My Luxman Integrated has AC Inlet Envy

I'm awaiting one more part from Mouser before I change out the inlet. I don't want to open it up and find out I have the wrong parts. :)

@imhififan 

To answer your question the Luxman transformer has 3 wires on the secondary and exactly 2 on the primary. These are not convertible transformers.

Best,

Erik

These are not convertible transformers.

Thank you for your confirmation!

I've dismembered my Luxman and have had the original C18 outlet on my workbench for a couple of days.

The pins measure exactly to spec.  I can't find anything at all wrong with the pins or the casing at all. In fact the pin to PCB construction is impressive.  They look like a single piece of cast metal that retains it's thickness through the PCB connectors. 

I'm now 100% sure that the weakness I was feeling in the grip of cables is due to the missing ground pin.  Also, without the ground pin the Wattgate 320i sucked.

Tomorrow I replace it.

Tomorrow I replace it.

Good luck and please keep us updated with your progress!

@imhifiman

Things got curioser and curioser as I worked.

Sadly the cord used from the power board to the inlet, about 8" long is 20 gauge. Kind of disappointing honestly, but probably exactly to spec. The choice of a Molex Spox connector I believe limits the maximum gauge to 18 anyway, so assuming I did have a Molex crimper ($700 or so for the manual versions) I still couldn't improve much here.

The big deal however is that the assembly leaves the wrong side of the AC inlet fused. I wrote about it in detail here:

https://inatinear.blogspot.com/2023/04/luxman-507ux-ac-inlet-mistake.html

Sadly the cord used from the power board to the inlet, about 8" long is 20 gauge. Kind of disappointing honestly, but probably exactly to spec. The choice of a Molex Spox connector I believe limits the maximum gauge to 18 anyway, so assuming I did have a Molex crimper ($700 or so for the manual versions) I still couldn’t improve much here.

If the power transformer primary winding wire is thinner than 20 gauge, I don’t see there will be any improvement using thicker wire.

The big deal however is that the assembly leaves the wrong side of the AC inlet fused.

I won’t say Luxman is wrong since it is a double insulated Class II equipment.

However, if your power cord is polarized, swap the wire let it fused on Live side. No harm to make it even safer.

If the power transformer primary winding wire is thinner than 20 gauge, I don’t see there will be any improvement using thicker wire.

Well there’s a practical reason for this. The transformer may be 20 gauge but the fuse is 15A. Also, it may be just how much effort I’ve put into this but I swear it sounds better. 😂

I won’t say Luxman is wrong since it is a double insulated Class II equipment.

Is it? I can’t tell by looking at the construction. I was expecting more plastic shielding somewhere compared to a non-double insulated amp. Looks the same to my untrained eyes. There’s nothing between the tin fuse caps and the bottom cover, for instance.

However, if your power cord is polarized, swap the wire let it fused on Live side. No harm to make it even safer.

Already fixed it internally.

Wow, I'm so glad my old Audio Research SP8 preamp has a captive power cord. Those connectors are just another point of failure. Even my ancient Mac MC40 monoblocks have a captive power cord, looks to be lampcord as well. All original and still in good condition. Can't come up with a reason to replace it unless it becomes brittle and starts to crack.

Way to many other things to think about, no need to invent imaginary issues.

BillWojo

Yes, but inferior sound quality.

The transformer may be 20 gauge but the fuse is 15A.

Interesting, 15A fuse for a 110Wx2 amplifier! No soft start circuit?

@imhifiman

THe unit was too heavy for me to play and trace it back and forth between the bottom PCB and the top, but no. It looked like the main transformer plugged directly to the fuse. You can see it in the picture I took. There’s a service transformer for the standby circuit, then the inlet plug, then fuses and then a wider plug which I believe goes straight to the main transformer.

Also, going from the drop in line voltage when I turn this beastie on, no, there’s no soft-start.

The PCB markings below the fuse say 15A and that’s exactly what was in there.

Luxman may have produced 10s of thousands of these units, so they probably know their materials very well, but given how difficult a field replacement of those wires, and fuse sizing I would have 100% used thicker than 20 gauge.