Running-in the UCD 180...

[ptwining]

Despite my difficulties with my UCD's (which I have nailed on my loudspeakers - thanks classd4sure and phase_accurate!) I find a curiosity...

I have maybe twenty hours on my UCD 180's (spread out over weeks of two to four hour listening sessions). I find that the longer they run the stronger and deeper they sound.

Will this always be so? Do the amps want to be "warm" before they really perform or will they "run-in" after a time and perform consistently from power on?

Don't get me wrong, they are always sweet and deep but always sound better the longer they run.

Is this a normal circumstance?

Regards,
Tom

[Tim__x]

Are you saying they sound better after listening to them for hours? Having played without you listening for several hours? Or that they sound better after idling for hours?

All of the above could be placebo.

A and B could be voice coil warming and the accompanying change in frequency response.

A (c/w)ould be you ears settling in.

C is the only one where, other than placebo, the amplifier warming is likely the dominant effect.

[serengetiplains]

Tom, I suspect the amp is breaking-in. Capacitors are evil and require time to work optimally.

[classd4sure]

Hi,

You know the modules are fresh when there's some edge to it, harshness. There even be a short period when you feel a slight pressure in your ears.. (I'm dead serious). This doesn't last long though, and thankfully it's the first thing to go.

Just leaving it powered up, not even enabled or playing music, will break it in most of the way after three or four days at the most, blast some music for a little while and you can speed that up to about a day. It will lose the harshness, and relax ever so slightly, and become enjoyable... how enjoyable it becomes depends on how well you wired it, grounding, everything!

It won't really tighten up unless/until you do something about the electrolytic coupling caps. Either remove or upgrade.

I leave my main supply on most of the time and just enable/disable, warm up time is then very little and really.. nothing you'd tend to notice.

From a total cold start after the first few days and it's fully run in, still nothing to cry over. I read one joker say it took something like an hour and I had to laugh (those silly reviewers). It might have the slightest edge until it has reached operating temp, which is just a minute or two. Any improvement after that, you'd have to be a dog to notice. That's my opinion anyway.

It might be a bit different if your transformer's normal operating temp is 50 degrees or something, mine stays nearly room temp unless I really blast it for an hour, in which case it isn't much warmer.

[Richidoo]

Current issue of TAS reviews 3 poweramps, one is ARC 300.2 (stereo) made with Tripath 'class T' amps. Reviewer complained of same phenomena, where the amp sounds better after it is "warmed up", but he said the warm up can take 24-48 hours of continuous on time before it loses the over enhanced treble. Note he was not referring to break in time, but a resetting of something that needed to be turned on a long time to go away, and mfg acknowledged it is true! In the manufacturer's response from ARC, they are aware of this little quirk, saying that the amplifier only draws 50w in standby and is intended to be powered all the time to avoid the warm up issue. Could UcD share similar quirk with extended 'warm up' time? In the manufacturer's comments it is also revealed that the reviewer purchased the 300.2 amp.

Sorry, I checked for a link, but TAS reviews are not free online anymore.
Rich

[lucpes]

Noticed this with both UcD 180 and UcD 400, also with most new gear. True even for PC soundcards

[classd4sure]

Originally posted by Richidoo
Current issue of TAS reviews 3 poweramps, one is ARC 300.2 (stereo) made with Tripath 'class T' amps. Reviewer complained of same phenomena, where the amp sounds better after it is "warmed up", but he said the warm up can take 24-48 hours of continuous on time before it loses the over enhanced treble. Note he was not referring to break in time, but a resetting of something that needed to be turned on a long time to go away, and mfg acknowledged it is true! In the manufacturer's response from ARC, they are aware of this little quirk, saying that the amplifier only draws 50w in standby and is intended to be powered all the time to avoid the warm up issue. Could UcD share similar quirk with extended 'warm up' time? In the manufacturer's comments it is also revealed that the reviewer purchased the 300.2 amp.

Sorry, I checked for a link, but TAS reviews are not free online anymore.
Rich

Hi,

I've scoured the net looking for such references and found no concrete evidence to support the claim other than something someone said by some dealer .... which isn't in my view concrete or by the manufacturer.

We also dont' have enough information to be able to judge their "warm up" conditions. However I see they use a 320 000uF power supply .... I'd I doubt would ever actually "warm up", but might take awhile before it settles into some magical chemical state of equilibriance.... ?

Maybe the caps they use are junk too. Keep in mind they probably don't want you to turn it on and hear it sound like hell for five minutes by starting to listen to it right after power up, so they'd prefer to sey "let it idle for two days" so you're all impressed for your four thousand dollars the first instant you hear it.

[angchuck]

Sorry to hijack the thread but i have an issue which has happened to 2 pairs of of 180ads.

I did basic mods on them, removed and replaced the eletrolytic caps. They work fine for awhile. However, after some plugging in and out and fiddling, one side becomes obviously louder than the other. It has happened twice over so i am abit irrate.

Is there somewhere on the board where i can start checking to troubleshoot the boards?

Thanks

Chuck.

[classd4sure]

Might I recommend starting a new thread for your particular problem, in which you detail the changes you've made that may have brought about this change in gain?

Also is this a change which you've measured... or how have you discerned this gain change? Alot of the mods including changing caps can make the low end alot more potent for instance.

The fact it happened to several modules after you've modified them leads me to believe this could be it?

[angchuck]

Chris, thanks for always helping out. I managed to solve the problem on the second pair of modules. It was the crips on the plugs acting weird at some angles.

And i have tried several PS options, with your suggestion of the paralleled jensens being spot on. Highly recommended.

Cheers

Chuck.