why is SFDR picking up more buzz than BF Bassman?

[Groover]

I was just comparing amps for a gig tonight and I noticed the SFDR is (re)producing a lot more buzz from my single coil Tele pickup than the Bassman.
This is not 60cycle hum, and I don't think it is poor power supply filtering, because it is mostly a HF and hi-mid sound sort of a combo of white noise and static, the kind of noise generally cause by badly filtered lighting etc. getting picked up by the guitar.

Same guitar, same cable, side by side in same room, and I tried the SFDR through the spkr the Bassman was in to make sure it wasn't just HF roll-off by the speaker that made the difference. Both amps have 3-wire AC cables.

NOTE: the SFDR has been modified with a switch to select solid-state or tube rectifier. This switch was put in place of the AC polarity switch. There may be no RFshunt cap in the amp anymore, I don't recall. Also the "bright" cap on the 2nd channel has been moved to the switch of a push-pull pot and was not engaged at the time.

Full disclosure: The Bassman has been modified to run EL34s. The SFDR has been more modified to run Rev and Vib in both channels, the pre-amp stage cathodes are all de-coupled, and it is running 6L6s.

[Gibsonman63]

Lead Dress/Heater Wires

I don't know what year your Deluxe Reverb is, but at some point Fender got away from using cloth covered wire. The non-cloth covered wire doesn't stay where you put it as well.

Also, Fender was notorious for crossing the heater wires on the power tubes. On both of those amps, there is a 50/50 chance that they got it right.

[Groover]

How should the heater wires be connected to power tubes - the same polarity to both, or opposite polarity?
Also is there a preferred method for connecting heater wires to the preamp tubes?

[Gibsonman63]

They should be the same polarity for hum cancelling. I do not believe that it makes a difference on the preamp tubes because they are single ended. Someone please correct me if that is not the case.

If you have to swap the heater wires around, fire the amp up, connected to a speaker load and listen to it before you mount the chassis back in the amp. My Fenders seem very sensitive to heater wire placement. I was able to correct ticking tremelos and other maladies simply by moving the heater wires slightly with a chopstick to find the best position.

I have also read that giving the heater wires more twist helps as well. I have tried this, but did not go crazy with it. You may want to mark one with a sharpie before you do because it can be hard to tell those green wires apart once you put a tight twist on them.