adding a fx-loop (send/return) to a DJmixer?

[Rorut]

Hi,
I have two vestax dj mixers. One vestax 05 pro 1 (first edition) and one vestax 05 pro 3.
The first one does not have an option for send and return like the later one. I found schematics for both of them and thought maybe I can build the send/return circuit from the vestax 3 on a vector board and try to connect/hack it to the older mixer.
Would it possibly work like painted in my pictures? I tried to compare how it was connected in the vestax 3

Service manual vestax 05 pro 1: http://rasteri.com/w/images/b/be/PMC-05PRO.pdf
Service manual vestax 05 pro 3: http://rasteri.com/servicemanuals/PMC-05ProIIIVCA.pdf

 

[MichaelaJoy]

I just did a google "flyby" and did not find any spare PC boards for your unit.
And they are not cheap units. Not like you can grab one being sold "for parts".

There are two possible approaches here:

1 ) See if you can get the PC board which is responsible for FX send / return and splice it into the older unit.

2 ) The other approach is to build the PC board from vector board yourself. Don't forget to use copper foil for
ground planes.

Of course you'll have to drill out holes for the controls and mounting holes.

Something like this.

https://www.electro-tech-online.com/threads/building-a-midi-keytar.155769/page-10#post-1345284

Best of luck.

 

[Rorut]

I just did a google "flyby" and did not find any spare PC boards for your unit.
And they are not cheap units. Not like you can grab one being sold "for parts".

There are two possible approaches here:

1 ) See if you can get the PC board which is responsible for FX send / return and splice it into the older unit.

2 ) The other approach is to build the PC board from vector board yourself. Don't forget to use copper foil for
ground planes.

Of course you'll have to drill out holes for the controls and mounting holes.

Something like this.

https://www.electro-tech-online.com/threads/building-a-midi-keytar.155769/page-10#post-1345284

Best of luck.

thanks, I also looked for a spare part board without any luck. My whole idea is what you suggest in nr2.
Im just not sure I managed to draw it correct and wanted some expert advices
(No problems drilling and soldering)

 

[rjenkinsgb]

For a simple "insert" capability, you may just be able to remove C55 & C57 (top of page 3 of the manual) and loop those connections to the added send/receive sockets with new series coupling caps.

The gain control of the insert gear would have to be done externally, but it should give the essential functionality.

 

[Rorut]

For a simple "insert" capability, you may just be able to remove C55 & C57 (top of page 3 of the manual) and loop those connections to the added send/receive sockets with new series coupling caps.

The gain control of the insert gear would have to be done externally, but it should give the essential functionality.

Thanks!
So no need for all the resistors added in my picture?
So I need to have two extra gain controls for the loop? I prefere if using the ones already there but I like your idea

 

[rjenkinsgb]

You do not necessarily need extra gain controls, only if there is a problem with level adjustments of the signal in to the external gear.

If that has the same input & output level or already has its own controls it may well be OK as it is.