Vox JMI AC50 MKI single channel layout

[Jalmeida]

*****REVISED to R3****

Corrections to layout:
-Add 750ma fuse to layout in different location
-Correct 16uf caps connections
-Correct V1 connections
-Correct wire colors


Hello all,

I took some time to put together a layout for the MKI single Channel AC50 JMI amp original layout. I have matched it against schematics and the best pictures I could find. But if you see something off, feel free to let me know and I will revise.

[Jalmeida]

Revised to R2. See above for current files and explanation of changes.

[pdf64]

I can't see a CT for the mains transformer HT winding?
Each lug of the corresponding poles of the DPDT output load impedance switch need linking across.

[Jalmeida]

I can't see a CT for the mains transformer HT winding?
Each lug of the corresponding poles of the DPDT output load impedance switch need linking across.

All of the CTs are internally grounded to the one common ground internal to the PT. So the ground that goes to the fuse is the CT grounds.

The MKi did not have an impedance load switch like the latter large box MK4 units had. So the speaker connections was my attempt to show the speaker connection barrier terminal blocks used on these.

Some of these early 2 input and diamond input amps had one XLR speaker connection and some had two XLR connections. Often confused by the one XLR looking connector on the rear RH which was actually not XLR and was a power plug connection.

Hopefully that covered your observations?

[Jalmeida]

Each lug of the corresponding poles of the DPDT output load impedance switch need linking across.

To your point, I will revise the barrier Terminal block to show links for continuity to make that more clear.

[Jalmeida]

Revision 3 loaded. Let me know if I missed anything.

Again, this is the JMI layout minus the voltage selector. So right or wrong for how it should be, this is the JMI layout.