2. tech-talk
  3. 183709-20253

My Luxman Integrated has AC Inlet Envy

I love my Luxman 507ux, it does so many things right, so soon after I got it I built a shielded power cable as an upgrade to the relatively plain cable that came with it.

To make a long story short, after trying out a number of different cables and female IEC plugs it seems the AC inlet has prongs which seem too short. For sure, the Luxman has no ground pin. I'm sure that this means it's not required, so that’s not an issue. What is an issue is that even a Wattgate plug, which are famous for a tight grip, can’t stay in. Even a little wiggle can disconnect the amp.

It seems either or all of these are true:

  • The missing ground pin is keeping plugs from feeling very grippy
  • The pins are too short
  • The pins are too thin

If I play with a cheap power cord, it seems like the AC doesn’t connect unti lthe very last 2 mm of travel of the plug. This seems wrong.

I bought a cheap replacement inlet and it just feels so much better. Meaning, I can feel the plug grip the pins much earlier, and they all grip much better.

Anyone else have issues with Luxman inlets??

 

PS - I absolutely insist on building my own power cables. This is my hobby not yours so please stop trying to convince me my problem is that I didn’t buy your boutique brand.

 

erik_squires
imhififan's avatar
imhififan
2,212 posts
 

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.

 

 

erik_squires OP
16,380 posts
 

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.

billwojo
397 posts
 

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

erik_squires OP
16,380 posts
 

Wow, I'm so glad my old Audio Research SP8 preamp has a captive power cord.

We'd sure have a lot fewer discussions if everyone did this. 🤣

ghdprentice
7,277 posts
 

Yes, but inferior sound quality.

More to discover