1965 Thomas Organ Vox V1 Pathfinder

[ChopSauce]

Great, thanks!

I'll have a look at it ...

[ChopSauce]

For the sake of completion, I finally had some time to draw a schematic from the layout. If I'm not mistaking too much(*), it should be close to

pathfinder-v1.jpg

... but...

1. I'm not sure about the 4k4 (?) resistor from the output jack tip to ground. Maybe from a switch ?

The gutshots from the "Vox Showroom" website

vox-V-1_pathfinder_chassis_ top_12.jpg

also suggest that the resistor is connected to the tip...

2. The above gutshot shows a (missing on the layout) connection to the pilot light and the 15R resistor to the heater wiring.

3. I'm still totally missing the connection to the footswitch for the tremolo...
___

(*) Please let me know about any possible errors and I'll update accordingly. I should also be able to make the corresponding .sch file available if it could be of some use to anyone here.

[vintagekiki]

https://music-electronics-forum.com/for ... post603276
Vox Pathfinder V1 (V101) & Vox UL 705 schematic

[ChopSauce]

Many thanks VintageKiki (for this and other ones) but the UL705 and the Pathfinder V1 really do not seem to share the exact same schematic, how close could they be...

At least, they do not share the same layout at all...

[WeaseTech]

For the sake of completion, I finally had some time to draw a schematic from the layout. If I'm not mistaking too much(*), it should be close to

pathfinder-v1.jpg

... but...

1. I'm not sure about the 4k4 (?) resistor from the output jack tip to ground. Maybe from a switch ?

The gutshots from the "Vox Showroom" website

vox-V-1_pathfinder_chassis_ top_12.jpg

also suggest that the resistor is connected to the tip...

2. The above gutshot shows a (missing on the layout) connection to the pilot light and the 15R resistor to the heater wiring.

3. I'm still totally missing the connection to the footswitch for the tremolo...
___

(*) Please let me know about any possible errors and I'll update accordingly. I should also be able to make the corresponding .sch file available if it could be of some use to anyone here.

Hi ChopSauce! I know it's been awhile! Hopefully you will see the completed pilot lamp path to the 15R resistor, the 4k4 is actually a 3k3 and is part of the tremolo circuit, look closely, it's not going to ground but in series with the 25uf cap.
I'll have to get back to you on the foot switch as I don't recall one nor a connection for one. Cheers.

[ChopSauce]

Of course!

Unfortunately I've lost the source file for the schematic. Yet I saved my work regularly, jschem crashed and corrupted the file in the process. As usual, you got what you payed for...
(and this software is free)

[WeaseTech]

Of course!

Unfortunately I've lost the source file for the schematic. Yet I saved my work regularly, jschem crashed and corrupted the file in the process. As usual, you got what you payed for...
(and this software is free)

I Know! Wonderful... right??? That's why I haven't updated DIYLC, for fear of it not working!

[ChopSauce]

Well, now I know that I have to make my own backup file manually. Not a great deal, but I'm not sure when I'll redraw that schematic...

So, finally:

- the 3k3 resistor might provide some sort of negative feedback &

- the tremolo vanishes with the wiper of the depth pot set to ground.

Right?

[WeaseTech]

Well, now I know that I have to make my own backup file manually. Not a great deal, but I'm not sure when I'll redraw that schematic...

So, finally:

- the 3k3 resistor might provide some sort of negative feedback &

- the tremolo vanishes with the wiper of the depth pot set to ground.

Right?

Yep! You're on it there.

[nielDa]

Hey, I'm very late to the party on this thread, but I have the original Vox Thomas schematic for the tube Pathfinder, and (maybe more important) a version of the schematic that I corrected based on the actual wiring of my two Pathfinders, and verified with two other Pathfinders. On first glance the diagram that WeaseTech posted matches the actual wiring of my two and the two others. The Vox Thomas diagram differs from the actual wiring mostly in the tone circuit. And "yes" for the 3.3k resistor and negative feedback, although it's not shown in the Vox Thomas schematic.

I can post the schematic here.

(Also, I found this thread because I was looking for a copy of the original Vox Thomas schematic for a tube Pacemaker. Any idea where to get one? I found a schematic online but it's not the original Vox Thomas version.)

[ChopSauce]

Sorry. I can't help. I haven't even seen any other source of information about the Pathfinder V1 elsewhere, which you seem to have done.

I can post the schematic here.

Yes, please, do.

[nielDa]

Here's a version of the Vox Thomas Pathfinder V-1 schematic that I revised to match the actual original wiring seen on my two Pathfinders and verified with two others. It differs mostly in the tone section, and that the actual amps were wired with negative feedback.

[ChopSauce]

Thanks a lot Daniel!

I'll have a look at all these three schematics soon, for your amps look like an evolution of the UL705 and the one from weasetech somewhat looks like something of a transitional model (or the opposite?), "modulo" some possible repair/mods like the 250k trem speed pot...

[ChopSauce]

So, but the odd 250k pots on the one from the OP, your pathfinders all share the exact same schematic, whose tone stack can also be sketched as
(if I'm not mistaking)

pathfinder-ts.jpg

The tone stack you're refering to as the tone stack on the "original Vox V-1 Pathfinder schematic" is the same one as the JMI Vox UL705, posted by Vintagekiki. So, maybe this was the plan at some point, and the document was never updated...