1970s Ampeg svt head questions

[jtylerrelyt]

I recently purchased a early 1970s svt head (black line) from guitar center and I had questions about the rear inputs/outputs. This will be my first tube head so I want know what to do correctly when I actually receive the head. Below I’ll attach some images from reverb on what I’m talking about, also I messaged the sellers to ask them to no response. My questions are about the 4 inputs/outputs on the back, there are 2 ext amp inputs/outputs, 1 300w power output, and 1 ext speaker output. Also how would one di out of this head since there is no xlr? I have an idea on what 2 of these are but I want to be sure given the age and that it’s my first tube head. Link Removed Link Removed

 

[coreyfyfe]

Plug one 4 ohm speaker into the main “speaker” jack.

If running a second 4 ohm cab plug that into the “extension speaker” jack. The vintage amps used switching jacks and plugging into the extension jack switches the output to the 2 ohm tap.

The “ext amp” jacks are preamp out/power amp in jacks.

For a DI, if you want the sound of the amp you can try a speaker level DI like the countryman type 85 or neve RNDI.

 

[jtylerrelyt]

Plug one 4 ohm speaker into the main “speaker” jack.

If running a second 4 ohm cab plug that into the “extension speaker” jack. The vintage amps used switching jacks and plugging into the extension jack switches the output to the 2 ohm tap.

The “ext amp” jacks are preamp out/power amp in jacks.

For a DI, if you want the sound of the amp you can try a speaker level DI like the countryman type 85 or neve RNDI.

Cool I’ll look into these thanks for the info

 

[Wasnex]

AFAIK the earliest SVTs had a pair of EXT Amp connections like yours. This is how my 69 blueline is set up.

These jacks can be use as inputs or output, but they cannot function as a loop. AFAIK the intent was to allow you to slave one SVT to another...so one preamp controls both power amps. You can problem loop through several SVTs.

By the mid 70s these were changed to Pre Out and Power Amp In. A switching jack was used on the Power Amp In, so the connections can be used as an effects loop. AFAIK you can only slave two amps together because of the switching.

The labeling may not be accurate, so IMHO check how your amp actually functions.