Problem with Drawmer 1960

[LuckyPony]

hey ya's

Just wondering if anyone could offer any suggestions as to what may be wrong with my Drawmer 1960.
The problem is : Channel ones output is 'thin' sounding and at a much lower level than channel two's. Also, when you switch channel one into 'bypass' mode (ie take the compressor out), you cant hear anything - very strange... any suggestions much appreciated,

Jol

[fremitus]

i would check the tube(s) first...