
I guess the cap used should also be a 200V or higher type to have a safety margin.
The single cap is easy but the RC snupper circuit is a bit more complicated to design. Do you have a recommended RC value that is better than "nothing" for the M2X PSU using 2x18 VAC transformers?
I guess the cap used should also be a 200V or higher type to have a safety margin.
M2X experience
Good morning M2X-builders,
yesterday a 'yellow submarine' on wheels from DHL was diving out of the traffic.
The yellow 'captain' gave me a parcel with something nice in it.
The german Schaeffer AG (front panel express) made something from my CAD - experiment.
The aluminum frontpanel is 4mm thick, black anodized. I tried to design a simplified MOSFET - logo. This was cut out of the aluminumplate.
I added the M2X-lettering.
I cut a second acryl plate (translucent dark grey) in the same size as the aluminumplate. Second layer.
Now the M2X - baby looks like this.
The NORWOOD-boards also sound great!
Greets Dirk
Good morning M2X-builders,
yesterday a 'yellow submarine' on wheels from DHL was diving out of the traffic.
The yellow 'captain' gave me a parcel with something nice in it.
The german Schaeffer AG (front panel express) made something from my CAD - experiment.
The aluminum frontpanel is 4mm thick, black anodized. I tried to design a simplified MOSFET - logo. This was cut out of the aluminumplate.
I added the M2X-lettering.
I cut a second acryl plate (translucent dark grey) in the same size as the aluminumplate. Second layer.
Now the M2X - baby looks like this.
The NORWOOD-boards also sound great!
Greets Dirk
Attachments
shielded cables discussion starting #1384
My experience is similar to MEPERs:
If you have cables which are very close to each other or they cross each other
it can be better to have shielded cables. Doesn't have to!
NF- audio- cables are surely shielded.
Is the same necessary to AC - cables. In my opinion not really - if the cables
are away from NF-cables.
I make my own AC-cables. Most of them are shielded.
In my amps I also use shielded AC-cables from the AC-input to the transformers
and often from the PSU / caps to the AMP-pcb. But I decide this dependent
how close the AC-lines run to the signal-wires (NF-cables).
But I can't say that shielded AC-cables sound better or worse!
This could become an endless discussion - as always if audiophiles discuss the
influence of cables....
My experience with signal-wires connecting the vinyl-turntable with the MC/MM-Preamp: the capacitance of the signal wires influences the sound
of your pickup. This is why you have switchable resistance/capacitance at
the input of a good MC/MM-Preamp. This should be well balanced depending
on the demands of the pickup.
My experiences. Yours can sure be different.
Greets
Dirk
My experience is similar to MEPERs:
If you have cables which are very close to each other or they cross each other
it can be better to have shielded cables. Doesn't have to!
NF- audio- cables are surely shielded.
Is the same necessary to AC - cables. In my opinion not really - if the cables
are away from NF-cables.
I make my own AC-cables. Most of them are shielded.
In my amps I also use shielded AC-cables from the AC-input to the transformers
and often from the PSU / caps to the AMP-pcb. But I decide this dependent
how close the AC-lines run to the signal-wires (NF-cables).
But I can't say that shielded AC-cables sound better or worse!
This could become an endless discussion - as always if audiophiles discuss the
influence of cables....
My experience with signal-wires connecting the vinyl-turntable with the MC/MM-Preamp: the capacitance of the signal wires influences the sound
of your pickup. This is why you have switchable resistance/capacitance at
the input of a good MC/MM-Preamp. This should be well balanced depending
on the demands of the pickup.
My experiences. Yours can sure be different.
Greets
Dirk
The cable I use for my speakers was some I got for free. It is some very flexible 20mm2 copper core cable. The length is 1.3 m and I bi-wire. Then I think my speaker cables must be out of the equation when evaluating the sound. But even then some of my "HiFi friends" think I should try my 3m QED 4mm2 reference speaker cables as they think it may "sound" better. The QED is a construction where the center is a hole so the surface is larger so electrons at the high frequencies has less resistance and it more "time coherent". Then I say…...what about all the filter components for the speaker units......delay of cone movement, phase between speaker units etc.?
It was a bit difficult to get the 20mm2 cable terminated. Not many standard banana speaker plugs are designed for 20mm2 cable.
The QED is a good cable I have used it but switched to the 20mm2 to cut the length down to what I needed for my setup. The QED has very nice connectors and is nice looking. In car audio 16 - 50 mm2 dimensions are used for the power cables as voltage is low. So cheap speakers cables can be made from that.
The QED is a good cable I have used it but switched to the 20mm2 to cut the length down to what I needed for my setup. The QED has very nice connectors and is nice looking. In car audio 16 - 50 mm2 dimensions are used for the power cables as voltage is low. So cheap speakers cables can be made from that.
M2X experience
I made some temperature measurements on the M2X.
(room temperature 24.2 C - it's winter and the sun is shining in)
temp on heatsinks (from outside where the FETs are mounted): 52.4 - 53.0 C
temp on topcover: 40.0 C
temp frontpanel: 40.7 C
temp CL60 (inrush current limiter): 52.4 C
temp AUSTIN board (bjt): 34.3 C
Cheers Dirk
I made some temperature measurements on the M2X.
(room temperature 24.2 C - it's winter and the sun is shining in)
temp on heatsinks (from outside where the FETs are mounted): 52.4 - 53.0 C
temp on topcover: 40.0 C
temp frontpanel: 40.7 C
temp CL60 (inrush current limiter): 52.4 C
temp AUSTIN board (bjt): 34.3 C
Cheers Dirk
cubicincher, those photos in #1403 are stunning. Gorgeous. Congratulations!
BTW the five input stage daughter card designs will operate at five different temperatures. Each design dissipates a different number of milliwatts, resulting in different temperature rise numbers. I'm sure many experts here are able to predict which daughter card has the highest, and which has the lowest, dissipation. Just by examining the circuit schematic diagrams, recalling they all run from the same ±23V DC supply rails.
_
BTW the five input stage daughter card designs will operate at five different temperatures. Each design dissipates a different number of milliwatts, resulting in different temperature rise numbers. I'm sure many experts here are able to predict which daughter card has the highest, and which has the lowest, dissipation. Just by examining the circuit schematic diagrams, recalling they all run from the same ±23V DC supply rails.
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answer to #1412
Hello Mark Johnson,
thanks for your kind words!
This was possible with your help, 6L6, Nelson Pass and many more!
The amp is running. I am switching between the inputboards and different
Preamps. It is a wide field to play and to listen to this amp.
Super cool project. Build this amp!
Cheers
Dirk
Hello Mark Johnson,
thanks for your kind words!
This was possible with your help, 6L6, Nelson Pass and many more!
The amp is running. I am switching between the inputboards and different
Preamps. It is a wide field to play and to listen to this amp.
Super cool project. Build this amp!
Cheers
Dirk
answer to MEPER #1414
Hello MEPER,
all 4 contacts of the inputboards are switched. But I only do this if amp is off.
Never tried during operation.
On the foto you see the 4 colours of the cables. The standoffs on the switcherboard have the exact same pattern like on the main-pcb.
The alps-switch is a 4-pole.
Greets
Dirk
Hello MEPER,
all 4 contacts of the inputboards are switched. But I only do this if amp is off.
Never tried during operation.
On the foto you see the 4 colours of the cables. The standoffs on the switcherboard have the exact same pattern like on the main-pcb.
The alps-switch is a 4-pole.
Greets
Dirk
Attachments
Ok....so it is not possible to do a A,B,C comparation "on the fly" where all input boards are at working temperature. That would have been a fun experience.
I just switched to my 300B SE amp and go via a passive pre (10k goldpoint attenuator) from a Bluesound Node 2i network streamer. It is just "singing" very beautiful. ACA, MoFo, BA3-pre has many qualities but difficult to reach the level of a 300B SE amp if speakers are a good match. Let us see with M2.....and maybe later a SIT amp? …..SIT may be the transistor which can simulate a triode best…..I read a bit about SIT yesterday…...triode curves.
A tube has a very clever way of dissipate its heat.....no need for large heat sinks…..but temp is a bit more than 54 C
You are from Germany......so you may know the Lidl shops. I got a couple of $20 DMMs from Lidl…...and they works….and are accurate. Tüv certified!!
I just switched to my 300B SE amp and go via a passive pre (10k goldpoint attenuator) from a Bluesound Node 2i network streamer. It is just "singing" very beautiful. ACA, MoFo, BA3-pre has many qualities but difficult to reach the level of a 300B SE amp if speakers are a good match. Let us see with M2.....and maybe later a SIT amp? …..SIT may be the transistor which can simulate a triode best…..I read a bit about SIT yesterday…...triode curves.
A tube has a very clever way of dissipate its heat.....no need for large heat sinks…..but temp is a bit more than 54 C
You are from Germany......so you may know the Lidl shops. I got a couple of $20 DMMs from Lidl…...and they works….and are accurate. Tüv certified!!
I just read the 6moons review of M2. He had the top off the amplifier:
6moons audio reviews: FirstWatt M2
Was the shields on the Edcor's "handmade" or something the factory makes? ….is it mu-metal or "just" steel?
6moons audio reviews: FirstWatt M2
Was the shields on the Edcor's "handmade" or something the factory makes? ….is it mu-metal or "just" steel?