tube pre amp and Krell FPB 600

12-04-14: Audiolabyrinth
I always get a thump sound over the speakers when I turn my amp off, it's really alot of power, seems normal to me.

I've always turn my amps off before pre and don't get a thump even with a Krell FPB600.

Hi Knghifi, yes, I am going to do the power up and power down that salectric has specified in the above post, interesting, you said that by doing this, I may not get that turn off thump with My krell 700cx that will be back from krell today with up-graded power supplies and along with complete new and improved caps that they installed earlier this year that was not the stock caps that was in the amp when manufactured,I am going to do what you and all have said about power up and down scheme, Thankyou Knghifi.

12-04-14: Audiolabyrinth
Roger Modjeski RM9 and RM 10 tube amps?, mmmm can you tell me more about them?, I have never heard of this!, are they U.S.A. branded, what's the story?

Hi Audiolabyrinth

Here is Rogers' US website. branded as Music Reference

I discuss the rm9 and rm10 in my virtual page. Feel free to stop by and say Hi.

Knghifi, A.L., et al

Re; the amp shutdown noise we have been discussing. here is some more info on it from Krell that sheds more light.

----------------------------------------------------------------------------------------------------

The noise you are experiencing is not a problem with the unit nor is it a byproduct of your AC mains (*). This is normal for large powerful amplifiers that are not “capacitor coupled” (AKA: no capacitors in the signal path or at their outputs).

*Were your line AC to consistently run low (at or below 100v) this could “possibly” (not definitively) cause the power supply to fall slightly out of regulation, which could possibly (again - not definitively) exacerbate this noise upward slightly.

Also, if the amplifiers are turned completely off (including the rear panel breaker) between listening sessions, this will cause the noise to be louder. Leaving the units in standby allows part of the power supply to stay warmed up, thus reducing this noise. That said, should one wish to not leave them in standby due to their power consumption, this noise should never be loud enough to damage the speakers upon turn on or off.

Regards, Patrick

Patrick Bresnahan
Sales, Technical Support, Service

Krell Industries LLC

45 Connair Road, Orange, CT 06477 - USA

Audiolabyrinth, my pre automatically mutes after turn-on and I always mute the pre before turning off the amp.

As you know, components are expensive and heavy to ship so I always operate them correctly.

HI Knghifi, Got my Krell 700cx amp back yesterday from Krell, Talking about holy fricken cow!, this amp sounds incredible with the modds we paid dearly for that appears to be worth every cent!, BTW, I did the power up and power down as specified, no matter what, I still get the not loud at all power thump over the speakers when I turn amp off at the rear panel breaker, I see in the post above this is normal,BTW, Patrick Bresnahan of Krell know's his product very well and then some, A very talented musician too!, we have become good friends over the course of the last 3 years, I talked to him yesterday, I recommend, that if you need any thing done at Krell, Patrick is the Man!, KNGhifi, I will try muting as you have said, that is informative, never tried that,I just turn the volume completly down, is that the same thing?, Oh, up packing the amp and doing re-set up was an incredible feat to say the least, you know, my amp does weigh 180 pounds, took hours, and a neighbor, plus the wife, whom took a vacation day from work to do all this, good thing she did, she was a huge help, I appreciate her, good woman to put up with this insanity.