Look closely, CB3 is on the M2x schematic {created by me} but it is not present on the official M2 schematic {created by Nelson Pass}
Unlike other folks, I actually do know with absolute certainty, why CB3 is on the M2x schematic. I know exactly why I put it there.
CB3 is on the M2x schematic (and on the M2x PCB in the diyAudio Store, which I laid out) to give DIYers the option, but not the obligation, to connect a film capacitor in parallel with electrolytic capacitor C3. Stuff and solder CB3 if you wish, leave it out if you wish. Your decision, dear builder. All I have done is give you the option.
Nelson Pass apparently didn't think CB3 was necessary. He didn't include it in his schematic. And I myself don't think it is necessary. But I do think: maybe it is fun. And maybe it will soothe any outbreaks of audiophilia nervosa, the irrational fear that you haven't spent enough money buying Premium Parts. Install CB3 or not, it's your call.
I included CB3 in my own M2x build even though I don't think it is necessary. Why? So it would be present in the photographs of my M2x; and because of this, I wouldn't have to answer a hundred nervous questions "why don't I see CB3 on your boards?"
The specific capacitor I purchased and installed, is the one called out in the M2x Build Of Materials, screen capture image below.
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Unlike other folks, I actually do know with absolute certainty, why CB3 is on the M2x schematic. I know exactly why I put it there.
CB3 is on the M2x schematic (and on the M2x PCB in the diyAudio Store, which I laid out) to give DIYers the option, but not the obligation, to connect a film capacitor in parallel with electrolytic capacitor C3. Stuff and solder CB3 if you wish, leave it out if you wish. Your decision, dear builder. All I have done is give you the option.
Nelson Pass apparently didn't think CB3 was necessary. He didn't include it in his schematic. And I myself don't think it is necessary. But I do think: maybe it is fun. And maybe it will soothe any outbreaks of audiophilia nervosa, the irrational fear that you haven't spent enough money buying Premium Parts. Install CB3 or not, it's your call.
I included CB3 in my own M2x build even though I don't think it is necessary. Why? So it would be present in the photographs of my M2x; and because of this, I wouldn't have to answer a hundred nervous questions "why don't I see CB3 on your boards?"
The specific capacitor I purchased and installed, is the one called out in the M2x Build Of Materials, screen capture image below.
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Waiting....
Mark, is that also why you have the 4 holes under C3 in case someone wants to use a small cap under the board?
I had a Dayton Audio Grade 1uF MPC laying in a box from a crossover upgrade, so I soldered it in. I was temped to solder a socket in to try some different stuff and see if I could hear any dif. I also have REW and XTC, so I can do some testing if I get round to it.
Before long it's just listening and doing the spring/summer thing. I enjoy building, but when it gets nice this is done until the water gets hard again.
Waiting on the cases and the Edcors. I still have to build the supply, but that's not an issue at this point.
Mark, is that also why you have the 4 holes under C3 in case someone wants to use a small cap under the board?
I had a Dayton Audio Grade 1uF MPC laying in a box from a crossover upgrade, so I soldered it in. I was temped to solder a socket in to try some different stuff and see if I could hear any dif. I also have REW and XTC, so I can do some testing if I get round to it.
Before long it's just listening and doing the spring/summer thing. I enjoy building, but when it gets nice this is done until the water gets hard again.
Waiting on the cases and the Edcors. I still have to build the supply, but that's not an issue at this point.
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Audio grade just means pay us more for the part. Mil Spec is another one they get you on although, both can have tighter tolerances, but there is no guarantee that one will sound better than the other.
This subject is a huge can or worms, so let's not go there.
Yes, I know there are differences between different capacitors technologies and some distort more then others.
My point is that instead of paying a lot for like say an "Audio series" PP-cap you just buy a good industrial PP-cap instead and save some money. The same for E-caps. That is a least my experience also by comparing objective parameters like ESR and loss factor at various frequencies.
My point is that instead of paying a lot for like say an "Audio series" PP-cap you just buy a good industrial PP-cap instead and save some money. The same for E-caps. That is a least my experience also by comparing objective parameters like ESR and loss factor at various frequencies.
When I look at photographs of the First Watt M2 that Nelson Pass sold to paying customers, I see a Panasonic electrolytic capacitor and no film bypass at all. Not aluminum foil, not copper foil, not silver foil. Nothing, nada, bupkis. Apparently Nelson Pass feels that all possible film capacitors with all possible dielectrics and all possible plate compositions, are inferior to: no capacitor. At least in this position, in this circuit, at this price point. But there are some people who fancy themselves to be better designers or better listeners than Nelson Pass, and they insist upon modifying his masterpiece, to suit their own temperament.
Copied from 6moons.com: (click on the image, THEN click on the white "X" at lower left):
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Copied from 6moons.com: (click on the image, THEN click on the white "X" at lower left):
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I will try optional parts and I will pull them and try as close as we can get to Nelson's design and liking.
We all have, "Two ears and a brain," and none are the same, so I think options are a good thing. If we all had Nelson's ears and brain, what he voices would be perfect for all, but that's simply not the case.
I think it says much that he is constantly tweaking an designing searching for something better, or more pleasing, or more pleasing to others.
I am a solder jockey, but I know what I like and trying to tailor sound to my own, to my ears and brain, is what I'm here for... well that and do it without spending thousands I do not have.
I bet Mr. Pass has learned a thing or two, or perhaps and idea for something to try from some of these temperamental designers out here.
I raced cars for a long time and my ears took some abuse, but we were always tinkering trying to make things faster, or handle better, or more robust. I think that is a good thing. I don't know Nelson personally, but he often chimes in to help people bastardizing his designs in one way or another. If he was offended, it doesn't show. Many times it's simply because the parts are no longer available.
Anyway, I mean no offense Mark, you are a great asset here, and what you have posted has helped my limited understanding. I appreciate your willingness to help. I don't quit understand what's got your goat....
Respectfully,
JT
We all have, "Two ears and a brain," and none are the same, so I think options are a good thing. If we all had Nelson's ears and brain, what he voices would be perfect for all, but that's simply not the case.
I think it says much that he is constantly tweaking an designing searching for something better, or more pleasing, or more pleasing to others.
I am a solder jockey, but I know what I like and trying to tailor sound to my own, to my ears and brain, is what I'm here for... well that and do it without spending thousands I do not have.
I bet Mr. Pass has learned a thing or two, or perhaps and idea for something to try from some of these temperamental designers out here.
I raced cars for a long time and my ears took some abuse, but we were always tinkering trying to make things faster, or handle better, or more robust. I think that is a good thing. I don't know Nelson personally, but he often chimes in to help people bastardizing his designs in one way or another. If he was offended, it doesn't show. Many times it's simply because the parts are no longer available.
Anyway, I mean no offense Mark, you are a great asset here, and what you have posted has helped my limited understanding. I appreciate your willingness to help. I don't quit understand what's got your goat....
Respectfully,
JT
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I think I remember seeing a set of M2 PCBs a couple years ago, which were laid out in such a way that the builder had the option to install either the Edcor transformer (as here), or another transformer by Jensen, or a third transformer by Lundahl, or a fourth transformer by Cinemag. This provided the builder an opportunity to re-create the listening tests which Nelson Pass performed before finalizing and publicly releasing the M2: Which transformer gives the most pleasing results, to you ?
I seem to recall that NP said he himself preferred the Cinemag, but a large majority of his trusted listeners preferred the Edcor, strongly, and that's why the Edcor got shipped in the final product. But, who knows, maybe some listeners will find that swapping out the transformer yields amazing sonic improvement vs. the Edcor. To their ears. The good news is, it's a comparatively cheap experiment to try. Most of the cost of an M2 or M2x is in the heatsinks, chassis, power transformer, and power supply. The amp channel PCBs & parts are comparatively inexpensive.
Sorry that I don't remember who created and displayed those PCBs, or whether they were for sale, or what they cost. Laying out an option-rich amp channel PCB yourself would be a viable alternative; it's a large roomy board with very few components and loads of space between them. You could even put the transformer on is own daughter card, if you wished; that would transfer the pinout-scramble from the amp channel PCB to the daughter card, and it would also enable builders to fabricate a mu-metal shield box which completely enclosed the transformer including its bottom side. With daughter cards, swapping transformers would take only 5 minutes; you could audition all four different possibilities in less than an hour.
You'd probably want to locate the transformer's Zobel network (R5-C1 in the M2x schematic) on the daughter card. That way each transformer gets its own unique and optimum Zobel. You don't need to find a "compromise" Zobel that sorta works okay with all four transformers.
I seem to recall that NP said he himself preferred the Cinemag, but a large majority of his trusted listeners preferred the Edcor, strongly, and that's why the Edcor got shipped in the final product. But, who knows, maybe some listeners will find that swapping out the transformer yields amazing sonic improvement vs. the Edcor. To their ears. The good news is, it's a comparatively cheap experiment to try. Most of the cost of an M2 or M2x is in the heatsinks, chassis, power transformer, and power supply. The amp channel PCBs & parts are comparatively inexpensive.
Sorry that I don't remember who created and displayed those PCBs, or whether they were for sale, or what they cost. Laying out an option-rich amp channel PCB yourself would be a viable alternative; it's a large roomy board with very few components and loads of space between them. You could even put the transformer on is own daughter card, if you wished; that would transfer the pinout-scramble from the amp channel PCB to the daughter card, and it would also enable builders to fabricate a mu-metal shield box which completely enclosed the transformer including its bottom side. With daughter cards, swapping transformers would take only 5 minutes; you could audition all four different possibilities in less than an hour.
You'd probably want to locate the transformer's Zobel network (R5-C1 in the M2x schematic) on the daughter card. That way each transformer gets its own unique and optimum Zobel. You don't need to find a "compromise" Zobel that sorta works okay with all four transformers.
I've really enjoyed trying several of the alternate IPS boards that come with the M2x kit, and have even tried some new flavors and variations of my own. Since this is all in the name of good fun, why not?
I will maintain that the biggest improvement that can be made with several of Papa's wonderful amps is to give them a dual-mono power supply. This would entail a significantly higher cost for a commercial product, but is within the reach of dedicated DIY enthusiasts.
I will maintain that the biggest improvement that can be made with several of Papa's wonderful amps is to give them a dual-mono power supply. This would entail a significantly higher cost for a commercial product, but is within the reach of dedicated DIY enthusiasts.
Edcor
Working away on my M2x build and Have to get the Edcor transformers. The BOM gives the secondary impedance but there also a lot of options for the primaries.
600, 10k, 15k among them. Or if the 15k mentioned in the BOM is for the primary then I need the secondary. Details! Thanks for the help.
PS, does it really take 8 weeks to get them? The site says to figure on it.
R,
Don
Working away on my M2x build and Have to get the Edcor transformers. The BOM gives the secondary impedance but there also a lot of options for the primaries.
600, 10k, 15k among them. Or if the 15k mentioned in the BOM is for the primary then I need the secondary. Details! Thanks for the help.
PS, does it really take 8 weeks to get them?
The site says to figure on it.R,
Don
@donhuges111
The spec'd Edcor transformer is the PC600-15k. On the PC series page, select "600 Ω to 15K Ω (1:5 ratio)". The website says that they are made to order and that the ship date is 8 weeks. I ordered a pair thinking they would take 8 weeks or more, but they shipped in a day or two and showed up in less than a week. Maybe I got lucky?
The spec'd Edcor transformer is the PC600-15k. On the PC series page, select "600 Ω to 15K Ω (1:5 ratio)". The website says that they are made to order and that the ship date is 8 weeks. I ordered a pair thinking they would take 8 weeks or more, but they shipped in a day or two and showed up in less than a week. Maybe I got lucky?
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