I wake this morning to find the subject that is dear to my heart being discussed..Isolation!
As many of you know I have been experimenting with this since day one. First a cradle to support the amp when in vertical position but of late using the amp flat which I have found slight sonic gains in using that way.
I first went the Still-points methodology route which is to mechanically decouple the amp and transmit electrical vibrations produced by the amp away from it to then dissipate to ground. I tried this with brass and wood (Oak) cones.
What it did in the positive was to give transients more speed and the music felt it had more life and energy. The Amp rested on the Oak or Brass feet which were mounted on a large slab of Granite. My experiments then stopped as the amp had to go back for modification but in that time I started to read about isolation and the various materials and what was best for tubes.
Now, the Still-point route is wonderful for solid state apparently but not so good for tubes so I devised a home made solution combining all the things I had read. In stayed the Granite, out went the brass but the Oak stayed to be modified.
We still need to turn the electrical vibrations to heat so as to dissipate them but we need something with more damping so that the tubes are not too lively. Imagine pinging an old incandescent light bulb, you can hear the filaments rustle and ping and it can end up with the filaments breaking or shorting. Now, the grid in a tube is far stronger but it is still vulnerable to the vibration and as I found out recently in comparing the two approaches there are substantial sonic gains to be made when treating this amp as a home tube amp, not a portable as Gavin has now found. Cork is a wonderful material to both damp and turn electrical vibration into mechanical and thus heat which is easily dissipated
So my method which I covered a while back but will repeat here is to use the granite base as a support. On to that go four large blobs of Blu-Tac (the visco-elastic putty that one puts posters on the wall with). On to this goes a 3/4" slab of marine ply which I covered with a vinyl wrap (the vinyl in my experience stabilized the wood and damped it a little more). This is the top base.
On top of this go three smaller blobs of Blu-Tac on which the Oak feet sit. The pictures below will explain it more but in detail I made the Oak feet into layered isolation feet. The rounded section rests on the blobs of Blu-Tac and the flat base is the support for the amp. On to the base I smeared a thin Layer of Blu-Tac on to which I placed a disc of cork which is approximately 2mm thick.
Two of these feet at the front under each transformer and one in the middle at the back. I have found three better than four as four gives too much damping I have found.
The sonic results are quite remarkable. My "pingiest" tubes are the Marconi's but they are also amongst my favourite in terms of depth, transparency, bass and texture. But they are noisy with the tinging sounds of the filaments (this is not tube noise by the way and does not show a failing tube like rustling noise does) So tubes display more tinging, others less, it just is..
But the tinging was annoying as it showed up every time I turned the volume or moved the cable or touched the case. I can say with this isolation method the tinging has almost disappeared. What this isolation method has also done is create an even inkier black background, tightened up and deepened the bass, given mid's more intimacy and more air to the top end. All the good stuff!
The last part is my "Shakti" solution! I had a small piece of Granite left so coated the base with the cork/Blu-Tac solution and rest this on top of the amp between the transformers. What this has done is more subtle but the improvements are there in terms of increasing the improvements from my isolation idea's.
Now I know this all looks terribly amateur and not slick at all and I am sure that there are far more attractive solutions that do the same thing that one can purchase but I would rather spend the several hundred bucks they cost on another set of headphones and spend what I did which was about $15 in total for this DIY solution. I am sure it can be "prettied up" a bit for the BWFH (as dear old Ken Kessler would say) factor
Hope I have not droned on too much and you found this interesting. Here are so quick pictures!
Oh yes, the Rolls Royce thing is a gift I received for attending the launch party of the new Phantom II last year. I have found it makes a great base to rest my DAP on when listening to the amp! Its made of Oak in the Rolls Royce wood workshops in Goodwood!
