Add a line out to a 1960's console record player?

[Sean Carter]

I have a 1960's Curtis Mathes Royal Dane console record player. I would like to add a line out to it after the preamp and volume and tone controls so that I can send the signal to a whole house system and have the sound of the preamp and record player. I am assuming that the signal path is line level throughout the circuit until it gets to the power amp stage. Does anyone know if doing this is possible? I will attach the schematic of the unit if that would be helpful.

I know I could get a speaker level to RCA adapter, however, I would like to take this one step further and use an Amazon Echo Link and put it in between the preamp and power amp stage so that I can use the line in distribution to other Alexa devices and to play in sync will require putting the Echo Link between the preamp and power amp portions of the circuit to introduce the delay compensation that the Echo Link adds.

 

[Lavane]

That schematic isn't clear enough. Does it have a tape monitor, tape in, tape out? If it has a tape out, you can use that. It will bypass the preamp line stage. What ever source you select will go right to the tape out.

 

[Sean Carter]

That schematic isn't clear enough. Does it have a tape monitor, tape in, tape out? If it has a tape out, you can use that. It will bypass the preamp line stage. What ever source you select will go right to the tape out.

No tape out. Thats the only schematic I have it is from the service manual. But the line out Im wanting would be after the preamp, before power amp.

 

[Lavane]

So, everything, tuner, preamp and amp are all on one chassis?

 

[cademan]

Pics?

If you want to use the preamp section with tone controls, you can usually tap off of the center wiper of the volume control.

 

[audiodummy]

There's no guarantee that any of the signals are "line level". You'll probably need to amplify or attenuate to get the right level into the next stage.

Just be careful, do not tap directly from the plates... There are blocking capacitors for a reason...

 

[cademan]

I'll reiterate..........no harm comes from tapping from the volume controls center wiper. There are no plate connections to or from the volume pot itself, just the first grid of the input (12AX7) type of preamp tube. Tone controls are usually past the first preamp input tube.

I didn't study your schematic but yes, it is possible to tap in somewhere to get ful tone and volume control.

 

[swechsler]

^^^ That was what I was going to suggest as well.

 

[gadget73]

honestly the sensible way here is a simple resistor divider at the speaker jacks. Thats the only source inside this thing with suitably low impedance to not make things act stupid when connected to something else, it gives functional volume and tone controls, and requires no modification to the amplifier itself.

Probably don't need more than a 10:1 divider either. 10 ohm and 100 ohm resistor in series across the speaker output terminals. 100 ohm to speaker +, 10 to speaker -. Output to the other amplifier from the junction of those resistors to ground. If thats not enough signal, you can jockey those values around as needed but I'd try to keep it greater than 50 ohms total. The small extra load won't bother anything enough for the amp to care.

 

[Tom Bavis]

Agreed - use speaker output. Impedance is too high everywhere else for a "line" output - even an unterminated shielded cable alone could add enough capacitance to reduce treble when connected to point with the level you're looking for. If you get hum, transformer isolation is needed.