Official M2 schematic

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Marra

Member
Joined 2009
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Having rechecked the readings across Q2 on the left channel again the reading id now zero and it plays music.
The right channel will still not go above 385mv across R13. I haven't tried music through this side though.
Is there anything around the 4N35 that could be giving problems?
 
M

Marra

Member
Joined 2009
Paid Member
Boy am I feeling stupid:eek:. You would have thought that I would recognise a wrongly inserted electrolytic after the years I've been building stuff.
I am happy to say that now having replaced C3 and correctly soldered it in position this time the amp is now biasing up ok and with zeroable offset.
I think that's a first.
 
chrismercurio

chrismercurio

Member
Joined 2006
Hi,

I've had a First Watt M2 since 2012. I was curious if any of you had tried other transformers outside of the stock Edcor at the input. I sent Nelson an email about it and discovered the thread after the email went out. The Plitron won't fit, but Lundahl, Magnequest, and many other companies make nice transformers for this application. Any feedback is appreciated.

Thank you!

Chris
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
as far as I'm informed , Pa tried several xformers there , ranging from Edcor to ones costing 3 digits per piece

he could easily pass price difference to customer , so price was pretty irrelevant .... and fact is that he chose Edcor

I take some tests of Edcor xformer in exact arrangement and it's scary good

so , no change , if you ask me , especially not with any costlier
 
chrismercurio

chrismercurio

Member
Joined 2006
Hey ZM,

I know he tried several. I think that bit was in the 6moons article from years back. He didn't try some of the usual suspects that I listed above. His feedback was that I could try Jensen, but that he hadn't tried Magnequest, Lundahl, Tribute, and Intact Audio. With a lot of people building them, there's always the chance that someone tried something different, but when the maestro give a $6 part the thumbs up I can also see the reasoning to not bother...

Magnequest B7-15K (Magnequest Products - MQ Iron Listing/Pricing)
Lundahl LL1680 or LL1689
Tribute and Intact are custom order

Kindest regards,

Chris

p.s. I'm not sure if this one works, certainly not in a stock one like mine due to space constraints, but if cost is not an issue, this one has pretty nice bandwidth:

Plitron PAT–4126-02
http://shop.plitron.com/specs/412602.pdf
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
chrismercurio said:
Hey ZM,

I know he tried several. I think that bit was in the 6moons article from years back. He didn't try some of the usual suspects that I listed above. His feedback was that I could try Jensen, but that he hadn't tried Magnequest, Lundahl, Tribute, and Intact Audio. With a lot of people building them, there's always the chance that someone tried something different, but when the maestro give a $6 part the thumbs up I can also see the reasoning to not bother...

Magnequest B7-15K (Magnequest Products - MQ Iron Listing/Pricing)
Lundahl LL1680 or LL1689
Tribute and Intact are custom order

Kindest regards,

Chris

p.s. I'm not sure if this one works, certainly not in a stock one like mine due to space constraints, but if cost is not an issue, this one has pretty nice bandwidth:

Plitron PAT–4126-02
http://shop.plitron.com/specs/412602.pdf
Click to expand...

that Plitron could work ( with decreased gain , comparing to original , 10k/600 giving A=4V/V , or 12db)

however , there is strong possibility that 10cm dia chunk of iron will sound worse than smaller one , considering that there is no significant power to transfer

but , be my guest and try .....

edit : I certainly didn't tried all of your possible candidates , but according to my previous experience with iron from best houses , I can't expect any dramatic benefit in replacement operation
 
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