7805 regulator doing.. what? AC bypass?

[brett]

This is hanging off the +24 V line of my Orange Crush amp. Bridge rectifier and one electro cap (marked 0uF) upstream.
It's not a DC regulator.
Maybe an "AC to ground" bypass of the subsequent filter caps?  Making the job less onerous for them?
Thanks for any explanations.

[Rob Strand]

I don't think it has any tricky function.

I suspect it's one of these:
- The schematic has an error.   The regulator connection goes somewhere but that's not shown correctly on the schem.
- The schematic is incomplete.   The regulator powers a part of the circuit that wasn't traced.
- The regulator is a left-over.  The regulator powers something on another amp model that does use the regulator.



It occurred to me some of the above items might come into play if there is a 5V relay used for switching channels or the reverb.

[niektb]

Right now it's just a heater 

[anotherjim]

Actually, a DC heater just for the preamp tube makes sense for high gain work. I've seen this in an orange amp but without a regulator, just a separately fused then rectified branch form the AC heater winding. However,  these Orange Crush amps don't have any tubes and that schematic makes no sense for the regulator.

[Kevin Mitchell]

My first thought was a 5v regulator for DSP reverb - though I thought most orange amps didn't have reverb (don't know why I thought that, perhaps my limited orange experiences).

Anyways, here you have it. 7805 on the PS board and a daughterboard reverb module towards the bottom right.


There's no mention of the half wave rectifier cropped out of the image (why did you do that?)
Perhaps the deal with voltage source was an alternative in the event 7805s started to burn out. I'd guess you can either jumper the DC source from the full wave circuit or use a diode as a half wave circuit for a few less volts - being less for the 7805 to have to burn off.
Makes sense?

Here's more of the power circuit. You'll a see a jumper and two optional diodes & an optional cap which lead me to my assumption.

[anotherjim]

I think there was a board connector for what looks like an FX send/return, ground and +/-15 supplies at the top on the fuller schematic, but it misses out mention of the +5v. You can see the connector in Kevins' pic.