[flipflop]

hi all!
 
Can anyone recommend a good headphone tap/adapter (a device which enables you to connect headphones to an integrated amplifier via speaker terminals) with gain controls? Found one called Can Opener by VinylFlat but the general consensus was that this was way overpriced (and no gain controls) Here's my situation...
 
I currently have an old NAD 304 amplifier which I have delegated primarily for headphone use.  The thing is, my amp's channels are quite unbalanced especially at low volume levels.  The channels balance out eventually but I would have to crank the dial a bit beyond comfortable listening levels.  For reference, if zero volume is at 7 o'clock, comfortable listening would be at 8 o'clock and channels balance out a little below 9 o'clock.  This is a common problem with NAD amps, and has something to do with their volume potentiometers.  I've tried cleaning the pots already (with "generic" contact cleaner) and had some improvement but i still practically don't have any control over the volume (it's either loud or unbalanced).  I'd like to keep my amp since the resale value is practically nil (vs what i paid for it), and I also use it to power my electrostatic energizer.  Any help would be most appreciated.
 
thanks!
 
P.S. I will primarily be using this setup for high impedance cans (AKG K141 600ohm; Koss Dynamic /10 230ohm) and am trying to build a collection of vintage headphones.  I have a separate setup for my more modern lower impedance gear.
 
P.P.S. My speaker outputs seem to be ok since my electrostatic set sounds balanced.  I'm not sure whether there's something wrong with the headphone output (failed resistor perhaps?) or i just get a better signal since i am able to go a bit beyond the 9 o'clock position on the volume dial.

 

[Orestes1984]

Use the line out, phono out or tape out or whatever and go to a headphone preamp.

 

[flipflop]

  Use the line out, phono out or tape out or whatever and go to a headphone preamp.

 
Not exactly sure what you mean. Should i try using the different inputs?
 
A headphone preamp? That would take my amplifier out of the chain right?  I would rather have the amp power the headphones than spend on another headphone amp/preamp.  My thinking is that I could get better performance from my NAD 304  + headphone tap versus an entry to mid level headphone amplifier.
 
I'm also looking into RCA Attenuators (by Harrison Labs or Rothwell Audio Products) as an alternative to a headphone tap (with gain controls).  Does anyone have info on these?

 

[ProtegeManiac]

Quote:

Originally Posted by flipflop /img/forum/go_quote.gif

hi all!

 

Can anyone recommend a good headphone tap/adapter (a device which enables you to connect headphones to an integrated amplifier via speaker terminals) with gain controls? Found one called Can Opener by VinylFlat but the general consensus was that this was way overpriced (and no gain controls) Here's my situation...

 

I currently have an old NAD 304 amplifier which I have delegated primarily for headphone use.  The thing is, my amp's channels are quite unbalanced especially at low volume levels.  The channels balance out eventually but I would have to crank the dial a bit beyond comfortable listening levels.  For reference, if zero volume is at 7 o'clock, comfortable listening would be at 8 o'clock and channels balance out a little below 9 o'clock.  This is a common problem with NAD amps, and has something to do with their volume potentiometers.  I've tried cleaning the pots already (with "generic" contact cleaner) and had some improvement but i still practically don't have any control over the volume (it's either loud or unbalanced).  I'd like to keep my amp since the resale value is practically nil (vs what i paid for it), and I also use it to power my electrostatic energizer.  Any help would be most appreciated.

 

thanks!

 

P.S. I will primarily be using this setup for high impedance cans (AKG K141 600ohm; Koss Dynamic /10 230ohm) and am trying to build a collection of vintage headphones.  I have a separate setup for my more modern lower impedance gear.

 

P.P.S. My speaker outputs seem to be ok since my electrostatic set sounds balanced.  I'm not sure whether there's something wrong with the headphone output (failed resistor perhaps?) or i just get a better signal since i am able to go a bit beyond the 9 o'clock position on the volume dial.

 

That's not exclusive to NAD amplifiers and no, it isn't dirty either - analogue potentiometers really just have a tendency for channel imbalance until you get past a certain setting (on a regular dial it's usually 9:00). If anything, better pots just have a less noticeable imbalance before then. Your electrostats work fine because you're likely using a higher setting on the knob but still at a comfortable listening level because those need much higher output voltage.

 

 

Quote:

Originally Posted by flipflop /img/forum/go_quote.gif

 

Not exactly sure what you mean. Should i try using the different inputs?

 

He means you hook up a headphone amplifier to the tape output, because he's assuming that you have an existing speaker system and just want to use headphones on it (which is how you normally integrate a headphone amplifier to a speaker system, the other method being to use a headmp with a preamp output and a dedicated speaker power amp) because he missed that part about your using the NAD 304 only for headphones. If that's taken into account, what he's saying is ditch the integrated amp and get a headphone amp.

 

 

 

Quote:

Originally Posted by flipflop /img/forum/go_quote.gif

 

My thinking is that I could get better performance from my NAD 304  + headphone tap versus an entry to mid level headphone amplifier.

 

As much as the problem with headphone amp design is that headphones and IEMs cover a load impedance of anywhere between 12ohms to 600ohms, and so some amps are better at a certain range (ie OTL tube amps only do well with high impedance, some amps can't deliver a lot of voltage at high impedance, etc), a speaker amp is designed mostly for low impedance loads. Still if your concern is gain, and you're using vintage high impedance cans that don't have efficiency ratings as high as, say, the Beyer T1, then might as well just try the speaker adapters without gain controls.

 

[flipflop]

 

 

That's not exclusive to NAD amplifiers and no, it isn't dirty either - analogue potentiometers really just have a tendency for channel imbalance until you get past a certain setting (on a regular dial it's usually 9:00). If anything, better pots just have a less noticeable imbalance before then. Your electrostats work fine because you're likely using a higher setting on the knob but still at a comfortable listening level because those need much higher output voltage.

 

 

 

He means you hook up a headphone amplifier to the tape output, because he's assuming that you have an existing speaker system and just want to use headphones on it (which is how you normally integrate a headphone amplifier to a speaker system, the other method being to use a headmp with a preamp output and a dedicated speaker power amp) because he missed that part about your using the NAD 304 only for headphones. If that's taken into account, what he's saying is ditch the integrated amp and get a headphone amp.

 

 

 

 

As much as the problem with headphone amp design is that headphones and IEMs cover a load impedance of anywhere between 12ohms to 600ohms, and so some amps are better at a certain range (ie OTL tube amps only do well with high impedance, some amps can't deliver a lot of voltage at high impedance, etc), a speaker amp is designed mostly for low impedance loads. Still if your concern is gain, and you're using vintage high impedance cans that don't have efficiency ratings as high as, say, the Beyer T1, then might as well just try the speaker adapters without gain controls.

 
sorry, can't figure out the multi-quote function...
 
Thanks for clearing that up Protege! Yes, I'd really like to use the NAD.  Really helpful since I use it to run my electrostatic set. And yes it would seem that the only reason they work is because of the higher voltage requirement.
 
My only concern with getting a speaker adapter (without gain/volume control) is that I might end up back where I started since everything else will remain the same.  I still won't be able to turn the volume knob all the way to where I can get a balanced output.  I've been mulling it over and below are my thoughts thus far (please keep in mind that I have absolutely no background in electronics. schematics are like hieroglyphics to me)...
 
1.  I'm assuming that like most other older integrated amplifiers, the headphone output on the NAD is basically a connection to the speaker outputs of the amp with resistors to lower the load.  (Would this be an accurate assumption?)
 
2.  Since the main issue is with the volume potentiometers, the recourse would be to attenuate the signal either:
 
      a.  at source (via RCA Attenuators from my CDP/DAC to amp)
      b.  at headphone level (via Headphone/Speaker tap with volume/gain control)
     *c.  at headphone level (via Headphone/Speaker tap WITHOUT volume/gain control but with higher value resistors than those in the NAD's headphone output terminal)
 
Is Option C viable? Is that how it works? I have the NAD's service manual on hand.  If I choose a box with higher value resistors, will I be able to effectively lower the audio signal than the current headphone terminal?  Really sorry if it seems like a dumb question.

 

[flipflop]

Option A:  http://www.head-fi.org/products/goldenjacks-attenuators-20db
Option B:  http://www.head-fi.org/products/rolls-pm57-headphone-tap
Option C:  http://www.zynsonix.com/Speaker-Amp-to-Headphone-Converter-Box_p_36.html
 
I know these MIGHT compromise the audio quality.  I'm just wondering which of the three would "do the least damage", so to speak. 

 

[ProtegeManiac]

   
sorry, can't figure out the multi-quote function...

 
Just copy-paste or hit Quote several times then edit each box as necessary and type between them.
 
 

 
Thanks for clearing that up Protege! Yes, I'd really like to use the NAD.  Really helpful since I use it to run my electrostatic set. And yes it would seem that the only reason they work is because of the higher voltage requirement.
 
My only concern with getting a speaker adapter (without gain/volume control) is that I might end up back where I started since everything else will remain the same.  I still won't be able to turn the volume knob all the way to where I can get a balanced output.  I've been mulling it over and below are my thoughts thus far (please keep in mind that I have absolutely no background in electronics. schematics are like hieroglyphics to me)...

 
Here's the thing though - are you running the electrostats off the speaker outputs? If you are then you can just keep using them that way and then just get an affordable but otherwise versatile headphone amp to hook up to the Tape/Rec output on the back for everything else.
 

 
1.  I'm assuming that like most other older integrated amplifiers, the headphone output on the NAD is basically a connection to the speaker outputs of the amp with resistors to lower the load.  (Would this be an accurate assumption?)

 
Not sure how the 304 works but I honestly just didn't like the headphone output on that - whether it's connected to the amp output stage or not doesn't matter because of its high output impedance. It made my SR225 sound like a tin can and while it's better on the 300ohm HD600, it actually sucks next to the headphone output on my Marantz CD60, which actually used a Philips headphone driver chip that Fiio later used in the E9 (and a newer, but similar type chip on the current K5).
 
 

 
2.  Since the main issue is with the volume potentiometers, the recourse would be to attenuate the signal either:
 
      a.  at source (via RCA Attenuators from my CDP/DAC to amp)

 
If you go with this you can get something like the Schiit Sys - it's a very affordable passive preamp.
 
 
Quote:

 
      b.  at headphone level (via Headphone/Speaker tap with volume/gain control)

 
The only speaker adapters I've seen that have a volume control though are the ones that come with electrostat headphones.
 
 

 
     *c.  at headphone level (via Headphone/Speaker tap WITHOUT volume/gain control but with higher value resistors than those in the NAD's headphone output terminal)
 
Is Option C viable? Is that how it works? I have the NAD's service manual on hand.  If I choose a box with higher value resistors, will I be able to effectively lower the audio signal than the current headphone terminal?  Really sorry if it seems like a dumb question.

 
You might want to ask that in the DIY forum - engineers hang out there more and can tell you of the drawbacks if any.

 

[flipflop]

 Just copy-paste or hit Quote several times then edit each box as necessary and type between them.

 

Ok, I think I got it.... Thanks!
 

 Here's the thing though - are you running the electrostats off the speaker outputs? If you are then you can just keep using them that way and then just get an affordable but otherwise versatile headphone amp to hook up to the Tape/Rec output on the back for everything else.

 
I actually have and old JDS Labs Objective 2 Amp.  They work well with lower impedance cans but sound quite thin with the vintage (generally higher impedance ones).  I'd rather not purchase another.
 

 Not sure how the 304 works but I honestly just didn't like the headphone output on that - whether it's connected to the amp output stage or not doesn't matter because of its high output impedance. It made my SR225 sound like a tin can and while it's better on the 300ohm HD600, it actually sucks next to the headphone output on my Marantz CD60, which actually used a Philips headphone driver chip that Fiio later used in the E9 (and a newer, but similar type chip on the current K5).

 
I'm actually quite happy with the NAD's headphone out.  I find that they work quite well with the vintage stuff.  Not as great with more modern 'phones though. My guess is that most modern headphones were designed to work with more modern circuitry (and vice versa).
 

 If you go with this you can get something like the Schiit Sys - it's a very affordable passive preamp.

 
Currently an option I'm considering, although it would cost me quite a bit (shipping, etc.)
 

 The only speaker adapters I've seen that have a volume control though are the ones that come with electrostat headphones.

 
Maybe electrostat amps.  My electrostat energizer (Stax SRD-7 Mkii) doesn't have volume controls.
 

 You might want to ask that in the DIY forum - engineers hang out there more and can tell you of the drawbacks if any.

 
Actually, this would seem to be the most cost-effective (and easiest) option.  While reviews for the ready built RCA attenuators (Harrison Labs, Goldenjacks, Rothwell) are mixed, the DIY route seems more favorable since it considers the output and input resistance of the gear involved.  I've been reading up on it and it does make more sense given my situation.  I'll probably go this route for now.

 

[ProtegeManiac]

  I'm actually quite happy with the NAD's headphone out.  I find that they work quite well with the vintage stuff.  Not as great with more modern 'phones though. My guess is that most modern headphones were designed to work with more modern circuitry (and vice versa).

 
It's not the era that the headphone came from, it's the impedance. Integrated amp manufacturers just for some reason thought that AKG didn't get to the K4-- and K5-- series, or that Grado didn't exist, and kept making headphone outputs that had a 120ohm or higher output impedance. 
 
 
 

 
Currently an option I'm considering, although it would cost me quite a bit (shipping, etc.)

 
Check in local audio forums in your area, there could be somebody bringing in stuff from the US with just a small mark up. Or you can try a cargo forwarder.