[JohnA1]

@Rob Watts
Hi Rob,

Question about TT2 driving Martin Logan SL3 Panels
The SL3 manufacturer's sensitivity is 89db/m. Stereophile measured them a bit lower back in the day, but they said it is a line source and these measurements are meant for point sources. Anyway..

I am getting brand new panels from the States, so efficiency will be at its maximum.
Would a TT2 be able to drive them? If so what would be the optimal way?

I'm thinking of an RCA splitter, where a power amp drives the bass units and the TT2 the panels (I've always been bi-amping them)
The panels may drop impedance to 2 Ohms at high frequencies.
For low/medium volume output, will the TT2 output stage be up to the task?

 

[IgeNeLL]

@IgeNeLL What IEM are those?

I mistaken post in this thread while intended in Hugo2 thread
My IEMS is made by local engineer, brand TXN, because of young history then it is hard for me to tell detail, the website is under construction now.
It has been improved based on my feedback, on the perception of perfection.
The special thing on this iems is using Nordost Odin2 in internal wiring( which significant improved the sound quality by valhalla2 cable). Due to the awg size(23 awg), stiff, solid cable, the wiring is insanely challenging, kind of masterpiece in handcrafting.
On the perfection notation, my IEMS require much power for example TT2 provide much headroom and control of bass line than hugo2.

 

[Christer]

I don't get on with IEMs. I had a couple of custom units, and after an hour my ears ache. I did like Noble Kaiser IEMs though, but I haven't tried everything available today.

Interesting to know,I personally fully agree, but if my memory serves me right, you used the Kaiser and also Audioquest´s Nighthawks while working on Dave didn´t you?
As far as IEMs are concerned I just don´t get why people want to stick any those into their ear canals, hairy or not, bypassing the outer ear completely other than on flights..


I would be interested to know what headphones you are using now if any at all?

I do enjoy both my Qutest and Mscaler a lot both via electrostatic speakers and my HEKV2 headphones but neither of the two headphones mentioned above impressed me much.
Nor was I much impressed by Dan Clark´s closed or open Aeons with large scale classical music which is on my main menue.
Neither of the two could reproduce big climaxes or soundstages to my satisfaction.Too small and a bit congested. But I remember his electrostatic headphone sounding very good at Canjam in Singapore a couple of years ago.

Imho to do full justice to your dacs and Mscaler via headphones one needs better headphones than closed backs,or headphones mainly designed for travel use with the compromises that involves.
My personal choices from the ones I know quite well with Dave/HMS would be Utopia or my HEKV2 or HEKSE used directly.

And even better than those, Susvara with a high quality headphone amp added, and several of the top of the line electrostatics from Stax or Hifiman also with suitable amps of course.
The low distortion and transparency of electrostatics is addictive and I can enjoy it on a daily basis via speakers.
But there are also some interesting highend headphone newcomers I´d like to audition like the AMT Heddphone or T&A´s planar SolitaireP/PSE for example.
Cheers CC

 

[Ards]

The panels may drop impedance to 2 Ohms at high frequencies.

I think it's worse than that - more like 0.5ohms at 20kHz. I had the SL3, prior to my current Montis. Both are hard to drive well because of this sloping impedence. I'm currently driving mine with a Bel Canto Black EX (500w into 4ohms) and *finally* the panels are under control.

 

[Rob Watts]

@Rob Watts
Hi Rob,

Question about TT2 driving Martin Logan SL3 Panels
The SL3 manufacturer's sensitivity is 89db/m. Stereophile measured them a bit lower back in the day, but they said it is a line source and these measurements are meant for point sources. Anyway..

I am getting brand new panels from the States, so efficiency will be at its maximum.
Would a TT2 be able to drive them? If so what would be the optimal way?

I'm thinking of an RCA splitter, where a power amp drives the bass units and the TT2 the panels (I've always been bi-amping them)
The panels may drop impedance to 2 Ohms at high frequencies.
For low/medium volume output, will the TT2 output stage be up to the task?

2 ohms at 20k would be fine; but I am not so sure about 0.5 ohms so tread carefully.

Interesting to know,I personally fully agree, but if my memory serves me right, you used the Kaiser and also Audioquest´s Nighthawks while working on Dave didn´t you?
As far as IEMs are concerned I just don´t get why people want to stick any those into their ear canals, hairy or not, bypassing the outer ear completely other than on flights..


I would be interested to know what headphones you are using now if any at all?

I do enjoy both my Qutest and Mscaler a lot both via electrostatic speakers and my HEKV2 headphones but neither of the two headphones mentioned above impressed me much.
Nor was I much impressed by Dan Clark´s closed or open Aeons with large scale classical music which is on my main menue.
Neither of the two could reproduce big climaxes or soundstages to my satisfaction.Too small and a bit congested. But I remember his electrostatic headphone sounding very good at Canjam in Singapore a couple of years ago.

Imho to do full justice to your dacs and Mscaler via headphones one needs better headphones than closed backs,or headphones mainly designed for travel use with the compromises that involves.
My personal choices from the ones I know quite well with Dave/HMS would be Utopia or my HEKV2 or HEKSE used directly.

And even better than those, Susvara with a high quality headphone amp added, and several of the top of the line electrostatics from Stax or Hifiman also with suitable amps of course.
The low distortion and transparency of electrostatics is addictive and I can enjoy it on a daily basis via speakers.
But there are also some interesting highend headphone newcomers I´d like to audition like the AMT Heddphone or T&A´s planar SolitaireP/PSE for example.
Cheers CC

So my travel headphones are Dan Clark closed Aeon 2. I think they are great, and are fine with large scale classical with Dave, Hugo 2 or TT2. I certainly prefer them to the Utopia. I am looking forward to CanJam when I can try the Aeon Noir and other new headphones.

Happy listening, Rob

 

[jarnopp]

2 ohms at 20k would be fine; but I am not so sure about 0.5 ohms so tread carefully.


So my travel headphones are Dan Clark closed Aeon 2. I think they are great, and are fine with large scale classical with Dave, Hugo 2 or TT2. I certainly prefer them to the Utopia. I am looking forward to CanJam when I can try the Aeon Noir and other new headphones.

Happy listening, Rob

Rob, the Aeon 2 Noire are the same as yours, but with the perforated ear pads. I prefer them and you might pick up a set of pads. A bit less thick mid bass. Still really great headphones!

 

[JohnA1]

2 ohms at 20k would be fine; but I am not so sure about 0.5 ohms so tread carefully.

Thanks Rob.
So what is the worst-case scenario if impedance tends to occassionally drop at 1 Ohm say, TT2 overheating?
Would temperature monitoring (with a laser-gun style sensor) pick it up perhaps?
My aim is transparency - I'm happy with the sound of QuTest, but would consider a TT2 if I could get preamp/pwr amps out of the way

 

[Christer]

2 ohms at 20k would be fine; but I am not so sure about 0.5 ohms so tread carefully.


So my travel headphones are Dan Clark closed Aeon 2. I think they are great, and are fine with large scale classical with Dave, Hugo 2 or TT2. I certainly prefer them to the Utopia. I am looking forward to CanJam when I can try the Aeon Noir and other new headphones.

Happy listening, Rob

Interesting ,so you actually prefer the Aeon 2 closed to Utopia?
That´s quite a surprise and may upset some real Utopia fans.
Post it over at the Utopia thread.
The Aeons I auditioned with my reference material were model 1 and good for their size and price imho, but not as resolving as my HEKV2 or any of the other headphones I quoted.
Compared to my HEKV2 the Aeons both closed and open, sounded a bit like a smaller almost chamber orchestra version versus big full orchestra to me.
Utopia is again, imho, a highly resolving headphone, but not ideal to me with large scale classical which needs "space to breathe". Utopia can sound a bit too upfront.

It might be interesting to compare Aeon 2 and Utopia with the DGG /Salonen Stravinsky Rite of Spring some here have liked recently, as an example of densely orchestrated music that goes both loud, very loud, and quiet, sometimes both a the same time depending on which section of the orchestra one chooses to pay attention to.
The ability to keep strands apart without congestion in dense music is one of the big advantages with your dacs and HMS.

But not all headphones are up to the job of keeping things apart without congestion or masking effects and good as they were Aeon one belonged in that category for me.
Aeon 2 closed must be quite something if they beat Utopia.

I definitely have to audition those when possible.
I Hope to see you again,at Canjam Singapore, although things currently don´t look very bright regarding travel and Covid in SE Asia.
Singapore hasn´t even opened up to Malaysia yet.
Cheers CC

 

[118900]

Not sure whether this has been seen already. I don't stream music or download MQA files myself but I know a lot of people do and this seems quite interesting, especially considering Chord's propensity to not support MQA .

 

[ecwl]

Interesting ,so you actually prefer the Aeon 2 closed to Utopia?
That´s quite a surprise and may upset some real Utopia fans.

Hmmm... I don't think this is new. When @Rob Watts first mentioned he really likes Aeon Flow 2 closed, I seeked out one to demo during my travels. And I have to admit, it is substantially better than Aeon Flow 1 Closed. Unfortunately, the clamping force on my head and glasses were just too strong to be comfortable for me, just like the HEKV2 was too big for my weird head (even if I prefer HEKV2 to Focal Utopia on brief listening comparisons). I never directly A/B Aeon Flow 2 closed vs Utopia. But Aeon Flow 2 is also much more portable than Utopia (even though I've taken the Utopia with Hugo 2 on short flights). And definitely the frequency response of the Utopia and Aeon Flow 2 are slightly different.

I'm very happy with my Focal Utopia but I'm also very happy with my Aeon Flow 1 closed and if my head shape is different, I'd happily upgrade the 1 to the Aeon Flow 2 closed for work and travel.

 

[Vyyy]

So my travel headphones are Dan Clark closed Aeon 2. I think they are great, and are fine with large scale classical with Dave, Hugo 2 or TT2. I certainly prefer them to the Utopia. I am looking forward to CanJam when I can try the Aeon Noir and other new headphones.

Happy listening, Rob

Rob, may I ask do you use with your Aeon's any provided filter pads or any other adjustment instead of original ones? Thanks.

 

[Jawed]

Yes it's a pulse array DAC in the ADC feedback loop - with a latency of just two or three master clock cycles - the whole ADC runs from 104MHz, so there is no significant delay to worry about. The problem has been getting from 104MHz down to 768k or 705k - and this has turned out to be a major headache.

The reason why it's a major problem is that studios run a common clock to sync up all their ADCs. Using an external clock is a crazy idea, as it adds to noise, jitter and aliasing. But in the case of studios they absolutely have to do this, there is no alternative.

Now to get the best analogue performance you must use a local clock - and one that is not being adjusted via a PLL, as this adds jitter and noise resulting in skirts and noise floor modulation. So to go from 104MHz (local clean clock) to 768k (synced to external clock) without any degradations requires using a very complex fractional interpolation filter. And that's exactly what I have been working on over the past 3 months. And I have gotten some interesting and perplexing results. I am not, at this stage going to publish my results, as I am still processing things - but the work suggests that aliasing, if it's observable on a digital domain measurement, is easily audible - even when doing single blind listening tests - as I couldn't believe what I was hearing.

I have still got a lot more work to do on this issue, but in principle the problem has been solved in that the output now no longer differs from the input with digital domain measurements.

I wanted to come back to this post because it seems there are two issues being described here:

1. 705,600 and 768,000 have a lowest common multiple of 112,896,000, whereas 44100 and 48000 have a lowest common multiple of 7,056,000, yet numbers "near" to 104,000,000 are not multiples of 7,056,000. The closest are 98,784,000 and 105,084,000, and then the next multiple is, ta-da, 112,896,000. So the "~104MHz" you use in the DACs and ADC force you to use a fractional interpolation.
   Is the ~104MHz clock a side-effect of having to use an off the shelf crystal? Presumably there is no crystal at 112.896MHz?
   You appear to imply that 44.1KHz or multiples (e.g. 705.6KHz) are exact divisors of the ~104MHz clock. e.g. a clock of 103,723,300 is 705.6KHz x 147. So fractional interpolation is not required in this case, only for multiples of 48KHz. Is that right?
   
   
2. Studios require that a clock that's either a multiple of 44.1KHz or 48KHz is sourced externally to the ADC, so you can't rely upon a crystal inside the ADC? The external clock causes noise problems and jitter.

So this would appear to imply that 44.1KHz (or 705.6KHz) output suffers solely with problem 2, but 48KHz (or 768KHz) suffers from both problems 1 and 2. Is that right?

But, in this post:

https://www.head-fi.org/threads/watts-up.800264/page-104#post-15312499

you say:

The actual number is an integer multiple of 44.1 kHz and 48 kHz - and the reason I needed an integer multiple is for generating the clocks for USB, which need to be 44.1kHz and 48 kHz, and integer division (or rather frequency synthesis) is very much easier to do.

Which implies some multiple of 7,056,000 doesn't it? If that were true then 705.6KHz and 768KHz would both be integer factors of 112.896MHz, but not "~104MHz". Which would then imply that problem 1 disappears entirely.

But you say that you are using a fractional interpolation filter, which implies problem 1 exists for 48KHz and all multiples up to 768KHz (since you describe the problem in terms of 768KHz output).

So I can't resolve the apparent contradiction. And, honestly, I'm curious why 112.896MHz isn't used instead, unless there simply isn't a crystal.

 

[Ronengeller]

I don't get on with IEMs. I had a couple of custom units, and after an hour my ears ache. I did like Noble Kaiser IEMs though, but I haven't tried everything available today.

found them talked about a lot here!
I came upon this article where
Stephen Kostas compared several IEMs and ended up with mojo + campfire audio atlas (which has single 10mm dynamic driver) and he also liked the Noble m3 https://bloomaudio.com/blogs/articl...h-2020-the-best-bang-for-your-buck-iem-setups

 

[mammal]

I had the strangest dream today, that pandemic was over and we could all travel and meet at CanJam London. Rob was there as well, signing everyone's Chord products, haha. What a dream.

 

[hmartin]

I wonder how Chord will release the new products that John Franks talked about when all hifi-shows are cancelled. Or is there any show that is planed to still run?