Acrylic Glass as a material in High-End Audio

Have you ever removed the cover of your amplifier? Perhaps a tube change was necessary in the preamplifier. Or you have cleaned the lens of your CD player.
Have you ever listened to music without a lid? Yes, I know that's not advisable in the long run. But it sounds better!

What's it about?

Many people think that airborne sound is a problem, which is why such nonsense constellations as "system rack sideways" come about in order to avoid the supposed bass impact in the middle.
But in fact structure-borne sound is the problem. We can perceive a small part of this sound spectrum as vibrations. Every electrical audio circuit reacts to this structure-borne sound. The result is distortions, overlaps and cancellations in the music. Every electrical audio circuit generates structure-borne sound itself! Important "micro-information" that, for example, creates the illusion of "being there" is lost.

Why Acrylic Glass?

Acrylic glass has a very high damping capacity! You already notice it when knocking, there is no rattling! Vibration energy absorbed by the material is effectively converted into heat. And since I replaced parts of the casing – on the spot – with acrylic glass, it works very effectively.

What about shielding?

Shielding of equipment and of cables is overrated. In fact, I believe that avoiding metal near audio signals is beneficial.

Cast or extruded?

There are two basic manufacturing processes for acrylic sheets: either it is extruded between two rollers and thus brought to the desired thickness. Or it is cast between two parallel plates at the desired distance.
Extruded acrylic has much lower thickness tolerances, which simplifies processing and accuracy of fit.
Cast acrylic has significantly less residual stress, which is why it is more suitable for audio applications. Whenever possible, I use cast acrylic.

How do I know whether an acrylic cover is worthwhile for my appliance?

Dismantle the bonnet of your unit and listen to music!

How do I get my acrylic bonnet?

You have an audio device that is suitable for an enclosure conversion? Write to me, I will make a suggestion for your device!




Acrylic Glass Projects:

Sansui AU111

A design classic from the 60s. Sansui no longer produces them today, but the units will probably find lovers forever.
Tubes benefit particularly from acrylic, as they react more strongly to microphonic effects than transistors. Large openings have been created in the area of the end-stage tubes, the heat is safely dissipated. The unit even stays cooler than with the original lid.
Not visible in the pictures is the new acrylic base plate in which the isolation feet (plate system) has been integrated.

  • lid, sidewalls and backwall made of 10 mm thick transparent acrylic glass
  • optional base plate with integrated isolation feet
  • cast low-stress acrylic glass
  • also available in "frost" or other colour
  • easy replacement of the original sheet metal cover
  • dampens unwanted vibrations / resonances

Prices
lid, sidewalls
and backwall
EUR 300.-
base plate with
integrated isolation feet
EUR 150.-





audio research LS17SE

The LS17SE preamplifier has been providing me with loyal service in my work for 5 years. Some time ago I had already taken off the lid and listened to "open" music. Simply sounds better. In the long run this of course is not a good idea, because the anode voltage is almost 300 volts. So a different cover was needed. Acrylic glass is an obvious choice and is widely used in the audio sector as housing material. Now I know why! If this is already a fantastic preamplifier per se, the acrylic cover catapults it very high up.

  • lid and sidewalls made of 10 mm thick transparent acrylic glass
  • cast low-stress acrylic glass
  • also available in "frost" or other colour
  • easy replacement of the original sheet metal cover
  • dampens unwanted vibrations / resonances

Price
EUR 250.-





creek 4040

Did Mike Creek realise back then that a metal lid on an amplifier doesn't necessarily sound better? At least I can't imagine that the original wooden lid was chosen for cost reasons.
However the acrylic glass lid enhances this amplifier treasure not only visually, but also sonically. A nice example of the effect of the acrylic is the screw connection of the heat sink to the lid. If the screws are not tightened, the cooling fins slowly fade out after hitting them. With the screws tightened, this resonance is clearly damped.

  • lid and side walls made of 8 mm thick acrylic glass "frost"
  • also available in transparent or other colour
  • einfacher Austausch des originalen Holzdeckels
  • easy replacement of the original sheet metal cover
  • dampens unwanted vibrations / resonances
  • Heat sink firmly screwed to the cover

Price
EUR 250.-





Acoustic Signature P723

There are probably not 10 of these power amplifiers in the world. What a monster of power and at the same time so sensitive.

  • Base and lid made of 20mm acrylic glass
  • power supply board mounted on 8mm acrylic glass