Using Headphone out as Preout ?

[spirovious]

Hi,

Many of Budget Amps/Avrs do not have preouts.So I was wondering, has anyone tried headphone out as preout?
This can be useful with stereo amp which has dedicated headphone amp and do not cut speaker out while using it. eg. some of Marantz PM amps have that design and no dedicated subwoofer preout.
So will it be safe to add a subwoofer with headphone out and drive fronts(L/R) connected to amp's speaker out?
Subwoofer volume can be fixed at certain level and stereo amp's volume can be used as master volume.I can sense that theoretically its possible, but need to know if practically/technically possible without damaging amp or sw?
Kindly reply.

Thanks.

 

[Hari Iyer]

Most stereo amplifier use a voltage divider network to convert watts to milliwatts for headphones to work without damage. Same method is employed in subwoofer input with speaker inputs. So I don't see any issues with that

On a different note - I am planning to built or copy the headphone amplifier ckt of my Sony tape deck of the mid 80s for it's magical sound which I have not seen in any preamp or integrated amp. This ckt uses an opamp, carbon resistors and electrolytic capacitors which is against popular belief and I am going to mimic that. I have yet to come across a better sounding headphone amp than that since 35+ years.
If they turn out well, will integrate with my existing preamp for sure.

 

[spirovious]

Marantz PM series amp use a separate headphone amp within and speakers keep playing even when headphone is plugged in.So I was thinking to use it as preout for SW.
Thanks for reply.

 

[Hari Iyer]

Marantz PM series amp use a separate headphone amp within and speakers keep playing even when headphone is plugged in.So I was thinking to use it as preout for SW.
Thanks for reply.

Yes you can without any issues imo.

 

[fLUX]

Marantz PM series amp use a separate headphone amp within and speakers keep playing even when headphone is plugged in.So I was thinking to use it as preout for SW.
Thanks for reply.

Not sure if it does that by default. I have Marantz PM6006 , i need to turn off the Speaker A/B to have the headphone running. If i biwire the amp(both A & B) then the headphone and speakers might work simulataneously

 

[spirovious]

Not sure if it does that by default. I have Marantz PM6006 , i need to turn off the Speaker A/B to have the headphone running. If i biwire the amp(both A & B) then the headphone and speakers might work simulataneously

I am talking about PM7005 which has only Speaker A and headphone out/amp which works at the same time.There is a button which can turm off speaker out if needed.

 

[Aravindan]

Not sure if it does that by default. I have Marantz PM6006 , i need to turn off the Speaker A/B to have the headphone running. If i biwire the amp(both A & B) then the headphone and speakers might work simulataneously

Hi, I am planning to purchase Marantz PM6006. can you share the experience..

 

[fLUX]

@Aravindan I have not really tried many amps to compare against. I have a cambridge audio azur 340A SE , compared to it the PM6006 sound warmer and are really musical. I pair them with my Concept 20s and they drive them very easily, can easily achieve 75-80 DB with 33% volume on the knob for my room

Which speaker do you intend to pair it with

 

[surfatwork]

You can connect headphone out to the amp line-in. Just keep the volume on the headphone out low so that you don't drive the slave amp into clipping.

 

[Aravindan]

@Aravindan I have not really tried many amps to compare against. I have a cambridge audio azur 340A SE , compared to it the PM6006 sound warmer and are really musical. I pair them with my Concept 20s and they drive them very easily, can easily achieve 75-80 DB with 33% volume on the knob for my room

Which speaker do you intend to pair it with

Thanks.
Q Acoustics 2020i

 

[fLUX]

The PM6006 should be able to easily drive it and the synergy also is good. Comments on basis of trying it out with the 3020i which I believe is on simialr lines of 2020i

 

[Kannan]

There is nothing wrong in using headphone output as line out.
But the issue will be it's low current and low output sensitivity which will not suffice to power the input stage of the amp (sub amp or otherwise)

 

[spirovious]

There is nothing wrong in using headphone output as line out.
But the issue will be it's low current and low output sensitivity which will not suffice to power the input stage of the amp (sub amp or otherwise)

Whenever l have compared any amp/avrs headphone out to its preout, I have found that headphone out sounds louder than its preout with same volume level.Tested both outs with same headphone.

 

[kapvin]

On a different note - I am planning to built or copy the headphone amplifier ckt of my Sony tape deck of the mid 80s for it's magical sound which I have not seen in any preamp or integrated amp. This ckt uses an opamp, carbon resistors and electrolytic capacitors which is against popular belief and I am going to mimic that. I have yet to come across a better sounding headphone amp than that since 35+ years.
If they turn out well, will integrate with my existing preamp for sure.

@Hari Iyer ,That's a very broad and courageous statement! Could you share which quality headphone amps you have heard, which in your mind perform so poorly?And as a person who is building speakers, you'll agree that the quality of the transducers play a huge role, so also share which headphones you heard your tape deck and these other headphone amps with. On a related note I had a TOTL sony deck (TC-K81) and I remember the headphone amp being fairly meh. Headphones where sony MDRv6, I think.

I am very eager to understand your perspective.

 

[Kannan]

Whenever l have compared any amp/avrs headphone out to its preout, I have found that headphone out sounds louder than its preout with same volume level.Tested both outs with same headphone.

Don.t check with headphones. Try driving an outboard amplifier with both outputs

 

[surfatwork]

There is nothing wrong in using headphone output as line out.
But the issue will be it's low current and low output sensitivity which will not suffice to power the input stage of the amp (sub amp or otherwise)

I don't agree.
Typically, the headphone out is tapped from the speaker out, where the voltage is rail To rail (less a little bit). The line out is 2V or 4V (prof equipment). The amp input is high impedance, so doesn't need a high current source.

 

[Hari Iyer]

@Hari Iyer ,That's a very broad and courageous statement! Could you share which quality headphone amps you have heard, which in your mind perform so poorly?And as a person who is building speakers, you'll agree that the quality of the transducers play a huge role, so also share which headphones you heard your tape deck and these other headphone amps with. On a related note I had a TOTL sony deck (TC-K81) and I remember the headphone amp being fairly meh. Headphones where sony MDRv6, I think.

I am very eager to understand your perspective.

I don't remember the model number of the headphone but it came with a medical equipment - Acuson colour Doppler in 1991. It was meant for listening heart beats from the colour Doppler machine. I only remember iit was fr9m Loss.

The same headphone sounded pathetic in my Sony amplifier headphone out but sounded from an another world in my Sony tape deck TC-FX44. I say this again I am yet to come across any sound that even come close. Period.

The price of the colour Doppler machine in 1991 was whopping 2 cr. Model - Acuson 128xp

 

[Kannan]

I don't agree.
Typically, the headphone out is tapped from the speaker out, where the voltage is rail To rail (less a little bit). The line out is 2V or 4V (prof equipment). The amp input is high impedance, so doesn't need a high current source.

Depends on the design. If there is a dedicated pre-out, it is better to go with that than the headphone output. Good designs incorporate separate preout and headphone outputs

 

[Kannan]

For further clarification,

Line outs (or line level outputs) have impedance less than 200 ohms to drive amplifier loads that normally have a large input impedance exceeding 5000 to 10000 ohms. This helps in lower noise floor and distortion.
Typical headphone outputs have even lesser impedance, and are rated to push headphones which have input impedance varying between 10 to 300 ohms. So some headphones with input impedance of 150 ohms and above may need a dedicated headphone amplifier aswell.
Here the design is to drive higher current with lower noise floor and distortion.
In effect, if you connect headphones to line outs, the bandwidth will be badly affected as the source impedance is too high for the input impedance presented by the headphones.
Headphone outputs can still be used to drive a main amplifier, but in general, the noise floor and distortion levels will not be as low as line outs.

 

[kapvin]

I don't remember the model number of the headphone but it came with a medical equipment - Acuson colour Doppler in 1991. It was meant for listening heart beats from the colour Doppler machine. I only remember iit was fr9m Loss.

The same headphone sounded pathetic in my Sony amplifier headphone out but sounded from an another world in my Sony tape deck TC-FX44. I say this again I am yet to come across any sound that even come close. Period.

The price of the colour Doppler machine in 1991 was whopping 2 cr. Model - Acuson 128xp

Hari,

that’s a really funny story. So you took a unknown headphone of unknown response and unknown impedance from a medical device possibly not optimised to listen to audio at all and compared it to fairly low end deck from Sony. (TC fx44 Was assembled in india with a matching amp) and used that to extrapolate that the Sonytape deck headphone amp is the best in the world. this kind of extrapolation is really troubling. The story gets even more incredulous that the guys who own a 2 crore machine, allowed you to take a purpose matched headphone from a Mission cricital medical device to your home and try with your amps.


On a lighter note, I hope you informed Sony, I am sure they can stop spending crazy R&D money developing new TOTL amp systems as they already have the best ever hidden in a midfi deck from 3 decades ago. And please tell all the guys in head-fi too. Considering the amount they spend on headphone amps, I am sure they will be thrilled to scoop up any living Sony decks at basement prices to finally end their upgraditis.

thanks for sharing. I love your stories. Very entertaining.

edit: is this it?