Turntable problem

[Idle wild]

Recently connected a turntable to my KW550 amp for the first time, every time I attempt to play vinyl the woofers on my speakers reverberate violently. This has never happened before with my cd player or DAB tuner is it the tone arm?

Set up:

MF KW550 amp
Teac Esoteric X-03SE
MF KW DAB tuner
Proac D15 speakers
Thorens 123 TT wt Linn Basic arm A&R P77 cartridge
BCD Engineering rack

Interconnects: LAT International IC 300
Mains: LAT International

 

[Operama]

If it's only while stylus is on the vinyl it suggests a bad case of rumble u can roughly gauge the vibration frequency from the oscillation of the speakers .check rumble by placing stylus on stationary lp, ie platter stopped. If problem goes away check out the mechanics, eg bearings (ball may be missing). Also can u detect any noise from the tt when on? (place screwdriver on deck & put handle up to ear -is mechanical noise v low?)

 

[RobHolt]

It will be the fundamental arm/cartridge resonance.
This is the product of the combined arm/cartridge mass and the cantilever hinge compliance of the stylus assembly.
The resonance usually occurs in the range 5-15hz depending on the arm and cartridge.
This resonance is excited as the cartridge tracks the record, especially if it falls at the lower end of the range.

There are two solution.
First is get a good cartridge and arm match so that the resonance occurs at or higher than 10hz. The Basik is a high mass arm and the P77 has high-ish compliance, so not the best match.
Second is to ensure that the phono amplifier has the IEC warp filter as part of the design - effectively this rolls away the response at very low frequencies.

Bass reflex speakers show this more than sealed box designs. You'll never eliminate the effect completely but you can reduce it substantially.

 

[vincula]

In addition to the above-mentioned, isolate the turnatble properly from vibrations and don't place it too close to the speakers.

Regards,

Vincula