[thrasher521]

Is it ok to put my turntable on top of my receiver as long as it it balanced correctly?

 

[nycbone]

As long as it doesn't block any ventilation holes in the receiver. I keep my tt on top of my preamp (fits perfectly; no ventilation holes). Works fine.

 

[Happy Camper]

Mechanical vibrations from the turntable are transferred to the receiver casing. How much impact that has is any one's guess.

 

[m1abrams]

I would be most concerned about heat from the receiver. Most receivers are designed to vent heat up and require a decent amount of open space above them. I know my Denon manual says 6 inches of clearance above.

 

[Uncle Erik]

Just make sure the turntable is level and make sure it doesn't trap heat - that would be bad for the receiver.

 

[NightOwl]

Turntables operate best when they're isolated as much as possible from low level resonances and vibrations. There are hundreds of isolation products on the market to address this for a reason. The effects of these resonances can be heard and in some instances seen (when the stylus jumps or mistracks as you walk across the floor).
Linn takes a contrary approach and believes that their tables should be coupled to a light rigid platform to dissipate frequencies in the audible range. Any resonances which get through are absorbed by the suspension or too low in frequency to be audible. This only works for turntables with spring suspensions.

In neither case is a receiver an ideal platform. It is not light and rigid. Nor (except for the receiver's feet) is it acoustically absorbant. The receiver's casing resonates. The folded thin metal is ideal for resonance transmission. Tap the shell of your receiver (without the turntable on it), then tap the shelf the receiver sits on. Which is more audible and vibrates more? In fact the weight of the turntable will probably help the receiver be quieter by absorbing the case's vibrations which unfortunately are then transferred to the turntable.

However, it's also not so good for the receiver. Class D amplifiers are very efficient. Class AB amplifiers (most receivers) aren't. The most efficient of these will convert 70% of the electrical input into power output. Most are around 50% efficient. The rest becomes heat. Heat is the number 1 enemy of electronics. There's not sufficient clearance in between the turntable and the receiver to dissipate the heat properly. Feel the top of your receiver after it's been in use for an hour. If you want, you can compare it with and without the turntable in place.
It's also not a good idea if you use the tuner part of your receiver. You have the electro-magnetic field generated by the turntable motor as well as the phono cables and the tonearm (wires inside) acting as antennae.
In addition, the turntable can generate resonances of its own. These can be transferred to the receiver and may have an audible effect (small though it may be).

Sometimes you have no choice, but the bottom line is that placing your turntable on top of your receiver is not ideal.