Getting oscillation

[JamesO]

I just finished a D'Lite with skyliner values in the tonestack.

When I power it up, I only get oscillation. Adjusting the volume and master don't change the rate or volume level of the oscillation. All of my shielded cable is properly grounded with one end of the braided shield going to ground.

I'll try to get some pics up, but I was hoping someone might know what to check for in general.

Thanks for any tips on this.

[Fischerman]

Is it that loud howl? If so you may just have the OT primaries reversed. Make triple sure your OT and PI are wired correctly and if they are then you could reverse the OT primaries (pin 3 on each power tube). If you want a quick and dirty test to see if this is it (although switching the primaries is already pretty quick), you could just disconnect the NFB from the PI (when the priimaries are reversed you have positive feedback instead of negative feedback and the amp howls uncontrollably...so you can just disconnect it to see if this is it).

[JamesO]

Terrific. I'll be sure to check that tonight. Thank you!

[JamesO]

Well, I switched the primaries. The squeal is gone, but replaced with a steay hum as soon as I flip on the standbye. No change in volume when I adjust or completely zero out the volume and master. I'll get some pictures today.

[JimiB]

also post vour voltages

[JamesO]

Will do. I'm moving a bit slow with this unfortunately.