did you attach it to the phono input on the Denon? That would be a mistake. Attach it to any other input and it should work fine. If you have it attached to one of the other inputs and are still getting this issue, I have had challenges when things are not properly grounded. Have you checked your ground on the turntable?

FC Lund wrote:

Hi all. I just bought myself a used, although fairly new, Pro-ject Tube Box II.

However, sadly, the sound when I tested it was downright horrible. The sound is extremely distorted and I noticed that the overall volume is now increased a lot while running through the Tube Box.

I have connected the Tube Box to my existing amp, a Denon DRA-425R. This amp already has build in RIAA. Could this somehow mess up the sound? I think the older Tube Boxes had some switches that needed to be adjusted to the corresponding pick up, but I don't see this feature on my box, so I guess that cannot be the problem.

Hoping for some help.

The output of the Tube Box Phono Preamp has been equalized and amplified so that it needs to be connected to a LINE input on an amplifer or receiver, NOT NOT NOT a phono input. Connect the output of the Phono Box II to the AUX/VIDEO INPUT OF YOUR RECEIVER!!

By connecting to the phono input of your receiver, you are overloading that circuit with a signal far greater than it is designed for. You are also putting the signal, which has already been equalized, through a second RIAA equalization circuit, which will totally screw up the frequency balance.

By the way, you have 4 available line-level inputs on that receiver.

In addition to the AUX/VIDEO input and CD input, the TAPE 1 and TAPE 2 inputs can be used as line-level inputs.

The PHONO input can ONLY be connected directly to a phono cartridge, with nothing in between.