DC-5 troubleshooting

[Reik]

I have DC-5 head that I've used mainly at fairly low volume...just for the sake of the neighbors. I recently bought a cabinet and started playing with some friends and I've actually had occasion to turn the volume knob past 3...Which is where my problem starts.

With the high gain channel on if I turn the volume past 3 (2.5 even) I start to get a weird volume/tone shifting kind of sound. Its not like the volume is dropping out..but more like the tone of the distortion is changing. So if I play a chord out and hold it there is almost this distorted vibrato kind of sound...I actually had the amp serviced fairly recently..so I'm not 100% sure its the amp.

Has anyone else had any kind of issue like this with a DC-5 or any other kind of amp? Is it possible that the cabinet I purchased is the problem?

Any advice is much appreciated!

 

[Monsta-Tone]

Did you have a speaker connected to the amp when using the Silent Recording feature?
How were you using it before you bought the cab?

At the bottom of page 8 it describes the Silent Recording switch. It is a bit misleading because it says in the 1st paragraph that you will not need a speaker load, but in the 2nd paragraph it says that you either need a speaker or a load simulation resistor hooked up to the amp.


If you ran it without a cab, it sounds like you will most likely need some power tubes at the least, and possibly an output transformer!
I think you should try some new tubes, power at least and the Phase Inverter (V6) If that doesn't work, then it needs to see a tech.
If you end up needing an OT, I have an original Mesa transformer from my old DC-5. I replaced mine with Mercury Magnetics and the original is sitting under my work bench.

 

[paintballnsk]

Also try getting rid of that pesky master volume resistor.