2. amps-preamps
  3. 156499-2546

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
tweak1 OP
3,645 posts
 
I neglected to add

Last night I listened to the SACD version of Blood Sweat and Tears, originally recorded 1968, but this is a Legacy DSD remaster 2000


This is one of the discs I always spin after making a significant change. Never ever ever has it sounded so open and spacious as it did last night


hth
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geoffkait's avatar
geoffkait
23,365 posts
 
Wow, you have six doors? That’s gotta be some kind of record. 🤗
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fleschler
1,997 posts
 
I replaced the solid but thin metal top cover of my preamp and phono pre as I assume the vibration and metal obfuscated the sound.  I replaced them with a plexiglass cover, secured the same way and with air holes for temperature relief.  I did not find that the plexiglass cover interferred with the sound.  My amps were designed with mounted transformers, giant electrolytic storage caps and tubes on an open chassis so no problem there.  My other system, I remove the Dyanco ST70 cover when in use, also better than when secured to the chassis.  My DAC has a anti-vibration, 3/4" solid billet (one piece) aluminum chassis which only opens at the rear.  I'm not messing with that unit.  
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