Amp or different headphones? What do u think?

[Bazza Hallward]

[color=rgba(0, 0, 0, 0.870588)]The OPPO doesn't specify its output impedance but I believe that it uses a Texas Instruments headphone stage. Texas Instruments recommended an output impedance between 10 and 100 ohms for their headphone stage, but I guess it depends on the application. [/color][color=rgba(0, 0, 0, 0.870588)][/color]
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[color=rgba(0, 0, 0, 0.870588235294118)]The NAD C165bee has a discreet headphone stage. And its 10 ohm output impedance is better than most stereo amps and pre-amps and in fact better than some dedicated headphone amps. The sound is definitely richer via the NAD over the OPPO, but isn't necessarily more controlled.[/color][color=rgba(0, 0, 0, 0.870588)][/color]
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[color=rgba(0, 0, 0, 0.870588)]I did also try a Quad PAOne tube headphone amp. It has a 32 ohm output. That didn't work so well with the Grados. But again, it may not have been an impedance issue, but just not the best match. With the Quad, the sound was too warm in the bass and hot in the midrange. It may have even lacked control at higher volumes because the sound became looser with more volume.[/color]
 
[color=rgba(0, 0, 0, 0.870588235294118)]When I owned the HD 600s I ran them out the headphone out of a Cambridge Audio 840A. I concluded that the HD600s needed a dedicated amp... it wasn't a volume issue, it was a lack of dynamics. But again, it may have been a poor match with the Cambridge Audio amp and CD player, which were both on the more staid side. The HD600s with the Quad... now that would be interesting to try.[/color]
 
[color=rgba(0, 0, 0, 0.870588235294118)]You're right in saying that I won't know if I am getting the Grado sound (or the sound I am after) until I hear them on a few well-matched headphone amps. It might be worth trying to trial some amps in a shop.[/color]

 

[sejsel]

Testing the Grado GS1000 with Quad Pa-One the other day around, I've got the opposite impression, the amp gave to the GS1000 what the can needs in terms om amplification, as well as character of the sound. Meaty, full, smooth, just enough, or more... Haven't done much comparisons apart from A-B with only one comparable (in the same price range, from equally impressive and renowned manufacturer of the high end audio amps) amp/dac with tube output headphone stage, which sounded flat and lacking depth and fullness in comparison to the Quad Pa One.

What I would like to have in Quad Pa One is gain control (turning knob for adjusting the gain of the
amp), as found in Pathos Aurium, so that the volume knob had more s(ch)wing room with Grados..., and thus, presumably finer degree of control... but then again, many have said that these cans were (presumably) not designed for really loud volumes. Still, got ear-deafening volume without disto or change of the sound characteristics, of of the Pa-One, and discovered only then (while testing with Pa-One) how good the can really is.

There is a short thread about Quad Pa One at head-fi; being here, I am still curious about getting the max of what GS1000 can give, so any thoughts or recommendations are highly welcome... Hearing what I have heard while testing, I am leaning towards the tube amps, those whos' output stage is run by tubes as well.

Pathos Aurium was together with GS1000 put as a top choice headphone system in (I believe) 2014. - 2015. , never had a chance to test it and compare, unfortunately...

 

[Bazza Hallward]

There's a couple of things I should say about my experience with the Quad PA-One with the Grado PS500 to put it into perspective.
 
First, the Quad PA-One that I was testing had damaged tubes (I'm pretty sure)... I probably should have mentioned that. There was a lot of microphony and more in one channel than the other. There was also a very loud hum through the tubes - which wasn't the transformer itself. And there was also a poor channel imbalance. I'm pretty sure that the tubes were damaged in transit.
 
Second, a couple of the tracks I was listening to had an overripe base and a shouty midrange - which was exaggerated by the Quad - which again the Quad I had was probably not a good example. These audio tracks sound better via the NAD headphone output, but you can still tell that the 'bloated' sound is on the recording itself.
 
But my lens at the time was through the 'impedance match' debate, which I now have doubts about. The 30 ohm output impedance of the Quad PA-One doesn't fit was some peoples rules regarding impedance matching with Grado's - being nominally 32 ohms. At the time, I wasn't sure if the tubes were damaged though. So I thought that the Quad wasn't controlling the Grado's very well. I have also read that tube amps don't like low impedance headphones.
 
So we have to be careful about what we read online from people's personal experiences. I tried my best to not focus on performance of audio equipment and talk about matching headphones to amp. Never-the-less, I'm happy with the NAD C165BEE and it's 10 ohm impedance with the Grados... the more I listen to it the more I like it.

 

[sejsel]

There's a couple of things I should say about my experience with the Quad PA-One with the Grado PS500 to put it into perspective.

First, the Quad PA-One that I was testing had damaged tubes (I'm pretty sure)... I probably should have mentioned that. There was a lot of microphony and more in one channel than the other. There was also a very loud hum through the tubes - which wasn't the transformer itself. And there was also a poor channel imbalance. I'm pretty sure that the tubes were damaged in transit.

Second, a couple of the tracks I was listening to had an overripe base and a shouty midrange - which was exaggerated by the Quad - which again the Quad I had was probably not a good example. These audio tracks sound better via the NAD headphone output, but you can still tell that the 'bloated' sound is on the recording itself.

But my lens at the time was through the 'impedance match' debate, which I now have doubts about. The 30 ohm output impedance of the Quad PA-One doesn't fit was some peoples rules regarding impedance matching with Grado's - being nominally 32 ohms. At the time, I wasn't sure if the tubes were damaged though. So I thought that the Quad wasn't controlling the Grado's very well. I have also read that tube amps don't like low impedance headphones.

So we have to be careful about what we read online from people's personal experiences. I tried my best to not focus on performance of audio equipment and talk about matching headphones to amp. Never-the-less, I'm happy with the NAD C165BEE and it's 10 ohm impedance with the Grados... the more I listen to it the more I like it.

Believe me, I was doing some testing of my own nowadays, and realizing more and more that Grados (PS1000 and specially GS1000) require a tube amp which has good synergy with them.
Edit: removed one part from my post: after couple of weeks of burn-in in very moderate volume, and long period of rest (not being used) - the GS1000 emerged as the can that sings of the headphone output of the MacBook Pro retina, the AudioEngine small USB dac, and from those sources would only need more amplification (volume), with some source tracks. Other than that, the Quad Pa One drove them without any hitches or the hum mentioned, but there was certainly a very thick and expensive power cable that I have seen coming out of the amp, there in the store where I auditioned, and probably the power conditioner that I did not seen, beneath, behind the shelf.

They (Grados) (edit DO NOT underperform of the solid states I have run across, with the type of music I listen to, and it is hand-picked, varied, high quality and very demanding on the system.

I was amazed how tight, controlled, yet rich and smooth the bass on these can was of the Quad. I could go up to the ear shuttering levels with the volume knob, and the amp never lost a millimeter of control, sound character was completely preserved.

I am very curious to how good a some more expensive tube headphone amps, such as Wa5 or Studio Six with Grado top models, or down the ladder, Wa6 and Wa3.

Amity head amps (amity.de) were mentioned to have particularly good synergy with Grados, and to control its' bass like no other budget offering.