Who's Gone Topless?


The idea of this goes back decades. Amps and preamps (for the most part) are designed on chassis free breadboards, then voiced, THEN are packaged inside a chassis, which can be the weakest link to hearing what the designer intended. In most cases the chassis sidewalls and bottom are essential, but the top?


First off, beware that doing so will likely affect your mfg warranty, but, if you live in a pet-free, child-free home, then the benefits can more than offset concerns about something getting in that could harm the components. Case in point my Ric Schultz Class D EVS 1200, dual mono IcePower 120as2 modules. HOWEVER, unlike others using the same or similar modules, Ric then sprinkles many decades of modifying pixie dust all around them which are mounted inside an understated (sans bling) Italian sourced chassis.

When I ordered mine it was mandatory to purchase 2 Cubes ($200) which are to be butted up against each board, requiring the owner to remove the top. After doing so, I was anxious to put it in my rack so I could properly isolate it from bad vibes, when I should have listened with and without the Cubes and top.


Ric is also a proponent of weighing down components, but due to the unnecessarily large chassis, it barely fit in my rack, but I had a 5 pound divers belt lead weight that I squeezed in. Now, because RIc chose to put the mute toggles on the back I placed the amp on the first shelf from the rack's top (but out of sight out of mind: I never mute it when done listening), upon which was my CD player/Transport, which I raised up to provide ~ 2" of air space above the top of the 1200 and the bottom shelf of the player. Even though the rack is open on all sides with plenty of air space all around the rack, the amp ran warm

Fast Forward to yesterday. I was listening to Leonard Cohen Essential songs, mostly instrumentally sparse. I removed the weight; and found the music much more open sounding. Encouraged, I FINALLY removed the top. Honestly, I was not prepared for how HUGE doing so could be. It was like the music went from a confined space to an open air 3 dimensional venue. This is so amazing that I am going to get a handle on it via different music before removing the Cubes. Oh, and the amp is now cool as can be. 


So, if interested, stay tuned
tweak1
my darTZeel NHB-468 mono blocks are a vertical design, with Plexiglas sides. you can look in and view the beautiful circuitry.

https://systems.audiogon.com/systems/615#&gid=1&pid=12

my previous amplifier, the darTZeel NHB-108 stereo amplifier, had a plexiglas top. it has similarly elegant circuitry and build quality.

the designer found that the amps sounded better that way. EMI/RFI effects were reduced.....not fully enclosed with metal sides.

can’t say every amplifier would get similar benefit. the darTZeel has a very minimalist design (low parts count in the signal path) and zero global feedback. very pure and quiet. so the little chassis design features matter.

YMMV and just my 2 cents....
The tops of both my Transnova 9505 (Bass amp) and BAT VK-D5, have been in a drawer, for going on two decades.      Can’t fit the top on the amp anyway, because of the power supply mods, which included some big capacitors.      At least, not without 3/8" stand-offs, anyway.      The CDP has six tubes in it, which I like to keep on the cooler side.      Just means, I have to clean the LASER, more frequently.     Everything’s separated, by some old-school,Texas Instruments RFI/EMI blocking, metal sheeting, lining every rack shelf (yep- grounded).      Some stuff Michael Percy used to sell.
Mike I agree...same way with my amps. I can easily lift the lids off on both..and hear a  difference . Same with my breaker box in my room with an audience to hear the change while doing so. With all the shielding used to keep RFI and EMI at bay maybe we are containing the RFI and EMI and allowing the pollution to remix with the intended signal..Same for vibration control systems. Without a clear and directed path out the self generated component noise will never leave, it will only be refilled and replaced by more of the same. Tom
A piece of metal, or whatever, covering the amplifier is hardly the universe. But it may be, if we all just wish hard enough.