A hiccup along the way. Finished up the amp and tried it out. One channel was dead. One advantage to the removeable front ends is being able to do an A/B swap with the cards. Something wrong with my Ishikawa card. So threw together the Tucson boards and now everything is sounding wonderful. Looking forward to trying the other cards as I get them built up, but for now, just happy the amp is working beautifully, driven by Wayne's BA 2018 preamp.
I have built many of the available daughter cards, and did not dislike any of them. There are small differences, which might matter to people. The Tucson, and IPS7 allow OpAmp rolling for even more flavors. It’s worth trying a few, you might find the magic.
This is a great amp, the flexible daughter board system makes it more fun.
This is a great amp, the flexible daughter board system makes it more fun.
Thanks grataku
Yes, it's a CRC by Jeff Young (decoupled stereo) and yes, the measurement is when both channels are powered but the other channel has a short input. All in all, I haven't researched powering only one channel yet so it's already on my "to do" list
Ive got a head scratcher folks. I just finished an M2X build last weekend. PS checked out, connected the boards, and biased everything just fine. Went to connect to music. One channel sang beautifully with zero noise. The other channel hums (Sounds like 60hz) quite loud with no music at low attenuator setting. Only when attenuator is maxed do you get some light music. hum does not change with volume. Nothing changes when you short the input. I have swapped input boards with no change. I have checked input, pos and neg power connections, ground connections, everything is good. I have even retouched the iron to each board connection. i have changed out all the silicone components and C2. I did this one component at a time and checked for improvement, same result each time. The only thing that is left is the edcor transformer and the board itself unless anyone else has ideas.
Input is connected directly to main circuit ground (bridge rectifier setup).
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There is a small 100hz differential when I disconnect one channel completely
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I can say that I am very pleased with Cedarburg (AD797).
It has less "white noise" than IPS6.
Room definition is very good and "silky" treble.
Good isolation of instruments.
I have now tried Tucson with OPA604, Norwood, IPS6 and now Cedarburg.
Which I prefer is difficult. Probably Norwood or Cedarburg.
If IPS6 was as silent as the other three boards.....IPS6 could be the winner.
Cedarburg is my first input board without an output cap!
I dared to put it in action!
It has less "white noise" than IPS6.
Room definition is very good and "silky" treble.
Good isolation of instruments.
I have now tried Tucson with OPA604, Norwood, IPS6 and now Cedarburg.
Which I prefer is difficult. Probably Norwood or Cedarburg.
If IPS6 was as silent as the other three boards.....IPS6 could be the winner.
Cedarburg is my first input board without an output cap!
I dared to put it in action!
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6L6 and I jointly came up with that. He dreamed up the three-hole footprint idea, to support builders who despise all possible connectors and only trust soldered wire connections. I came up with the brilliant observation "fingers are fat so we had better leave at least 1 cm of empty space around each male blade." Fortunately Nelson's M2 is a minimalist design, and its small number of components on the board can be spread apart generously.
Are you shorting the input(s)? I don't know what would cause the imbalance...are the two channel drawing the same current? Can you repeat the experiment by powering each channel using the same side of the PS to see if the 100Hz comes from the PS or if it is intrinsic to the amp board?