Marantz MA9S2 choke input power supply

[Veysel]

Hi. Could you check pictures there is red circles my friend signed? He wants to know Where are they connecting

 

[Markw4]

Red circles?

 

[Veysel]

Yes there is thin circles that my friend circled on the left and right. Difficult to seem ,needs enlarging picture

 

[Markw4]

what are the J numbers in the service manual?

EDIT: Looks like J505 has a wire going to the chassis bottom plate. J504 appears unused. J642 also appears unused.

 

[panterka]

Those marked points (J504, J505) in the 3D photo are just the vias connecting the upper and lower layers.

In the photo below you can see that there is a wire soldered to J504, this probably goes somewhere on the chassis.

 

[panterka]

Yes there is thin circles that my friend circled on the left and right. Difficult to seem ,needs enlarging picture

This is where the path is missing, I marked with an orange line.

 

[Markw4]

There is no J506 in that location. It is actually J505. J505 connects J501 and to J503. J503 is then grounded through the PCB mounting hole screw. J505 also has a wire soldered in it that goes down to the chassis bottom plate and connects to ground there.

It is like this on the PCB:

 

[panterka]

Markw4
My post above was to Veysel, I misquoted but already corrected.

Your information is valuable because the pictures don't show all the ground wires.

 

[Markw4]

A few more pics:

 

[Veysel]

Thanks a million for the help and the pictures Mark ! This amplifier is a pure art.We are clonning it.We hope we can work it well.Maybe i can make it only one pair of output because of i do not need such high wattage but want to experience this amplifiers quality.

 

[Markw4]

Maybe better to make it as Marantz intended, sell it to a rich audiophile, then use the earnings to help pay for yours

Otherwise, it wasn't really designed to run with one end of the speaker tied to ground. You might have to tweak the circuit a little for that to work optimally.

 

[Veysel]

We searched but could not find a modification for this amplifier.Marantz did it in the best way.Yes maybe we can sell and make it free amplifier for ourselves

 

[Markw4]

One more pic:

 

[umut1001]

Hi Mark! We will order choke input transformer from transformer producer. But do not know how to describe it.Is it built like an emi filter or toroidal transformer. Any datasheet or example? Regards Umit

 

[Markw4]

Any datasheet or example?

Not that I know of. Sorry.

 

[umut1001]

Ok I see. We also need to know at which frequency 0.18mH coils inductance measured.

 

[Markw4]

Seems likely it was measured at some AC line related frequency. Also, the fact that it is in a round metal can suggests it is likely torroidal.

 

[umut1001]

I have yellow cores.But it seems they are made with toroidal transformer cores because 180mH value is high.

 

[analog_sa]

Ok I see. We also need to know at which frequency 0.18mH coils inductance measured.

Not critical as long as it exceeds 180mH. If the current is known it's easy to calculate the critical inductance for choke input.

I don't really see the point of obsessing about that choke. It's contribution to the overall sound is quite minor imho.

 

[Markw4]

Isn't the point to obsess about every little thing, like Marantz presumably did?