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

No issue with my Luxman L-590AXII. I have an Acrolink 7N-PC9700 mains cable connected to it. It's a tight and secure connection.

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.

Yes, change the IEC C-14 is the best option!👍

I found some photos online the Luxman use 3 prongs inlet, is your 507ux utilizes quick connect (no soldering required) C-14?

 

I have a nearly new L505uxII. It does not have the ground pin in the inlet. I use a DIY power cable with a WattGate plug, and it seems to hold fine. When you replaced the AC intlet, did you just leave the ground plug unwired? I am guessing you just about had to if the original inlet did not have the plug there.

Try wrapping a piece of white Teflon tape around the female IEC.  It should provide a very snug fit. 

@stereo5, I can make the plastic snug in the socket with tape. The issue is what feels like onlhy 1-2 mm of contact in the conductors, the contacts don’t touch until the plug is almost completely in. That’s when the Amp lights suddenly turn on..Using the same cable with a cheap, Mouser sourced inlet I can feel it make contact with the pins a lot sooner. Pulling the plug out maybe 1 mm is enough to turn the amp off.

It’s not just about keeping the plug from falling out, it’s also about ensuring a wide contact area and this inlet isn’t giving me the confidence.

Imagine if the pins on your coffee maker got cut in half.... Yeah, I can tape it to the wall, but still it doesn’t inspire confidence.

Luxman use 3 prongs inlet, is your 507ux utilizes quick connect (no soldering required) C-14?

@imhififan  - Well I have no idea what those are but mine is definitely a 2 prong.  I haven't pulled the connector out yet.  I'm can deal with either situation, and it's definitely not gold plated. :)

@erik_squires Wrote:

It’s not just about keeping the plug from falling out, it’s also about ensuring a wide contact area and this inlet isn’t giving me the confidence.

I couldn’t agree more! FWIW, Boulder does it right no standard IEC. See below 1-2:

Mike

https://boulderamp.com/wp-content/uploads/3060-OM-V3-1.pdf

https://boulderamp.com/wp-content/uploads/32A-Power-Connector-Explanation.pdf

Sorry, to be clear: I bought a cheap replacement inlet but it’s not yet in the Luxman. I just bought it to test fit my cables and it seems to do a lot better than what’s in the Luxman both electrically and mechanically.

I’m considering a Furutech replacement but my luck with the brand has been terrible. OTOH, they only run $20.

 

Boulder does it right no standard IEC.

Another good AC connector is Neutrik powerCON, too bad no home HiFi use it.

@imhififan, I buy all locking AC power cords. See below:

Mike

 I use custom made locking IEC AC mains power cords on all my audio equipment. Example in blue see below:

Mike

Step 1. Choose a Plug


 Select... C14  C14 DOWN C14 RIGHT C14 LEFT C14 UP C20  C20 RIGHT C20 LEFT 5-15  5-15 HG  5-20  L5-20  6-15  6-20  L6-20   Blunt   ROJ  

Step 2. Choose a Connector


 Select... C13  C13 RIGHT C13 LEFT C15  C15 RIGHT C15 LEFT C19  C19 RIGHT C19 LEFT C13 WS-Lock  C13 WS-Lock DOWN C13 WS-Lock LEFT C13 WS-Lock RIGHT C13 WS-Lock UP C15 WS-Lock  C15 WS-Lock DOWN C15 WS-Lock LEFT C15 WS-Lock RIGHT C15 WS-Lock UP C13 IEC Lock  C19 WS-Lock  C19 IEC Lock   Blunt   ROJ  

Step 3. Choose a Jacket


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Color
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Length Select... 0.3m / 1 foot 0.4m / 1.25 feet 0.5m / 1.5 feet 0.55m / 1.75 feet 0.6m / 2 feet 0.7m / 2.25 feet 0.8m / 2.5 feet 0.85m / 2.75 feet 0.9m / 3 feet 1.0m / 3.25 feet 1.1m / 3.5 feet 1.15m / 3.75 feet 1.2m / 4 feet 1.3m / 4.25 feet 1.4m / 4.5 feet 1.45m / 4.75 feet 1.5m / 5 feet 1.6m / 5.25 feet 1.7m / 5.5 feet 1.75m / 5.75 feet 1.8m / 6 feet 1.9m / 6.25 feet 2.0m / 6.5 feet 2.05m / 6.75 feet 2.1m / 7 feet 2.2m / 7.25 feet 2.3m / 7.5 feet 2.35 m / 7.75 feet 2.5m / 8 feet 2.55m / 8.25 feet 2.6m / 8.5 feet 2.65m / 8.75 feet 2.7m / 9 feet 2.8m / 9.25 feet 2.9m / 9.5 feet 2.95m / 9.75 feet 3.0m / 10 feet 3.2m / 10.5 feet 3.4m / 11 feet 3.5m / 11.5 feet 3.7m / 12 feet 3.8m / 12.5 feet 4.0m / 13 feet 4.1m / 13.5 feet 4.3m / 14 feet 4.4m / 14.5 feet 4.5m / 15 feet 

Step 5. Review Prices and Add To Cart

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Custom Molded Power Cord - L6-20 Plug to C13 WS-Lock Connector 0.3m / 1 foot 15A/250V 14/3 SJT BLUE

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https://www.stayonline.com/cordbuilder/molded-cord-configurator.asp

 

That's great guys, just great.  What I really need to do is either switch to Boulder, or hack the cabinet of my amp to put in a connector with a completely different form factor.

 

🤣

@imhififan  No, but again, it's not just about how easily it pulls out, but how good a contact it makes.  :)

I could use superglue if I wanted, doesn't make the metal to metal contact any better.

@erik_squires Wrote:

@imhififan  No, but again, it's not just about how easily it pulls out, but how good a contact it makes.  :)

I agree, all non locking IEC will not make a good electrical contact because they arc. IME, the money audiophile amps cost they should have locking IEC for the AC mains. 😎

Mike 

Replace the inlet is the only solution. Use a 3 prongs and leave the ground pin unconnected.

I could use superglue if I wanted, doesn’t make the metal to metal contact any better.

@erik_squires

The IEC LOCK+ is utilize a metal plate at an angle to clamp the ground pin. However, you may not need it if the replacement inlet is good enough.

Anyone else have issues with Luxman inlets??

BTW, the Luxman 507 photo that I posted earlier could be an aftermarket IEC socket.

I hope my responses make sense.😉

I did have such problems but not with Luxman.  One intermittent drove me crazy.  The receptacle had a pin break loose and would be push inward as the plug was inserted.  But the pin would be pull back outward when the plug was removed.  Visually it looked okay.

Since you make your own power cables and have already Replaced the inlet receptacle, this should not be a problem for you to perform.  But you have to have a lot of commitment to the cord you are using. 

If it does not Feel Right, I bypass the inlet receptacle altogether and hard wire the power cord straight to the power supply circuit board or wherever those wires from the inlet receptacle go to.

@erik_squires there is no ground pin on the IEC inlet of my L-590AXII. Just two pins. Perhaps try a power cord which can stay firm inside the inlet of your L-507UX? There's no issue with my Acrolink cord staying put inside the inlet. 

My Marantz Ruby has no ground on the IEC C-14 like yours.  I have quit using Wattgates as their IEC plugs have a bad design as you have found out. Try these instead--much better pin geometry:

https://www.amazon.com/gp/product/B08332R442/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

I plan on replacing the two pin IEC C-14 with a three pin.  Easy to swap out.  Just leave the ground unconnected.

It's rather easy to resolve.  I wouldn't modify the Lux except to ever so slightly bend the pins inward 2-3mm.  Then take the end of the cord that plugs into the Lux and shave the end back to bring the mating contracts closer to the end.  A belt sander makes short work of this but can be done by other methods.  I did this on a MoodWright years ago and completely resolved the connection issue.

A simple way is to find a Furutech dealer and try there how tight is the fit between their inlets and iec plugs. That means probably you would have to change the iec inlet on your Luxman.

My 505UXII has had no issues with cables from Pangea, Shunyata, Cullen, or PS Audio.

Thanks @Ryder I guess it’s possible my particular unit, the original UX, not UX II version of the 507, got a bad inlet.

It has no ground pin, so locking plugs are useless, and even if they are, the short contact distance between the plug and inlet has to change.

I am going to change this inlet. I have one from Mouser (3 pin) I can use right now or I can order a Fancy Furutech from Parts Connexion.

I just think it’s weird I’m the only one who had this problem.

It seems many who reply are missing the part about SHORT CONTACT DISTANCE. Let me try to draw this out:

=== Luxman IEC inlet

....========= Plug

====== Cheap Mouser IEC Inlet

 

In the diagram above you see the Mouser sourced inlet has much more overlap with the plug contacts. Gluing the plug or bending the contacts inwards doesn’t increase the contact distance.

This is not your normal loose plug problem. :) Again, imagine you go to plug in your coffee maker and notice the pins are half as long as they should be.  I might be able to keep it attached to the wall by tape or bending the pins but neither really solves the contact area problem.

 

It seems many who reply are missing the part about SHORT CONTACT DISTANCE.

The inlet on your L-507UX is a C18 (2 prongs), the pin height should be 12mm. A C14 inlet is 3 prongs, the two pins height are 12mm and the ground pin is 15mm.

Have you measure it?

 

 

 

I bought a cheap replacement inlet but it’s not yet in the Luxman. I just bought it to test fit my cables and it seems to do a lot better than what’s in the Luxman both electrically and mechanically.

Seems like replace the inlet in your Luxman is the solution. No?

 

My Anticables plugs have good connectors but the stiffness of these cables can sometimes make them sag enough to affect contact. Lately, I have been making loops from tape that first wrap around the cable just behind the plug and then are brought to adhere to the top of the chassis enclosure and tensioned enough to resist gravity. Same approach with HDMI cables which often have poor contact as well.

Of course, these are not issues with pin "grip" so much as they are issues with the weight of the cables.

@imhififan

 

Have you measure it?

 

I will after I pull it out! :)

 

Seems like replace the inlet in your Luxman is the solution. No?

 

Yes, that's why I'm about to replace it.

I think I came here to see if anyone else had a similar problem, because these parts are so standardized and Luxman is not known for being cheap that I’m honestly more than a little surprised at the issues I’m having.

PS - Thanks for the image, @imhififan  I have been trying to find that from parts drawings without any luck.

Eric,

I read this yesterday and decided to wait and see what you had to say about replacing the male fitting on the amp. I don't have any experience with Luxman so I can't answer your actual question.

With Furutech not being the pancea that most people think it is, you might try an upgrade to a screw type connector. Since you make your own power cables this would not be a problem for you and when you sell the amp, this would be a nice upgrade that should be positive.

The problem with this is that a quick search didn’t find anything I like at a reasonable price.

But I’ll keep an eye open and if you like this idea and find something you like I’m sure you will post it. I’m having a custom amp built and the power cables between chasses are screw type so I’ll ask my amp builder what he used.

I have a mill with a DRO so it is easy for me to drill precise holes so if you need an adapter plate made, sketch it up and I’ll be glad to make it for you.

Jerry

Post removed 

carlsbad

... you might try an upgrade to a screw type connector. Since you make your own power cables this would not be a problem for you and when you sell the amp, this would be a nice upgrade that should be positive ... I have a mill with a DRO so it is easy for me to drill precise holes ...

Mods such as that on gear such as Luxman tends to hurt resale value, even when it's pitched as an "improvement."

@cleeds Wrote:

Mods such as that on gear such as Luxman tends to hurt resale value, even when it's pitched as an "improvement."

I agree!

Mike

I'm not sure what a screw type connector is.  I think I'm going to go with a very discrete replacement.  Either the $2 Mouser or a $20 Furutech which looks identical from the outside. :)

fo.q ta 32 tape, it's 0.3mm thick has anti static properties too, a bit like furutech ncf. Dampens vibrations too, also comes in ta102 which is 1mm thick.

 

highly reccomended can be bought on eBay from Japanese sellers very reasonably.  

Eric, re-read my post.  You're not the only one to notice this.  Your bigger problem is the poorly designed Wattgate.  If you are afraid to change the IEC on the amp(which may NOT fix the problem) , just try a better plug such as the one I listed.

Thanks @Corelli !

I agree the Wattgate feels wonky.  After extensive testing with the Mouser inlet I agree the replacement of the inlet is the way to go.

When I first built the AC cable I used a Parts connection plug.  It was always a little loose so I thought (incorrectly) a Wattgate plug would fix the problem. It did not.  Both plugs do significantly better on the new inlet that's sitting on my workbench behind me.

PS -

I’ve done some totally not scientific testing of the contact overlap. Using a multimeter and shorting out the plug I’ve determined that from the point that the plug reaches minimum resistance to the fully seated position is 5 mm. That is, you have to pull the plug out 5 mm before the resistance would rise above zero. That’s a lot better than what I’m experiencing on the Luxman which seems to disconnect at 1-2 mm.

PPS -
 

Yeah, I'll use a 3 pin plug, and add a little heat shrink on the inside so it looks purty.

@ditusa

As a matter of fact, what I ordered wasa not a C14 but a C16 inlet. The only difference I can tell is that the C16 inlet has a plastic ridge under the ground pin.

If you notice a lot of DIY male plugs have a little ridge cut out under the ground pin. That’s to mate with the C16.

I’m not sure if there’s any practical benefit to the ridge in a C16 inlet except to ensure a straight fit. Based on this chart, the only difference I can see is the maximum pin temperature, which I hope never actually gets near 70C:

 

https://www.webberelectronics.com/info/iec-chart

@erik_squires Wrote:

As a matter of fact, what I ordered wasa not a C14 but a C16 inlet. The only difference I can tell is that the C16 inlet has a plastic ridge under the ground pin.

I agree, I think your Luxman originally has a C-17 C-18 two prong plug.

Mike

Great! @erik_squires 👍

Please let us know your progress. BTW, since you going to open the chassis of your Luxman, Would you do us a big favor to check the power transformer primary winding if there multi tap or not, so we can be sure the possibility of voltage conversion.

TIA

 

@imhififan I will IF I open the Lux.

I have a chance I can do everything through the outlet hole.

I'm afraid that in my years of reading on Accuphase vs. Luxman, the lack of a multitap primary on the transformer was always a given.  If I find out otherwise I"ll let you know.

I have a chance I can do everything through the outlet hole.

If possible, try turn the original C18 inlet 180° before you replace it, perhaps that can help the aftermarket plug stay in better since the two pins are on upper side.

Hopefully you don’t need to replace the inlet after all 😌

IME, install the IEC inlet 2 pins on upper side is better even if it is a C14 inlet.

The aftermarket plug is fine in every other inlet. Ground goes on top. 😀

I am absolutely replacing the inlet.

Whether I use a generic, Connex or wattgate it feels wrong. When its out Ill be able to measure more adequately.

Ground goes on top. 😀

Unlike AC Receptacles, IEC 60320 inlets can install in any orientation, some Marantz and Denon even put it sideways.😀

@imhififan 

This is a purely personal aesthetic. It's my equipment and I get to be the decider. :)