andyjm said:
Gaz37 said:
I read an article on TNT audio suggesting that modifications to the case of the Marantz CD63 could improve sound quality by reducing resonance, they suggested sticking Blutac inside the case to achieve this.
I found some self adhesive car sound deadening in my shed and set about sticking it to the inside of the CDP cover and to the bottom.
On reconnecting I found what I believe to be a notable improvement in SQ, especially bass sounding deeper and tighter.
Is this for real or has the power of suggestion made me think I'm hearing something that isn't there? On one hand I'm sure it's real but on the other hand how can a rattle casing effect sound?
Some electronic components are microphonic. Their electrical properties change with strain or vibration. If you are unlucky enough to have valve based equipment, tapping a valve with a pencil will give a decent 'boing' out the speaker as the innards in the valve wobble about. Semiconductors are generally non-microphonic, but resistors and capacitiors can also be microphonic.
This can be a good thing, Clapton's guitar sound owes a lot to his Marshall valve amp combo having unintended feedback as the speaker in the cabinet rattles the valves. In most cases however it is best avoided.
Modern surface mount electronics are pretty much immune to microphony - the components are so small and so well fixed to the PCB that vibration doesn't really effect them.
It is easy to test. Put a CD in the player, put it on pause. Turn your amp way up, tap the CD player with a pencil. Hear anything out the speaker? If yes, then you have microphonic components in your CD player and just maybe the blutack makes a difference. If no, then put that TNT article straight in the bin and see if you can dislodge the blutack without breaking anything.
This is, of course, utter twaddle. Valves are only microphonic to an extent that matters if they are faulty or at the end of their lives. I have never had any issue with microphonic valves from any of the Valve Amps I have owned over the years. Tapping the Valves of my current S8's either Pre or Power valves causes no sound through the speakers. Valve innards do not 'wobble' about. You clearly have had a very bad experience with Valves, which if true, is not general, or you feel compelled for some reason, to spread FUD about them (I suspect the latter).
If Valves are truly as bad as you believe, please explain why manufacturers such as Luxman, Audio Note, MacIntosh, EAR Yoshino, Unison research, Icon Audio, Audio Research etc., - some of the most respected brands in Hi-End HiFi, continue to use them?
You really should read up on how feedback works in Guitar Amps too. - You really have made yourself look very foolish here.