NAD 3020e output impedance and aux/cd

[MrNice13]

Hi everyone

I'm still new in the HiFi world and I would like to know if someone know the output headphone out impedance of the NAD 3020e as I don't want to drive 56 ohms headphone if it's too high.
I currently have it hooked up with some old missions speakers but I don't know if I can plug a DAC in the aux/cd input via RCA. I have a old smls SD793ii that can work as a dac and if so... I can plug it in the NAD if it's possible. And also.. does the aux/cd can be plug to a cellphone with a Samsung USB C dongle ?

Thanks a lot

 

[Jimbob54]

Don't know about the headphone out but you should be fine plugging either the dac or the phone in via the aux rca

 

[MrNice13]

Thanks. I read somewhere that the headphone output impedance of the nad 3020 was something like 200ohm.
It's seem so high and impossible. So it's technically impossible to plug my phone in the aux via RCA and 3.5 as my source and listening with the 668B if the impedance is so high.

Thanks again

 

[Doodski]

Thanks. I read somewhere that the headphone output impedance of the nad 3020 was something like 200ohm.
It's seem so high and impossible. So it's technically impossible to plug my phone in the aux via RCA and 3.5 as my source and listening with the 668B if the impedance is so high.

Thanks again

It's 220 Ohms.

NAD 3020 Stereo Integrated Amplifier Manual | HiFi Engine

www.hifiengine.com

 

[restorer-john]

Thanks. I read somewhere that the headphone output impedance of the nad 3020 was something like 200ohm.
It's seem so high and impossible.

The output impedance is indeed 220 Ohms and that is perfectly normal for connecting headphones to the power stage of an amplifier capable of otherwise destroying delicate headphones in a split second...

If your headphones have a flat enough impedance curve, you'll be safer.

 

[restorer-john]

It's 220 Ohms.

Same numbers, but that's the 3020, not the 3020E schematic.

 

[Doodski]

Same numbers, but that's the 3020, not the 3020E schematic.

Need better labelling on these schematics.

 

[restorer-john]

Need better labelling on these schematics.

Hand-drawn. I love them. And if you find a mistake, you know it was a human who drew and annotated the schematic. Most likely, it doesn't matter as you have the device and the second channel on the schematic to crosscheck.

Have a look at the current Marantz/Denon AVR schematics in SMs. They are illogical, poorly laid out, jump all over the place and honestly are utter garbage. Compared to the gold standard Sony, they look like 3 year old kid's fingerpaintings.

 

[Doodski]

Hand-drawn. I love them. And if you find a mistake, you know it was a human who drew and annotated the schematic. Most likely, it doesn't matter as you have the device and the second channel on the schematic to crosscheck.

Have a look at the current Marantz/Denon AVR schematics in SMs. They are illogical, poorly laid out, jump all over the place and honestly are utter garbage. Compared to the gold standard Sony, they look like 3 year old kid's fingerpaintings.

Where does one get the current models of Marantz/Denon AVR service manual schematics?

 

[MrNice13]

Thanks for the reply guys.

Damn 200ohms. So it's not recommended to listening from the phone out of the Nad with low impedance headphone if I understand..so why put a headphone sockets on these. But the sounds with a good DAC plugged to it and with good speakers is so GOOD. So warm. So if I have my cd player plugged I cannot listening from the phone out even with 250 ohms cans? sorry for my bad English.

 

[Jimbob54]

Thanks for the reply guys.

Damn 200ohms. So it's not recommended to listening from the phone out of the Nad with low impedance headphone if I understand..so why put a headphone sockets on these. But the sounds with a good DAC plugged to it and with good speakers is so GOOD. So warm. So if I have my cd player plugged I cannot listening from the phone out even with 250 ohms cans? sorry for my bad English.

You will get sound out of the headphones. Depending on the headphones you might get an impact on the frequency response due to varying impedance. What are you using?

 

[AnalogSteph]

It is not so much a matter of headphone impedance itself but rather its variation. So e.g. planars of 40 ohms would not be affected much at all (their impedance response tends to be nearly ruler-flat), but 50-150 ohm Sennheisers with their much more variable impedance response would be npticeably colored.

Speaking of which, if speakers sound super warm even in comparison to other amplifiers (despite tone controls being at neutral and loudness being off) this could be a sign that the switch contacts in the headphone jack may appreciate a cleaning...

The most common fix for a problematic headphone output is connecting a headphone amplifier to the tape (recording) out. With a unit sporting a mechanical input switch like the one in question, that signal path generally keeps working even when the speaker amp is turned off.

 

[staticV3]

Speaking of which, if speakers sound super warm even in comparison to other amplifiers (despite tone controls being at neutral and loudness being off) this could be a sign that the switch contacts in the headphone jack may appreciate a cleaning...

How could a dirty headphone jack affect the speaker output ?

 

[twsecrest]

An 56-Ohm headphone can be driven by a headphone jack with a 220-Ohm output impedance, but there will be poor damping control.
It will give the headphones a bloated (louder, less detailed) bass and other weird sounds.
I would suggest investing into a modern headphone amplifier.

 

[staticV3]

It will give the headphones a bloated (louder, less detailed) bass and other weird sounds.

That depends on the headphone's impedance response.
Some headphones indeed have more midbass with high output impedance:


others (the majority) don't:

 

[twsecrest]

Thanks for the reply guys.

Damn 200ohms. So it's not recommended to listening from the phone out of the Nad with low impedance headphone if I understand..so why put a headphone sockets on these. But the sounds with a good DAC plugged to it and with good speakers is so GOOD. So warm. So if I have my cd player plugged I cannot listening from the phone out even with 250 ohms cans? sorry for my bad English.

I'm guessing in the old days a lot of headphone sold were in the 250-Ohm to 600-Ohm range.
For use with home speaker amplifiers and in recording studios.

Building a dedicated headphone amplifier into a speaker amplifier or receiver adds costs to manufacturing.
It's cheaper to just run the headphone socket off the speaker amplifiers, which gives the headphone jack a high output impedance.

 

[restorer-john]

I'm guessing in the old days a lot of headphone sold were in the 250-Ohm to 600-Ohm range.
For use with home speaker amplifiers and in recording studios.

Actually, most home 'headphones' were modified 8R 2 1/4" speakers and then small 25-80mm mylar dynamic drivers with impedances from 8R to 50 or 60R.

The NAD output impedance is fine. There's so much BS being peddled in relation to low Z HPAs.

 

[MrNice13]

You will get sound out of the headphones. Depending on the headphones you might get an impact on the frequency response due to varying impedance. What are you using?

Superlux 668B, Dt770 80 and 250.

 

[MrNice13]

I think is the NAD warm signature.

I don't see how the sound could be super warm because the headphone socket could be dirty... BTW the unit was cleaned before I buy it and it was a good bargain.

It is not so much a matter of headphone impedance itself but rather its variation. So e.g. planars of 40 ohms would not be affected much at all (their impedance response tends to be nearly ruler-flat), but 50-150 ohm Sennheisers with their much more variable impedance response would be npticeably colored.

Speaking of which, if speakers sound super warm even in comparison to other amplifiers (despite tone controls being at neutral and loudness being off) this could be a sign that the switch contacts in the headphone jack may appreciate a cleaning...

The most common fix for a problematic headphone output is connecting a headphone amplifier to the tape (recording) out. With a unit sporting a mechanical input switch like the one in question, that signal path generally keeps working even when the speaker amp is turned off.

 

[Jimbob54]

Superlux 668B, Dt770 80 and 250.

Have a look at @solderdude site- he sometimes measures impedance response https://diyaudioheaven.wordpress.com/headphones/measurements/

If Amir has tested them I think he does too- sure other reviewers too.

668B look pretty stable.