Conrad Johnson Owners.com

Hi...I have used HRS damping plates to good effect with my CJ preamp...and am currently testing out Artesania damping plate which was new to our local dealer. Also excellent. I have heard putting some kind of isolation under the CJ preamps is also a great improvement. Anyone else try this? I have not yet. What have others found to be successful?

ll21,
When you are talking about dampening plates, are you talking about internal dampening or external? When I did my phono preamp mod, which can be seen here, I used dampening for the internal case. You can see this in the picture below and in the link I just referred to. Maybe you can post a few pictures so I can see exactly what it is and how you employed it's use in your system. I look forward to hearing about your results with these. I'm always looking for innovative ways to get every last ounce of performance from my system!

Interesting...i have only done HRS damping plates, nimbus/couplers, Finite Elemente Resonance plates (dont work well imho), and ARtesania damping plates...which work really well. I also think EAT Tube dampers are incredible. My rack is 4" thick shelving of birch ply, laid on top of 1" slab of slate. Relatively inert, and with the HRS couplers, a nice result.

In all honesty, even though I put dampening material into the unit when I was doing the various upgrades I'm not sure how much it really helped (if at all). I know there is a lot of debate in the audiophile community about whether vibration dampening in electronics (other that turntables) really makes a difference. When I first started this hobby I was a doubter of many things, including speaker wire, interconnects, etc making a difference. However, when I upgraded my interconnects the sound in my system totally changed (for the better) and then I decided to give these things another look. I now have many of these audiophile voodoo aspects in my system including dampening, custom RCA cables, cable risers, amp stands, high end power cables, etc. I think many don't effect sound, some may have a small benefit, and some have substantial benefit (most notably the interconnects). At the end of the day, when your sinking thousands (or tens of thousands) into your stereo it's worth experimenting with these "relatively" inexpensive avenues of possible sonic improvement.

Agree...it also depends on the equipment. I found my CJ GAT definitely benefits from having a damper on top...and a few have said it benefits from some form of absorption underneath...A10U8s or HRS Nimbus Couplers/Footers.

My tube DAC is even more sensitive...that things has HRS stuff below and on top. But my SS amp...no difference. And Finite Elemente REsonators...got 'em cheap and glad i did not pay more. i use them on GAT...on top of tube pyrex...marginal but using mainly because i've got them. EAT tube dampers made far bigger difference.

I just went to the HRS site to check out their products. They seem really nice. It seems my nearest high end audio store is one of their official dealers so maybe I will ask about them the next time I am there. I use jelly isolation feet for my CJ amp but I've never done A/B comparisons as they came with the amp and it weights 115 lbs which makes it a hassle to lift and move around! It would be nice to get some isolation feet for my CJ PV12 and a set for my phono preamp. Definitely something to think about.

Good luck. I think HRS is excellent and probably my favorite all around isolation/rack manufacturer. I have not heard a lot, but HRS stands out for me.

Now I just have to make some plans to get down to my local high end audio store!

I find removing the covers for CJ preamp works the best. The metal covers form a giant low level; capacitor in relation to the circuit board and tends to roll off the extreme top end. I make covers out of plexiglass and drill as needed for cooling and that seems to work well sonically and still have dust rejection.

For the bottom of the later CJ preamps with the easily detachable bottom cover, the effect is even greater as the metal bottom plate is even closer to the PCB, I use a 3/32, 18 inch plexi for the tops and a 1/4 inch thick piece for the bottom.

The benefits are not only sonic but it really shows off the internals and CJ does use some of the highest quality parts available.

Stu

unclestu52 wrote:I find removing the covers for CJ preamp works the best. The metal covers form a giant low level; capacitor in relation to the circuit board and tends to roll off the extreme top end. I make covers out of plexiglass and drill as needed for cooling and that seems to work well sonically and still have dust rejection.

For the bottom of the later CJ preamps with the easily detachable bottom cover, the effect is even greater as the metal bottom plate is even closer to the PCB, I use a 3/32, 18 inch plexi for the tops and a 1/4 inch thick piece for the bottom.

The benefits are not only sonic but it really shows off the internals and CJ does use some of the highest quality parts available.

Stu

Stu,
Welcome to the site! That sound really cool. I didn't really think of taking the metal covers of my equipment. Do you think you can provide some more information about this. Perhaps post some pictures? Also, where do you buy the plexi glass and get it to the exact dimension. I think I could manage drilling holes, but how do you get it to the exact dimension in terms of width and length. You can't just take a hack saw to plexi glass!

I've been very pleased with these little guys:


http://www.vibrapod.com/

They are made by a company that actually specializes in vibration control. They work best if you use them together and they don't cost an arm and a leg. The isolator pods are sold in 4 packs by weight ranges whereas the cones are "one size fits all".
The only thing I would warn you about is to take seriously what they say about letting the isolators sit on a wooden or painted surfaces. From their site:

"VIBRAPOD Isolators and Cones can leave rings on woods, acrylics, and painted surfaces. They may also dissolve the paint, especially if it is lacquer. To protect these surfaces and your equipment please use BAR COASTERS or Playing Cards between the VIBRAPOD Isolators and these surfaces. Wal-Mart sells some 1/16" cork that is also a good alternative. One customer uses this with some goop glue and has had great results. Another technique, for those who buy VIBRAPOD Isolators in 4 packs, is to use the packaging for this. Cut out the dome area slightly below the crease and then cut out the center. Hopefully we will have this as a die cut in the next order of packaging. Another alternative is AOL CD-ROM's."

Trust them on this, they WILL leave a ring if you don't put something (and it can be saran wrap, that works very well) underneath them.

I use them under my cd player but my surface is granite, no problem yet but thank's for the warning.

In regards to the plexi glass covers I made: Simply took off the old covers and measured them and went down to my local plexi supplier and had them cut to size. If you hold the original against the plexi cover, you can trace out the mounting holes to make an exact fit. If no supplier, You can cut the plexi using a regular table saw, although I do use a fine toothed carbide blade (40+) with very slow manual feed.

The newer CJ models all use a modular chassis with the top and bottom covers bolted to the side frame rails. On older models like a model 12 preamp, etc., you have to glue the covers up. I use 3/32 plexi for this and reinforce the corners with a piece of 1/4 inch plexi square stock.

Be aware that if you use polycarbonate which is cool because it is shatterproof, you need to use jeweler;'s type clear epoxy. The regular plexi glue , a solvent, will cloud the polycarbonate.


Stu

@unclestu52

The plexi glass project sounds interesting. I like doing DIY projects. Do you have any pictures of the covers you made so I can see how it looks? I would really like to consider perhaps making some plexi glass covers for some components, especially the tube based ones like my PV12. I like to see those beauties glow but they're not visible currently. Thanks.

agree...this plexiglass thing seems quite cool.

I am a cheap Errrr Frugal person. I used the asphaltine foil backed flashing tape from Home Despot to damping the chassis lid etc. I also had some plate glass cut and placed it on top of some Bubble wrap to stand my preamp on. works for CD players and even turntables.

billyz wrote:I am a cheap Errrr Frugal person. I used the asphaltine foil backed flashing tape from Home Despot to damping the chassis lid etc. I also had some plate glass cut and placed it on top of some Bubble wrap to stand my preamp on. works for CD players and even turntables.

I find that sometimes people can make their own custom equipment and even though it's "cheaper" than a commercially available product, it can be just as good (if not better). I have made some small projects myself (like my speaker feet) that literally cost only a few dollars but I think are really excellent. Same thing with my RCA interconnect cables, relatively inexpensive but great performance. I also like the fact that I actually made them, I take pride in that. Furthermore, it's kind of cool to have something in my system that I know that nobody else in the world is using in their's.

So here is to being "cheap Errr Frugal."

I'm due to receive a set of four Stillpoints UltraMini footers for evaluation this week, and one of the components I'll try them out with will be my Premier 17LS (I may also give them a shot under my MF2500). I've used original-version Aurios and Mapleshade IsoBlocks under the 17 prior to this. The Aurios increased perceived detail, but at the expense of adding a patina of brightness, and the IsoBlocks seem to soften transients, so I'll have to see if the SP Minis strike a happy medium. I'll let you know.

I tried out the initial four-unit set of Stillpoints Ultra Minis received for evaluation under my Oppo BDP-83, and the results were so good that I left them there and ordered two more four-unit sets.

Those arrived yesterday, and I put the first set under the Premier 17LS. To say that the footers achieved the happy medium I was seeking between the Aurios and the Mapleshade IsoBlocks would be a gross understatement. Pick a parameter--bass, soundstage, imaging, detail, grunge elimination, spatial cue retrieval, instrumental/vocal timbre, dynamics, transients, whatever--placement of the footers in a "diamond formation" under the 17LS delivered more than I expected, the overall result being a greater sense of "in the room" presence and musical naturalness with anything from a "good" to "superb" recording. For digital playback, the risers built on the already same-order substantive improvements observed with the set under the Oppo. Vinyl playback was similarly improved--even before I put the third set under the 3"-thick maple platform on which my SOTA Sapphire is parked.

Like metal cones, the Ultra Minis are more internally-generated energy drainers than "isolation" devices. In my application, at least, they do extremely well in that role.

unclestu52 wrote:I find removing the covers for CJ preamp works the best. The metal covers form a giant low level; capacitor in relation to the circuit board and tends to roll off the extreme top end. I make covers out of plexiglass and drill as needed for cooling and that seems to work well sonically and still have dust rejection.

For the bottom of the later CJ preamps with the easily detachable bottom cover, the effect is even greater as the metal bottom plate is even closer to the PCB, I use a 3/32, 18 inch plexi for the tops and a 1/4 inch thick piece for the bottom.

The benefits are not only sonic but it really shows off the internals and CJ does use some of the highest quality parts available.

Stu

Oh that is just a BEAUTIFUL idea. For years I just ran my PV1 naked and cleaned it often for dust. What is your, or any one else's, pros and cons on plex/acrylic vs. real glass. Sad thing is I have literally a ton of 1/4" opaque plex, but I want to see my gears guts, and the pretty lights of course. Did you have any issue with cooling? I am thinking that I will use my 1/4 opaque for the sides with maybe 1" vent holes and a glass top. Opinions?