Try again….first post was with wrong image....
I had my first M2X listening session tonight. First with Korg as preamp but it seems there was too much amplification in the loop. This caused a bit of "hiss" noise from tweeter with ear close to the unit. With input to M2X shorted tweeter was silent so I decided to go with passive pre. In my case it is a 10k Goldpoint 24 step attenuator. With passive pre this gives perfect amount of amplification with normal listening level at around 2-o'clock. I need to listen more to be able to write about the sound. But so far very positive. Sound image seems a bit "lighter" than MoFo which seems a bit to the "dark side" compared to M2X.
I had my first M2X listening session tonight. First with Korg as preamp but it seems there was too much amplification in the loop. This caused a bit of "hiss" noise from tweeter with ear close to the unit. With input to M2X shorted tweeter was silent so I decided to go with passive pre. In my case it is a 10k Goldpoint 24 step attenuator. With passive pre this gives perfect amount of amplification with normal listening level at around 2-o'clock. I need to listen more to be able to write about the sound. But so far very positive. Sound image seems a bit "lighter" than MoFo which seems a bit to the "dark side" compared to M2X.
Attachments
Yes, different input boards…...but I feel right now that I stay with passive pre. Seems to work perfect (no need to add more "noise" in the loop 
). I stream high res music via a Bluesound node which seems to have a good output driver. Probably the best setup to hear pure M2X sound. I have received a lot of Tucson boards from MJ. Now I just need some opamps to put on them. I have the OPA 1611 which will be the next Tucson. Probably hard to find opamps with better specs than OPA 1611?
). I stream high res music via a Bluesound node which seems to have a good output driver. Probably the best setup to hear pure M2X sound. I have received a lot of Tucson boards from MJ. Now I just need some opamps to put on them. I have the OPA 1611 which will be the next Tucson. Probably hard to find opamps with better specs than OPA 1611?
And what might those opamps be and what traits makes them better for you than the OPA1611?
I will send them to you. Two Tucson PCBs will have opamps painted blue and two more Tucson PCBs will have opamps painted orange. You can decide whether you prefer the sound of the blue or the orange. You don't need to know which is which, to decide whether you like the blue or the orange. Right?
I'll send you the decode map: blue=OPA1611, orange=??????, in an encrypted zip file at the beginning of the test. Then when the test is over I'll send the encryption password. You've had the answer all along but you weren't able to read it till you've filed your report and publicly declared your favorite.
What do you think?
I'll send you the decode map: blue=OPA1611, orange=??????, in an encrypted zip file at the beginning of the test. Then when the test is over I'll send the encryption password. You've had the answer all along but you weren't able to read it till you've filed your report and publicly declared your favorite.
What do you think?
A generous offer, to be sure, but I will have to decline. After cycling through all of the M2x input buffer boards, I've settled in on the Ishikawa with the Toshiba JFETs -- not be cause it's the best -- but because I couldn't pick a clear winner and liked the zen of the Ishikawa. Like Einstein said "Things should be made as simple as possible, but not simpler".
I'm happy and content enjoying wonderful music from my Pass B1 and Korg preamps feeding my F5 and M2x amps. I've sold off all my Audio Research, Bryston, Sonic Frontiers and McIntosh gear and totally immersed in the joys of DIY.
Thanks to you, Jim and especially the generosity of Nelson for this wonderful journey!
I'm happy and content enjoying wonderful music from my Pass B1 and Korg preamps feeding my F5 and M2x amps. I've sold off all my Audio Research, Bryston, Sonic Frontiers and McIntosh gear and totally immersed in the joys of DIY.
Thanks to you, Jim and especially the generosity of Nelson for this wonderful journey!
I just rotated the Mtn View boards back into my M2x, and still really love the way these boards sound. And that is after having recently completed my Aleph J. The M2x plays music really well. My two favorites so far are the Mtn View and the Austin, but I still need to finish my veroboard Ishikawas with some enhanced power supply filtering. I suspect they will hold their own once on more equal footing with the other boards.
I am thoroughly enjoying my Aleph J as well. It does have a different character, and by virtue of a full dual-mono power supply has a solid 3D presentation that the M2x with its common PSU doesn't quite match. I treated it to a pair of 300VA, 20V toroids and CRCRC PSU boards with 87000 uF of capacitance on each rail. The two channels only have the power cord in common, everything else is separate for each channel.
I am thoroughly enjoying my Aleph J as well. It does have a different character, and by virtue of a full dual-mono power supply has a solid 3D presentation that the M2x with its common PSU doesn't quite match. I treated it to a pair of 300VA, 20V toroids and CRCRC PSU boards with 87000 uF of capacitance on each rail. The two channels only have the power cord in common, everything else is separate for each channel.
I wonder if it could be fun to try some of these for Tucson input board?
Supreme Sound Opamp V6 – Burson Audio
For those who has built Ishikawa…...how did you adjust pot? …..did you use distortion analyzer to get a special distortion profile? With BA-3 pre there was some hard work to get both channels 100% identical. I guess it is a bit of the same here.
Supreme Sound Opamp V6 – Burson Audio
For those who has built Ishikawa…...how did you adjust pot? …..did you use distortion analyzer to get a special distortion profile? With BA-3 pre there was some hard work to get both channels 100% identical. I guess it is a bit of the same here.
Could you record the audio (good recording with high DR and if possible with acoustic instrumentation) from a speaker in the very near field and upload them?
Like xrk971 with fourteen DIY amps.
Virtual Audition of Very Simple Quasi MOSFET Amp
Then I could differentiate them clearly, at least the ones that sounded the best. Now my second system sounds much better than then so it should be more easy!
-> Virtual Audition of Very Simple Quasi MOSFET Amp
Virtual Audition of Very Simple Quasi MOSFET Amp
Then I could differentiate them clearly, at least the ones that sounded the best. Now my second system sounds much better than then so it should be more easy!
-> Virtual Audition of Very Simple Quasi MOSFET Amp
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I didn't install the pot so I wouldn't have to obsess with the constant tweaking.
FirstWatt doesn't use one either in their commercial offering.
I used REW along with a Behrenger sound card. I measured the distortion of Tucson, Austin and Mountain View. They all had equal amounts of 2H and 3H on each channel. So I adjusted P3 on Ishikawa for equal amounts of 2H and 3H on each channel. The adjustment was 1 - 2 turns off center, so I thought the adjustment was good. As opposed to 7 - 9 turns off center, which I would have returned P3 to center and left it.