It's quite simple. Class D amps when on, they're just standing by and using little to no power and could stay on and on and on endlessly
What Would Be the Reasoning Behind Leaving Class D Amps On?
I think my Marantz Ruby integrated sounds better if it is just permanently left on. I'm a bit of a tubehead, but I've had 2 other Class D amps and I recall them sounding better left on.
I've seen a handful of manufacturers that even recommend their Class D amps be left on--e.g. PS Audio, etc.
In addition to the potential improvement in sound quality, I suppose keeping caps and things on might be easier on them too.
Do you agree? Do you know why this may be true or at least the theory behind it?
Thank you in advance! I'm super curious about this stuff.
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It seems like most if not all recently designed equipment have a main power switch on the back with a power switch on the front that puts the unit in stand-by mode. I’m not a double E but have to believe there is a good reason for this. I have a class D and it doesn’t have an on/off switch on the front so I leave on most of the time. I do tend to turn everything off when leaving for a week or two. I’ve not noticed a significant change in sound quality either way. I just trust the designers. |
Some aren't left in standby that's why. I have Nord Buffers on NC500 modules it's one or the other. I set mine to stay on and NOT go into standby. I run them for 4 months out of the year, and combo of class ds and valves the rest of the time. It takes 20-30 minutes of playing music even when I leave them on. If they go into standby, 2 hours to warm up and sound ok. Big difference in mine anyways. I also use class Ds for bass management 12K for subs and columns. 30 minutes to work well and warm up the VC in the bass system. 20 drivers for that alone. Cold gear sounds wonky, so does overheated voice coils. :-) Regards |
@testpilot , HA! That made me smile. @oldhvymec, You too! I knew you had a valve thing going but not Class D too! We might be cut from the same cloth. I have this weird sense that what you are saying is what I'm experiencing. I know it's observational and prone to subjective interpretation but it feels like the amp is dry and lifeless if you just turn it on from a dead stop. |
OP: I've had exactly the same experience. I have IcePower amps and they sound really scratchy for about 48 hours then just open up. I only noticed this because I went away for a week and decided to unplug the stereo. When I came back I kept looking for an explanation and then magically the sound just really transformed on day three. Other A'goners have had very similar experiences. This may very well explain why some listen to Class D and decide it's not ready for prime time. On the other hand, my Luxman 507ux is good in 5 minutes. I have ZERO idea why. :-) |
@erik_squires , THANK YOU! E. I know you have some technical knowledge and background. How wonderful it is to hear someone like you say, Yep, this is my experience and I'm not sure exactly why. Certainly the notion of caps being charged up and everything staying warmed up makes sense. But many of us have found the Class D "warm up period" is not ideal unless it's really given some time--not just 30 mins. I want that Luxman, Erik. I'm lusting after their Class A stuff now. |
I have a pair of Wyred 4 Sound SX1000 (no R). Two day to sound good. A lot of people said the "R" model was a lot better. The fact of the matter was they have to be driven and on at least 48 hours. Mine actually "Boomed" and hated longer cables. I added some FAT speaker cables and a FAT power cable. It was like night and day between the first 2 hours vs a week later with cables. I actually kept the amps.. Powerful too, man alive!! Oh they like a good power supply to. I added Triplite 2400 to maintain 120vac, too that was an eyeopener when I drove 100-300hz bass columns to over 110 db, with no audible distortion.. Without they got hotter and did distort at 10 minutes or so. After the maintainers.. 15 degrees cooler with the same ambient temperature, sound wonderful. I moved to 12Ks they will pound the poop out of your ears. Best bang for the buck on the planet.. I have 4 LOL NU12000s. I can't break one! Where I live class A stopped when I hit 55. :-) 115 degrees is not uncommon where I live. Class Ds are king. Preamp are usually valves, here. I need a warehouse!!! "The Church of Sound" nonprofit. :-) |
Yes, Riley this has been said many times. Also, I think we all know the general idea that some stuff likes to be warmed up before use. I was, however, looking for more of an explanation as to what is going on in a Class D amp, if anything, that increases the need for more idle time. For example, I think lots of us will agree that a tube amp warms up enough after say some range--30 minutes to 2 hours--at which point it’s warm and sound performance doesn’t improve anymore. But, with Class D, it seems to many of us that 30 mins to 2 hours might not even do it. So the question is why? Many folks seem to believe (and I think that includes me) that Class D may need more warm up than say a Class A/B amp. Why would that be? That’s what I’m asking. I wasn’t looking for the garden variety basis--hey warm up your car, snowblower, etc. and it works better. I wanted to know what is it, if anything about Class D, that seems to give better performance if the unit is nearly always on or on for hours upon hours. Is there something specific in the topology of this type of amp that lends itself to far more warmup time or always on status? It's a fascinating technology and I was looking to learn more about that. |
Thank you @oldhvymec . I have a nice tube preamp here that I may drive the Marantz ruby with just to see how valves fronting Class D sounds. I did that once before with an NAD M22--I put a Schitt Freya in front of it and it sounded great that way, yet sterile on its own. The Ruby was voiced by Ken Ishiwata and he really dug tube amps, holographic pictures of sound and 3D imaging. So it's not as dry as that NAD that I had.
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Next time I'm 6 drinks in and talking hifi with someone who cares or is not bored of me, I'm going to say this plebeian thing.... When Class A/B idles, it's only running at say 1000 rpm--to use a motor analogy. When Class D idles, it's only running at say 100 rpm. So, Class D needs longer idle times to keep stuff warm because its rpms are so low. PS. I have a masters degree in BS, but it sounds good. 🤣 |
mrskeptic what is that suppose to imply? That you're tough to please or everyone on AG has a lack of some type of higher education. A higher education doesn't always equate to wisdom about a subject. Nor do fact that others have obtained in their class rooms always stand the test of time. Science is malleable these days. Just depends where you look and what you chose to educate yourself with. Me I'll try anything at the neighbors house. I have 2 2" fire hoses I can hook to the hydrant in 2 minutes, FIRES OUT.
Science at work, hydraulics 101. And be nice, your a newbie. Sure you are.. :-) |
A stiff back would be a reason to leave them on.
Ok then,,, just try it both ways for a month. You’ll get people that swear upon stacks of holy books that it makes a difference. And others that don’t. (Personally - I doubt it matters) And they use such little energy that if you left them on all weekend I would not feel guilty about things like the climate… so you could power them off M-Th and leave them on Friday through Sunday… there are no hard-n-fast rules. |
@mrskeptic , good point, but there are many here who know a good bit about amp topology, engineering and so on. Maybe this site is too subjective for you? Have you tried AudioScienceReview? That's a special place over there. $500 Topping amps that measure better than D'Agostino are gospel because of their objective stats. 😏 |
I may need to restate my original point. While sure, I leave on my DAC, in terms of amplifiers, no solid state amp I’ve never owned takes as long to warm up as my Class D amps. It’s not even close. My A/B amps have taken no more than an hour while D takes days. You don’t even have to play music. Just leave them on. Good thing each monoblock idles at about 5 watts! What's funny is how some of these conversations develop on A'gon: Poster: I came back home and my system sounds like crap and I don't know why, help! Me: Are you using class D amps? Poster: How did you know?
Best,
Erik |
The issue of leaving a class D on all the time vs. turning it off is probably more dependent on what the Class D amp is. I have had experience with Class D amps which use ICE output modules and I never liked them. Those amps definitely seemed to smooth out if left on to warm up for an extended amount of time vs. just turning the system on and using it. However I found the upper frequency range to be harsh even after warmed up; it was better, but it grated on me with use. I am currently using a pair of Anthem M1 mono block Class D amps. This is a whole new world vs. the ICE based amps. The M1's do not use any devices such as the ICE modules, it's all proprietary design and liquid cooled. The M1's play super smooth at all times, I don't need to warm them up and I don't leave them on; it makes no difference that I can hear. I prefer to leave them off and unplugged from the 240volt outlets when not in use just in case of storms or surges. I do not trust surge protection devices as I have had major destruction due to lightning hits. I also own a Parasound A 51 which runs in Class A up to a certain output power before is swaps over to Ab. That amp seems to like some warming up to smooth out, but even when at a fully warmed up state of operation, it doesn't come close the M1's in performance. I use it now to drive surround/rear/middle channels when using streaming music or HT films. For two channel stereo, the M1's do the heavy lifting.
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If you’re listening regularly the answer is, because it sounds better. If you seldom listen to your system, turn them off. But if you listen to your system on a regular basis, and you care about the way your system sounds, leave your class D amplifier turned on. Yours in music, Ted Denney III Lead Designer/CEO Synergistic Research Inc. |
@aj523 , I love it. I’m really starting to think that several of the nice class the amps I owned before we’re not really given the best opportunity to perform as I did not leave them always on |
