All

Just wanted to let everyone know that I purchased the ADI-2 DAC FS from Amazon Canada on 07/22/2022 and even tho it indicates an ASIN number of B081CWQXGD (per the spreadsheet this should be a 12/2017 model) - mine has this ASIN but shipped with the new ESS chip - my serial ends with a "C" - so it seems that we have another variant of the ADI box out there.

Cheers

VP

This works from ADI-2 DAC V49 and ADI-2 Pro V113 Firmware, and up.

There‘s been one or two FW versions before where B/T already was integrated into PEQ, but displaying the curve had minor quirks sometimes.

Originally B/T was separated from PEQ, that‘s what you see on one of your ADIs.

I suggest to install the latest FW‘s on both ADI-2‘s.

This is explained in the first post. According to the photo, you have an ADI-2 DAC FS. According to the table (1st post in this thread), there are 2 of these devices. It can either be a model with AKM or ESS chip. The text also states that only the model with ESS chip has a D/A filter called Brickwall.

Just check whether your device has a Brickwall filter, if so, then you have an ESS chip, otherwise AKM.

Hi all,

Before I buy it, I would like to be sure that the ADI 2 DAC FS can be set to 10V output on the two rear XLR outputs so that it is a perfect match for my power amplifier (Purifi HPAS400ET need 10V input sensivity to reach full power).

Is it possible? If yes, how I can do it?

Tell me if I’m correct:

- 10v is required by the power amp for full power;

- But 10V out of the DAC mean full 100% volume pot; and full power out from the power amp mean 400W and my speakers are 250W. So i think I dont need such full power and such high SPL;

- Since I need good listening level with  volume pot at 50-70% I think 5 / 8V could be more than enough

It is right?

So…

- if 10V is +22,2 dBu, how much volts are 19 and 21,5 dBu?

- and how should the ADI 2 FS be set to reach +21,5 dBu?

10 V = 22.2 dBu
9.2 V = 21.5 dBu
6.9 V = 19 dBu

To reach 21.5 dBu on ADI-2 DAC’s XLRs simply turn up it‘s volume to +2,5 dBr when the unit is in factory default settings, say Auto Ref Level is on.

If you want to manually select the reference level - not suggested - use +13 dBu.
The nominal ref. level references to the RCA out, XLR is 6 dB higher (double voltage), so nominal 13 dBu is 19 dBu at the XLRs.

Enough number crunching confusion?

BTW:
With real speakers and music, most power amps do not reach their full power all the time.

Speakers are so called “complex loads”, even act as generators themselves.
This means the power amp needs some amount of it’s power to eliminate the energy stored in moving membranes, and load and unload components in the x-over.

So, if you leave the power amp a little bit of headroom you will be rewarded with a cleaner sound.

A real world scenario:

Imagine the amp just pushed the speaker’s woofer membrane with 200 Watts of power outside, because the music (e.g. a bassdrum punch) asked for it.
The very next swing period of this same bassdrum sound is much smaller, as the real sound is decaying fast after the beater had hit the drumskin.

The typical woofer is much less dampened than a drum, so it tends to, once pushed, oscillate on for several periods.
98% of the energy the amp had pushed into the speaker is stored there in form of mechanical energy, in compressed or decompressed air inside the housing and the spring-effect of the woofer’s suspension.
Only 2% (real figures) is converted into sound (10-20 % at best in a very big horn speaker).

OK - now for this next much smaller swing of reproduced drum sound, the amp has to use almost the same amount of power (think 180 W) it had used to push the woofer in the 1st place, to stop it from moving now, plus some extra amount of power to correctly form the next wave-part.

So for real, the amp can at worst only deliver 1/2 of it’s nominal power into a speaker to produce music.
The other half is needed to eliminate the energy from former music events stored in the speaker.

This is specially true for most class-D amps, as they don’t have too high current capability margin, maybe just 50% extra.
They might run of of steam (current) earlier than their specs might suggest when driving a real speaker, not just an artificial resistive load used for the specs measurement.

On the other hand some designers like Mark Levinson built amps that have ten or twenty times the (steam) current capability they would need for their nominal power - these don‘t have problems being driven almost full scale.

To make the life of an amp even harder, the behavior of a speaker is “complex“, which just means the voltage and the current are not synchronous.

A lot lot of amps struggle if this a-synchronicity (phase angle) is too big, because their control mechanism, called NFB - negative-feed-back, has a limited capability to handle this.
This capability is called “phase margin” and typically ends at +/– 180° the latest - voltage and current full anti-phase.
If you now force an amp into it‘s power or current limit on such a complex load, it will completely loose control on the speaker, resulting in momentary very nasty distortions.

If all this sounds bad and problematic to you, don’t worry:
Practically, with a 400 W amp, your neighborhood’s tolerance to sound might be the real world limit - usually somewhere in the 1-figure watts region, which every amp can handle easily.

All clear now ?