geoff004
Well-known member
With the holidays here I'm totally tapped out for cash. My bigger projects will have to be on hold for another month or so.
So I decided to do a little recycling. I've got an old (late 1960s) Sony TC-260 reel to reel. It had been dropped so the case was in pieces and the last time I tried to use it the gearing and other mechanics collapsed in on itself. I figure it's a good unit for doing a little learning on.
I extracted all the guts pertaining to my project out of the rest of the chassis. The recorder is setup with 2 independent power supplies and transformers - 1 for running the motor/record/playback stuff, the other for running a couple amps and driving some speakers. The speaker side will sit for a while until I decide what to do with it.
My goal is to get 2 'vintage' mic pres out of this.
Here are the little issues I'd like to resolve before actually putting the thing in to a rack:
1. The ins are unbalanced - I'd like to add transformers for balanced inputs. Also the input is really hot. I can't get the gain knob up very much before I'm overdriving the whole thing. I'm hoping a transformer could help attenuate a little.
2. I'd like add phantom power. The 'mic' board runs on ~13 volts (single ended). I found threads explaining how to get phantom going and it shouldn't be that difficult.
3. The outputs are unbalanced - I think I'd like to add transformers to these to balance them out. The issue here is that I can't seem to get as much gain out as I'd like. They top out -18db below all my other stuff (that is to say, -18db before I clip my convertor). I guess this is what's to be expected from line out/analog. If I could get the output up I'd be happy, even if it were not balanced. I know I could add something like a THAT1646 on the out, but somehow I feel like it'd be almost sacrilegious in a way.
Here are some pictures. If any one has any suggestions I'd appreciate it. If you want to try this yourself you can get one of these machines on ebay for under $50.
This isn't what I started with - -just a picture off ebay of what it should look like.
So I decided to do a little recycling. I've got an old (late 1960s) Sony TC-260 reel to reel. It had been dropped so the case was in pieces and the last time I tried to use it the gearing and other mechanics collapsed in on itself. I figure it's a good unit for doing a little learning on.
I extracted all the guts pertaining to my project out of the rest of the chassis. The recorder is setup with 2 independent power supplies and transformers - 1 for running the motor/record/playback stuff, the other for running a couple amps and driving some speakers. The speaker side will sit for a while until I decide what to do with it.
My goal is to get 2 'vintage' mic pres out of this.
Here are the little issues I'd like to resolve before actually putting the thing in to a rack:
1. The ins are unbalanced - I'd like to add transformers for balanced inputs. Also the input is really hot. I can't get the gain knob up very much before I'm overdriving the whole thing. I'm hoping a transformer could help attenuate a little.
2. I'd like add phantom power. The 'mic' board runs on ~13 volts (single ended). I found threads explaining how to get phantom going and it shouldn't be that difficult.
3. The outputs are unbalanced - I think I'd like to add transformers to these to balance them out. The issue here is that I can't seem to get as much gain out as I'd like. They top out -18db below all my other stuff (that is to say, -18db before I clip my convertor). I guess this is what's to be expected from line out/analog. If I could get the output up I'd be happy, even if it were not balanced. I know I could add something like a THAT1646 on the out, but somehow I feel like it'd be almost sacrilegious in a way.
Here are some pictures. If any one has any suggestions I'd appreciate it. If you want to try this yourself you can get one of these machines on ebay for under $50.
This isn't what I started with - -just a picture off ebay of what it should look like.
