OCD Alert: Power On Sequencing

Hi Simon,  I'm a bit fussy over sequenced start-ups (as we have discussed before over LAN sequence)  in a previous life I've been hit by some scary speaker noises when powering up PA amps & would never switch on simultaneously & also fearing a MCB or fuse blow. 

But your post has got me thinking - A couple of years ago I was playing CD's & had a power cut,  while I was groping around for a torch that "someone" had moved,  the power came back on.  The SQ wasn't the same,  I assumed the power failure had affected supply voltage & fearful of the equipment I switched it all off - in correct sequence of course -   Voltage check was OK so I switched it back on & the SQ was then OK, I just assumed it was the power supply.

When I have to turn on my system again after some mains occurrence, I always turn the source on first, then after a few minutes I turn the SN's preamp on, then leave it alone for some 15 minutes or so, then I turn the SN's power amp on. Usually the sound quality is what I expected. The rest of the times it is, so to speak, zen.

Hi. Yes I have similar experiences, but many times wigling the snaics, hiline and pulling out and back powercords a little. Sounds crazy but I love it.

Simon, you should never turn on the power amp before the preamp, it's a recipe for destroying your speakers. Is that what you meant to say, or did you do it the other way around?

Hungryhalibut posted:

Simon, you should never turn on the power amp before the preamp, it's a recipe for destroying your speakers. Is that what you meant to say, or did you do it the other way around?

Mike-B posted:

Hungryhalibut posted:

Simon, you should never turn on the power amp before the preamp, it's a recipe for destroying your speakers. Is that what you meant to say, or did you do it the other way around?

+1 .......  hadn't spotted that

This is what I was talking about when I wrote "...... in a previous life I've been hit by some scary speaker noises when powering up PA amps ......" 

Indeed, something I spotted, but presumed knowing Simon's technical expertise, it was a lapse of concentration.

Hi HH no I power up the amp first then the preamp, as the preamp has the mute protection .. Yes if the mute protection fails it is potentially a recipe for disaster otherwise disaster could equally occur the other way around... The amp has has no relay protection as far as I am aware. But I guess my angle was SQ rather than risk management. Certainly my speaker clicks are less this way than powering up the pre first, let it come out of safety and then switch on the power amp.

Simon

All power supplies first, then all sources (and things connected to power supplies), then power amps 

OK I am going to ask a dumb question - how does one power up the preamp and power amp separately in a SN?

I don't understand how the pre-amp's mute can do anything if it's not powered up. Surely if you want to follow that sequence it would be better to disconnect the speakers first, then mute the pre when it has been powered up and finally plug the speakers back in...

Personally,  I always do what my dealers have recommended, which is source, pre, mute, power - and that has always been consistent for SQ as well as speaker safety.

Gents there is of course info about this in FAQ......

https://forums.naimaudio.com/to...d-power-off-sequence

DrMark posted:

OK I am going to ask a dumb question - how does one power up the preamp and power amp separately in a SN?

I've always run switch on   ...... source - PSU (pre) - power  .........   however I don't see any issue on what sequence provided it does not cause a speaker noise other than a soft dfff like noise,  & as such personally I would not risk turning on power amp first as that is the only way to power & zap a speaker.  

Thanks Dusty for the FAQ link, I will try powering on that way as well and compare the SQ effect, I have been a little perturbed before from the level of click into the speakers when powering the amp finally.. but it might have been a transiently thing. I tend leave the equipment left powered up.. and have typically powered up in rapid succession.. The recent benefit and the prompt for the post appears to have come from the pausing between the NAC and the NAP powering .. it might be click aside the sequence isn't as important as the pause.. Wish I knew what was going on... I do have my suspicions however..

Simon

Simon-in-Suffolk posted:

Hi HH no I power up the amp first then the preamp, as the preamp has the mute protection .. Yes if the mute protection fails it is potentially a recipe for disaster otherwise disaster could equally occur the other way around... The amp has has no relay protection as far as I am aware. But I guess my angle was SQ rather than risk management. Certainly my speaker clicks are less this way than powering up the pre first, let it come out of safety and then switch on the power amp.

Simon

 

 

If you get a DR, there is no switch on thump - not with my 250 anyway - just a sort of boing from within the amp itself. 

What about simply setting the volume knob to zero before powering up the amp?

HH, yes 250 DR home demo is on the to do list.

Joerand, why would that make a difference? Certainly on the 252 when it powers up it is force muted by the control circuitry until it's circuits have stabilised. But yes I don't tend to power up with the volume greatly advanced just for common sense... unless there is short rural style power cut, and restore and the whole system will come on together as set.

I've always followed the methodology in the FAQ, although I do sometimes switch on and off the 555 powering the NDS without powering everything down, but mute the pre and select a different source.

We had a power cut earlier this week while everyone was out. Everything was powered up when I got home, but perhaps it's worth going through the full ritual later if that will give me a sonic lift.

Keith

Keith, do let me know what you find please. Thanks

Hungryhalibut posted:

Simon-in-Suffolk posted:

Hi HH no I power up the amp first then the preamp, as the preamp has the mute protection .. Yes if the mute protection fails it is potentially a recipe for disaster otherwise disaster could equally occur the other way around... The amp has has no relay protection as far as I am aware. But I guess my angle was SQ rather than risk management. Certainly my speaker clicks are less this way than powering up the pre first, let it come out of safety and then switch on the power amp.

Simon

 

 

If you get a DR, there is no switch on thump - not with my 250 anyway - just a sort of boing from within the amp itself. 

No thump with my 300DR either. The pre-DR 300 did create a  thump in the speakers.

Switching on  sequence : Sources, source PSU's,pre-amp (552 psu) : switch on mute, select unused source on pre, volume @ zero, switch on power amp.

DrMark posted:

OK I am going to ask a dumb question - how does one power up the preamp and power amp separately in a SN?

Hi Mark,

if you're powering the SN's preamp with a HiCap...

ciao

Max

So I should turn on the HC prior to turning on the back switch on the SN?  I think that is what I do now - the SN back switch is the next to last thing I turn on.  I think the CDP is the very last, although as long as it isn't playing a disc I am not sure if the CDP even matters in the order. (?)

I must schedule an in-person training session in Monza soon!  

Turn on at least one source first  CDP (doesn't need to be playing) or Tuner etc.,  then HC,   then SN (back switch) 

What is the significance of first powering up the (or better, a) source Mike?

DrMark posted:

What is the significance of first powering up the (or better, a) source Mike?

It's just so that any surges caused by the power-up don't get transmitted to the speakers. Everything else should be on and stable before the power amp is switched on.