Official M2 schematic

[Zen Mod]

papasfirstname is Nelson


so , papasfirstname@passlabs.com is equally functional as ******@passlabs.com

go figure

 

[gaborbela]

papasfirstname is Nelson

Ah, I sent it wrong. You always kiding....🙂
Now I understand I send it again
Thank you

It did not come back yet, somewhere went, maybe to you ZM

 

[Zen Mod]

see , that's good idea ....... I'm going now to register that email , so from now on ,will intercept entire Papa's correspondence



(they already owe me opldf@passlabs.com addy , but their Administrator is lazy)

 

[Nelson Pass]

Ah, I sent it wrong. You always kiding....🙂
Now I understand I send it again
Thank you

It did not come back yet, somewhere went, maybe to you ZM

I got the message this morning from Desmond, who retrieved it from a
bin on the server....

 

[steefdebruijn]

Hi,

What is the power rating of the 100R resistors?
- For R8/R9 I have 1/8W
- For R10/R12 I had 0.6W planned but I did not order enough of them

Is 1/8W for R10/12 ok too or should I really go for bigger ones

Steef

 

[Zen Mod]

all resistors in M2 are regular 600mW jobbies (what we know as usual size metal films) except two 0R47/3W source resistors

100R resistors - yes , you can use 1/8W

 

[steefdebruijn]

Thank you sir!

 

[mpmarino]

Send me your address.

Can I send you mine? I have the transformers, I just need the rest.

> 🙂 Greedy 🙂 <

 

[Nelson Pass]

Fine by me.

🙂

 

[mpmarino]

Sounds good, but you'd better hurry

I'd hate to see these Edcors corrode in the New England humidity before I get off my **** and etch a set.

 

[steefdebruijn]

Hi all

First power up of left channel.
No blown thingies, so that is good 🙂

But alas... 9mV from between R3/4 and GND so I presume I should fiddle with R3 and R4 values (both pretty exactly 10R now). Q3/Q4 are pretty close match as far as I know.
Any suggestion on value(s) to try?

And DC offset on outputs: With P1 at factory value (not measured) somewhere between -700mV and -800mV. P1 fully clockwise lowers this to about -280mV. So I am about to increase R7 to 56k. Or should I jump higher? Have 68k and 73k2 on hand. Both R6 and R7 are 47k at the moment.

Steef

 

[Zen Mod]

buffer offset positive or negative?

regarding output offset - try first value you get in hand

then you'll know more 🙂

 

[steefdebruijn]

buffer offset positive or negative?

Positive

regarding output offset - try first value you get in hand then you'll know more 🙂

Ok will do and report back

Thanks
Steef

 

[Zen Mod]

lower R4 (ref to post #1) for 10-20%

for test - solder 100R across R4

if that is not enough , solder 47R across R4

that would be change to 9R1 or 8R2 ..........

final value , lazy to calc , but there is principle

 

[steefdebruijn]

Ha! I got it. Thanks.

 

[steefdebruijn]

One other quick question. Looked for it on the thread but did not find it (that could be me 🙂 )

I was planning to put two mono volume pots at the back of the chassis for master volume adjust and volume matching (acoustically - nasty rooms). I had a NAD 916 a long time ago which had this and I found this very handy at the time. Any pot recommendations (at least which impedance to use)?

Steef

 

[steefdebruijn]

Hmm

DC at Edcor: Parallelling 133R with R4 lowers R3/4 junction to GND from 0.009V to 0.007V. Parallelling another 133R (so 10R + 133R + 133R) lowers further to 0.006V

The DC offset at output jumped (with P1 full clockwise) from -300mV to +2000mV when increasing R7 from 47k to 56k. Fully turning P1 to counterclockwise lowers to 424mV

Steef

 

[Zen Mod]

you're increasing wrong side ?

 

[scottjoplin]

even Sparrows knows it

HA!

YouTube

 

[steefdebruijn]

Hi
Guess not because offset went from neg to pos ?
Steef