Help: Orange TH30H Adjusting Treble adjusts Volume- problem is also transitive

[L_O_H_WNC]

I have an Orange TH30H, I bought it the year it was released. It has a cab with a pair of Fane speakers, that's how old it is.
Here is the schematic:
https://music-electronics-forum.com/...81ae6dd&attach mentid=47693&d=1521589896
Note: I have also added the schematic as an attachment.

The treble is linked to the volume(see between VR5 and C32) and along the way it looks like several caps, and even a logic gate and a 12ax7 tube that could go wrong.

Here is the deal: At a gig, I don't like the TH30H to get shrill and it will if I use my SG HSP90's that can happen with the combo of the Pig90 and a Stockholm, so I make a treble adjustment on my TH30H and start strumming a few chords, and I realize: If turn down the treble, the volume is also cutting out by the same amount. So I tried to see if there was transitivity and at the loudest volume possible the treble was maxed, I cut the volume- treble cut.

I can read enough of a schematic that I was able to intuit the above about the path between C32 & VR5 but that is it.

Blown PCB ? Blown cap at C32 ? Blown Cap at C33 ? Aliens ? Gremlins ? Does the amp need to go the clinic and get on Valtrex ?

Thanks. Lost in far Western North Carolina. If anyone knows an amp tech Waynesville all the way to Chattanooga or Knoxville I would be extremely grateful to learn anyone out there. Also I need a snapped and badly repaired SG headstock fixed properly.

I live beyond Murphy NC at the NC/TN/GA state line: closest to me is Culberson NC 28903 & Murphy NC 28906, then Blairsville GA 30512, Young Harris GA 30582, Blue Ridge GA 30513, McCaysville GA 30555, Copperhill TN 3717.
45min away is Cleveland TN, 1hr 30 min away: Waynesville NC to the east and in the West direction is Chattanooga TN, go north is Knoxville TN, south is Kennesaw/Marietta/Calhoun/Rome

Thanks gentlemen ! Any help is appreciated.

[Jon Snell]

If VR6 is fully anticlockwise, it effectively shorts all but the signal across R40 to ground. That will have the effect of reducing the volume when you reduce the treble because there is not much signal left.
C32 is just a treble boost capacitor. VR4 is a volume control.
There are no 'gates' because this is an analogue valve amplifier.

[L_O_H_WNC]

The treble volume increase-decrease issue can happen no matter where VR6 is...

[Jon Snell]

The treble volume increase-decrease issue can happen no matter where VR6 is...

You didn't state that. You stated;
"so I make a treble adjustment on my TH30H and start strumming a few chords, and I realize: If turn down the treble, the volume is also cutting out by the same amount."
Please clarify.

[J M Fahey]

I have an Orange TH30H,

The treble is linked to the volume(see between VR5 and C32) and along the way it looks like several caps, and even a logic gate and a 12ax7 tube that could go wrong.

No. You have a volume control VR4 with an associated bright cap C32 into a triode V3b gain stage driving the tone control.

I don't like the TH30H to get shrill and it will .... so I make a treble adjustment on my TH30H and start strumming a few chords, and I realize: If turn down the treble, the volume is also cutting out by the same amount.

[Irrelevant data removed for clarity]

You have what is known a VOX tone control, in part responsible for their famous "bright and jangly" sound.
Where to boot, setting Bass high (fully clockwise) shorts R40 and murders midrange, making sound even shriller.

Yes, if you lower Treble in a "lots of Treble" amp, thereīs not much left, as mentioned above.

Nothing broken, you have what you have, a VOXish amplifier.

In principle do NOT set Bass above 6 or 7 but in the long run, if you donīt like it, get a different amp.

[Mick Bailey]

That's right - it's a classic Vox tone stack with some component variations. If you go to Duncan's online tone stack calculator and select Vox, you can edit the table with your actual component values and see what is happening by sliding the bass and treble controls. Another factor that affects the volume output is the frequency spectrum of your guitar - your HSP90's have a good mid and upper range and this makes the volume loss through the tone stack more pronounced. I'm also inclined to think that without any other qualifying information, what you're experiencing is normal behaviour.