CAM400 fins vibrating with music

[Eliav]

HI
I have recently noticed a metal vibration sound coming fro the m400 fins. My listening room is pretty well acoustically treated, when I clap my hands, I can hear an echo coming from the fins sounding like metal strings. Double checked with music - When i mute, i can detect that very short echo again.
I got my ears close to the fins and confirmed this observation, it is coming from there !
Cam400 owners, any experience with this?
Thanks
Eliav

[RebelMan]

Eliav, do you keep the amps powered on at all times or do you keep them in Standby mode until you are ready listen? I have noticed when the amps are cool and as they start to warm up the chassis will snap crackle pop a little until it has reached normal operating temprature. It is my understanding that these expansion and contractions are normal and their affects can be adjusted to "taste" (tollerance) by Classe' or by the unabashed DIYer. I am wondering if what you are noticing is taking place during warmup time. Once the amps (chassis) are running at their rated temperature they should be dead silient.

[Eliav]

RebelMan

Let me clarify further. I was referring to a mechanical noise coming from the aluminum fins. it can be reproduced by just tapping your fingers over the fins, making them actually vibrate like a tuning fork,it is this sound i was bothered by. I do not think this is coming from the rest of the chassis.I indeed noticed this phenomenon while the amps where on stand by mode ( this is how i keep them when not listening). I will let them run for a while ,heat up and check again, maybe with the expansion effect created by the heat this "tuning fork effect" will be defeated ?( I doubt it).
Thanks
Eliav

[RobP]

Wow, that is very odd, you may want to take them in and make sure that the heatsinks are 100% tight.

[Eliav]

hi guys
having the amps heated to working temperature did not change a thing.
I dont see where these fins can be further tightened, it is their edges that seem to be doing this.they are definitely not loose however. I tried a simple way to solve this by placing a cloth on top of them, it significantly tames the vibration sound.
Interestingly, I tried to get the same sound from my Rotel rmb1095 fins,it is dead quite (floor standing amp). may be it is the amps stands ? I assume the space between the floor and the stands acts like an echoing box accentuating the vibratory properties of the aluminum edges,veyy much like a tuning fork placed on top of a box?

Eliav

[RobP]

You know, just looking at pics of your setup, it may be the interaction between your amp stands and amps, those are VTL stands right? If they are I know that they are hollow with MDF shelf tops. That may be a part of it. Set them on the floor or put something underneath the amps to soften the contact a bit and see what happens, I bet it goes away.

[Eliav]

will try ASAP and keep everyone posted with the results.
Thanks, happy and peaceful holidays to ya' all !
Eliav

[sikoniko]

dont throw out your back moving those amps! I practically did moving the CA-3200...

[dyazdani]

He has 3 kids that can be employed in such a service Eliav, let me know if you need help...

[Eliav]

Danish
Thanks. I will contact you as soon as I am back from my vacation. Are you still in Crossett ? ( have'nt seen the Porsche around for a while.. :W )
Eliav

[RebelMan]

I'm with SG on this one; there must be some form of vibrational interaction in the room. It could be radiating sound waves in close proximity to the amps. I get the tuning fork feedback when I slightly brush up against the heat sink fins when I am performing my routine cleaning but nothing coming out of mid air. I wouldn't expect much of the vibration distortion to come from a physically coupled source as in between your amp and stand given the Navcom LimbSaver feet but anything is possible.

Maybe your amps are sitting on the crescent of a standing wave and they are resonating as a result of it. I would suggest moving the amps around to see if it tames the willies. Curious Eliav that you haven't noticed this before. Anything change with your system, the room, or the items in it recently?