Krell has a system for adjusting bias.
1 Like
Well it getting more interesting guys, as last night i plugged all my naim back together and left it powered up.
Also this vitus left on and not in standby does wack the heat out and i must admit i was abit concerned about it, as leaving it on all the time so its at its best when needed is recommend, but this is going to use quite a bit off electric and not that happy about leaving the house unoccupied with it like this.
I was told last night to switch it to A/B mode when not using it, so i did last night and the difference in temperature is huge, still warm but much better. Apparently it will need about half an hour to get back to almost full performance, but full performance will take longer. Thats a bit off a negative for me, but its a class A thing and i need to live with it or dont have it.
So with that nagging at me and me thinking about it all, i decided to plug the speaker cables back into the 500 and see how it stack up. Before i do, got to point out that the vitus is in the rack and the naim is on a small table infront offthe rack, so the naim is not optimised, but the cables are all hanging ok, etc, its just that the 4 boxes are all on top of each other, with the 552 top, 500 next, 552 ps and 500 ps on the bottom.
So off we go, London grammar first up, the naim straight away sounds different, her voice is just not as clean, sharp and now sounds dull, the instruments the same, the bass sounds the same and certainly not the huge difference the rest sounds. So quickly swap over the speaker cables back to the vitus and yes its a huge difference, so much so i canât believe it, yes i know the naim is not set up 100% and would sound a bit better if it was, but its not going to make up this gap, plus the vitus wasnât warm either and only just turned back into just class A.
My wife, that doesnât really get involved in it all, said the difference was lovely and she did think i was being silly about messing once again with my hifi, as like she said i thought you had finished with swapping bits now.
But the nagging heat problem, i need to over come as i canât go back to my naim now, not now i have done this quick test, but going to leave the naim on for a few days, to see if it can close that gap, but i think the vitus will pull even away once it has warmed up fully, as the difference in class A cold or warm to hot is also noticeable.
Just interesting as i didnât think the difference in sound was that great, yes i knew it was different, but this is quite a big jump, its certainly not cable swap difference. Its now dull sounding the naim is in comparison and even a bit flat, i was expecting to miss the engagement from the naim, but infact it was the other way round, quite strange i think.
Anyway like i said i am going to leave the naim powered up and also get another table, so i can put the 2 power supplies on one and the 500 /552 on the other, they will still be sitting on each other, but i think thats the best i can do. That i feel with give the 500 a more fighting chance to recover, but i feel its a losing fight, as its like a middle weight boxster up against a heavy weight, but we will see and its only fair. I know you 500 guys are not going to like what i have put above, but i can honestly say that is now it is right now.
Cheers dunc
9 Likes
The 552 is hugely sensitive to placement, with its internal suspension. If you are going to do the final comparison with the 552 sat on the 500 and on a table you may as well box it up and sell it now. Itâs simply not a fair comparison, which I think itâs important that you make. Given the nature of the Vitus Iâd suggest you find a way to have it on the top of one of your racks. You donât want a fire!
If the Naim was back on the rack and the Vitus on a piece of wood on the floor, and you still clearly preferred the Vitus, it would be a much more conclusive result I feel.
4 Likes
As i said i will give it a fighting chance, but the difference is too great i feel for it, the vitus isnât going to set fire to itself or the rack, its not that hot, its just much hotter than the 500 ever got.
The vitus can be sat on the floor no problem as it has stillpoints and you can sit it on anything and its not affected apparently.
Think i will sit the 552 inplace off my P10 later, as that will be even better placed than it was when it was in the rack.
ââŚI thought you were finished with swapping bits nowâŚâ 
1 Like
Now letâs not turn into the 2 grumpy men on the upper circle in the Muppet Show HH. 
ATB Peter
Dunc is so going to end up with an SIA-30! The temptation to try one after the SIA-25 will be too great⌠
4 Likes
Perhaps - but then it will be said, perhaps fairly(?), that speakers better than the Fact 12s will be the order of the day.
âŚwot a game this is.
1 Like
Not as much of a contribution as the removal of people who think like this.
.sjb
2 Likes
Thatâs a lot of changes to make at once.
Will be hard to make a simple comparison of the 2 amps with all of that going on.
I really think he should. It may even be he prefers its optional internal DAC to the Rossini. Iâd certainly be tempted to give it a try in his shoesâŚ
1 Like
When I replaced my 250 with a 500 I put the latterâs power supply on the rack next to my 552 on a shelf half a step higher with a 555ps below it. I found I wasnât enjoying the 500 nearly as much as I had the 250. The 500 went off for a service and DRing and the 250 went into the brain stack where the head unit had been, the music was restored to its former glory. I put this down to the 500 needing a service but when it came back the music left again, until I moved the 552 up a shelf when the system started showing just what a 500 can do. Unfortunately Naimâs multibox approach, particularly at the 500 level, needs a fair bit of cosseting to give of its best and can sound very ordinary if it doesnât get it. Itâs not just a little bit off, itâs WTF have I wasted my money on off.
Now Iâve no idea if the Vitus integrated can beat a 500 system at its best or only wins if the Naim setup isnât quite there; or it may be a question of system matching. It may well suit the DCS and PMCs better than the Naim. Iâve only heard Vitas at Munich in 2018, I forget with what speakers and the Naim rooms at that show sounded embarrassingly bad. Based only on that Iâd have picked the Vitus (or more likely the Kondo, their room was one of the best). Its a big step to sell on a 552/500 but if its not earning its place that may be for the best. Youâd want to be sure though.
3 Likes
If you can afford it and assuming you have the space, you can always keep both Vitus and 552/500 for say 2 to 3 years and swap them around systems. That way you will have plenty of time to decide which one will eventually need to go. No hasty decisions. You may end up keeping both too, using both amps in different systems.
2 Likes
âŚsilly comment but to be expected these days, I suppose. Given itâs de-rigeur for Naim users to leave their gear powered up at all times should you not be throwing stones from your glasshouse? Disappointing that even such a long thread of great posts isnât immune to someone throwing an offensive remark.
2 Likes
One other thing that may be worth bearing in mind @Dunc and please donât take this as some snide snipe, which it isnât, but are you sure your 552/500 are OK? I remember you commenting on having found little difference between the NDS and ND555, which surprised me (I would never have swapped my CD555 for an NDS despite really wanting to get rid of all my CD jewel cases, but did so readily for the ND555). If this was in your home system rather than a dealers, this could be a valid question⌠Otherwise itâs maybe a red herring.
1 Like
Dunc If I may ask, how are the 552 and 500 plugged into the mains
do they have they own wall sockets, or going through some kind of mains extension
I leave my SIA 030 on 24/7 , on Mute in A/B mode at zero volumeâŚunit does not run hot at all. Very much doubt that it is burning more coal than a 552/500 left on 24/7
4 Likes
That made me chuckle out loud.
silly? offensive? I suppose thatâs all perspective. Certainly I have given strong consideration to my use of Naim 24/7.
.sjb
1 Like
I worked it out last year and from a fading memory, I believe the dual PS 555/ 500/ 552 uses about 170watts/ hour altogether. ATB Peter