[ra990]

I'm using the XLR-outputs to power my TC's too, but I find that there isn't enough juice to drive these properly. Sound is slightly weak/soft and bass isn't very impactful.
Someday I'll have to try out running speaker amps like Pass Labs XA25...

The XLR outs can be used single ended or balanced. Make sure you're using the correct Pins 2 & 3 to get the balanced connection with more power. I found I had more than enough power with ample slam with my TCs out of the TT2/balanced.

 

[Rob Watts]

[QUOTE="Rob Watts, post: 16091242, member: 394072"
XLRs into 16 ohm loads or greater is fine. But 18v RMS is a lot of voltage to feed into a headphone!

Whilst on the subject of XLRs, some amplifiers on the XLR inputs short pins 1 and 3 together. This can cause damage to TT2, so take care that XLR inputs are truly balanced.

Is Rob, in referencing the 18v using the XLR's from the TT2, essentially saying that it is not a good idea to use the XLR outputs for headphones even above 18 ohms?

If using a 2, 3 pin female XLR to 4 pin female XLR balanced cable do we just need to be sure to have the 3 pin XLR wired as:

pin 1 (shield / ground)
pin 2 (+ / positive)
pin 3 (- / negative)
[/QUOTE]

Yes that wiring for XLR is fine.

On the Abyss though, the HP is 47 ohms and 88dB SPL with 1mW. Using the XLR outputs you can get a max of 7W RMS per ch - hot smoking ears. And the SPL would be a deafening 126 dB. Single ended is 1.8W, and still too much at 120dB SPL. So I would stick with single ended even with the Abyss AB-1266 Phi...

 

[nwavesailor]

Thanks, @Rob Watts!
It sounds like others have used the XLR outputs with the susvara at 60 ohm and 83dB so I'll go that route as well

 

[Ragnar-BY]

On the Abyss though, the HP is 47 ohms and 88dB SPL with 1mW. Using the XLR outputs you can get a max of 7W RMS per ch - hot smoking ears. And the SPL would be a deafening 126 dB. Single ended is 1.8W, and still too much at 120dB SPL. So I would stick with single ended even with the Abyss AB-1266 Phi...

Your math is absolutely right, but practical experience with inefficient headphones shows different results somehow. HiFiMan HE-6SE and Abyss 1266 with TT2's balanced output clearly sounds better than SE. Maybe headphone manufacturers measure sensivity in a wrong way, maybe it has something to do with bigger voltage swing. I don't know what exactly is the reason, but on complex orchestral music benefit of additional power is very clear to me.

 

[GreenBow]

With some luck though, Rob's digital amp might be along soon. I don't know much about. I think it takes the upsampled signal via from the TT2 (and other DACs), and possibly the M-Scaler. Then just gives the samples some digital gain, I think like the output stage of the DACs might do.

I think it can run with only the M-Scaler, which would rock. (Like the m-Scaler would be the front end of a DAC. Then the digital amp would be the back end.)

Anyway, there will be folks who know way more than me. ... That's what I think I understood about the digital amp, anyway. It would be nice to connect to digital amp via USB from whichever future source, to easily nullify any noise. Like from M-Scaler or DAC.

 

[InstantSilence]

Your math is absolutely right, but practical experience with inefficient headphones shows different results somehow. HiFiMan HE-6SE and Abyss 1266 with TT2's balanced output clearly sounds better than SE. Maybe headphone manufacturers measure sensivity in a wrong way, maybe it has something to do with bigger voltage swing. I don't know what exactly is the reason, but on complex orchestral music benefit of additional power is very clear to me.

It really is this way, but if thr math checks out, why doesn't the sound? Very weird.

 

[GreenBow]

@Ragnar-BY

I swear I saw a What HiFi review of the Abyss 1266 Phi tc. It was not a very good review though. Whenever I look again for the review I can't find it. Maybe I read it first when I was tired-out, and remembered the reviewer wrong. The HiFi News review though, (linked below) has reservations. From users in threads though, those headphones are supposed to rock.

Abyss AB-1266 Phi TC Headphones | Hi-Fi News

Anyway, just saying. Not really making any point in this thread.

 

[Redwingnine]

Seems like the easiest way to connect the 1266 to the TT2 XLR out is to just use XLR cables out to Mic adapter, and connect the TT2 up to the 1266.

Anyone try this?

 

[zenlisten]

I'm using the XLR-outputs to power my TC's too, but I find that there isn't enough juice to drive these properly. Sound is slightly weak/soft and bass isn't very impactful.

The XLR outs can be used single ended or balanced. Make sure you're using the correct Pins 2 & 3 to get the balanced connection with more power. I found I had more than enough power with ample slam with my TCs out of the TT2/balanced.

I can definitely say that the sound for me isn't weak or soft, the bass is quite powerful and tight at the same time. Of course, it may be even more powerful with a good amp but currently I don't have one (not even an Abyss-classified Tier D, see the list below).

Maybe it depends on how the pins are connected as @ra990 writes. I use a female-to-female joiners, see the picture below.

I can confirm that connecting the Abyss AB-1266 Phi TC headphones via the NEUTRIK female-to-female XLR joiners to the TT2 works flawlessly.
TT2 has been set to Low Gain, and it seems to have enough power to feed these headphones; the volume is usually below 0. The sound is amazing.

Amplifier	AB-1266 Tier	Video
XIAUDIO Broadway	A​	1:38
XIAUDIO Broadway S	B	2:17
Benchmark HPA4	A½	3:13
XIAUDIO Formula S	A (with Powerman A+)	4:08
iFi Micro iDSD Black Label	C	6:11
HeadAmp GS-X Mini	A	8:03
HeadAmp GS-X mk2	C	9:21
Cavalli Liquid Spark	B	10:39
Woo Audio WA33 “JPS Edition”*	A+	11:57
Woo Audio WA33 Elite Edition	A	13:43
Woo Audio WA33 Standard	A	14:44
Wells Audio Headtrip II	A	15:26
Audiovalve Solaris	B	17:12
THX AAA 789	D	19:05
Topping A90	B	20:13
Moon Audio 430A	B	21:58
iFi xCAN	C	24:12
JDS EL Amp II	B	25:14
Woo Audio WA11	C	26:26
Woo Audio WA5-LE	B	27:45

* Note that Woo Audio currently doesn’t offer a single variant of WA33 called “JPS Edition.” Instead, there are two JPS variants: “Standard + JPS Wires,” and “Elite Edition + JPS Wires.”

 

[bpcans]

Seems like the easiest way to connect the 1266 to the TT2 XLR out is to just use XLR cables out to Mic adapter, and connect the TT2 up to the 1266.

Anyone try this?

I know this might sound crazy, but has anybody tried plugging a pair of Abyss 1266 Phi TC’s into the front of a Hugo TT2 using a single ended cord?

 

[Redwingnine]

No need for sarcasm. I'm sure the 1266 sounds just fine with the SE input. The Hugo-2 can drive the 1266 plenty loud.

I believe the issue is a lack of perceived dynamics with the SE input.

 

[zenlisten]

So I just tried the front panel 6.3mm jack with a few tracks, and the 1266 sounds nice. Via the XLRs the same tracks sound amazing. The difference is easy to perceive (unfortunately I am not trained to put it into words). One is alright, but the other is so good, I don't want to stop listening. (Based on this experience it would be probably a good idea to test different amps.)

EDIT (Jan 21): Turns out the two modes were not volume matched. According to @Rob Watts the difference is 6dB, and indeed if this is kept, the perceived difference in the sound disappears. Looks like there is no need to use the XLR outs.

 

[InstantSilence]

No need for sarcasm. I'm sure the 1266 sounds just fine with the SE input. The Hugo-2 can drive the 1266 plenty loud.

I believe the issue is a lack of perceived dynamics with the SE input.

Will resolution and details be lost form SE? Va the xlr for the TC?

 

[Redwingnine]

Will resolution and details be lost form SE? Va the xlr for the TC?

Not lost, per se. Just less impact.

It's the same type of change when one goes from a 50 watt amp for speakers up to a 200 watt amp. Suddenly, the bass has much more impact, Soundstage gets wider and deeper, etc. Both amps work, but the extra power helps across-the-board.

 

[Redwingnine]

So I just tried the front panel 6.3mm jack with a few tracks, and the 1266 sounds nice. Via the XLRs the same tracks sound amazing. The difference is easy to perceive (unfortunately I am not trained to put it into words). One is alright, but the other is so good, I don't want to stop listening. (Based on this experience it would be probably a good idea to test different amps.)

Thanks for the feedback. There are a lot of observations that the TT2 headphone amp can be bettered with an external amp. Not sure I agree. If the XLR out is reference class, it would follow that driving a resistive load of 42 to 48 ohms from the same output would sound just as good driving headphones directly.