TU-8200 L/R channel volume unbalance issue

[Samlic]

Hello,

I am new to tube amp and the TU-8200 is also my first kit.
First switched on, green light, happy days, but noticed:

• When the volume pot at around 9 oclock position - L speaker twice as loud as R.
• When volume pot at 3 o'clock position - R speaker slightly louder than L.
• Kind of balanced at 12 o'clock position.

All voltage check point is within spec.
amp tube swap, preamp tube swap, speaker swap but all same symptoms.

Is it something normal to tube amp?
didn't dare to warm to up too much for now. or should I give it a go?

The amp sounds great tho, no hum no noise at max volume.

Thank you in advance, any help are appreciated.

 

[dhaen]

I was expecting someone with actual experience of this kit to answer you, but they haven't, so I'll try.
If the volume control is wired (rather than a PCB insert) the symptoms you describe could be caused by a swap-over of the top (signal in) and the slider (signal out) on one channel.
As mentioned, I have never seen one of these. A picture of the volume control might be interesting.