With Power Scaling when is additional heat sinking and/or a fan necessary? Is there a certain temperature at which one should worry? I'm guessing chassis up in the cabinet designs are more problematic that the typical Marshall configuration.
Hi Guys
SV and VCK should be mounted where there is airflow over the outside of the chassis. From, there it is obvious which physical constructions are problematic and which are not.
The preferred mounting position for SV is on the TUBE PLANE of the chassis. This is true for bias pots, as well. Side aprons are no good as there is zero air flow.
There can never be too much cooling, but in general, fixed bias amps up to 100W amps with moderate idle heat can rely on the chassis for cooling the mosfets. Over 100W may need a fan and/or heat sink. SV and VCK DO NOT have to be mounted near the power tubes, and really, that is not a preferred location because of the tube heat.
Cathode-biased amps run hot all the time, so adding a fan to cool the chassis and push air past the tubes out of the box is always "a good thing" and highly recommended.
RBX should be at the PSU end of the chassis. In some cases it has to be at the other end, so it is important to twist the related wire pairs and keep them away from signal wiring.
There are not a lot of choices with some amps.
Vox and VHT amps are total nightmares for servicing and modifying. It can be difficult in VHTs to mount a fan and one should really think carefully about whether this brand is worth the investment to Power Scale.
Another thing to remember is that no matter how simple the OEM circuit is, they will try to occupy as much of the chassis space as possible. When doing any mod, you will most often have to shift things around to make space for the new circuitry.
Have fun