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Ultimate Audio Playback => Phasure NOS1 DAC => Topic started by: manisandher on September 17, 2018, 04:52:17 pm



Title: DC offset issue?
Post by: manisandher on September 17, 2018, 04:52:17 pm
Hi all, I've got two NOS1s - one in my main system, and one in my office system. Not only do the two NOS1s show very different DC offsets, but the DC offsets in my office NOS1 are pretty much rock solid, whereas the DC offsets in my main NOS1 vary continuously:

Main: 15.0-16.1 (upper meter) and 10.8-12.0 (lower meter)
Office: 1.7-1.8 (upper meter) and 2.7-2.8 (lower meter)

Is my main NOS1 behaving normally, I wonder? [It sounds bloody good, I have to say.]

Mani.


Title: Re: DC offset issue?
Post by: briefremarks on September 17, 2018, 06:41:57 pm
Mani:

There is almost no variability in DC offset on my NOS1a.  The DC offset dropped after the G3 upgrade, but other than that values remain constant.

Ramesh


Title: Re: DC offset issue?
Post by: PeterSt on September 17, 2018, 08:46:07 pm
Mani,

All is perfectly normal. Generally, though, the DC Offset is a bit higher with most of the /G3's. This is inherent to the chips used for it. So it is in the specs and it is accepted.

Peter

PS: I think the variability is constant indeed, and if not it isn't automatically changing each second. But don't confuse that with music playing because the lower the (sub)low, the more it changes on the melody of the bass. This is DC just the same, though varying per LF wave cycle (I am sure you understand).


Title: Re: DC offset issue?
Post by: manisandher on September 17, 2018, 09:03:02 pm
Thanks Peter. But I should have mentioned the following:

1. the changes on the main NOS1 happen every 1/2 second or so - jumps of up to 0.5mV are common
2. this is all with no music playing at all
3. both NOS1s run off exactly the same AC mains circuit

Still normal behaviour?

Mani.


Title: Re: DC offset issue?
Post by: manisandher on September 17, 2018, 09:04:43 pm
There is almost no variability in DC offset on my NOS1a.

Nor on my office NOS1 :). It's just my main NOS1 that seems to exhibit slightly different behaviour. But perhaps it's still within 'specs'.

Mani.


Title: Re: DC offset issue?
Post by: PeterSt on September 18, 2018, 09:40:32 am
Quote
Still normal behaviour?

Maybe not. But I estimate the NOS1a/G3 of concern not to be the issue. I said estmate. :)

First thing to try is to unplug the USB cable, try to have the DC Offset right (it can be dine but can be difficult) and look again. Still the same ?

Then I hope it is not too difficult to put your othet NOS1a/G3 in that place. No need to try without USB connection.

If this remains unconclusive, I have a few more cards to play ... (could be false trumps)

Regards,
Peter