[ursdiego]

Hi there... just a head-fi newbie question.
 
My nice DNM preamp does not have a headphone output. But it has two line outs, that are meant to be connected to the power amp.
 
So... connecting a full headphone amp to it would mean, to have two preamps. This means, two times loosing quality over potentiometers etc.
 
Is there such a thing like a power amp stage for headphones? Or kind of a headphone-adapter for a (potentiometer regulated) line level output?
 
Thanks for any help! Cheers!

 

[Edoardo]

Wait.
 
Can you give us the exact model?
 
how many output couples are there? are those "line-outs", "rec-outs", "tape-outs" or "pre-outs"?

 

[ursdiego]

Hello Edoardo!
 
First of all, thanks for answering!
 
the one I want to connect to is a "tape-out" - but it IS volume regulated (I can switch it from fix line out to regulated for level balancing over the high grade potentiometers of this preamp  - it is known to serve as a mastering tool, too)
 
So... as far as I understand, "line out", "rec-out" and "pre out" are the same, only that "pre out" has variable volume level. In this particular case, this applies also for the "rec out"-connection in this DNM model. I suspect, that the pre-out and the rec-out are the same in this case. But this is only a guess.
 
Here are the specs. http://www.dnm.co.uk/techspecs.html
 
I am not sure, which model it is, but they are all the same, with regards to the specs.
 
What I see right now is the following: it is written: "1 Tape out (or for headphones)"
 
What does this mean in your opinion? Can headphones be connected directly??? Its a DIN connector, but that would just require some adapter...
 
Thanks for your help! Urs

 

[Edoardo]

 
Quote:

Hello Edoardo!
 
First of all, thanks for answering!
 
the one I want to connect to is a "tape-out" - but it IS volume regulated (I can switch it from fix line out to regulated for level balancing over the high grade potentiometers of this preamp  - it is known to serve as a mastering tool, too)
 
So... as far as I understand, "line out", "rec-out" and "pre out" are the same, only that "pre out" has variable volume level. In this particular case, this applies also for the "rec out"-connection in this DNM model. I suspect, that the pre-out and the rec-out are the same in this case. But this is only a guess.
 
Here are the specs. http://www.dnm.co.uk/techspecs.html
 
I am not sure, which model it is, but they are all the same, with regards to the specs.
 
What I see right now is the following: it is written: "1 Tape out (or for headphones)"
 
What does this mean in your opinion? Can headphones be connected directly??? Its a DIN connector, but that would just require some adapter...
 
Thanks for your help! Urs

Well,
 
usually, rec-out, tape-out, and line-out, are quite the same thing: fixed-level line outs.
 
If you can switch it from fixed-line level mode to volume controlled mode.... Well... put it on "fixed-line" mode.
 
In any case, you can't put headphones directly there.
 
that "for headphones", means that you can connect the fixed level tape out to a headphone amplifier... Just get a DIN-to-RCA (couple) connector, as I don't know any headphone amp which has DIN input, but only RCA ins and XLR ins.
 
Hope I could help. a photo would be very useful
 

 

[ursdiego]

The connector won't be an issue, I craft it myself. Here are a couple of pictures of the same model (not mine):
 
http://www.soundscapehifi.com/used-hifi/displayimage.php?album=27&pid=167#top_display_media
 
What is interesting, that in the 3D - lineup, DNM offers a headphone output - while the design remains rather similar...
 
I wonder if there could not by some DIY - solution for making a minimalist "power amp" for the headphone - taking advantage of the fact, that the preamp already features the volume regulation.
 
Cheers!

 

[Edoardo]

first of all, it depends on your budget for the headphones you want to drive... An enjoyable headphone rig may be far cheaper and easier than the solutions I'm going to suggest...
 
 
Building a headphone power amp?
I just can tell that very big and power-demanding headphones (which are also the best-ones, and expensive ones), such as othodynamics, or the dynamic Sennheiser HD800, could be driven by (better: could bear) a power amp that puts 2 to 4 Watts into 32 Ohms. The Shiit Lyr puts 6 Watts but the producers themselves ask their customers to be veeery prudent when turning on the volume, especially if they are not driving orthodynamic type headphones with that.
 
Well I'm not a DIYer at all... But if you are you can easily find some shemes on the internet to built yourself an output transformer to put "between" the power amp and the headphones, to soak the power amp's power so that you can drive your headhones with it... you'd be using your "normal" pre+poweramp couple, and drive the headphones with that through the output transformer
 
I know a guy on an Italian forum that has put just 4 resistances between the speaker-outs of his power amp and the headphones's wires...!
 
These two solutions are much much easier than building a whole amplifier (and according to those who implement them, the best-sounding)
 
 
 
Or else... if you are interested Electrostatic headphones, such as the Stax headphones, (which, I must tell you, are very expensive also!) you could try this piece of gear
 
http://wooaudio.com/products/wee.html
 
it allows you to use your current power amp to power a couple of Stax through
 
 
So... if you want to use your current preamp or you current pre+power amp and you are a DIYer, you can build something to soak your power amp's power through resistances, or a transformer, or else build yourself a very little power amp.
 
it depends on your budget for the "headphone rig". It may not be worth it!
One of the best dynamic-type headphone rig that comes into my mind, or else, my dream rig, is Sennheiser HD 800 + Lake People G100 Headphone amp.
Everything (both headphones and amp) made in Germany, 900 + 400 EUR, more or less.

 

[ursdiego]

Thanks! While you were posting, I posted this...:
 
Well... googling a bit, I just got over a similar thread here:
http://www.head-fi.org/t/149577/headphone-into-preamp-out
 
Over there, JaZZ wrote, that the line output would have to be as the following:
 
- presence of (low-value) coupling capacitors (bad for low-frequency extension)
 
- output impedance below 120 ohm for a 300-ohm headphone
 
Now... checking on the specs, it looks like my preamp does the ohm - requirement. It has 75 ohm on the line output.
 
About the coupling capacitors ... I don't have the slightest idea! I am not an engeneer, unfortunately... How can I find out if they are present? And if not, is there a way to add them... for instance as part of the adapter cable?
 
Cheers!

 

[ursdiego]

And now to your last post:
 
Thanks again... so it really seems that there is no way around a headphone amp... Actually, I already got one, an audio-gd fun, which I guess to be a pretty nice tool, and even though its a DAC, too, it has an analogue RCA input that I can feed through my preamp.
 
However, I consider my preamp to be far superior. That is why I wanted to find a way to avoid another preamp - circuit that would alter the sound. In particular, my preamp has certainly the better potentiometers... and two potentiometers in a line just does not make sens, I guess.
 
I still don't have any cans, I am in the deciding process. After reading a couple of hours, I guess I am the Grado type of listener. I am still not sure, if I shall start on a budget with SR225i, or save up a while for the RS-2 or even RS-1. Or maybe go for an ATH-AD900. Or a AKG K181 DJ that seems to please not only DJs...
 
Cheers!

 

[Edoardo]

Quote:

 
What is interesting, that in the 3D - lineup, DNM offers a headphone output - while the design remains rather similar...
 

Cheers!

Yes and the fact the site specifies that it's driven from the "line out amps", or else, by the same preamp circuit, makes it a very high-quality solution, since usually they put just a very cheap "chip" (op-amp) headphone amplifier instead, little bigger than the ones used on our mobile phones...

 

[Edoardo]

Quote:

Thanks! While you were posting, I posted this...:
 
Well... googling a bit, I just got over a similar thread here:
http://www.head-fi.org/t/149577/headphone-into-preamp-out
 
Over there, JaZZ wrote, that the line output would have to be as the following:
 
- presence of (low-value) coupling capacitors (bad for low-frequency extension)
 
- output impedance below 120 ohm for a 300-ohm headphone
 
Now... checking on the specs, it looks like my preamp does the ohm - requirement. It has 75 ohm on the line output.
 
About the coupling capacitors ... I don't have the slightest idea! I am not an engeneer, unfortunately... How can I find out if they are present? And if not, is there a way to add them... for instance as part of the adapter cable?
 
Cheers!

 
the only way is to email the producer, to see if the output impedances and the capacitors match... I can't tell more on that, I'm not a technician either.
It's just that usually pre-outs have a far higher impedance than that 75 Ohm... And most headphones have even lower one...!

 

[Edoardo]

Quote:

And now to your last post:
 
Thanks again... so it really seems that there is no way around a headphone amp... Actually, I already got one, an audio-gd fun, which I guess to be a pretty nice tool, and even though its a DAC, too, it has an analogue RCA input that I can feed through my preamp.
 
However, I consider my preamp to be far superior. That is why I wanted to find a way to avoid another preamp - circuit that would alter the sound. In particular, my preamp has certainly the better potentiometers... and two potentiometers in a line just does not make sens, I guess.
 
I still don't have any cans, I am in the deciding process. After reading a couple of hours, I guess I am the Grado type of listener. I am still not sure, if I shall start on a budget with SR225i, or save up a while for the RS-2 or even RS-1. Or maybe go for an ATH-AD900. Or a AKG K181 DJ that seems to please not only DJs...
 
Cheers!

 
did you buy the amp before the cans? Not a good move, honestly.
 
I then must tell you that all Grado, AKG and ATHs headphones have very low impedance, Grado's are all 32 Ohm for instance. Any headphone you mentioned will NOT match the pre-amp's line outs for matters of impedance... But these headphones are very easy to drive also, and will not suffer a lot from the amp's quality. I mean in these cases the most of the sound quality is given from the headphones, and going for a "big" amp will not be a big change in terms of quality, as long as the amp is decent (fairly neutral frequency response, no electric noises, ground loops, etc.) AudioGD product have a high quality/price ratio and the FUN can do a good job with these easy-to-drive headphones!
 
 
 

 

[ursdiego]

Well that sounds good anyway, even if it goes through the audio-gd preamp, then!
 
In any case, thanks a million for your replies, you really helped me understand some basics about using headphones!
 
The way was actually not very standard... I bought the FUN primarily as a DAC/preamp for my backup (speakers) equipment. There it will be used with a audio-gd panther power amp, which is a fairly cheap amp he does not produce anymore.
 
Having a Headphone amp on the shelf, I got to the idea of connecting a pair of old cheap Aiwa- Cans to it, just for curiosity… And then the curiosity was big enough to consider to buy some mid-priced cans, just to hear what that gives.
 
However, then I read about my preamp, and the new version of it has a headphone plug – without much more amplifying in it, as the preamp itself has already a good power base. I was then wondering, what would be necessary to “convert” my preamp output to connect the headphones, without as few “degrading” steps in between as possible.
Hence my question…
 
I have another thread going on, a typical head-fi-newbie thread, it’s here:
http://www.head-fi.org/t/571385/we-all-like-such-threads-help-200-choice-4-head-fi-newbie-hi-fi-oldie-wanting-involving-music
 
The cans I mentioned where some of those who got recommended on that thread. There is however another one, the DT880 600 ohms – however, just by one person – and it seems a little bit on the pricey side right now, but I would go for it, if was my taste (as described in my thread…), and if it allowed direct connection to my preamp (as I am still convinced that DNM gives the best quality signal and it can only get worse, even if slightly, when driven through other components).
 
The power-amp-to-headphone options sound as a good idea to try, too, but I still want my speakers to stay connected. I connect them quite carefully, using a contact cleaner and then a contact enhancer liquid, that do a nice job. However, connecting and disconnecting every time I want to use the cans would be rather annoying. So this option is not ideal for me, I'm afraid.
 
Still... at the end... might there be some headphones that can be connected to my line-out? It has 75 ohms and +- 19V.
 
Can I do harm to the headphones if I just try?
 
Anyway, how should the headphone-connection and headphone ohm - ratio be? I am a bit confused by that.

 

[Edoardo]

 
Quote:

There is however another one, the DT880 600 ohms – however, just by one person – and it seems a little bit on the pricey side right now, but I would go for it, if was my taste (as described in my thread…), and if it allowed direct connection to my preamp (as I am still convinced that DNM gives the best quality signal and it can only get worse, even if slightly, when driven through other components).
 
The power-amp-to-headphone options sound as a good idea to try, too, but I still want my speakers to stay connected. I connect them quite carefully, using a contact cleaner and then a contact enhancer liquid, that do a nice job. However, connecting and disconnecting every time I want to use the cans would be rather annoying. So this option is not ideal for me, I'm afraid.
 
Still... at the end... might there be some headphones that can be connected to my line-out? It has 75 ohms and +- 19V.
 
Can I do harm to the headphones if I just try?
 
Anyway, how should the headphone-connection and headphone ohm - ratio be? I am a bit confused by that.

 
Again I'm not a technician....
 
75 Ohm is perfect for a High impedance headphone out (let's say from 250 to 600 Ohms)... For example, once I used a professional headphone amplifier impedance-matched with the BeyerDynamic DT880 250 Ohm, and it had a 120 Ohm impedance out.
Anyway it was far, very far from producing 19 Volts, which are a lot of stuff for a pair of headphones! Some very good and powerful headphone amps produce 6,5 Volts into 32 Ohm headphones, 15 Volts into 100 Ohm and 20V in 600 Ohm ... Voltage "produced" "inside" a headphone increases with the headphone impedance. But I cannot tell you, because I do not know, how impedance out and impedance in and out mutually act with each other relating to voltage... It may amplify them very well though...
 
I'm not a technician... I can't help much than this...
 
if I were you I would:
- Open a thread in the dedicated head-fi section (DIY or sth)
- Mail the both the preamp and the headphone producer and ask about compatibility for direct connection with 250 Ohm headphones onwards
 
If you try to connect the low-impedance headphones you are likely to... I don't know, I've never tried
 
 

 

[ursdiego]

Yeah. All the headphones I am currently considering are rather low impedance, I think. So to start with, I will rather try to use the FUN. I will however ask the manufacturer of my preamp, to see what he sais. However, he has the reputation not to answer very quickly. I will see. Next step could eventually be to ask DIY - experienced head-fiers, what could be the most non-altering step between the line out and the headphone. Maybe something like a headphone amp without volume control.

 

[Edoardo]

 
Quote:

Yeah. All the headphones I am currently considering are rather low impedance, I think. So to start with, I will rather try to use the FUN. I will however ask the manufacturer of my preamp, to see what he sais. However, he has the reputation not to answer very quickly. I will see. Next step could eventually be to ask DIY - experienced head-fiers, what could be the most non-altering step between the line out and the headphone. Maybe something like a headphone amp without volume control.

Mmmh no, without volume control = poweramp. You don't need more amplitude,  just something to match the impedances, or a power soak after your power amp. Or a HighImpedance headphone you may like. Can I ask you where are you from?