Electronics that must stay "on"

[dennisE]

Who understands the physics of this? I am an engineer, all practical and all. I have had to re-learn this many times over the years. Some stuff must be hot, that is, it has got to have been on for a day or more to sound "good". My best example is a Benz Lukachek I have owned for 10 years, it is one of my backup phono stages, not user adjustable, high output for MC only. I've never owned a Benz cartridge. The other day I pulled it out of the closet and hooked it up to a DD Micro Seiki wih a Denon 103N in my garage system. Wow, it sounded so bad I turned it off and walked away. I left it powered up, however. Why haven't I sold that POS after all these years? I have owned and sold many phonostages over the years, why is this thing still here?

The next night I tried it again. Wow, different story. I touched the little chrome box, its hot, powered by a wallwort. Oh yeah, I remember, it must be hot.
I am not into subtle differences, if I hear it, anybody can. Of course, MC phono stages deal with tiny signals, it that it? I don't know, but there it is.

D

 

[audioarcher]

I have a Plinius M-14 phono stage as a backup. I recently hooked it up and initially it was not great. After a couple of days it was much better. From reviews I have read it is mentioned that it sounds much better after being on for a couple of days. I'm not sure why that is but it is certainly true for this piece of gear.

I generally leave any solid state gear in my system on 24/7. The only SS gear I use now is my amps and a Linn Ds.

Sean

 

[treitz3]

Any SS amplifier from Klauss. As soon as they cool down or are unplugged for more than 2 or 3 minutes? Might as well walk away for three days. Day two is actually worse than day one. Somewhere close to 36 hours into it being plugged in? Everything falls into fruition. I got rid of mine due to the excessive amount of lightning storms we have here.

 

[mep]

I generally leave any solid state gear in my system on 24/7. The only SS gear I use now is my amps and a Linn Ds.

Sean

Ditto with the exception of my Krell KSA-250. The KPE Reference phono stage has no off-on switch and nor does the KBL preamp. That's a sure fire hint that Krell intended for you to keep these powered on 24/7 and they clearly state that in the owner's manual. My HT system has an older Denon AVR and it has never been turned off except when the power goes out.

 

[DonH50]

There are changes in bias and various other device parameters with temperature, and more subtle effects with voltage (e.g. capacitor hysteresis). That said, a substantial change to me implies poor design, although I admit not everyone is designing things that have to work perfectly a few ms after turn-on whether the temp is -55 degC or +125 degC.

 

[treitz3]

Poor design or thermal precision matched heat sinks that are beyond the norm? In other words, it takes the unit time to reach the optimal parameters of all of the associated electronics to yield what the engineer designed to begin with to yield sonic bliss from that particular unit. Without optimal operating temperatures [sometimes taking days] the end result as to what hits your ears is not what the engineer designed for you to hear. Both the instant great sound and the days to great sound have their own sound signature, attributes and deficiencies. At least in my experience.

To say that the substantial change implies poor design? Eh, I see where you may be coming from but I have to agree to disagree.....or possibly ask if you have heard gear that takes up to 3 days to get up to snuff?

All due respect,

Tom

 

[DonH50]

Not sure about 3 days (not that I recall) but have never claimed to have the system and ears the rest of you have. I have had components that change over a period of hours, usually tubed (but not always). My old D79 was one of them; despite a fairly complex power supply it changed pretty dramatically the first ten minutes, somewhat over an hour or so, and would measure just a little different a few hours later before essentially flattening out. I was able to measure the changes if I took the time and effort. Other components would change very little from a few seconds after turn-on to hours later. I don't usually leave stuff on for days and am not sure I would trust my ears to say the sound was changing day to day due to the electronics, my own body, the weather, phase of the moon, or whatever.

I am not sure what precision matched heat sinks have to do with it? Poor design in the sense that there is obviously some sensitivity to bias and/or thermal changes in the component. "Poor" is probably a poor choice of word; some designs are minimalistic and do not have the bias circuits and other components that are required to achieve a high degree of insensitivity to PVT (process, voltage, temperature) changes and other effects. And, "optimal" is hard to define as there will always be minute variations in performance over time. Nothing's perfect, entropy, and all that jazz. Finally, if it is that sensitive, does the sound change if you cycle the HVAC? What if the room temp changes 5 or 10 degrees? What if the line voltage sags a bit, or you shine a light on the case? Where does it stop?

Stuff I designed usually had all kinds of tweaks for stability over process and environmental changes. The higher the resolution, the harder it was, and the less likely to stay tweaked over time or other changes. I have never worked on something as high as 24 bits (or rather, worked on stuff with that sort of dynamic range, but have not personally designed more than an 18-bit DAC, albeit one that targeted 100+ MS/s).

I do wonder if the equipment settles in, or our ears, but am not competent to say. I honestly don't know either way, but it would be very interesting to characterize the performance with test equipment over say five days and see what changes. I am curious about that...

No worries - Don

 

[Bruce B]

Any "vintage" equipment that I have in the studio gets left on. The Pass amps do as well. Good thing I have AC!!

 

[DonH50]

Only vintage equipment left in my room is me...

I have seen a lot of components that shift over the first hour, and it has pretty much always been because biasing changed significantly. Tubes were nearly always the worst because the tubes themselves vary as they heat up (they are thermionic devices, after all) and because tube gear often had the simplest (and thus most likely to vary) bias circuits. Hot-running SS gear, which included a lot of pro gear fell into the same category (simple signal path design, simple power supplies, high biasing to provide clean sound at high output levels -- preamps, processors, and power amps).

 

[JackD201]

I was in and out of town for three weeks. The days I was home, I had no listening time down stairs. When I did get to fire the system up, I was definitely not satisfied. 10 Hours of continuos play and all was right again. Weird thing is, if it's only a day or two, it normally doesn't take more than a couple of hours, an hour playing while I'm out of the rom is normally enough.

I don't leave my gear on 24/7. They consume a lot of electricity at idle. It hurts my electricity bill A LOT.

 

[amirm]

I have to side with Don. Any equipment that doesn't approach its target performance within a few minutes of being turned on is not designed right. Nothing extra should happen after hours and days of being on. If there is, why would it stop? It would keep drifting and drifting...

 

[asiufy]

That's why I love my darTZeel gear
It's good to go within 5 minutes of turning it on. It even says so in the manual!


alexandre

 

[Bill Hart]

My Lamm line stage (L2) definitely sounds better after it has been on for some time. It is an odd bird, in that the audio path is solid state, but the power supply is tube driven. I always assumed it needed time because of the solid state circuits. Vlad apparently recommends that it be kept on all the time to reduce stress on the power supply tubes. I do know that when I pull power due to electrical storms (and we have had quite a few this summer already), it takes a while for it to get going again, once I plug it back in.
As to warm-up, I was never sure that simply leaving stuff on all the time did much once the circuit-capacitors, etc. were fully charged. But playing the system for a while (rather than just letting it idle), does seem to make a difference. All the rest of my equipment is tube (phono and amps), so what circuitry changes are occurring there? Anything to do with the transformers?

 

[DonH50]

It's more likely the tubes as they are changing the bias conditions for the SS circuits.

Transformers are very unlikely to change significantly, I certainly would not think enough to be audible.

 

[JackD201]

I have to side with Don. Any equipment that doesn't approach its target performance within a few minutes of being turned on is not designed right. Nothing extra should happen after hours and days of being on. If there is, why would it stop? It would keep drifting and drifting...

Tell that to my ML amps too Amir.

 

[DonH50]

I wasn't going to name names... Let's just say I have heard and measured some very expensive class-A monoblocks that would shift significantly over the first hour or so as the circuits warmed up. When asked, the designer said he wanted a simple bias scheme and as little in the signal path as possible so made the trade of stability vs. best sound (for him). Sort of proves everyone's point... That is why I said "poor" was not the right word choice. To me it is a "poor" bias design, but it was exactly what the designer intended, and he understood the consequences. These days there are fairly cheap, extremely accurate and stable references that with proper design should minimize any such shifts. However, not everyone designs bias circuits for a living, including me, and the simplest things can turn in to hairy design efforts very quickly. Properly biasing a high-power amp is not trivial.

 

[joeinid]

That's why I love my darTZeel gear
It's good to go within 5 minutes of turning it on. It even says so in the manual!


alexandre

+1

It's 95% at turn on and 5 minutes later even better.

 

[treitz3]

Poor design or thermal precision matched heat sinks that are beyond the norm? In other words, it takes the unit time to reach the optimal parameters of all of the associated electronics to yield what the engineer designed to begin with to yield sonic bliss from that particular unit.

Sorry fellas, please allow me to clarify. That didn't quite come across the way it was intended too.

In a discussion with a fellow audiophile a couple of years back, we were discussing why it would take three days for Klauss' Oddysey SS amplifiers to sound their best. Now, I'll be the first to tell you that I am definitely not the authority when it comes to the electronics and how certain things affect the end result as to what hits your ears [the audio]. What I do know is that temperature can change the specifications of the outputs of some electronic gear. Working from memory, Klauss' amplifiers had close to 20 transistors that were all coupled to two very large heat sinks. One to the left of the amplifier and one to the right. The heat sinks were so large that they were actually the entire sidewall of the amplifier. Each one was about 6" tall, had fins that reached out maybe two inches and ran the entire depth of the amplifier. They basically held the amplifier together.

Our line of thinking during this conversation many moons ago was that if the transistors may have "operated" at certain temperatures, sonic fruition was not achieved until the fins were up to temperature [which, in theory, took three days due to the size and mass of them]. When the fins and the transistors were both at optimum operating temperature, then and only then would the amplifier be playing to what Klauss had designed. I'd like to remind all of you once again that I no longer have this amplifier due to having to unplug it so many times during the summer because of the frequency of the lightning storms we have here in the Carolinas but I am curious to find out whether our conclusions of that conversation were correct in assumption or whether we were completely off base with our thoughts.

I'm willing to concede that it may have been a poor design but at the time, it sounded great after the third day. I'm curious as to why and I'm hoping that someone with more knowledge than I on the subject would be so kind as to shed some light on the subject. Was it actually a poor design or just the way that the designer engineered it?

Tom

 

[Gregadd]

I don't mean to pick a fight. Or maybe I do.

Humans and machines have an optimum operating temperature. Whether you need to keep something on all the time is dependent on how quickly you need to use it after turn on and how long it takes to reach that temperature. Many ss devices have a standby mode. They operate an idle current making it easier for instant on and to prevent voltage surges on power-up.

So turn it on and go hoist a few. Pay a source. It should be fine when you come back.

 

[treitz3]

Well, the Oddysey amplifier had a power switch but it was very inconveniently located in the back. Klauss even mentioned several times in his manual that it was designed to be kept on 24/7. I dreaded unplugging it or even turning it off for more than two or three minutes. The Musical Fidelity AC3r Dual Mono amplifier I have now? I turn it on and she's good to go from the get-go. No more waiting. The longest wait I have right now is waiting about two minutes for the Dodd MLP tubed pre-amp's relay to kick on [safety feature as to not introduce a DC pulse]. 2 minutes I can deal with. 3 days? Not so much.

Tom