Switching Tuner to CD input on preamp, and CD to Tuner input on preamp, any issues?

[Sandman1221]

My NAD 317 integrated amp, when turned on, defaults to preamp CD input as being active. Problem is I normally use Tuner, so have to select preamp Tuner input almost every time. Finally decided to switch the Tuner RCA cable to CD input on preamp, and CD to Tuner input on preamp. Tuner sounds good on CD input. But wondering if there is any issue with doing that, and if preamp CD circuit is different from preamp Tuner circuit in any important way.

Here is a screen shot of the preamp inputs closeup and full diagram to output, they all look identical to me. Amp has no DAC, DAC is in CD player.

Maybe I just answered my own question, but I am no expert in reading schematics.

 

[RVT1K]

There should be no problem at all. Most things like tuners and CD players all put out close to the same level.
The only issue is with phono sources which have much lower signals and need special circuits.

If you wanted to be EXTRA sure, look up the specs for both the tuner and CD player and compare output voltages.

 

[Sandman1221]

There should be no problem at all. Most things like tuners and CD players all put out close to the same level.
The only issue is with phono sources which have much lower signals and need special circuits.

If you wanted to be EXTRA sure, look up the specs for both the tuner and CD player and compare output voltages.

Thanks, just put in a CD to check it on Tuner preamp input and it sounds good too, so guessing Tuner and CD output voltages are pretty close based on amp Volume levels.

Then remembered OPPO CD can be on variable or fixed output volume, have it on variable volume set to a level similar to Tuner so I can A/B same station on OTA FM and internet FM

 

[RVT1K]

Thanks, just put in a CD to check it on Tuner preamp input and it sounds good too, so guessing Tuner and CD output voltages are pretty close based on amp Volume levels.

Good news and you're welcome.

My pre-amp has its inputs identified by only numbers -except for the phono input and the 3.5mm jack input.

 

[Tom A.]

Both the tuner and CD signals go through a 1K resistor and end up at pins 9&11 of connector J602, so they should sound identical.

 

[egellings]

There should be no problem at all. Most things like tuners and CD players all put out close to the same level.
The only issue is with phono sources which have much lower signals and need special circuits.

If you wanted to be EXTRA sure, look up the specs for both the tuner and CD player and compare output voltages.

CD and tuner have similar line level output signals, so I do not see a problem with swapping them in your setup.

 

[Sandman1221]

Thanks for the feedback everyone, appreciate it! Just listened to an Eric Clapton CD through preamp FM input and it sounded great! So no more having to always switch preamp input from CD to Tuner when turning system on. Less wear on the relays too.

 

[twiiii]

Some more sophisticated modern pre-amps you can adjust the gain a bit for each input. Which might be a good thing when a tape deck, Tuner or disc players have different output levels. Those advanced pre-amp, HT processors, or integrated amps or receivers do usually allow you to change the title on each line level input, too. Some even let you change a phono input to a line input.

MY DVD and CD players have a Max out put level of 2.5 volts, some of my tape decks the normal output was around 1.4 volts, other over 2 volts. Some cassette machines were one volt. Tuners were 2.0 volts, DAT and laser disc players were different also. Apple TV module and sound levels from the satellite receiver, and Blue tooth receiver were different also. So Having a unit where you could adjust input levels when you could not adjust output levels of the sources was a great benefit. At one time I had 16 inputs for my HT system. Today its 8. The stereo system had 10 now its only 6. Thats what happens when you get rid of all your tape machines, dvd recorder, and laser disc player CD combi player that required 2 inputs.

 

[Sandman1221]

deleted

 

[Tromatic]

Man, you cause yourself more trouble than anyone.

 

[Sandman1221]

Man, you cause yourself more trouble than anyone.

Yeah, I moved that post to the "in pursuit of static free OTA FM rafio" post where it belongs.

 

[Doug G.]

CD players and tuners do not have the same output, typically. Most CD players have an output of around 2 volts, unless they have variable output, which most didn't/don't. Tuners are typically 100 - 150 mVolts output.

CD players can overload standard line-level inputs and result in distortion if there is circuitry in front of the volume control such as tape out preamps and jacks.

It may be that the CD inputs are no different on a typical amp.receiver, however, so it wouldn't make any difference which one you plug into which input. A schematic helps determine this.

Doug

 

[jheu02]

In general, all inputs OTHER THAN PHONO are considered "Line Level" and should be interchangeable despite what it's labeled on the front panel. So, put your tuner in the CD or Aux or Tape, or... It doesn't matter. Others have already addressed the slightly varying (as compared to phono) output level of these different devices, but no harm should be done to your NAD.

 

[lini]

In general, all inputs OTHER THAN PHONO are considered "Line Level" and should be interchangeable despite what it's labeled on the front panel. (...)

In case of the OP's NAD 317 it indeed doesn't matter, as all line-level inputs are technically the same. However, for example there are quite a few Yamaha integrated amps, in case of which just the input parameters (sensitivity & impedance) are the same, while the actual implementation differs and some more effort went into the CD input (then usually also including an additional "CD Direct" function). See for example there in the schematic for the AX-596: https://www.manualslib.com/manual/950078/Yamaha-Ax-596.html?page=13#manual

Which also means, that it can make sense to check the service manual/schematic, if easily availabe, and compare, if one would like to use the best line-level input for what one would deem one's highest quality source component.

Greetings from Munich!

Manfred / lini