1 (edited by xls215 2020-12-19 18:21:07)

Topic: Help with adi-2 dac fs as preamp

Thanks for accepting me. I owned a pair of nad power amp and  preamplifier. I bought rme adi-2 dac fs as a dac after a lot of research and the result was great. One day after reading the manual i decided to try it instead of the main preamplifier and i didn't noticed any difference and actually the rme behaved better. So I removed from the chain a device less. I left with my 2x150 power amplifier and rme as a preamp.nad power amplifier had gain setting.

I upgraded the power amp to a rotel rb-1590 which. I connected via rca since i dont have xlr cables yet. The problem starts here. The sound level is very low. I feel there is no volume enough. I tried to increase the dbu to 13 and the level increased. but was much conpared tto he previous less powerful amp. Rotel is 2x350w without gain settings.
According the manual rme has almost 3.4 volt with the 13dbu. Autoref setting makes it much less powerful

After that i asked a friend to borrow me his intergrated amplifier which had 1v preout and the behavior of the system became more reasonable about volume level and finally the power of rotel came out.(rme locked volume as dac only)

I hope that it has to do with nad settings because i am very disappointed with this. Any advice help would be highly appreciated.

2 (edited by KaiS 2020-12-19 19:29:19)

Re: Help with adi-2 dac fs as preamp

Stupid question maybe:
Did you set the balanced/unbalanced switch on the back of the NAD to the correct position?
Be carefull when switching not to blow your speakers.


Now that we have this out-of-the-way:
ADI-2 DAC has a very powerfull output, so usually it's is the other way around, volume needs to be dialed down quite some.
ROTEL needs only 2.2 V for full power, ADI-2 DAC can send 4.6 V (with Vol. set to +2.5 dB), so more than sufficient.


Q: What is the source you are playing your music from?
If it's a streamer or PC there might be a volume setting that needs to be dialed up.

Re: Help with adi-2 dac fs as preamp

Nad c275bee had only rca inputs and gain control always set to the half.

Rotel rb-1590 has xlr and rca without gain control. Till now used only rca... because i dont have yet xlr cables

In both cases common equipment was

Source pc with daphilehifi os with locked volume at max something like wasapi... no problem i think with this

Preamplifier was rme adi-2 dac fs
Speakers atc scm19 v2

The problem is that with nad which was 2x150 had a power x,  now with rotel 2x350 i feel like 0.75x.

The intergrated I borrowed and saw/felt the power of rotel was sansui au 517 which has only 1v preout....

With nad i felt that nad c165bee was useless.... but now with rotel unfortunately things are not the same..

4 (edited by KaiS 2020-12-20 01:17:17)

Re: Help with adi-2 dac fs as preamp

Checklist, don't skip any of the below :

• Test Rotel balanced/unbalanced switch in both positions
• Switch ON Auto Reference Level
• Dial Volume to +2.5 dBr (do you see the "r" behind the dB?)
• Look at ADI-2 DAC's green level bars in the lower part of it's screen: they should go up to full and your ears should start bleeding smile

• Report back


ADD:
The problem is in the Rotel amp somehow, as the NAD amp with gain at about middle position is much less sensitive but loud enough.

Re: Help with adi-2 dac fs as preamp

Today i received the xlr cables.
Rotel settings were ok for both cases even rca or xlr.
I already had auto reference level on
The letter r follows the db all the time from -99 to +6
The letter  r is showed down at the bar meters and also next to biggest volume counter.

Xlr made improvement to control and improved bass compared to rca.

When i increase the volume at the -20dbr it goes from -5dbu to +1dbu. At the -10dbr it goes to +7dbu...

It never went to +19dbu max was +13dbu

I cant say that i am impressed.... compared to nad there is a huge improvement to soundstage and generally mid frequencies but the double power didn't bring the i total improvement i expected..maybe i need some extra time to get used to the amplifier and understand the amplifier better.

With nad i was absolutely sure that rme could easily replace the preamplifier now i am not yet.

6 (edited by KaiS 2020-12-22 22:48:33)

Re: Help with adi-2 dac fs as preamp

xls215 wrote:

When i increase the volume at the -20dbr it goes from -5dbu to +1dbu. At the -10dbr it goes to +7dbu...

It never went to +19dbu max was +13dbu

The level situation looks OK based on this.

xls215 wrote:

I cant say that i am impressed.... compared to nad there is a huge improvement to soundstage and generally mid frequencies but the double power didn't bring the i total improvement i expected..maybe i need some extra time to get used to the amplifier and understand the amplifier better.

With nad i was absolutely sure that rme could easily replace the preamplifier now i am not yet.

I think you overestimate the difference of doubling the power.
Doubling the power means just 3 dB more level.

Anyway, more power only makes sense if you really use it, a stronger amp does not necessarily sound better.

Small drivers like the 6" LF drivers in your ATC SCM 19 V2  do produce a limited amount (literally!) of bass level.
If you drive them hard, only midrange gets louder, bass gets distorted.

Add 1 or better 2 subs, maybe instead of a stronger amp.

Re: Help with adi-2 dac fs as preamp

It is not only more than double power. It has many other characteristics better than the previous amplifier.
Damping factor almost double.dual.monoblock dual transformers. Less distortion . Xlr connection .bigger frequency response. Maybe some more

Also i am not a technician but i started being curious since a 42 year's old intergrated with 1v pre out totally wins the rme something that didn't happened with nad c165bee which is a preamplifier.

I will try to find for test the rc 1590 to check the how the system will play,since it is its factory pair preamplifier. Thanks for the info.

8 (edited by KaiS 2020-12-22 23:46:01)

Re: Help with adi-2 dac fs as preamp

A car does not fly if you fill in rocket fuel - maybe a short distance when it explodes smile

Speakers have magnitudes more influence on the sound than any electronics.
I your case I strongly suggest to consider an active subwoofer with integrated xover for the satellites.
Freeing them from the lower bass gives your ATCs more headroom to breath.


Meanwhile give ADI-2 DAC's Loudness function a try - manual page 14 and 23.
Set "Low Vol Ref" 20 dB below the loudest Volume dial "dBr" number you would listen normally.
Might be what you're heading for.

Re: Help with adi-2 dac fs as preamp

xls215 wrote:

...

I cant say that i am impressed.... compared to nad there is a huge improvement to soundstage and generally mid frequencies but the double power didn't bring the i total improvement i expected..maybe i need some extra time to get used to the amplifier and understand the amplifier better.

With nad i was absolutely sure that rme could easily replace the preamplifier now i am not yet.

Am I reading this right?, you expected much improvement with a new power amplifier with more watts and less distortion?

Re: Help with adi-2 dac fs as preamp

Before making any comparison as to sound-staging, timbre, etc, ensure that you level match your volumes. That being said...
For music I actually prefer my RME into my Decware Torrii mark 4 which is a dual mono el34 amp putting out 25 watts. More power or better specs imho don't guarantee a significantly better sound experience.

11 (edited by Curt962 2021-01-02 08:11:09)

Re: Help with adi-2 dac fs as preamp

@Stolze.  Good Contribution!    Level Matched comparisons are the "Great Equalizer"  Much Audio Baloney goes away when we do Level Matched comparisons.

@XLS215...

You've got fine gear.  We need to do a bit of Room Analysis!   Your Room has the final say on SQ.  Many here know me as "that guy!"    A few afternoons of measurements, and Speaker/Seating Tweaks can take your listening experience to a much higher level!   Then perhaps you'll know why so many of us are convinced the RME is the closest thing to the Studio Experience that Money can buy!

Shall we?

Best Regards Friend!

Curt

Vintage 2018 ADI-2 DAC. "Classic AKM4490 Edition"
Cables:  Red, and White Ones.
Speakers:  Yes

Re: Help with adi-2 dac fs as preamp

First of all i wish happy new year to everyone with health and happiness.
My current amplifier compared to previous is better in every spec so i don't know why you are trying to say the different. Also my system from
1)rme + nad preamp + nad power amp
Then became(since rme destroyed the nad)
2) rme +nad power amp
And now with extra 200 euros totally since nad combo sold and bought the rotel
3)rme + rotel power amp

Both had the same speakers and sources. When i connected the rotel i noticed at once the mid and high frequency improvement nad especially the pianos who were hidden all this time.

But I couldn't understand the volume control and its behavior. After the suggestions of other members settings were ok. But 2 days before I remembered that the comparison with my friends intergrated happened with cd/optical and not with Usb.... so i tested with cd/optical straight to rme now....

OMG... Frank's sinatra Christmas cd totally like listening for the first time.... eva cassidy the same ....

Daphile had failed to auto update 2 weeks ago and went back to previous version but with kernel mode. Volume was from bit perfect to manually 78% set for unknown reason . Reinstalled here from scratch.
Rme had never been updated so i installed firmware 34  version.

Well now more than -10db starts being very loud, with autoref on.. music comes flawless easily and more relaxed. Also i noticed that rotel needs 1 hour of warming to perform max and also it never gets warm
For me the rme is a miracle dac and a versatile device.
Now that problem solved i am curious about 2 things

1)rme with optical/cd cimpared to daphile/usb flac rupped with the same tracks played I think better with the meaning of easiness to listen more clear.
Rme resurrected my teac transport!
Maybe i should try dsd ...
2) I think rotel has low voltage gain control

http://www.rotel.com/sites/default/file … oSheet.pdf

Can someone confirm it combined with impedance.

13 (edited by KaiS 2021-01-02 12:12:25)

Re: Help with adi-2 dac fs as preamp

xls215 wrote:

2) I think rotel has low voltage gain control

http://www.rotel.com/sites/default/file … oSheet.pdf

Can someone confirm it combined with impedance.

You’re right, Rotel has 27 dB voltage gain, that‘s about 5 dB lower than usual.
But - I‘d consider this a good thing, saves you from using external passive attenuators to max ADI-2 DAC‘s dynamic range.
As you tell you still have some spare level range on the ADI-2, don‘t need to drive Vol full up.


Impedance: the Rotel is spec‘ed to deliver it‘s max power of 350 W into 4 Ohms.
Your ATC speakers have 8 Ohms, therefore Rotel drives them with only about half the power.
Depending on Rotel‘s PSU design it might be a bit more, about 200 W would be my estimate.


Your comments let me think you‘re listening quite loud.
This makes me still I think you need an active subwoofer to unburden the ATC‘s from some of the low frequencies.
Those litte 6“ speakers cannot handle 200 W of bass.

You seem to be quite sensitive to sound changes, a sub would be the biggest step forward in quality, magnitudes more than different sources can give you.

14 (edited by Curt962 2021-01-02 14:11:26)

Re: Help with adi-2 dac fs as preamp

Did someone mention Subs?

SVS is the correct term!   SVS is the finest product, with the best Customer Care on Earth!  (10 year owner. One service requirement which was handled like a Medical Emergency. WOW!)   XLS, contact Ed Mullen, or Jack Gilvey at SVS.  They'll make you happy!  Those Guys know their Science!!

Completely RME Worthy!!!

Curt

Vintage 2018 ADI-2 DAC. "Classic AKM4490 Edition"
Cables:  Red, and White Ones.
Speakers:  Yes

Re: Help with adi-2 dac fs as preamp

Of course the next step seems to be subwoofers! But before that i am trying to utilize the my gear at maximum. Before finding the problem at daphile volume i started reading a lot about voltage gain etc. Without being so much technically familiar i realised that rotel needs at least 4v. Rme delivers i think near that but i read other stereo preamplifiers deliver 10 15 and ever more volts max.
Also before buying the rotel i asked my technician service and told me they are reliable and flat sounding analytical tools but told me more than 10 times that this specific amp needs very powerful preamplifier(i didn't ask what he means). 1 volt or 2 are nothing he said.

Also i cant see 19dbu with xlr but max 13dbu... why?

I saw that the rme pro version goes 24dbu, so that means that the voltage output varies.... but i dont understand the practical side of voltage output compared to the voltage gain....

Now i have bass at + 1.0 db., thats true i need extra bass specially now that the other frequencies improved.

I will measure my room and inform again.

Yes i can hear the differences when they are and when they don't also.(i removed the nad preamplifier when i saw that rme was sufficient enough)

16 (edited by KaiS 2021-01-02 17:48:55)

Re: Help with adi-2 dac fs as preamp

You don‘t see the +19dBu in ADI-2 DAC‘s display, because the numbers shown there are related to the RCA output.
XLR has 6 dB more, 13+6=19 dBu.

In fact the max level is even 2.5 dB more, as the volume control goes up to +6 dB, where the last 3.5 dB are for weak digital sources only.

So ADI-2 DAC‘s max XLR level is 13+6+2.5=21.5 dBu = 9.2 V, more than double what your Rotel amp needs to be fully driven.



School:

Gain = amplification = how much louder (or quieter) something comes out related to the input.
Can be expressed as a factor i.e.
• x2 (two times more)
• or in dB i.e. +6 dB.


Level is an absolute value.
Can be expressed in:
• Volt (V) i.e. 1.55V,
• or in dBu, relative to a reference of 0.775 V i.e. +6dBu,
• or in dBV relative to a reference of 1 V, i.e. +3.8 dBV,
• or any other reference, the two above are the most common.



The good thing about calculating in dB is, as it’s a logarithmic size, multiplications like Gain can simply be added instead:
I.e. a gain of 6 dB followed by another gain of 12 dB simply adds to 18 dB
In Voltage Gain the same calculation would be x2 * x4 = x8.