Mystery Holes in Rear of Amp Chassis

[The New Steve H]

I know I'm begging for abuse--nothing new there--but I am going to go ahead and ask what may be the dumbest question ever posed here.

Last year I started working on an amp with a 5F6A preamp and four EL84s on the output. I put the chassis together, got distracted, and quit. I just got back to it.

There are two mysterious holes in the back of the chassis. I have accounted for everything I can think of. Fuse, cord, input jacks, speaker jacks, pots, light...I cannot, for the life of me, figure out what I planned to put here. I have a board layout, but that's about it.

The holes are down near the preamp end. They are about 1/4" in diameter. It looks like one of them had a label that ended in "rd." "Cord"? "Board"? Danged if I know.

Can anyone hazard a guess as to what was going on in my head when I drilled these holes?

This thing will have a 12AY7 followed by 2 12AX7s, just like the original 5F6A. The holes are very close to the first and second tubes. I know I was planning to use a big chassis-mounted resistor instead of a choke, but I don't think it would require two huge holes 8" from the PT.

[shoggoth]

FX loop?

[The New Steve H]

I don't think I'm smart enough to build that.

[Reeltarded]

Vibratord or Reverbrd?

[Firestorm]

Label them both "Pulse Adjust."

[John_P_WI]

"Talent" Switch?

[shoggoth]

Bias testing jacks? Footswitch? Some kind of "Power Level" adjustment?

[Reeltarded]

Label them both "Pulse Adjust."

omg hahaha

[surfsup]

"rd" = re-drill the holes...?

[The New Steve H]

Man. I wish I had left myself some clues.

I'll just build it and leave the holes sitting there. It's conceivable that they have some relationship to the big resistor, but I don't think I'd put it at that end of the box.

[Smokebreak]

Well worth a dollar, because now it's a mystery. If you were to get it engraved oh my.. http://www.homedepot.com/p/Unbranded-1- ... p67nMRDvwg

[Deric]

"Talent" Switch?

This!

Since there are 2 holes: "Talent" switch and "Suck" knob.

[Synchu]

I always seem to get the "suck" feature internally hardwired in all my amps Will be good to make it switchable

Now that you have two holes drilled anyway that opens a number of opportunities to install some mods. With that configuration - looks like some sort of power scaling will be nice

[Gaz]

Okay, I think the premise of this thread is totally insane, BUT my guess is that the holes are for mini toggles, one of which is switchable cathode cap on the first stage (this can be done without adding extraneous noise), and perhaps the other is for some sort if tones stack switch, like bigger treble cap, or bigger mid cap for a more Fender-y type curve. Could also be a switchable bypass cap on the 2nd stage. Maybe you were thinking bias test points - those are 1/4".

[matt h]

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