Hello,
I am having a love-hate relationship with my M2X (presently with Cedarburg cards). Whenever I turned it on, I seem not being able to do anything else but listen to music! Same with the Aleph J. Dishes and laundry are piling up. Backyard weeds are overgrown. Hate it! I also have to work! Thank you, Mark Johnson. Godspeed.
I am having a love-hate relationship with my M2X (presently with Cedarburg cards). Whenever I turned it on, I seem not being able to do anything else but listen to music! Same with the Aleph J. Dishes and laundry are piling up. Backyard weeds are overgrown. Hate it! I also have to work! Thank you, Mark Johnson. Godspeed.
Thrilled that you're happy with it!
Builders who love the Cedarburg input cards, usually also love one or the other of IPS6 and IPS7. Professional, fulltime jet pilots seem to love Norwood, a bewildering but delightful fact which I can't explain.
Builders who love the Cedarburg input cards, usually also love one or the other of IPS6 and IPS7. Professional, fulltime jet pilots seem to love Norwood, a bewildering but delightful fact which I can't explain.
Interesting about the rectifiers. In my build of the M2x I had some noise so I built a new power supply outside the chassis which made the amp completely silent. Since I didn't use the old power supply I wasn't able to rule out noise coming from the rectifiers or Antek transformer.
I was planning on building a dual mono external power supply to use with all my future First Watt builds that I was going to mount inside a Pesante 4U chassis and connect using these
https://www.digikey.com/en/products/detail/jae-electronics/SRCN6A16-7P/1283280https://www.digikey.com/en/products/detail/jae-electronics/SRCN2A16-7S/1283266https://www.showmecables.com/16-awg...d-conductor-shielded-vntc-tray-cable-per-foot
Since I never built it I can't tell you how well that would have worked.
I’ve been able to build two other amps with dual mono supplies housed inside the main amp chassis. Both used different configurations; I was in an exploratory phase of building. The Aleph J has a CRCRC with LVB2560 rectifiers. The F6 has a pair of SLB supplies which use synchronous rectification and capacitance multipliers. So, both on the upper end of DIY overkill, and they sound wonderful.
This rebuild of the M2x is starting with a somewhat more modest supply, so we’ll see how well it works. The is plenty of room in the chassis to try other options.
This rebuild of the M2x is starting with a somewhat more modest supply, so we’ll see how well it works. The is plenty of room in the chassis to try other options.
I am interested in your take on the sonic differences between the M2x and the Aleph J. I'm always looking for my next project. Yes indeed, a sincere thanks to Mark and others for their efforts to bring these wonderful amps to our DIY table.
Hello,
I am the wrong person to describe sonic differences between amps. All I can say is that they are both very good. The M2X changes its character, based on the daughter cards in use. In my ears and in my system it can be warm, Aleph J-like, when the Ishikawa cards are in use, clean and clear when Norwood cards are in use, precise when using Austin cards or “bionic-sounding” with outstanding bass when cards are Cedarburg.
Now, if I wanted to remind myself why I built these amps, I always go back to the Aleph-J. For me there is something special in the Aleph J’s matched MOSFETs and JFETs rendition of smooth and relaxing sound, preferably jazz and blues. Just my opinion. Godspeed.
I am the wrong person to describe sonic differences between amps. All I can say is that they are both very good. The M2X changes its character, based on the daughter cards in use. In my ears and in my system it can be warm, Aleph J-like, when the Ishikawa cards are in use, clean and clear when Norwood cards are in use, precise when using Austin cards or “bionic-sounding” with outstanding bass when cards are Cedarburg.
Now, if I wanted to remind myself why I built these amps, I always go back to the Aleph-J. For me there is something special in the Aleph J’s matched MOSFETs and JFETs rendition of smooth and relaxing sound, preferably jazz and blues. Just my opinion. Godspeed.
IMO, the Aleph J is a "stronger" amplifier when used with XRL (balanced) inputs. The M2x is a bit more "delicate, and precise" and RCA (unbalanced) only. So, if you have pre-amp with RCA only, one of the positives of the Aleph J is minimized. If you have less sensitive speakers, the Aleph J makes a bit more sense, particularly if you have a balanced pre-amp to drive it.
Coarse terminology, but there it is.
Coarse terminology, but there it is.
The M2x Revisited
Now I know why our Zen Mod loves this amp so much. The differences between the shared supply and an optimized dual-mono supply are striking. This amp now shares a peer relationship with my Aleph J and F6. My big old Vandersteens disappear completely with the best recordings; no mean feat. The recorded soundscape fills the entire back wall of my listening space, though it stays midway between forward, and laid back. The amount of articulation and detail are surprising, especially with a newer variant of Marauder / Tuscon FE cards. (more later)
I began with the Mtn View cards, which have been one of my favorites in the M2x. These remain smooth and easy to listen to, while benefiting much from the cleaner power. The revised amp still needed about 20 hours of run-in before it really started sounding great, and the single-ended Class A nature of Mtn View helped with that. The newer Marauder variant has a level of detail that is likely to be merciless with un-thoughtfull recordings.
Given the sound of the revised amp, I will maintain that the Edcor transformer leaves nothing to be desired. As ZM has been saying all along, this is a special Haiku of carefully selected components.
The Triad power transformers are performing better than I anticipated, maintaining almost 19V AC under load. This may be helped by a tweak I made to the synchronous rectifiers on the PSU boards. I switched to the IPP040N06N which have a lower total gate charge than what I was using previously. They seem to be more efficient, as I'm loosing less voltage in rectification. I've also switched to a CLC configuration of 33mF, 3.0 mH, 33mF + 2200uF. The chokes are Hammond 154B, which run cool and collected with 1.3A bias current, despite looking small. I took the precaution of bypassing the chokes with 2.2Ω resistors to reduce any back EMF during power up and power down. The result is set of very strong +/– 25V power rails and a silent background for the music.
Now I know why our Zen Mod loves this amp so much. The differences between the shared supply and an optimized dual-mono supply are striking. This amp now shares a peer relationship with my Aleph J and F6. My big old Vandersteens disappear completely with the best recordings; no mean feat. The recorded soundscape fills the entire back wall of my listening space, though it stays midway between forward, and laid back. The amount of articulation and detail are surprising, especially with a newer variant of Marauder / Tuscon FE cards. (more later)
I began with the Mtn View cards, which have been one of my favorites in the M2x. These remain smooth and easy to listen to, while benefiting much from the cleaner power. The revised amp still needed about 20 hours of run-in before it really started sounding great, and the single-ended Class A nature of Mtn View helped with that. The newer Marauder variant has a level of detail that is likely to be merciless with un-thoughtfull recordings.
Given the sound of the revised amp, I will maintain that the Edcor transformer leaves nothing to be desired. As ZM has been saying all along, this is a special Haiku of carefully selected components.
The Triad power transformers are performing better than I anticipated, maintaining almost 19V AC under load. This may be helped by a tweak I made to the synchronous rectifiers on the PSU boards. I switched to the IPP040N06N which have a lower total gate charge than what I was using previously. They seem to be more efficient, as I'm loosing less voltage in rectification. I've also switched to a CLC configuration of 33mF, 3.0 mH, 33mF + 2200uF. The chokes are Hammond 154B, which run cool and collected with 1.3A bias current, despite looking small. I took the precaution of bypassing the chokes with 2.2Ω resistors to reduce any back EMF during power up and power down. The result is set of very strong +/– 25V power rails and a silent background for the music.
Attachments
Nice work TA!
What’s the VA rating of the Triad Trafo’s?
Dual mono supplies definitely bump up construction cost, but I agree the added cost is worth the effort for “Keeper” projects.
What’s the VA rating of the Triad Trafo’s?
Dual mono supplies definitely bump up construction cost, but I agree the added cost is worth the effort for “Keeper” projects.
Tungsten,
You've inspired me to build the dual mono PS for my M2x! I was leaning towards building a standalone PS to deal with my 60 cycle noise. The noise is barely audible at idle, so I haven't been that motivated. But with the sonic benefits you describe you've pushed me over the precipice and I think I'll go completely dual mono in a separate chassis. Appreciate your feedback on your mods! Keep us posted as your impressions continue to form.
You've inspired me to build the dual mono PS for my M2x! I was leaning towards building a standalone PS to deal with my 60 cycle noise. The noise is barely audible at idle, so I haven't been that motivated. But with the sonic benefits you describe you've pushed me over the precipice and I think I'll go completely dual mono in a separate chassis. Appreciate your feedback on your mods! Keep us posted as your impressions continue to form.
The power supply boards were from a Group Buy almost a year ago, back when Prasi was still using the Lion head logo on his PCBs. I had some input into their design. I don’t recall if Gerbers were made available. I would like to get some more, as they have proved to be very effective. I only have two boards remaining.
If anyone knows of Gerbers or another supply of these, it would be great to have that information.
If anyone knows of Gerbers or another supply of these, it would be great to have that information.
Just stumbled across this as I was looking for information on some of the newer alternate FE cards. It is basically what I did with the Marauder/Tucson variation. I removed the 10V Zener diodes and replaced them with 22 Ohm resistors. The 6.2k resistor was replaced with a 62V Zener as a “just in case” form of voltage protection. The opamp is an OPA551 in the basic unity gain configuration. This does a remarkably good job of driving the Edcor. The sound reminds me a lot of the Marauder FE in my VFET amp. This is interesting as the Marauder eliminates the Edcor as a component of the gain stage.
I am looking forward to trying some of the newer FE cards, IPS6 and Cedarburg in particular. I also have my own version that I want to try again with the improved power supply.
AFAIK, these boards are still commercial product, so no free gerber files. Last time I asked (August 21.), prasi said he will manufacture another batch with 1.6 mm/70 um PCB substrate as his supplier run out of thicker one.
I have boards from previous batch in my amplifier and they are of unprecedented quality - 2.4 mm/70 um.
I have boards from previous batch in my amplifier and they are of unprecedented quality - 2.4 mm/70 um.
Mark i admire your creativity youre showing here. I have a quick question about how the decoupling is done on your cedarburg module. Correct me if im wrong but it seems to me even if there was a ground connection (of which the ips's are not disposed with as i understand it) the rail to rail decoupling is ideal for a unity gain opamp since by the nature of how the opamp as a buffer operates it needs no reference to ground? And tho theres now no noise going to the ground does the opamp see from the cap double the noise in its rail to rail connection or does it not matter?
Thanks for your time
Thanks for your time
I don't have strong feelings one way or the other; suggest you consult Jerald Graeme's (very thorough book) which contains several chapters devoted to best and worst practices for opamp supply bypassing.