[henree]

The nad receiver is model 7240PE. It has tape, cd and phono rca's in the rear. I am just confused how to connect the rca cables. As of now. I have optical from pc to Bifrost. And Rca from Bifrost to Nad's rear CD rca inputs.

 

[Alcophone]

If the Bifrost is the only device connected to the receiver, I would go RCA from Bifrost to Loki's IN, and RCA from Loki's OUT to the receiver. This way Loki always gets a full range signal from the Bifrost, applies EQ, and sends it to the receiver.

However, the NAD 7240PE appears to have a processor loop, so you could remove the bridges between its "pre out" and "main in", connect "pre out" via RCA to Loki's IN, and Loki's OUT to "main in" on the receiver. The receiver picks one of its inputs, adjusts the volume based on the knob, sends it to Loki , which will apply EQ and send it back to the receiver.

Definitely do not connect the Bifrost directly to the main in since that is like turning up the volume all the way. You could risk it if you control the volume digitally (I wouldn't) or you could put a preamp between the Loki and the receiver's main in to use the receiver as a power amp only (main in would be the only input used in that case).

 

[henree]

If the Bifrost is the only device connected to the receiver, I would go RCA from Bifrost to Loki's IN, and RCA from Loki's OUT to the receiver. This way Loki always gets a full range signal from the Bifrost, applies EQ, and sends it to the receiver.

However, the NAD 7240PE appears to have a processor loop, so you could remove the bridges between its "pre out" and "main in", connect "pre out" via RCA to Loki's IN, and Loki's OUT to "main in" on the receiver. The receiver picks one of its inputs, adjusts the volume based on the knob, sends it to Loki , which will apply EQ and send it back to the receiver.

Definitely do not connect the Bifrost directly to the main in since that is like turning up the volume all the way. You could risk it if you control the volume digitally (I wouldn't) or you could put a preamp between the Loki and the receiver's main in to use the receiver as a power amp only (main in would be the only input used in that case).

I am confused about the pre-outs. If I connect to these. Which Function do I select? The nad has Cd, Phono,Tuner & video.
Also I use to have an old Yamaha equalizer. And I remember using the tape function for it. Is that an option?

 

[Alcophone]

I am confused about the pre-outs. If I connect to these. Which Function do I select? The nad has Cd, Phono,Tuner & video.
Also I use to have an old Yamaha equalizer. And I remember using the tape function for it. Is that an option?

I think you would benefit from learning a few fundamentals. A DAC produces a line level signal, which basically means that the loudest possible digital signal will be turned into a ~2V analog signal. Less loud parts will have less than 2V. A CD player, tuner, tape deck, etc. will also try to produce a line level signal, i.e. analog signal such that the loudest segments won't exceed 2V or so.
The signal from a phono cartridge is lower and also changed in terms of frequency response to better fit on a record, so a phono preamp is needed to fix the frequency response and apply gain, that is increase the volume of the signal to line level. Your receiver has a built-in phono preamp.

So now we have a bunch of line level signals. We need to select one that we want to hear, which is one of two functions a dedicated preamp would have. Next we need to attenuate the volume, i.e. reduce it, which is the other typical function of a preamp. Your receiver has such a regular preamp built-in as well. Its output is available via the pre out connectors.
Just like with a regular preamp you could connect that to a power amp (such as the Vidar or Aegir, or powered speakers (basically speakers with a built-in power amp). Or a subwoofer, which is essentially a powered speaker that specializes on low frequencies.
However, your receiver has a built-in power amp as well, accessible via the "main in" input. Otherwise it would just be a preamp.

And a power amp makes the input signal a lot louder and drives a loudspeaker with it. Since the gain is typically fixed, i.e. a power amp increases the volume of the input signal always by the same fixed amount, it needs to be attenuated beforehand to have some control - hence the term preamp.

Now for the tape out/in. If I remember correctly, the tape out passes on the selected line level signal as is, before the volume knob is applied, unless the tape input is selected (since that would result in a loop).

So if you simply use the CD input and tape in, the volume control and the pre out, your receiver is like a Saga, a preamp.

If you only use the phono in, select that input and use the tape out, your receiver is like a Mani, a phono preamp.

If you only use the main in, your receiver is like a power amp.

You can probably send one signal into the receiver and send its preout to a Vidar, and send a second signal to a SYS, and that into the main in, and your receiver would control the volume of the Vidar (signal A), while sending signal B to the loudspeakers attached to the receiver.

The cheapest regular receivers only have a fixed internal connection between the built-in preamp section and the built-in power amp section. Better models also have pre outs, for example to control a subwoofer in addition to the connected speakers. It's rare for receivers these days to expose the power amp section directly like the NAD does. But it's convenient if you want to process the signal externally, like you do.

I don't know how that would work with tape in/out since selecting tape in would mean no other input is selected, so nothing is sent to the tape out.

 

[henree]

I think you would benefit from learning a few fundamentals. A DAC produces a line level signal, which basically means that the loudest possible digital signal will be turned into a ~2V analog signal. Less loud parts will have less than 2V. A CD player, tuner, tape deck, etc. will also try to produce a line level signal, i.e. analog signal such that the loudest segments won't exceed 2V or so.
The signal from a phono cartridge is lower and also changed in terms of frequency response to better fit on a record, so a phono preamp is needed to fix the frequency response and apply gain, that is increase the volume of the signal to line level. Your receiver has a built-in phono preamp.

So now we have a bunch of line level signals. We need to select one that we want to hear, which is one of two functions a dedicated preamp would have. Next we need to attenuate the volume, i.e. reduce it, which is the other typical function of a preamp. Your receiver has such a regular preamp built-in as well. Its output is available via the pre out connectors.
Just like with a regular preamp you could connect that to a power amp (such as the Vidar or Aegir, or powered speakers (basically speakers with a built-in power amp). Or a subwoofer, which is essentially a powered speaker that specializes on low frequencies.
However, your receiver has a built-in power amp as well, accessible via the "main in" input. Otherwise it would just be a preamp.

And a power amp makes the input signal a lot louder and drives a loudspeaker with it. Since the gain is typically fixed, i.e. a power amp increases the volume of the input signal always by the same fixed amount, it needs to be attenuated beforehand to have some control - hence the term preamp.

Now for the tape out/in. If I remember correctly, the tape out passes on the selected line level signal as is, before the volume knob is applied, unless the tape input is selected (since that would result in a loop).

So if you simply use the CD input and tape in, the volume control and the pre out, your receiver is like a Saga, a preamp.

If you only use the phono in, select that input and use the tape out, your receiver is like a Mani, a phono preamp.

If you only use the main in, your receiver is like a power amp.

You can probably send one signal into the receiver and send its preout to a Vidar, and send a second signal to a SYS, and that into the main in, and your receiver would control the volume of the Vidar (signal A), while sending signal B to the loudspeakers attached to the receiver.

The cheapest regular receivers only have a fixed internal connection between the built-in preamp section and the built-in power amp section. Better models also have pre outs, for example to control a subwoofer in addition to the connected speakers. It's rare for receivers these days to expose the power amp section directly like the NAD does. But it's convenient if you want to process the signal externally, like you do.

I don't know how that would work with tape in/out since selecting tape in would mean no other input is selected, so nothing is sent to the tape out.

Welp. I will be returning the Loki now. This gear is too complicated for me. LOL

 

[Alcophone]

And I'll buy myself a new T-shirt!

 

[henree]

And I'll buy myself a new T-shirt!

"However, the NAD 7240PE appears to have a processor loop, so you could remove the bridges between its "pre out" and "main in", connect "pre out" via RCA to Loki's IN, and Loki's OUT to "main in" on the receiver. The receiver picks one of its inputs, adjusts the volume based on the knob, sends it to Loki , which will apply EQ and send it back to the receiver."
Hi again. I got it working through the method above. Thanks...

 

[audiobomber]

I am confused about the pre-outs. If I connect to these. Which Function do I select? The nad has Cd, Phono,Tuner & video.
Also I use to have an old Yamaha equalizer. And I remember using the tape function for it. Is that an option?

The tape loop is a good way to go, as it allows you to use the Loki EQ, or bypass it. Connect the Bifrost RCA outputs to the receiver's CD inputs. Connect the Loki to the receiver's Tape In and Tape Out, just like you did with your Yamaha equalizer. Select CD to play with no EQ. Select CD and Tape Monitor to hear the equalized version.

 

[henree]

The tape loop is a good way to go, as it allows you to use the Loki EQ, or bypass it. Connect the Bifrost RCA outputs to the receiver's CD inputs. Connect the Loki to the receiver's Tape In and Tape Out, just like you did with your Yamaha equalizer. Select CD to play with no EQ. Select CD and Tape Monitor to hear the equalized version.

Thanks a bunch. By the way. I am using a Hifiman HE-400. And I noticed while fiddiling withthe rca inputs in the back a switch that says 4ohm-8ohm. It was set to 4. Would the switch to 8 bring any gains to the sound through the heaphones?

 

[Alcophone]

The tape loop is a good way to go, as it allows you to use the Loki EQ, or bypass it. Connect the Bifrost RCA outputs to the receiver's CD inputs. Connect the Loki to the receiver's Tape In and Tape Out, just like you did with your Yamaha equalizer. Select CD to play with no EQ. Select CD and Tape Monitor to hear the equalized version.

Ah, so select CD sends the CD input to tape out, and tape monitor sends the tape in to the volume pot, etc., overriding the CD input selection? Then Loki would get a line level signal, which is probably better. Thanks for that. Didn't know about the tape monitor functionality, I don't think my receiver back then had that.

 

[audiobomber]

Thanks a bunch. By the way. I am using a Hifiman HE-400. And I noticed while fiddiling withthe rca inputs in the back a switch that says 4ohm-8ohm. It was set to 4. Would the switch to 8 bring any gains to the sound through the heaphones?

I don't know whether the NAD has a dedicated headphone amp chip, in which case the 4-8ohm switch would have no effect. More likely there is not a dedicated headphone amp, and instead there are resistors on the power amp output to condition the signal for headphones. In either case, it won't hurt to listen both ways, just reduce the level before switching to avoid transient noise. Most likely the 8 ohm output will be more suitable.

Ah, so select CD sends the CD input to tape out, and tape monitor sends the tape in to the volume pot, etc., overriding the CD input selection? Then Loki would get a line level signal, which is probably better. Thanks for that. Didn't know about the tape monitor functionality, I don't think my receiver back then had that.

A preamp has two functions, switching and level control. The tape loop works on the signal in between these two stages. In this case, with the Bifrost connected to the preamp's CD input:

• "Tape Out" on the NAD connects to the Loki "In" connectors. This puts it after the NAD input switch selector, and before the preamp's level control.
• Loki "Out" gets connected to "Tape In" on the NAD. When Tape Monitor is selected, the signal coming from the Loki goes to the NAD preamp, ahead of the level controller, so equalization is applied to the signal and the level is controlled by the NAD.

 

[henree]

I don't know whether the NAS has a dedicated headphone amp chip, in which case the 4-8ohm switch would have no effect. More likely there is not a dedicated headphone amp, and instead there are resistors on the power amp output to condition the signal for headphones. In either case, it won't hurt to listen both ways, just reduce the level before switching to avoid transient noise. Most likely the 8 ohm output will be more suitable.

A preamp has two functions, switching and level control. The tape loop works on the signal in between these two stages. In this case, with the Bifrost connected to the preamp's CD input:

• "Tape Out" on the NAD connects to the Loki "In" connectors. This puts it after the NAD input switch selector, and before the preamp's level control.
• Loki "Out" gets connected to "Tape In" on the NAD. When Tape Monitor is selected, the signal coming from the Loki goes to the NAD preamp, ahead of the level controller, so equalization is applied to the signal and the level is controlled by the NAD.

Below is the specs of my receiver. Does the part that says Phones mean headphones? I can't make since of the voltages they are listing. I am a little afraid of the impedance switch. I don;t want to blow out my ears. LOL Planars are a low impedance of 35ohms by the way.

 

[audiobomber]

Yes, Phones means headphones and the output impedance is extremely high, so it's clearly taken off the main power amp output. Low impedance headphones like the HE400 are far from ideal, damping factor will be a negative value. This headphone output would be best with 600 ohm headphones.

As I said above, you can try both settings and see which one you like. You won't cause any damage as long as you turn down the volume prior to switching, but I expect 8 ohms will be preferred. If you're serious about head-fi, you should consider a separate headphone amp or higher impedance headphones. OTOH if you're happy with the sound, just enjoy.

 

[henree]

Yes, Phones means headphones and the output impedance is extremely high, so it's clearly taken off the main power amp output. Low impedance headphones like the HE400 are far from ideal, damping factor will be a negative value. This headphone output would be best with 600 ohm headphones.

As I said above, you can try both settings and see which one you like. You won't cause any damage as long as you turn down the volume prior to switching, but I expect 8 ohms will be preferred. If you're serious about head-fi, you should consider a separate headphone amp or higher impedance headphones. OTOH if you're happy with the sound, just enjoy.

I actually have three separate headphones amps. From the matrix to the asgard. I just find that the nad has that old school thick liquid presence that modern amps don't have.
I find the modern amp has an almost sterile and anemic sound in comparison. Thanks so much for all your help.