View Full Version : marble under Mana
A mate has a 5 shelf Mana rack on a large Soundbase which in turn is on a marble slab on top of his laminate floor. LP12, Ittok, Troika on top. All was well with his Black Cube SE with sub bass filter facility. So he buys a Linto, loves it but it would seem to have no bass filter and when he turns the volume up just a bit there is a layer of crap/sludge in the background as in infra bass feedback. Itīs your laminate flooring says I so we sank 4 great screws into bronze bushes/rawlplugs through the laminate into granite tiled on concrete floor taking care that the screws did not touch the laminate. So effectively we removed the laminate from the equation. But the sludge continues. Any ideas ??? the only thing I can think of is the cartridge suspension - I must admit it does ride a bit low but Murphy canīt be that much of a swine, can he ? Or is marble a no-no under Mana in your experience ?
Would be grateful for any tips.
Chris
Could it be that is just how it sounds?
Thanks for moving this Marco. I didnīt know where to post.
Chelsea,
I take it you mean that mana might always sound like that or this particular combination. From my own experience I know that Mana does not always sound like sludge but I, myself use soundstages and a mini table only - my doubt is about using the marble under a Mana rack.
Reid Malenfant
20-03-2012, 20:26
Seems to me as though the removal of the high pass filter that removed the subsonics is coming into play here. Phono stages while different are not that much different. A subsonic filter will make a huge difference in removing garbage that eats up amplifier power, this may well have some effect on just about everything else that you can hear.
Get a good look at the bass speaker cones when a record is being spun next time you are there. If they are moving in & out at subsonic frequencies it's quite possible that you may be hearing intermodulation distortion caused by this further up the frequency range.
An average bass or bass/mid driver will have a linear travel of 4mm each way. If the speakers are a reflex design & are moving anywhere near this then you'll get non linear distortion due to the cone excursion & this will also be heard up to the crossover frequency of the next driver up...
Yes, cone travel is quite marked. The merest tap on the LP12 plinth means the woofers almost jump out from the boxes. And we are talking 3-5 inch Totem Arros here.
Hi Chris,
How's it going, matey? Long time no hear! I hope you are well :)
Sorry that I haven't had a chance to reply to your PM, but things have been hectic, with one thing and another, so I may as well answer your query here! Cartridge suspension aside, what I think it may be is that Mana racks don't particularly work well when sat on a hard surface (creating a 'ringing' effect with the glass shelves), therefore the marble will be doing it no favours whatsoever... :nono:
Mana tends to work best on wooden floors (not directly onto laminate, though, of course), so that there is something for the spikes to 'bite' into. Therefore, what I'd do is whip out the marble, and all the rest of the gubbins you've used, screws, etc, and put the rack on top of a thick and heavy piece of MDF (perhaps painted to compliment the colour of the laminate floor). Make sure that it is fixed into position as level as a very level thing!! The weight of the rack and equipment on top will keep it securely in place.
If you have a spare Mana board, from a Soundstage, you could try that first and see if it helps, before buying the piece of MDF. If it works, then go along to your local DIY store and buy, say, a 2" thick piece of MDF, wide enough to support the rack properly, and this will basically act as the 'floor', giving the rack the material interface it prefers, which should improve the sound significantly.
Whether this completely cures the problem, I'm not sure, but it should certainly improve how the rack performs, and thus the equipment placed upon it.
While you're at it, make sure that the spikes at the bottom of the rack, making contact with the MDF, are as short as possible: i.e. most of the thread has been screwed into the base of the rack, and only the minimum of spike, in order to ensure stability, is left exposed - and then ensure that they are NOT over-tightened, and simply 'nipped up'.
Incidentally, the above applies to all spikes used, particularly the ones underneath the glass shelves: minimum spike exposure and nuts only gently nipped up, with the spanner, from a position of being finger tight. Anyway, try that, and see how you get on! :cool:
Marco.
ursus262
21-03-2012, 13:20
This is interesting, because I have a suspended laminate floor, and I have considered putting sorbethane feet under it, thus isolating it from the floor. I've already done this with my speakers with positive results (not so much boom or sludge). Would this have the same effect?
My rack isn't a Mana, by the way, but I'm wondering if the principle is correct.
Dave
Thanks Marco.
Piece of mdf duly placed and things have greatly improved overall but the CD is still well ahead of his vinyl. His LP12, Ittok , Troika/ Linto sounds very small and little bass and strident highs. Assuming we can take the Mana out of the equation now, all I can think of is that the cartridge suspension has somehow "gone soft" and the basic Troika/Ittok combo has become a mismatch. The Troika certainly seems to ride very low compared with mine. I would say there is barely a millimetre between the "bulge" of the coils package and the record surface.
What would be the sonic effect of excess suspension compliance if he still tracks at the recommended 1.8 grams ?
Hi Chris,
Yup - sounds like the Troika is fooked! I suspected that might be the case... Still, at least the overall set-up sounds better now :)
All is not lost, however, on the Troika. My advice would be send it to Dominic Harper, of North West Analogue, see here: http://northwestanalogue.weebly.com/
Fixing the suspension would be a piece of piss, for Dom, and it wouldn't cost the earth. You could even have the cartridge re-tipped, at the same time, and it'll come back sounding better than ever!
Honestly, Dom knows his stuff, is a smashing chap to deal with, and his turnaround times are rather quicker than those of Expert Stylus!! ;)
Marco.
Dominic Harper
23-03-2012, 17:15
Cheers Marco, some repairs are easier than others, thats all I will say on the subject! lol
Joking aside, the Troika prob just needs a tweek to the suspension, but I would need to see to confirm.
No worries, matey... Maybe Chris could send some pics? :)
Marco.
Chris, have you asked about this before - but with regard to the woofers on his Totem speakers flapping? I don't remember any marble slab then?
Hi, Itīs been a slow process - Since then the amp has had a new volume pot fitted and all the internal earths checked at Patrick of Sugdenīs instigation. The marble slab was placed on the heads of the four screws we had sunk into the concrete floor under the laminate without touching it. Now the Mana is on an mdf slab on top of the marble slab. It now seems quite obvious that a mana RACK is a different kettle of fish from my own multi soundstage set-up.
Iīm going to take my test disc round to his house to see if the re is a resonance problem in the Ittok/Troika arm/cartridge combo which would then presumably point to the cartridge suspension as the culprit.
PS.
The Arro woofers still flap, and after fitting the mdf into the puzzle perhaps even a bit more then before. Itīs this movement that actually diverts your attention from the sludgy background noise and lack of bass.
Chris, I realise that this may not be easy to achieve, but could you possibly try the LP12 sitting directly on the marble slab (resting on the screw heads) and remove the Mana stand entirely from the equation.I realise this is not a practical long term solution, but it would be very helpful to remove on of the variables in this way.
Iīll see what can be done. Moving a Mana rack is about as tempting as a hole in the head. My mate has had to go out with the family this weekend so itīll be during the week.
Thanks for the interest.
Well, we placed a simple mdf board on the marble and the rack on top of that and it has definitely improved. He still needs to shorten the downward pointing spikes etc. and then all the upward shorties under each glass shelf so heīs got his work cut out but itīs definitely sounding better already. This must be a rack thing īcos with my stack of soundstages and a mini-table on top of course I have several boards in between even though my downwards pointing spikes on the bottom stage are straight into the granite-tiled (and hopefully) solid floor.
Thanks again Marco
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