Ampex 440 help/question

Hello,

I recently purchased an old, Ampex 440c locally here in Nashville. I love the sound of these machines and despite needing a decent amount of work, it looked worthwhile as I was able to pick it up for a few hundred dollars. I figured I could always just take my time and restore it, gradually.

However, after reading more into these machines, it seems that a lot of the particular character of the machine is in the transformers in the line amps. I already have a high speed, half track Revox B77 that I restored and am very satisfied with the tape saturation I get from it. I only do small track work and track to an rnd portico 5012 then into the revox and straight into my Lavry ad11 so the humble Revox is just fine for what I do. Therefore, I decided that the best bang for the buck here would be to keep the line Amps and part out some of the transport.

Now to my question. I am about to order a couple of the original input transformers because the line amps currently have no input transformers or unbalanced plugs. Once I do this, will I be able to already run audio through them and out to my other equipment or do I need to modify them to do this first? I am having a hard time figuring out the signal path in these. If it is possible to run Audio through the line amps without the heads working, does the signal go through the reproduce amp and then out or what?

Schematics:

http://www.ilk.org/~ppk/Manuals/Ampex_AG-440C/

Thanks for any help,

Matt

Just put the electronics in Input mode; the signal will go through the input xfmr, preamp, output amp and output xfmr.

Hi Matt,
There was some discussion about the 440C's VU meters on the Ampex mailing list back in 2011.  Kurt Greske mentioned the 440C's meters did not use the low distortion copper oxide rectifier design of earlier 440, 440B, MR70, 300-series etc. nor were they buffered.
So you might want to compare the output with the meter switch set to 'bias' (out of the audio path) to see if the VUs are adding audible distortion (and maybe the higher distortion will sound more interesting on some material).