[Wayner]

Yes, I back to this thing again, this time I think I have it conqured. I have two systems in the studio. One is powered by an older Insight+ EC preamp with tape buffers, the other a new Insight+ without tape buffers.

The problem is that I have only one tuner and CD player and I wanted to share from one system to the next without constantly changing patch cords.

What I did was use the new Insight+ EC preamp as the primary "host" for the tuner and CD player, then I ran a pair of cables from tape out 1 to the older Insight+EC preamps spare 2 so it would be on the selector switch.

Now when I play the tuner or CD player, on the first system, it's just as normal. When I listen to the second system, I simply set the selector switch to spare 2, then put the selector switch on system one to CD player or tuner and it works! The great thing also is that the preamp from system one doesn't even need to be on. Line level signals are bussed to the tape output one regardless if the system is on or not.

Wayner

[oneinthepipe]

Wayner:

But you need to have at least one preamp with the tape buffer for this to work, correct?

[avahifi]

Actually if you are busing line level signals from one unit to the other you would not need the buffered tape output circuits, which are most useful driving the weird dynamic input impedences of analog tape recorders and their input bias trap filters.

However, if you do have the buffered tape output option, that will work just fine for this application too, but of course you would then need to have both preamplifiers energized to provide power to the active tape buffer circuit.

Regards,

Frank Van Alstine

[Tone Depth]

Yes, I back to this thing again, this time I think I have it conqured. I have two systems in the studio. One is powered by an older Insight+ EC preamp with tape buffers, the other a new Insight+ without tape buffers.

The problem is that I have only one tuner and CD player and I wanted to share from one system to the next without constantly changing patch cords.

What I did was use the new Insight+ EC preamp as the primary "host" for the tuner and CD player, then I ran a pair of cables from tape out 1 to the older Insight+EC preamps spare 2 so it would be on the selector switch.

Now when I play the tuner or CD player, on the first system, it's just as normal. When I listen to the second system, I simply set the selector switch to spare 2, then put the selector switch on system one to CD player or tuner and it works! The great thing also is that the preamp from system one doesn't even need to be on. Line level signals are bussed to the tape output one regardless if the system is on or not.

Wayner

Hi Wayner,

Does your dual system configuration, using an extra interconnect between the two preamps, seem to give better performance than using a switch box on the output from a single preamp to switch between your two sets of amplifiers and speakers?

[Wayner]

Frank,

That is why I had the preamp w/o the tape buffer be the primary source, so I could have it off while the other is running. Works great!

Tone Depth,

I really don't have room for yet another switch box and I'd have to run the switch box backwards and then could only source one component as most switch boxes I have seen have only one output. This way I didn't need anything except for the extra cable. This way I can't tell any signal degradation at least with my casual FM HD listening.

Also, when you run the source component on system 1, move the selector switch on  that sourced component on system 2 or the selector switch Frank uses will shunt it (direct short) and it will not work.

Wayner

[Tone Depth]

The System 1 preamp (turned off) serves merely as a switchbox for your tuner or CDP sources, when those line level signals are sent via Tape 1 output to the System 2 preamp (turned on) Spare 2 inputs for listening on System 2? 

If I am visualizing this correctly, the System 1 preamp active circuits are bypassed in your configuration for this scenario, as the Tape 1 input must first go to the tape buffer circuit, and then the tone and volume line stages, and finally to the preamp outputs.

Gee, I'm concerned that my questions/comments may be even more complex than your description!

[Wayner]

You've almost got it right. The first preamp does not have the tape buffer circuits in it or this would not work. If I switched the 2 preamps around it wouldn't work at all. So I think you got it.

To sum it up in an easier fashion, I'm using the first preamp (w/o tape buffer) as a switch box and am busing signal via it's tape outputs to preamp 2 (that does have the tape buffer circuit (but not used in the situation), as I went directly to the selector switch (spare 2).

It's really handy as going from phono on preamp 2 to tuner or CD player is one click away! Then I use preamp 1 via it's selector switch to pick between CD player, tuner or I guess I could even buss the other turntable thru to preamp 2.

Wayner

[Wayner]

Oneinthepipe,

I didn't even see your response, sorry man. No you don't need to have the tape buffer option to make this work. You actually have to work around it like I did or it will be a problem. The "host" preamp can't have an active tape buffer in it or you will have to leave it on.

Wayner

[Tom Alverson]

Isn't there a problem if you use the one preamp to drive the amp in that system, and have its tape output connected to another preamp but do not have that input selected?  Many preamps have shorting selector switches that would short out the tape out of the first preamp and cause problems.  If the tape out had its own dedicated buffers it may be able to tolerate this, but you might be causing some large "ground currents" that way that could get into the active audio path.

Tom

[Wayner]

Tom, the system works very well. The secret is going to the selector switch on the second preamp insted of the tape input. With Frank's preamps, the selector switch does short out everything except the valid input so if I want to listen to FM on preamp 2, I have to have the selector switch on preamp 1 to tuner and on preamp 2 to spare 2. If I want to listen to the tuner on preamp 1, I have to have everything in the same position. If I would move the selector switch on preamp 2 to something else, it would short out the signal from preamp 1. It's confusing, but you need to have the systems to prove it to yourself.

Wayner

[avahifi]

Note that the Tape Inputs are NOT grounded when not selected.  If they were grounded, that would eliminate the possibility of tape monitoring.  All other inputs are grounded when not selected to reduce source to source crosstalk.

Since the Tape Outputs are always connected to the output of the selector switch, ahead of the active line circuits, what Wayne is doing is essentially using the first preamp as an extension to the selector switch providing more sources and allowing one phono circuit to serve two preamps.

Simple, yes?

Frank

This idea, by the way, allows you to use an old stereo receiver as just an AM FM tuner by coming out its tape output, switching its selector to tuner, not even bothering to connect any speakers, just an interconnect set to a spare input on your main system preamp.  Since the tape out is ahead of the tone controls and active circuits and volume control, you are using the receiver just as a tuner.

[WGH]

This is just so cool, thanks for bringing up the topic Wayner.

I have the tape out connected to my computer's soundcard so I can listen to music and NPR while I work without having to blast the speakers which are in the other room. I never tried to listening with the tuner on and the Insight pre-amp off but it works like a charm.

Wayne

[doug s.]

Note that the Tape Inputs are NOT grounded when not selected.  If they were grounded, that would eliminate the possibility of tape monitoring.  All other inputs are grounded when not selected to reduce source to source crosstalk.

Since the Tape Outputs are always connected to the output of the selector switch, ahead of the active line circuits, what Wayne is doing is essentially using the first preamp as an extension to the selector switch providing more sources and allowing one phono circuit to serve two preamps.

Simple, yes?

Frank

This idea, by the way, allows you to use an old stereo receiver as just an AM FM tuner by coming out its tape output, switching its selector to tuner, not even bothering to connect any speakers, just an interconnect set to a spare input on your main system preamp.  Since the tape out is ahead of the tone controls and active circuits and volume control, you are using the receiver just as a tuner.

the marantz model 18 receiver has a fantastic tuna inside - the marantz 20, which many folks say is their best tuna, even better than the fabled 10b.  i have one, and have run it exactly as frank describes.  i have also driven a second amp/preamp/speaker system in a remote room from my main rig by using the tape outs from the main rig's preamp to a line input in the second rig.  if your preamp has separate record/listen selectors, you can actually listen to different sources in each system at the same time.  and yes- the preamp in the main system does not need to be powered on to send powered the source in that system to the remote system.

doug s.