ARC Ref 6 plexiglass cover

 The proper fix would have been a hole above the 6550 to act as a chimney and vent the heat.  The extra thick cover may solve a symptom but not the problem. The cover is still too close to the 6550 and trapping too much heat. Excessive heat is bad for electronics. For this reason I run my Ref 5se without a top.

You could go to home depot and get some 1/4 inch nylon spacers to put in between the top and the chassis. You may have to get some longer screws. This would stop most dust from getting in and still let out the heat.

@lostbears ...The proper fix would have been a hole above the 6550 to act as a chimney and vent the hold.                                                                        Yes but at least with the thicker plexiglass for those that want to keep the cover on at least it wonlt melt. And i just got dont listening to it for about 2 hrs just now and the top was hot above the 6550 but not where it would feel like it was getting soft for the heat from the thinner original cover. This cover is so much thicker than the original cover that they even beveled the front and 2 sides of it.. Looks very nice too.. I would highly recommend it over the original thinner cover. Also the feel of it is like a piece of thick piece of glass compared to the chintzy thin one.

 Dweller, That is a very good idea. That would help vent heat and still look good.

 tattooedtrackman, I have no doubt the new cover looks really nice. I just wonder how hot it actually gets inside the case.

Dweller... Not more hotter than the thinner cover i would think. 

It will sound better with the cover off anyway. No matter how thick the cover it traps and amplifies vibrations, assuming you don’t have small children I’d remove it

 Probably not. But if the cover is close enough for the 6550 to melt the thinner cover, I have my doubts that the 6550 is getting enough ventilation. Heat build up can cause tubes to age more rapidly and fail prematurely.  I wish ARC had also done something to improve the ventilation. That is my only point. 

@folkfreak  No there are no small kids in the house. But the cover also protects from dust. 

The cover has holes in it, so dust will get in anyway. At least with it off you can see and remove the dust, and if you’re bothered put it back, or another type of cover, when not listening

the metal covers are worse as they resonate in a more problematic range then Perspex, although Perspex has its own sonic signature

btw @tattooedtrackman hope you’re also getting some Herbies dampers. And you might also play with footers for under the preamp as well

@folkfreak .... Yes the Hebies dampers are def on my to do list. And yes i can also take off and put back on the cover after listening . No big deal.. BTW  Just ordered the Oyaide carbon fiber aluminum base covers . WPC-Z2 and WPC-Z to go with with my 3 Furutech GTX -d r 

@folkfreak  What footers are you using for your 6 ?

Marigo Mystery feet F8 -- two sets given the Ref 40 is a two chassis. I also have a SR Galileo LE power cord.

 folkfreak, have you compare the Marigo Mystery feet to the new IsoAcoustics Orea  isolation feet? I am thinking of borrowing a set of the Indigo from my ARC dealer to try.

@lostbears no, I’m waiting on Ron’s latest H series feet and then I’ll let the Fs trickle down to my other components

I would think when they redesigned the plexi cover, it was taken into account, the amount of heat it could withstand.  You are looking for a solution to a problem that isn't there.  Just enjoy the preamp.

folkfreak writes that "[t]he cover has holes in it, so dust will get in anyway. At least with it off you can see and remove the dust, and if you’re bothered put it back, or another type of cover, when not listening"

I own several ARC pieces and they all have metal covers with air vents.  Can't say that I noticed excessive heat, but I'm sure dust works its way into all of my gear.  Why is dust a problem?  Does it affect performance or reliability?

If so, I could always use our home vacuum cleaner (with extension tubes) to clear the dust out.

Thanks.

BIF

@stereo5 ....I agree....ARC had to take into account now when they redesigned the new plexiglass cover about how much heat it could withstand. Wow what a difference . Its at least twice as thick as the original thin and flimsy plexi glass cover., You will not even be able to bend it its that thick. Also the front and 2 sides are beveled because it is higher than the chassis. Makes it look very nice too. Also i have a split system ac mounted on my wall behind the ARC 6 and with the ac on it blows ice cold air on top of the ARC 6 . No heat at all on the top of the 6550 power tube. It feels cold to the touch.. I didnt even think of this when i put my ARC 6 there until i started using the AC. But even if i didnt have the ac on with the new cover i would not even worry about it getting to hot and getting a heat warp bubble on top like my used 5 se when i bought it the first thing i noticed was that warp bubble on top of the 6550. Very unattractive. So now with the brand new Ref 6 and newly designed cover and the ac right on the wall in the back of the 6 i think i got the best of both worlds. Btw my ac split system is whisper quiet.   

@folkfreak   Marigo Mystery feet ...Wow they are very expensive. About $1400 for 3 ? 

Yep, the series H are $2k a set, but the upgrades are audible

the key issue with alternative footers on ARC preamps is clearance under the amp. There isn’t much room between the front of the amp and the raised under cover so larger footers will not fit. Putting the footers only on the metal under cover sounds terrible.  In the case of the Marigo you need to have it half on the frame and half on the under cover which is not ideal but works

@folkfreak ..... Putting footers only on the metal under cover...  I thought you had the plexiglass undercover. Dont you have the Ref 40? 

@folkfreak   I would love to buy the Marigo but i just cant afford them at this time... So i did buy the Vibrapod Cones and Pods for the Ref 6 and for my Rega Isis CDP.. I will see how they work for the time being... I also want to buy the Herbies Big And Tall Tender feet extra firm for my Krell FPB 600 amp when i buy the Herbies tube dampers for my Ref 6

I misspoke in a prior post. The Ref 40 undercover is always metal and stands proud of the frame, there is no option of a perspex undercover. 

You can can get a lot of the benefit of the Marigo footers by dropping a puck of his material under your existing footers and the cost is a couple of hundred. You can reach Ron at marigoaudio@frontier.com

@folkfreak ......... Can you put the footers under the ARC feet? Since there is not enough room between the plexiglass and chassis ? And since the chassis is raised more than the undercover , and then there is the plexiglass bottom cover. Wow i just looked and there really aint no room at all for footers. 

@folkfreak .. This is the bottom of my Ref 6 btw. 

Adding any other  footers under the existing ARC ones would not be a good idea as the sorbothane in the existing feet will fight the new footer. The one option that would work would be small sub based/platforms under each existing foot. Ron sells a set of these, cost is about $200. I guess you could also try an inverted footer that rises to a point like the Synergistic ones (which I have never liked)

As I said I get it to work with two points of contact on the chassis and one on the undercover (the design of the Marigo mystery feet is such that they end in points which is wher contact is made).

I have also tried bits of material above the footer to bring the chassis and sub cover level but this sounded terrible

By the way is the undercover on the Ref 6 truly plexi? If so all my rules about contacting it are out the window as plexi is so much less rigid than the older metal under covers I have, I’m not sure I’d like any footer contacting plexi

@folkfreak  Please look at my system on the virtual systems. Just posted pictures of the bottom of the Ref 6...

I see, that’s plexi for sure. You can easily remove the existing rubber feet which will give you some more room to play with. The bigger issue may be the rear where there is even less clearance behind the plexi. In all my installs I’ve ended up needing the rear foot to be on the bottom plate not the frame.

All in it may be that a set of four feet that screw into the existing ARC holes may be a better bet. The Nordost sort fut can be purchased with threaded adaptors for example.

Anyway as you can see ARC have still not made any progress from the super basic feet their amps have always come with

@folkfreak   I guess ill just play around for now. I did buy the Vibra pods and cones for now and waiting for them in the mail,as my pockets are empty from buying the new 6 lol. But really not sure if they are better than the ARC basic feet.  

Have fun! The Ref 6 should reveal whatever changes you make in feet or platforms.

 what's with the plexi glsss,lol!, no vented quality aluminum? 

@audiolabyrinth it’s an interesting question. Clearly plexi sounds better to ARC, ie performs better in resonance terms, than aluminium. Certainly there’s no cosmetic reason to change out the bottom plate for example. However plexi does have its own sonic signature. Applying a small damping device like a Marigo dot could help but given the mesh design there’s no single place to put it that would damp the whole surface I suspect. 

@folkfreak ....Thanks , I will have fun experimenting... And i was wondering that myself about ARC putting plexiglass on the bottom of the 6. Certainly not for cosmetics. 

Solved the whole plexiglass problem.  Just traded in my Ref 5SE (which had a metal cover) for a demo Ref 6 (only 610 hours on it) .  The dealer had asked ARC to switch out the plexi cover for a "standard" metal cover when he acquired the Ref 6.  So my "new" Ref 6 has a metal cover, … thanks to a smart dealer.  No heat warping problems for me.  lol

BIF

P.S. -- I posted some initial comments about my new Ref 6 as compared to the Ref 5SE.  If interested, you can find them on the other Ref 6 threads on A'gon.   

@bifwynne ............ARC had already solved the plexiglass problem. The brand new Ref 6 come standard with the new twice a thick and beveled edges clear or smoked plexiglass cover . There will never be heat warping with this new twice as thick cover.  The new covers just came out right in time when i bought my new Ref 6 from ARC about 3 weeks ago. And i must say that it is very nice to see inside of the unit and see all the tubes glow when listening and not having to worry about any warping what so ever.. Way to go ARC !!!!!

@tattooedtrackman - I caught that in previous posts.  To each his own. I like the metal cover because I do.  The most important thing is that the problem has been resolved, … which appears to be the case.  Even more important, … I hope you really enjoy your Ref 6.  It is a terrific piece of kit.  
Regards,

BIF 

@bifwynne ..............Yes that is the main thing that the problems were resolved ....And of course to each his own which make this such a fun and personal hobby....I hope you really do enjoy your Ref 6 too!! I know i do..Yep its a terrific piece ...Happy listening !!!