Pioneer sx1050 _ headphone out.

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Hi !

i am looking for information about the vintage receiver Pioneer sx1050.
There are rumors about the excellence of its headphone out.
I have found a free service manual online but i am not able to spot the HP out circuit :eek:
I would like to know if it uses the signal coming from the speakers out.

Another maybe silly question.
To judge the sound quality of an amp could a pair of HPs be a useful tool ?
i was thinking to build a resistors circuit to connect to the speakers out and with a HP out.
Many times i found amps around that are interesting but the locations are not the best for a decent evaluation.
I have already a nice pair of closed HP, quite transparent.
Thanks a lot.
Regards, gino
 
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Nothing excellent about it I'm afraid :) Its the standard series resistor approach tagged to the main output.
 

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Nothing excellent about it I'm afraid :)
Its the standard series resistor approach tagged to the main output

Hi ! thank you very much indeed !!!
Let me elaborate a little more.
I was reading some comments about the very good sound quality of the HP outs in some old vintage receivers with the sx1050 being one of the best sounding and with highly quality and extremely revealing HPs (i.e. Sennheiser hd800). Maybe they have only a nice distortion ?
I now wonder if using HPs at the speaker output of an amp with a resistor adapter could be a good tool to assess the sound quality of an amp.
If i am not wrong just two 150ohm/3W resistors are needed to adapt speakers out to HPs, plus connectors of course.
Could this work as a very basic and mobile testing rig for amps ?
Thanks a lot again for the very kind and valuable support.
Kind regards, gino :)
 
This would be a very unnecessary practice, as all amps "sound" the same. If you couldn't see what you were using, you wouldn't be able to tell any amp apart. The reason people seem to claim this particular model is because Pioneer units of this vintage is very popular, and this is one of the biggest and most desirable models. This is of course not due to sound quality, but peer pressure only.
 
This would be a very unnecessary practice, as all amps "sound" the same. If you couldn't see what you were using, you wouldn't be able to tell any amp apart. The reason people seem to claim this particular model is because Pioneer units of this vintage is very popular, and this is one of the biggest and most desirable models. This is of course not due to sound quality, but peer pressure only.



I most strongly beg to differ.

I have several "good" amps I without any problem can separate with my hearing alone.

But the hype of certain vintage amps I can relate to.
 
Hi and thank you All very much indeed for the helpful advice.
However looking at the schematic and if i am not wrong the 150 ohm resistors in series with the speaker outs increase the HP outs impedance to 150 ohm.
Is not this value a little on the high side ? So only high Z headphones could be used. If not the control on the bass would be not perfect for the damping factor issue.
Just asking.
Thanks again, gino
 
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However looking at the schematic and if i am not wrong the 150 ohm resistors in series with the speaker outs increase the HP outs impedance to 150 ohm.

;) Well spotted. I didn't elaborate on that earlier because it might have confused the issue.

From the point of view of 'level matching', a series resistor is a good compromise. Low impedance phones need little voltage and that is precisely what they get with a high value series feed resistor. High impedance phones typically need much higher voltage levels for a given level (perhaps 2 volts compared to say 100 to 200 millivolts for the low impedance) and the series resistor automatically provides that. Just put some numbers into the series circuit and work out the power levels.

Damping is another matter. Headphones (like speakers) are designed to be voltage driven from a low impedance source. This is where the series resistor fails, and as such the unique impedance curve of each particular headphone will give a unique (and inaccurate) frequency response.
 
;) Well spotted. I didn't elaborate on that earlier because it might have confused the issue.

From the point of view of 'level matching', a series resistor is a good compromise. Low impedance phones need little voltage and that is precisely what they get with a high value series feed resistor. High impedance phones typically need much higher voltage levels for a given level (perhaps 2 volts compared to say 100 to 200 millivolts for the low impedance) and the series resistor automatically provides that. Just put some numbers into the series circuit and work out the power levels.

Damping is another matter. Headphones (like speakers) are designed to be voltage driven from a low impedance source. This is where the series resistor fails, and as such the unique impedance curve of each particular headphone will give a unique (and inaccurate) frequency response.

Thank you very much again !
so there is indeed an impedance issue.
A proper headphone amp is the sane approach.
No more doubts about it.
Thanks a lot again.
gino :)
 
I have listened to the headphone output of the SX1050 of someone I knew, and spent many years afterwards trying to find one for myself. As far as dynamic range and speed is concerned, I have never heard better. Unfortunately I did not have access to the kind of headphones I own now, but the KOSS and Sennheiser headphones I had then never sounded any better.
The SX1050 is also the heaviest receiver I ever had to lift.
 
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