All of the daughter cards are designed for a power supply built with a dual 18VAC transformer. Not a dual 20VAC transformer. That will cause the main amplifier boards to pump about 11% more heat into the heatsinks, which will make the amplifier run hotter than before.
Higher-than-designed-for supply voltage is not good for the daughter cards either. The "Ishikawa" daughter card was designed by Nelson Pass, not me, so he and the many dozens of people who've already built an M2 amplifier (found in the thread "Original M2 schematic") are the ones to ask: Are 20VAC secondaries fatal to an M2 with the Toshiba dual JFET input stage called Ishikawa?
Of the other four daughter cards, higher supply voltage is a credible threat to reduce lifetime and degrade performance. Ranked in order of danger, with #1 being the most dangerous (most likely to fail quickly) and #4 being the least dangerous, I would guess they might be ordered this way
However: it's DIY. Perform whatever experiments you wish, nobody can stop you. Have fun, make videos, gather data, enjoy your hobby. If your amp catches fire, big deal, that's a lot of fun too.
Remember how hilarious the first Iron Man movie was, when Tony Stark's unsuccessful experiments keep setting his home lab on fire? And his butler robot kept blasting him in the face with a fire extinguisher, time after time? That could be you and your safety buddy (wife). Hilarious.
Higher-than-designed-for supply voltage is not good for the daughter cards either. The "Ishikawa" daughter card was designed by Nelson Pass, not me, so he and the many dozens of people who've already built an M2 amplifier (found in the thread "Original M2 schematic") are the ones to ask: Are 20VAC secondaries fatal to an M2 with the Toshiba dual JFET input stage called Ishikawa?
Of the other four daughter cards, higher supply voltage is a credible threat to reduce lifetime and degrade performance. Ranked in order of danger, with #1 being the most dangerous (most likely to fail quickly) and #4 being the least dangerous, I would guess they might be ordered this way
1. Austin. Don't run Austin at higher voltage. If you do you'll regret it.
2. Mountain View. Don't run Mountain View at higher voltage.
3. Tucson. If you use the OPA604 opamp (as called for in the B.O.M.) and the exact Zener diodes in the B.O.M., it will probably survive
4. Norwood. This thing is built like a tank. You can try to hurt it but I don't think you will succeed.
2. Mountain View. Don't run Mountain View at higher voltage.
3. Tucson. If you use the OPA604 opamp (as called for in the B.O.M.) and the exact Zener diodes in the B.O.M., it will probably survive
4. Norwood. This thing is built like a tank. You can try to hurt it but I don't think you will succeed.
Remember how hilarious the first Iron Man movie was, when Tony Stark's unsuccessful experiments keep setting his home lab on fire? And his butler robot kept blasting him in the face with a fire extinguisher, time after time? That could be you and your safety buddy (wife). Hilarious.
Dennis is correct, but the holes for this style of RCA are larger, and if the RCA plugs on your cables go on, I suppose it is still functional. They are not designed to mount from the inside. Screws should be on the upper left and lower right. But whatever.
Russellc
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M2X experience
Hello M2X-builders,
after 2 weeks of intense listening with the M2X I can say:
This is a beautiful soundmachine!
All the inputboards are fantastic. But each in its own way:
The NORWOOD is a very detailed sounding board. Very little to no hum or
noise hearable. Room information, depth, bass and clear highs are present.
Build it. Also if it is your first experience with SMD-parts-as it was mine!
Use a fine soldertip and tin-lead-solder I will never use lead-free-solder with
SMD-parts again!)
The TUCSON is also OPAmp based. Similar sonic characteristic like the
NORWOOD. Sounds very detailed, clear and without hum or noise. I use the OPA1611 on it at the moment. (OPA604 will be tested, but is in my Whammy at the moment - with adapter, this is a single OPAmp!)
The AUSTIN is based on BJTs. It seems to be be a little bit reduced and not that clear in the highs like NORWOOD and TUCSON. Bass response is very
good. But Austin is noisier. And some audible hum.
The MOUNTAIN VIEW is based on a JFet (J112) combined with a BJT.
I like it a lot - soundwise. Highs are reduced (a little bit) and seem to sound
smoother/silkier than the others. Bass is also deep but sounds different to NORWOOD and TUCSON. But my MOUNTAIN VIEW boards are the
noisiest from all. I prefer this board if I listen to JAZZ or music with focus on VOCALS.
I switch to TUCSON or NORWOOD for ROCK and modern kind of music.
But they all sound fantastic!!!
For me it is a question of taste.
BUILD your M2X and enjoy! I am pretty sure nobody will be dissapointed.
No, you will be surprised.
Cheers
Dirk
Hello M2X-builders,
after 2 weeks of intense listening with the M2X I can say:
This is a beautiful soundmachine!
All the inputboards are fantastic. But each in its own way:
The NORWOOD is a very detailed sounding board. Very little to no hum or
noise hearable. Room information, depth, bass and clear highs are present.
Build it. Also if it is your first experience with SMD-parts-as it was mine!
Use a fine soldertip and tin-lead-solder I will never use lead-free-solder with
SMD-parts again!)
The TUCSON is also OPAmp based. Similar sonic characteristic like the
NORWOOD. Sounds very detailed, clear and without hum or noise. I use the OPA1611 on it at the moment. (OPA604 will be tested, but is in my Whammy at the moment - with adapter, this is a single OPAmp!)
The AUSTIN is based on BJTs. It seems to be be a little bit reduced and not that clear in the highs like NORWOOD and TUCSON. Bass response is very
good. But Austin is noisier. And some audible hum.
The MOUNTAIN VIEW is based on a JFet (J112) combined with a BJT.
I like it a lot - soundwise. Highs are reduced (a little bit) and seem to sound
smoother/silkier than the others. Bass is also deep but sounds different to NORWOOD and TUCSON. But my MOUNTAIN VIEW boards are the
noisiest from all. I prefer this board if I listen to JAZZ or music with focus on VOCALS.
I switch to TUCSON or NORWOOD for ROCK and modern kind of music.
But they all sound fantastic!!!
For me it is a question of taste.
BUILD your M2X and enjoy! I am pretty sure nobody will be dissapointed.
No, you will be surprised.
Cheers
Dirk
While building 30 Norwood boards, I experimented with a few different assembly techniques. The recommendations that gave the greatest benefit, in my experience, were
1. Use an SMD board-holder vise like the Aoyue 328
2. Change the tip on your soldering iron to a conical shape with fine point. I used the T18-BL tip in my Hakko iron, and it worked extremely well for Norwood
3. Use the smallest diameter solder wire you can find, and get the 63-37 alloy (not lead-free). I was lucky and found a spool of authentic Multicore brand 63-37 in 0.38mm (0.015") diameter on eBay. Digi-Key also sells it, part no 82-117-ND
4. Use a headband magnifier / on-the-nose magnifier like the YOCTOSUN
5. Get one of those Amazon packages of several different SMD tweezers and experiment with the options. I liked the ones with curved tips, photo
2. Change the tip on your soldering iron to a conical shape with fine point. I used the T18-BL tip in my Hakko iron, and it worked extremely well for Norwood
3. Use the smallest diameter solder wire you can find, and get the 63-37 alloy (not lead-free). I was lucky and found a spool of authentic Multicore brand 63-37 in 0.38mm (0.015") diameter on eBay. Digi-Key also sells it, part no 82-117-ND
4. Use a headband magnifier / on-the-nose magnifier like the YOCTOSUN
5. Get one of those Amazon packages of several different SMD tweezers and experiment with the options. I liked the ones with curved tips, photo
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For me it is a question of taste.
BUILD your M2X and enjoy! I am pretty sure nobody will be dissapointed.
No, you will be surprised.
Cheers
Dirk
Dirk,
Thanks for sharing your experience and good to see that you are enjoying the different flavors. Great initiative from Mark Johnson and 6L6, and of course thanks to Mr. Pass for giving his design to the DIY community.
Another option you might/might not have heard about is the Melbourne daughtercard:
Melbourne Daughterboard for M2X
I want to correct my impression of the M2x with the Norwood board. The drums and bass were exaggerated because I was developing a problem with my Whammy and a Lowther getting out of alignment. With Tea-Bag's help I got the PM6A back in alignment and removed the Whammy from my system.And with the Ultra Perm sheet suggest by Meper, I reduced the hum significantly by wrapping a piece of tape around the Edcor coils and mounted a cap on the entire Edcor. With the M2x on Hi and the F6 on Low, the sound is terrifically balance. Now I can try some of the other boards. Thanks all.
