I'm in the process of designing a switch box. What it will do is connect in the tape loop of my Scott LK-72A amp. It will be used with my RTR and my computer.
Here's what the switch box will do

record to RTR
record to computer
play from RTR to amp
play from computer to amp
record from RTR to computer. computer out to amp
record from computer to RTR. RTR out to amp
record to RTR. RTR output to computer. computer out to amp
record to computer. computer output to RTR. RTR out to amp

See attached schematic.
My reason for doing this is it will save on swapping cables and prolong the life of the RCA jacks.
I will be adding a vacuum tube circuit on the record input so the Scott sees more than it's recommended minimum load impedance of 220K on the record output jacks. The way I will do it is use a dual triode as a voltage amp, another dual triode as a cathode follower which will feed the record output jacks on the switch box. Then to keep the impedance to the tape input jacks on the scott high I will use another dual triode which will take care of the phase inversion of the first dual triode. I would like yopur opinions on what tubes I should use. I would like to stick with current production tubes if at all possible. If you all have a better suggestion on how to do this let me know.

bump.....

that sounds like a realistic tape control center, pt. number 42-2115

Oh ok. Where do I find one.

A dbx 400 route selector should do the trick!

there's this website, its really huge, and people put ads on it for stuff they wanna auction off. i forgot what it's called, but i'm sure someone can chime in and help us remember ; - ))

And if anyone remembers the name of that website, don't remember this number - 170222945639! :no:

I did not find a DBX 400, but I was able to buy a new DBX 200 which is the same as the DBX 400 minus the lights. Consider the switch box problem solved.

I still need an input buffer and an output buffer so the Scott sees a high impedance on the record output jacks as well as the tape input jacks. I would like to stick with tubes if at all possible. It would have to be non inverting though.

i've got a dbx 200 that about broke my brain trying to figger out how to use, and i never have. good luck with it, TR, and let me know if you get it workin'. you probably will, being an old DIY'er. i did get my Realistic tape control center working.

In order for the tape section to work you have to bridge the encoder input and output jacks together and also bridge the decoder input and output jacks together. Right to right and left to left. I used wire and soldered it to the jacks inside the unit since I will never use a noise reduction unit with this device. At first I thought there was something wrong with my unit until I dissasembled it and saw on the circuit board where the connections ran to the encoder and decoder jacks.

thanx, TR-- i'll take another look

No problem.

TR-- just went through the 200's manual again; found on page 6 something i've probably stared at 100 times-- 'If you don't intend to use a noise reduction unit, then leave the jumpers (they look like large staples) that came with the unit in place; no signal will reach your preamp or your recorder if they are not used'-- i can't tell you how many times i must have cruised by that. however, mine came sans jumpers, but i have some around and will be using them---but you put me on the trail!!

the guy that sold it to me on the bay a few years ago refunded me my $$ immediately, no q's asked when i got back to him and told him 'it doesn't work'--

If you can't find the jumpers any old pair of RCA patch cables will do.