Official M2 schematic

[Dennis Hui]

or the Babelfish XA25

Hah! I'm eagerly awaiting that as well.

 

[Attila I]

Sooo...finally...
my new M2 (thank you teabag) with external psu and internal selector and (secret-)preamp.
as always with a selfmade housing made from 2.hand heatsinks and alutrash.
doorknobs for volume and input selection.
500VA toroid with 2x22Vac, 2x 35A/400V bridges, 48x 6800µF/35V/105° nichicons
in C-reg-C-C-R-C mode.
matched LSJ74/LSK170 from the store and FQA12P20/19N20.
no hiss, no humm, dead silent at full power.
zero offset and very low ripple.
makes a wonderful soundstage and lively imaging.
much more than i expected.

thanks to everyone at diyaudio, Nelson Pass, and ZenMod for promoting the M2-circuit.

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[Nelson Pass]

Happy Valentine's day.

 

[Zen Mod]

Sooo...finally...........

Fugly!



M2 is for Sissies

 

[chede]

Happy Sissy here ...

 

[Attila I]

Thanx for the kind response.
...yeah! that's my second "Fugly!" (first for my MacMini based ACAs)
not afraid of being called Sissy
...
what's next?
...
A.

 

[Zen Mod]

some of things I'm cookin' are posted as teasers in Most Greedy Boy, of them all... or (there is no) DEFiSIT of Papa's Koans

 

[Eric]

again ugly sinks and motor run caps for signal

This is interesting - somehow my head didn't equate Obbligato caps with what I perceive to be more generic Motor Run caps...

 

[Zen Mod]

that's just me ........ joking about fact that Obbligato aren't anything else than fancy-packed motor-runs

at least that's my perception

 

[flocchini]

some of things I'm cookin' are posted as teasers in Most Greedy Boy, of them all... or (there is no) DEFiSIT of Papa's Koans

Does that include a Babelfish XA25?

 

[flocchini]

that's just me ........ joking about fact that Obbligato aren't anything else than fancy-packed motor-runs

at least that's my perception

One day I may have replace the Obbigatos with 10uF Simlic IIs and give a listen

ZM - what is that MKC bypass you like?

Thanks

Bob

 

[Zen Mod]

polycarbonate

 

[Zen Mod]

Does that include a Babelfish XA25?

maybe

 

[Zen Mod]

........and ZenMod for promoting the M2-circuit..........

btw. ZM is World's Biggest Fan of Zappa,Jethro Tull ,MC5,Furtwängler and M2




you need proper Big Speakers for listening of all of them

 

[flocchini]

polycarbonate

something like this?

2 x NOS 1.0uF 1uF 250V Philips Chicklet MKC 341 HQ Axial Polycarbonate Caps | eBay

 

[Zen Mod]

yup

find cheapest ones , 1uF and upwards , and try them

combined with Silmics , to add up in needed value , they're sublime

 

[flocchini]

Found 15 or so each of these in my capacitor bin - time to experiment

Thanks ZM

 

[steefdebruijn]

jfet matching

Hi all

<newbie alert/>

I have obtained a couple of 2SJ74BL and 2SK170BL JFETs. I tried to match then for Idss following the instructions on page Transistor matching

I have a pair of 8.78/8.44mA and a pair of 9.22/9.32mA. The others are 6.71mA for the K170's and 9.xxmA for the J74 so I conclude these are not usable as pairs for the M2.

Questions:

• Should I fiddle with the source resistor R3/R4 values within a pair (in one channel) because Idss is not exactly matched?
• Should I fiddle with the source resistor values between pairs (left vs right channel) because they are about 1mA off?
• Should I check matching for other JFET parameters other than Idss?
• Should I match any other paired parts within one channel and/of between channels? (like the R8/R9, R10/R12, R13/R14, Q1/Q2 or Q6/Q7 pairs)

Thanks for the info,
Steef

 

[Zen Mod]

-if resulting DC offset is more than , say, 5mV then include source reistor to correct it , simple for xformer health purposes
-naah
-naah , if you're sure they're genuine
-naah

 

[steefdebruijn]

Hi ZM,

Thanks. They are from BDEnt so I think they are genuine. So all is OK unless more than 5mV DC offset when all is ready for electrical test.

Steef