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 71 
 on: June 15, 2017, 07:52:26 am 
Started by manisandher - Last post by acg
Mani, are you talking about this happening in two different systems with two different NOS1 G3, both systems tubes/horns, regardless of HQPlayer or XXHE doing the digital attenuation?  If so, then I assume that each system has different tube amps which leaves the G3 as the common denominator.

Perhaps what Peter says above regarding the PCM1704K chips is relevant, but you have two G3's and it is probably unlikely that they would display the same behaviour if it was a quirk between different individual 1704's.

A lot of tube amps need 6VRMS or more before clipping, it just depends on the first stage tube and to a lesser degree the circuit, but the winding of the output transformers and the speaker load, as Peter says, can also induce clipping in the amplifier.  That both of your systems display the same trait still leads me to think there is something about the B'ass driving those amps, but even that is unlikely in my view.

Do you have a spec for the input sensitivity of the amplifiers?  What about impedance plots of the speaker load that they are driving?  Probably not to the latter, but it can be measured, and you may even have the gear there to do it.

LATER:  Reading your post above Mani, where you mention the Orelo's, perhaps it is something that others with that "known" system can try to emulate?  Surely you must have some other way of attenuating full power with 20w/30w amps and 118dB/m/v sensitive horns?  How do you even test that?

 72 
 on: June 15, 2017, 07:37:08 am 
Started by manisandher - Last post by manisandher
A very quick post for now, with a few points...

1. I don't think it has anything to do with the amp - the effect is the same in both my systems (totally different amps)

2. I noticed this quite a while ago, when I still had the Orelo speakers (though I may not have posted immediately)

3. The 'character' of the sound at -3dB with PE is very different to that at -6dB without PE - levels identical, so this has nothing to do with the 1704 'sweetspot'

4. The 'character' of the sound at 0dB without PE is similar to that with PE at any attenuation level

More later (gym first!).

Mani.

 73 
 on: June 15, 2017, 07:13:29 am 
Started by PeterSt - Last post by PeterSt

Quote
May we get MQA ?

Hi Tore,

It will be in there ...

Quote
Do you like it?

It seems like I am starting to be addicted to it.
I will try to write a little about it in your topic about it : Tidal + MQA.

Regards,
Peter

 74 
 on: June 15, 2017, 07:06:38 am 
Started by manisandher - Last post by PeterSt

It can just as well be caused by that amp etc. Same thing about the voltage rails, BUT you'd need to play at maximum "power". Read : your amp could be clipping.
Not sure !


If I remember correctly, Mani was hoping for more output from the B'ass I/V so that he could drive his amplifiers louder.  This would indicate that the amp is not clipping with anything the G3 can throw at it (nominal 1.5vrms I think?).  Of course that is no guarantee that the amp in not clipping, but is an indication that it probably needs more than 1.5vrms to achieve full power, and therefore induce clipping, so 0dB attenuation in XXHE should be no different to -1.5dB.

Hi Anthony,

Hmm ... that makes me think twice. But I think that only for some sense of "logic" you may be right. This does not mean that technically you need to be right per se. So I think the other way around :
With exactly the same thought (there's lack of power in general), you thus feed the amps with full voltage (whatever that is for the moment) and thus for that situation it requires the most power. So of course you can think that a DAC with e.g. 2x the output voltage should be able to work too for any situation (because "an amp is an amp" ?) but it doesn't really work like that. So I think the other way around : we have some amps that suffice for 109dB sensitive speakers (at say 3 Ohms) and that thus siffices the same for 115dB sensitive speakers (at 3 Ohms) ? I don't think so. And thus : if the amp suffices "just" for the 115dB speakers it lacks a factor of two for power on the 109dB speakers.

So all what's required to let the amps clip is :
a. have underpowered amps;
b. feed them with a voltage which is just more than they can handle.

Ad b.
Make that a little less (digital attanuation or by other attenuation means) and they are fine.

Right.
And now I say that all is moot because I said that I have dreamt that I saw a text from Mani telling about "since this tube amp and speakers" but I don't think I dreamt and Mani rather pulled that text (because ... and I didn't look it up - Mani had the problem prior to that already).

I already said "not sure !" and it is far more easy to think that the NOS1a clips. But then "unnoticed" for me and it should be related to a frequency because I coincidentally checked it for exactly this phenomenon (clipping) and it does not (but with 3dB more IIRC it does). It does not at 1KHz.

While this would be some technical explanation from my side, I only present you this information because it is an understandable explanation (I hope). But what I really think and should say is that each NOS1 has its sweet spot for attenuation which is related to the PCM1704 chips which has the sweetspot and which is not equal at al for each chip. But as you can understand in itself, this is not any explanation to bring forward because nobody can deal with it (I wouldn't be able to either). From there, another explanation is more feasible and this is that the MSB (Most Significant Bit) from the chips (or one of them etc.) implies a "not the best" sound. So remember, when we attenuate digitally even the slightest, that bit is turned off and never comes up throughout and piece of music (no matter how loud). Or an even better explanation for those understanding the PCM1704 : that one half of the chip (forming the 24th bit (MSB)) is shut off and which is special (regarding to all of the other bits).

... And of course it is already known that about each person trying to digitally attenuate with a preamp (or analoge volume of other means) present, always comes up with this 6dB. I never tried it, but this may not be a coincidence.
So in the end it is nothing new ?

blablabla ... Happy
Peter

 75 
 on: June 15, 2017, 07:01:17 am 
Started by manisandher - Last post by acg
XXHighEnd 2.08 can mute instantly ...

Nice!

 76 
 on: June 15, 2017, 06:40:02 am 
Started by manisandher - Last post by PeterSt
XXHighEnd 2.08 can mute instantly ...

 77 
 on: June 15, 2017, 05:07:56 am 
Started by manisandher - Last post by acg

those who refuse to go the preamp route (everyone here?):


I am determined to find an active preamp that does justice to the G3 but that is proving difficult.  My most basic needs are instant muting and source selection...neither of which the G3 can do.  Analogue volume control that does not mess with the sound would also be nice...

 78 
 on: June 15, 2017, 05:01:50 am 
Started by manisandher - Last post by acg

It can just as well be caused by that amp etc. Same thing about the voltage rails, BUT you'd need to play at maximum "power". Read : your amp could be clipping.
Not sure !


If I remember correctly, Mani was hoping for more output from the B'ass I/V so that he could drive his amplifiers louder.  This would indicate that the amp is not clipping with anything the G3 can throw at it (nominal 1.5vrms I think?).  Of course that is no guarantee that the amp in not clipping, but is an indication that it probably needs more than 1.5vrms to achieve full power, and therefore induce clipping, so 0dB attenuation in XXHE should be no different to -1.5dB.

 79 
 on: June 14, 2017, 08:04:42 pm 
Started by PeterSt - Last post by Tore

May we get MQA ?

Do you like it?


Tore

 80 
 on: June 14, 2017, 07:09:27 pm 
Started by PeterSt - Last post by PeterSt
Hi there Rudolf,

Yes, thank you !
I already knew it. And for you ? closely look at the differences you will encounter with Tidal herself. See the three pictures below.

Best regards,
Peter (working hard to finish 2.08 with the major things done now)

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