[Tech2]

Haven't posted here for a while, but I have a question for Little Dot MKIII owners.

My LD MKIII has been happily sitting on my desk at work receiving fairly regular use. It is about a year-or-so old. Note that I work in an office cubicle and there is nothing in the air that can be considered hazardous or a contaminant (I hope).

Anyway, the top half of the black anodized case has turned a sort of gold color. It is not completely gold, more like black with a gold hue as though there is some gold substance on top of the housing.

Anyone else experience this?

I'm thinking of just masking the entire housing off and spraying it flat black.

 

[Happy Camper]

When metal turns color, it usually indicates a heat problem. How hot does it feel after running all day?

 

[Stitch]

I have mine for a bout 6-7months and can see no discoloration at all.
I would first ask david about if i where you, before attempting anything.

 

[Tech2]

Quote:

Originally Posted by Happy Camper /img/forum/go_quote.gif When metal turns color, it usually indicates a heat problem. How hot does it feel after running all day?

I rarely use the amp for an entire day, usually up to 4 hours max and it doesn't get exceptionally warm in comparison to my Woo6. My old LDII got a LOT hotter than the MKIII. I certainly wouldn't rule out heat as a factor though.

 

[Tech2]

Quote:

Originally Posted by Stitch /img/forum/go_quote.gif I have mine for a bout 6-7months and can see no discoloration at all. I would first ask david about if i where you, before attempting anything.

Probably my best course of action, though being a year old I'm wonderiing if there is anything he'd be willing to do. The amp is functionally sound, but this cosmetic defect does kind of bug me.

 

[Donnyhifi]

No issues here either, bought it used and it seems like its one of the earlier releases and its in fine shape!

Edit:

Forgot to mention that this thing gets tons of usage due to living in a Japanese apartment and not being able to crank up the tunes on my Paradigm Titan speakers.

 

[Happy Camper]

Pics?

 

[Tech2]

I'll try and get some pics but I'll have to bring it home first - no cameras allowed at work.

Besides that I don't know if it will be very evident in a picture. I did email Little Dot and I imagine that they may be interested in a picture, so I'll give it a shot.

What is the finish on these amps anyway?...black anodizing?

 

[the.sting]

My LD MKIII has that gold discoloration as well. It is as you describe: more like a fading of the black, rather than a pure gold color. For me, it's not evenly faded around the amp...the gold color is somewhat "rippled" looking, and is more visible on the right side of the amp (while looking at the front plate) than the left.

I bought the amp in early June from a fellow Head-fi member, who had it for two years before that (and used it quite regularly), and the discoloration was there when I got it. It has not gotten noticeably worse since I've had it (if at all).

As far as temperatures are concerned, I have been running it for the past 2.5 hours or so with ef95 driver tubes, and the metal chassis is warm, but not too hot. I can touch it and hold my hand there without any discomfort.

I took some pictures of it this evening. It's somewhat difficult to see the discoloration, because it varies based on the lighting. Is this the effect you are seeing?

 

[Happy Camper]

I'd rule out heat as the entire chassis has this effect.

 

[the.sting]

I've done a little digging. It seems that black anodized aluminum (which I believe is used for the LD MKIII chassis) can indeed fade to bronze/gold (clearly, as we are observing it). Its resistance to this effect is based on:

1. The quality of the dye seal
2. Exposure to UV lighting (more exposure --> more fading)
3. Temperature (hotter --> more fading)
4. "Over-the-counter ammonia-based cleaners" (I hope no one is using those!)
5. The light-fastness of the dye

It is possible that the fading we have observed is due to a poorly sealed anodize job, but given that not everyone has observed this effect, I'm going to guess that either they've changed the process or that the fading is caused by the other factors given above. Mine had faded before I got it, so I cannot confirm this.

The finish doesn't bother me personally, as it's difficult to see the fading except in the right light. You might want to talk to David and see what he says about restoring the black finish...he might have a solution (or at least might be able to tell you about the heat-safe-ness of spray-painting it black). Feel free to use my photos, if it would save you the trouble of bringing your amp home from work.

Cheers.

Edit...my sources:
Type II black anodizing discoloration (gold)
Black anodize turning bronze color

Another edit: I'm fairly certain now that the discoloration, at least in my case, is from the UV radiation from the sun. As I mentioned, the gold color is more present on the right side of my amp than the left, and after looking at it some more, I've noticed that the gold does extend across the top of the chassis from the right to the left, except immediately to the left of the tubes and the transformer. These must have blocked the sunlight from those areas, leaving them the original color.

 

[Tech2]

Quote:

Originally Posted by the.sting /img/forum/go_quote.gif My LD MKIII has that gold discoloration as well. It is as you describe: more like a fading of the black, rather than a pure gold color. For me, it's not evenly faded around the amp...the gold color is somewhat "rippled" looking, and is more visible on the right side of the amp (while looking at the front plate) than the left. I bought the amp in early June from a fellow Head-fi member, who had it for two years before that (and used it quite regularly), and the discoloration was there when I got it. It has not gotten noticeably worse since I've had it (if at all). As far as temperatures are concerned, I have been running it for the past 2.5 hours or so with ef95 driver tubes, and the metal chassis is warm, but not too hot. I can touch it and hold my hand there without any discomfort. I took some pictures of it this evening. It's somewhat difficult to see the discoloration, because it varies based on the lighting. Is this the effect you are seeing?

That is EXACTLY the same problem I'm having.

Your assessment as to the cause is also correct, at least according to the response I received from David. He explained to me that UV light can and will cause this phenomenon. I suppose it is the lighting at work that has caused mine to fade. His remedy was to:

a) Paint the case

or

b) Purchase and install a new housing

I'll probably just live with it for now though I may try painting it at some point. I also spoke to a friend of mine who said he can sandblast the case and have it powder coated for me.

 

[El_Doug]

Quote:

Originally Posted by Tech2 /img/forum/go_quote.gif I'll probably just live with it for now though I may try painting it at some point. I also spoke to a friend of mine who said he can sandblast the case and have it powder coated for me.

DO IT! A firetruck-red LD would look sick

 

[Tech2]

Quote:

Originally Posted by El_Doug /img/forum/go_quote.gif DO IT! A firetruck-red LD would look sick

There is a very high probability that I will change the case color if I go with a powder coat finish. Red would be pretty cool.

 

[the.sting]

Ahh good, glad to hear your confirmation of the issue...and David's fixes to it.

Quote:

Originally Posted by Tech2 /img/forum/go_quote.gif There is a very high probability that I will change the case color if I go with a powder coat finish. Red would be pretty cool.

This might be a strange suggestion after this discoloration problem, but why not coat it...bronze?

A nice, even bronze, of course.