Viking reel to reel tube mono preamps

[Andy]

In my quest for finding some sort of external electronics for one of my decks I was digging around in my garage and found these viking preamps. I think people sell them as tube mic preamps (someone gave them to me after pulling the tubes). I brought them up on a variac after replacing the missing tubes and they work. I used the high level input with a cd player and I assume the low level input is a mic input.

There are three cables coming out of the back of each chasis all rca terminated. Two black one red, I believe the red is power for the transport, one of the black needs to be plugged into the jack below the high level input (labelled "record switch") in order to get any output (or at least it was the only way I could get any output). I'm assuming the remaing rca would connect to the head output. I am hoping that these preamps have a tape head preamp integrated but having not seen the transport I don't know and I don't have a direct head output yet to experiment with.

On the top of each chasis are two access points for trim pots and there is a lable reading "adjusted for 1/4 track heads". The front right corner panel of the faceplate it reads "NAB". Anyway, if anyone has any idea if there is a tape head preamp integrated would appreciate knowing..I will probably just have to try these to see how these sound.

I can't at the moment afford the bh eros or anything up the chain (tube repro, cello), would like to find a pair of the ampex preamps but those are pricey as well. I just want external electronics to experiment with (I don't have any TP tapes yet, I just want to play around with my decks and my prerecorded tape collection).

[Andy]

Looking at the three rca terminated cables one had a P marked on the connector (and was the only one that sounded active when the preamp was switched to play). I thought I would try connecting that to a CD player to see if it overloaded (like a phono input would) and it did so I am guessing that it has a head preamp. I opened up the otari mx5050mkii to see if I could quickly kluge a tape head output (and realized it had balanced outputs and not fully understanding that aspect of outputs), I unplugged the two plugs from the wire bundles coming from the headblocks, I was able to get some output but it was pretty quiet so I am not sure if I was properly accessing the heads directly or not (but made me think it might be a potential impedance mismatch or something). I did discover something about the otari, I thought it was malfunctioning because it was making these horrible squeaking noises when playing and would be sluggish on rewind (a tape tech told me it was the tape itself and I disagreed, I thought it was a mechanical noise), anyway, it turned out to be the tape I think, an old sony reel (sticky tape I guess), I tried another reel after putting the otari back together and it plays with no squeaking.