alp
Rank: Trio
Posts: 160
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Post by alp on Jul 14, 2020 20:15:55 GMT
I had been using the D90 with volume set to 0dB for some while thinking that would be the same as being in "DAC mode" but discovered that DAC mode is set from the menu reached by holding down front-panel on button while powering on using the power switch at the back. A surprising difference in the sound, certainly a lot smoother and fluid. I just wish I had found it earlier. You can also alter the I2S settings from this menu.
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Post by wannarock2 on Jul 14, 2020 20:53:48 GMT
Hi alp, are you saying you are now using your pre-amp volume control or are you still using the D90 to control the volume?
What I would like to know about the D90 are the harmonic differences you hear between running the D90 directly to your amp vs. running it through your pre-amp and then on to the amp. Thanks
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alp
Rank: Trio
Posts: 160
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Post by alp on Jul 14, 2020 22:38:13 GMT
In both cases I was running it through my passive preamp but in DAC mode the volume can only be changed with the preamp. To me, this sounds a lot better, a smoother, richer sound, if that helps at all.
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Post by wannarock2 on Jul 14, 2020 22:53:56 GMT
In both cases I was running it through my passive preamp but in DAC mode the volume can only be changed with the preamp. To me, this sounds a lot better, a smoother, richer sound, if that helps at all. Thanks, yes that helps. In the interim I had a chance to look-up the D90 manual and see the options of either Pre-Amp Mode or DAC Mode regarding D90 volume control. As you mentioned Pre-Amp Mode is volume adjustable whereas the DAC Mode volume is non-adjustable. As MartinT had mentioned in a different thread new DAC’s with volume control need to do a better job with their output drive circuit. Even at 0dB in the Pre-Amp Mode you were probably experiencing that substandard sound phenomena. Given the D90 is a top tier DAC this is a cautionary tale that volume controls on current DAC’s are still suspect to reducing the sound/music euphonics. Glad you got it resolved. Many purchasers would miss this subtlety given Pre-Amp Mode is the default setting on the D90.
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Post by MartinT on Jul 15, 2020 7:05:13 GMT
Agreed. To explain:
In DAC mode, you're using a preamp to adjust volume and drive the power amp. Preamps usually do an excellent job of driving a power amp.
In 'preamp' mode, you're using the DAC to adjust volume and drive the power amp. My experience is that DACs don't have the welly to properly drive a power amp and the resulting sound is often lacklustre.
If you use 'preamp' mode with the DAC adjusting the volume, but run it through a buffer, you get terrific sound quality. By taking the preamp out you definitely lift the system's potential. It also proves to me that digital volume control in a DAC has come of age, utterly transparent at any setting and with very precise volume steps. You won't lose precision at low volumes as a modern DAC chipset will use 32-bit words to calculate the volume data. The buffer just gives you what is missing: sufficient output drive to the power amp.
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alp
Rank: Trio
Posts: 160
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Post by alp on Jul 15, 2020 7:25:32 GMT
I would agree that the digital volume control is very good. I could not detect and reduction in quality when I used the remote to reduce volume from 0 dB.
Could you explain what you mean by a buffer in this context?
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Post by MartinT on Jul 15, 2020 7:39:53 GMT
A buffer is a simple unity gain amplifier circuit that drives the outputs with higher current capability. It does not amplify the voltage.
My Burson AB-160 XLR is one example.
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Post by jandl100 on Jul 15, 2020 7:51:25 GMT
I've a D70 and that's the same. It sounds noticeably better in DAC mode.
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Post by John on Jul 15, 2020 7:59:51 GMT
I tried a Balanced preamp but to much gain for my system as I volume would be either to loud or quiet. It was very hard to get the volume right. Since then I not bothered trying. Any preamp would have to output XLR and RCA and either be passive or have a very low gain structure for it to work in my system.
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Morph
Rank: Duo
Posts: 31
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Post by Morph on Jul 15, 2020 11:41:43 GMT
Did your new grounding box turn up Dave? Hello, sorry for the delay in replying. Yes it arrived last Saturday morning. I've grounded the signal using XLR and am very impressed with the outcome so far. The SGS box is settling in nicely. Greater depth of soundstage with raised separation of instruments and quieter background. Bass seems more punchy too. I think I can ascribe those characteristics to the new grounding box but there's quite a few new things going on in my system all at once(ish). I received the D90 MQA towards the end of May and initially was pleased as it sounded preferable to my four year old Mytek Brooklyn. However after a few weeks, Audio Nervosa kicked in. The system was actually sounding pretty brittle and sharp. A bit grating on the old ears. I had pretty much decided that I'd taken a wrong turn and was going to take a small hit and move it on once I'd researched what to go for next. However, a couple of days after that decision I noticed that the shelf the DAC rests on was in need of dusting. Removing the unit to be able to dust I unhooked the Uptone Audio isoRegen from the USB input and immediately noticed that the ISO ( galvanic isolation ) option was switched off. It had been turned off because the Brooklyn provides galvanic isolation and with it on, the Brooklyn sounded harsh. I hadn't noticed or truthfully even remembered about this when the D90 was hastily hooked up initially. So of course having dusted I switched the ISO option on and had a listen. Everything fell into place. Harsh edges gone and much better bass and mids. The D90 was staying! A few weeks later I noticed MartinT's Chinese word clock experiment for the etherREGEN switch and got on board with that. Yet another improvement to the system. One that's well worth investigating IMHO. With the arrival of the SGS grounding box, another new element has been added that has further enhanced the listening experience of the D90. Andrew at SGS also included a second cable which I clamped to the grounding pin of an old IsoTek Multiway block I dug out to put all of the networking kit into ( router, etherRegen, OCXO clock, fiber optics and isoRegen ). He assured me that the box could handle all this and I haven't removed anything as yet so can't really tell either way what's what there tbh but it's all sounding great. So.... the D90 MQA finally sounds absolutely superb in my system. A decent DAC for the money no doubt about that, but the additions have really made a huge difference. Bit of a rambling post but that's where I am with this DAC. Cheers Dave
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Post by MartinT on Jul 15, 2020 11:55:40 GMT
That's a nice outcome, Dave. So glad the master clock and grounding box are working out for you.
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Post by julesd68 on Jul 15, 2020 12:25:27 GMT
Excellent write up Dave.
It's very satisfying when everything comes together. I can imagine the D90 is an excellent DAC as I have been delighted with the performance of my D70.
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Post by Firebottle on Jul 16, 2020 8:00:47 GMT
I have only just set my D90 to Dac mode, had it in Preamp mode. It was something I had been meaning to try not long after I had it but never got around to it. Definitely better performance with more depth and air, so a solid recommendation to run in Dac mode if you also use a separate preamp.
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Morph
Rank: Duo
Posts: 31
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Post by Morph on Jul 19, 2020 10:35:43 GMT
Hello So this morning a problem has developed with the D90. The unit is putting itself into standby mode after one minute. I leave the DAC on all the time and it was off when I got up earlier. Every time I start it again it just goes to standby. Any suggestions as I'm stumped here.
Thanks Dave
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Morph
Rank: Duo
Posts: 31
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Post by Morph on Jul 19, 2020 11:05:18 GMT
And now it's working as normal. I've unhooked the grounding box though. Hmmm, I really hope the grounding box isn't the culprit. Going to hook it back up and see what happens next. Very odd indeed. Will report back later.
Thanks Dave
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alp
Rank: Trio
Posts: 160
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Post by alp on Jul 19, 2020 12:03:54 GMT
I have not had that happening (yet), but no grounding box either. Mine goes into standby when there is no USB input, perhaps there's something going on there with yours.
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Morph
Rank: Duo
Posts: 31
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Post by Morph on Jul 19, 2020 12:21:55 GMT
Thanks alp. I went over all cables and made sure everything was fitted tightly plus hooked the grounding box back up. Not sure what was going on there but everything's solid again and hopefully will remain so. Don't think the grounding would have done that on reflection. An unexpected glitch in the audio matrix on a Sunday morning!
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Post by MartinT on Jul 19, 2020 15:59:09 GMT
Dave - didn't you say you were connecting the grounding box to the D90 and also mains ground? I dare say the latter is upsetting it. Try disconnecting the mains ground and just leave the SGS doing its job with the D90.
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Morph
Rank: Duo
Posts: 31
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Post by Morph on Jul 19, 2020 17:09:26 GMT
Dave - didn't you say you were connecting the grounding box to the D90 and also mains ground? I dare say the latter is upsetting it. Try disconnecting the mains ground and just leave the SGS doing its job with the D90. Hi Martin Since I last posted I decided to remove the XLR signal ground and experiment using the cable with a clamp kindly provided by Andrew. I've attached it to the Bluetooth aerial and actually prefer the outcome so I'll be sticking with that I reckon. Dave
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