Official M2 schematic

[Zen Mod]

you have a problem with your regs , too wimpy for current nvolved

also , 10K in bias network is way too small , resulting in 5K or so input impedance of OS , further divided to buffer via xformer ....with square of voltage ratio

if xformer is having 4V/V , that is 5K/16 , taking too much burden to small toshibas

so , increase values in bias network

 

[blackdod]

Thanks ZenMod.

I use a similar PSU that F5ha so I don´t think that the psu is the problem. I measured around 165mA for rail. It´s not much

I use 3.3R on R16 and R22 and I measure 0.525Volt, a Bias around 160mA so this is ok.

What value would you recommend increasing the Bias network? Do you mean R6 and R24?

 

[Zen Mod]

open new thread , give us necessary info and we will solve your problems

post reg schematic , and maybe even picture or two of amp itself

 

[blackdod]

open new thread , give us necessary info and we will solve your problems

post reg schematic , and maybe even picture or two of amp itself

Thanks Zen Mod.

You are right, I changed r6 and r24 for 20K and.... tachannnnn

Now both rails works with +-15volt and a very stable offset but the Bias down from 160mVolt to 36mVolt. Maybe is a better idea change R16/22 ???

I´ll open a new thread tomorrow for share all information/pictures/schematics about this amp.

 

[JimT]

If anyone has a spice circuit for this I would appreciate a copy. I will need the model for the transformer and the 4N35.

Thanks
Jim

 

[flocchini]

Toshiba 2SK1530 / 2SJ201

Completed my M2 changeover

Added Toshiba 2SK1530 / 2SJ201, reduced source resistors to .33 ohms and 0 ohms at R11. Using Tea Bag boards

Power by umbilical cord.

Nice involving sound with wide and deep soundstage. Great detail without fatigue

Highly recommended.

Best

Bob

 

[Zen Mod]

again ugly sinks and motor run caps for signal



(what's Iq now?)

 

[flocchini]

Iq is approx 1.7A

I had to use those Obbigato caps I had in a box

Maybe one day I will replace with Simlic II and your favorite bypass

 

[Zen Mod]

OK

everything is forgiven , seeing those sinks

 

[chede]

Completed my M2 changeover

Added Toshiba 2SK1530 / 2SJ201, reduced source resistors to .33 ohms and 0 ohms at R11. Using Tea Bag boards

Power by umbilical cord.

Nice involving sound with wide and deep soundstage. Great detail without fatigue

Highly recommended.

Best

Bob

+1 for the same combination.

In my case built on JPS64 boards, with PSU in the same box, and I have a WIMA MKP10 for C2 and Elna Silmic II 3300 µF for C3 (bypassed by 1 µF MKC ERO1860).

My M2 runs with Iq of 1.81 A (Rails at +/- 24V).

Best regards,
Claas

 

[flocchini]

OK

everything is forgiven , seeing those sinks

4 of these are waiting for one of your M2 variations

 

[KweeSong Lim]

Anyone has a pair of spare M2 boards to sell? Read so much good things regarding M2 on this forum. Must try to build one to enjoy.

 

[KevinHeem]

Anyone has a pair of spare M2 boards to sell? Read so much good things regarding M2 on this forum. Must try to build one to enjoy.

Did you check with TeaBag?

Check HERE

 

[KweeSong Lim]

Ok. I will pm him

 

[grimberg]

I still have a few sets of M2 PCBs available. You can see them in earlier posts in this thread.

 

[KweeSong Lim]

Dear Grimberg, Great, thanks. I would like to have a pair please.
Thanks, Song

 

[zman01]

Completed my M2 changeover

Added Toshiba 2SK1530 / 2SJ201, reduced source resistors to .33 ohms and 0 ohms at R11. Using Tea Bag boards

Power by umbilical cord.

Nice involving sound with wide and deep soundstage. Great detail without fatigue

Highly recommended.

Best

Bob

Interesting mod, thanks for sharing.

Did you have the SK1530 / 2SJ201 with you or got them recently? if bought, then can you recommend a reliable source?

 

[flocchini]

I had 3 of each.

 

[flocchini]

4 of these are waiting for one of your M2 variations

or the Babelfish XA25

 

[zman01]

I had 3 of each.

Lucky you.