Official M2 schematic

[Zen Mod]

well , when you started like that , send few dozens in my way .......

 

[Soundhappy]

Non magnetic resistors ? Any experience ?
wire with protect magnetic field screen and
http://www.antekinc.com/content/CA-xxx.pdf

I see Pioneer made class A amps with psu transformers covers.

 

[Soundhappy]

Ok anyway try this time circuits with all non-magnetic materials R.
Can't resist to interesting M2 non-feedback transformer coupled push-pull amp.
I get super Tea-Bag full kit woow yuoopiiii
Have a nice day

 

[Zen Mod]

try also with non-magnetic input xformer
while you're there ,use non-magnetic mains xformer , too

 

[generg]

I have found out that putting some small magnets in the four corners give a much better sound!

:-----))))

 

[Soundhappy]

try also with non-magnetic input xformer
while you're there ,use non-magnetic mains xformer , too

Yeah shure and make sense only with non-magnetic speaker drivers

Separate box for the psu donuts

 

[Soundhappy]

I have found out that putting some small magnets in the four corners give a much better sound!

:-----))))

Deposite patent and enjoy to be come millonaire

 

[Full Range]

Just a quick midway update on my M2

So far I have installed a Schaffner filtered IEC switch
A shielded AC cable
And reworked / peplaced the star earth for neatness
"No " CL 60 was fitted to safety earth - as per Zen Mods tip

Also had my electrician friend make up a shielded power cable of the same type as the amps AC power supply cable - so now from power point to amp switch the same cable is used

Results
M 2 is still humming at same level - testing noise level on iPad with db app @ 44db as an average at speaker

Next steps are
Prepare the torodial cover and fit as time permits
Wait for MuMetal to arrive to make box covers for the Edcore transformers

If that does not reduce the hum then I'm contemplating to swap out the Toshiba 2SJ74GR 2SK170G with the spare set I have on hand

 

[Soundhappy]

Just a quick midway update on my M2
.....

If that does not reduce the hum then I'm contemplating to swap out the Toshiba 2SJ74GR 2SK170G
with the spare set I have on hand

@ Full Range
Do you try test or experiment what happen if psu transformer is out the chassais box
with much much longer distance from step-up Edcor ?
Greetings

 

[Full Range]

@ Full Range
Do you try test or experiment what happen if psu transformer is out the chassais box
with much much longer distance from step-up Edcor ?
Greetings

No - but it has been suggested before in conversation
That will be my last option as I prefer one chassis

 

[Soundhappy]

No - but it has been suggested before in conversation
That will be my last option as I prefer one chassis

I was think about temporary "try only" option if hum is gone so jfet's are ok.

 

[Full Range]

I would like to ask a question.

Is there a difference between the BL and GR JFets
The BOM recommends BL but I have purchased GR ( as per the entry below )

Toshiba Original 2SJ74GR / 2SK170GR Matched Pair (0.05 mA)

Good Detective work was spotted by Wdecho

 

[Zen Mod]

what's their Idss ?

 

[Full Range]

what's their Idss ?

Very low
See photo

 

[Zen Mod]

it'll work , but I presume sort of wimpy sounding

do you have 4 pairs , by chance ?

it'll help if you parallel them ......

 

[wdecho]

I agree, wimpy sounding. Maybe even higher noise level because of this?

 

[Full Range]

it'll work , but I presume sort of wimpy sounding

do you have 4 pairs , by chance ?

it'll help if you parallel them ......

I purchased 2 sets - 1 set as spares just in case - But I won't bother now
It's easier to purchase the BL

The sound is not as lively as the F6

I agree, wimpy sounding. Maybe even higher noise level because of this?

Are the ones in the DIY shop suitable for the M2
Or do I start looking

Linear Systems Matched JFET pairs (Grade B) – diyAudio Store

 

[wdecho]

Perfect, you will be sure they will work satisfactory.

 

[Zen Mod]

yup

 

[Full Range]

Thank you gentlemen - that's what makes the DIY Audio community so good
Let's hope the information will help others that follow

Will return again with a report after I order and install the new JFets