Hello AK'ers I have a small problem with my SA 9500 Mk 1 After about 10 - 15 mins of use I get a crackling sound on the LH channel. Observation of the L/S shows that this is accompanied by a large, gradually varying, dc voltage which moves the cone in and out over about 2 seconds. The sound and the movement of the cone then disappear for a while. This is only noticeable in no signal conditions. The problem reoccurs every ten to 15 mins or so but it isn't consistent. Observations so far: 1. If I separate the control preamp and the power amp - no crackling. 2. The sound appears to be independent of volume control position i.e. it is always about the same loudness 3. It is always in the LH channel. If I turn the switch to Rev, or L etc it still comes out of the LH channel. 4. It appears to happen on any input selection i.e. aux 1 and 2 or tuner etc. 5. Tone controls are switched off. 6. LF and HF cut are Off As the problem does NOT occur when the pre and per amps are separated I conclude that the per amp section is fine. As the volume control does not seem to vary the crackling I assume that the problem is after the vol control. My suspicions are on q3 and q5 on the Switch Ct ass AWS-082. Alternatively I think that q1, q3, q5 on awg-032 could be suspect. Does anyone else have a constructive opinion that might help please? Is my reasoning ok?