Studio Preamp versions?

[Aart]

Hey,

I noticed that there are multiple versions of the studio preamp:

1985 catalog:

Later version?:

Does anybody knows exact the differences?

 

[ytse_jam]

Wow, I've never seen/known anything about the version in the first pic...

 

[Bullen]

The Quad looks different too. The later ones doesn´t have any input or footswitch jacks on the front.

Maybe those are just prototypes. I´ve never seen any that looks like these.

 

[4nkam]

I saw those too and was wondering about it. Most likely, those are just early versions which didn't make it into production. I have an old review of the studio and quad and they look like the ones we all know