Topping LA90 Review (Integrated Amplifier)

[antcollinet]

Which superposition will better in this matter?!

Other than the possible low volume issue you have mentioned, it will make absolutely no difference.

I think the low volume issue you mention will be channel imbalance - possibly non linearity if at very low volumes. In this case, then yes you will be better off using the DAC volume.

If you are going to do that, I'd suggest turning the DAC up to full, setting the amp volume to the maximum you could ever want to listen to (or alternatively the maximum safe level for your speakers), and then use the DAC to turn it down from there.

 

[SashaR]

I'd suggest turning the DAC up to full, setting the amp volume to the maximum you could ever want to listen to (or alternatively the maximum safe level for your speakers)

Thank you very much for your advice!
But please forgive me for the stupidity of my clarifying question:
Will switching the amplifier to “direct” mode (bypassing the volume control using a switch on the back of the amplifier) be the correct implementation of your recommendation (my speakers have more than twice the power reserve compared to the maximum power of the LA90 amplifier)?



Please tell me in which mode is it better to use D90SE? With the 5-volt version, I set the D90SE to -35 dB as the “central” point of the “volume control” - but in Amir’s measurements it is clear that the local minimum of SINAD is achieved at 2.5 Vrms (in the 5V mode)... How can you make the D90SE work in the best area of SINAD, varying the settings of the DAC - at what decibels on its screen do I get closer to the least DISTORTION and at what its mode (5V or 4V) ?

https://www.audiosciencereview.com/forum/index.php?attachments/topping-d90se-thd-n-vs-level-measurements-balanced-usb-dac-png.135764/

 

[SashaR]

This is a graph of THD ratio versus generator level. This is for checking the allowable signal level of the LA90 input section.

Is there a similar graph for the TOPPING D90SE DAC (THD as function of the dB-on-the-screen) in its "PRE-amplifier" mode - and anything about its DAC mode to be able to comare with PRE mode?

 

[nagster]

First of all, my English ability is that of a 3-year-old. Please don't be offended.
I'm using Google Translate but I don't understand it well. Is this link helpful?

Cheap but non-degrading solution to add volume control between dac and amp.

I've got a Yamaha AVR as a 2.1 amp, set the AVRs volume level to "0db", use a Topping L30 as volume control, works great.

www.audiosciencereview.com

What is "PRED-amplifier mode"?

 

[nUUK25]

I ask for the help of experts!

How to use the Topping D90SE and Topping LA90 kit with the greatest efficiency?

1. The D90SE DAC should be used in DAC mode, WITHOUT volume control, - and the LA90 amplifier should be used in volume control mode.
2. The D90SE DAC is used as a volume control - and the LA90 amplifier is switched to the mode WITHOUT volume control.

USB cable comes to the input of the DAC, and 4-ohm speakers with a sensitivity of 88.5 dB (Vela 408) are connected to the output of the amplifier. The interblock cables are XLR.


Thank you very much!

What works perfectly for me: Ad2. Go to D90SE (in preamp mode) and the setup and set from 4 v to 5 v. Keep the low gain on LA90 and no volume - only set to high gain if you need more output from speakers. Just a tip about speaker plugs. Get the bananna plugs which are male tube shape : they will have a large contact surface on the plug in the speaker. Don't get the ones (male) which push the plug to the side in the speaker plug by a spring. They are all shit with less contact surface but quite common !

 

[SashaR]

What is "PRED-amplifier mode"?

Thank you! I have corrected this typo. I meant pre-amplifier.

Is this link helpful?

Thank you very much for the information! Do I understand correctly that we are talking about improving SINAD using the PRE-90, which is the most effective of all these "volume controls"?
Thank you again!

 

[SashaR]

tip about speaker plugs

Thank you for sharing !!! Now I use this way (D90SE in pre-amp mode).

The only difference is that I don’t use plugs, but screw the wire directly onto the speaker clamp nut: I’m not a pre-sales dealer and I don’t need to constantly reconnect cables between different amplifiers and different speakers.
Thank you again for your sharing!

 

[nagster]

Thank you! I have corrected this typo. I meant pre-amplifier.


Thank you very much for the information! Do I understand correctly that we are talking about improving SINAD using the PRE-90, which is the most effective of all these "volume controls"?
Thank you again!

Okay. I've never seen a THD sweep graph for the D90SE.
The graph in post-1208326 is a comparison measurement of SINAD when the volume is adjusted before the D90SE and when the volume is adjusted after the D90SE.
The settings for the D90SE are as written in the graph.

The connections are as follows:
AP => TOSLINK => D90SE => XLR 2m => Volume control device => XLR 2m => AP (200kohm)
AP => TOSLINK => D90SE => XLR 2m => XLR 2m => AP (200kohm)

About the measurement of the D90SE in "PRE mode".
A, The volume of the input signal is fixed at 0dBFS, and the volume is adjusted inside the "PRE mode D90SE". (Front panel or remote control)
B, The volume of the input signal is variable, and the D90SE is in "DAC mode"
In preliminary measurements, the SINAD of A and B was within the measurement error range. Therefore, we only plotted "B", where automatic sweep measurement by AP is possible.

 

[SashaR]

the SINAD of A and B was within the measurement error range.

Thanks a lot for your clarifications!

I don't really understand the meaning of the words "within the limits of measurement error" and would be very grateful for any information that could help me have an idea of the amount of intermodulation distortion created by the D90SE at different dB values (that it shows on its screen) - at several points within the range from -45 dB to -10 dB (and at -00 dB too - for comparison with the DAC mode).

Thank you very much again!

 

[nagster]

As I recall, we compared 5 to 6 points during the preliminary measurements. The difference between A and B was about plus or minus 0.1dB.

 

[SashaR]

The difference between A and B was about plus or minus 0.1dB.

I thank you again - not only for your clarification, but also for your patience and forbearance with my inability to formulate my question clearly and understandably! Thank you very much!

I hope I understood your graph correctly: the best SINAD is provided by using the Behringer Monitor1, whose SINAD is better than the D90SE SINAD by 7 dB at a signal level of -27 dB.

I am interested in a slightly different question: how much does SINAD of the D90SE deteriorate when I'm using D90SE in PRE-amplifier mode (volume adjustment with the built-in digital volume control) compared to SINAD D90SE used in DAC mode?
From your graph I couldn’t figure out exactly this: it seems to me that you were figuring out the SINAD of the superposition of the D90SE DAC with an external volume control - but I’m interested in how much the SINAD of the D90SE deteriorates when it is used in PRE-amplifier mode?

For example, TOPPING insists that volume control must NOT performed using the D90CE, but using the LA90 volume control - apparently due to the significant deterioration of the D90CE's SINAD when used in PRE-amp mode. It is this difference that I would like to know at several points in the range from -50dB to -10dB , when they are shown on the D90SE display.

Once again, excuse me for my inability to ask my question clearly and simply!

 

[staticV3]

I am interested in a slightly different question: how much does SINAD of the D90SE deteriorate when I'm using D90SE in PRE-amplifier mode (volume adjustment with the built-in digital volume control) compared to SINAD D90SE used in DAC mode?

When you use the D90SE's Preamp function, then you lose ~1dB SINAD for each dB in volume reduction.

D90SE in DAC mode and D90SE in Pre mode with volume set to Max will result in identical SINAD.

 

[SashaR]

then you lose ~1dB SINAD for each dB in volume reduction.

That is, the intermodulation distortion of the D90SE at -20 dB on its screen means in practice that I have degraded the sound purity by ~20 dB?

 

[antcollinet]

That is, the intermodulation distortion of the D90SE at -20 dB on its screen means that I have degraded the sound purity by 20 dB?

No, most (or all) of the loss in Sinad, comes from the reduction of SNR. You are reducing the signal, but the noise floor doesn't reduce. So SNR reduces. The level of disortion products will also go down with the volume.

However this doesn't really matter If the noise was inauduble before you turned down the volume. Then it is still inaudible after you've turned down the volume.

 

[staticV3]

That is, the intermodulation distortion of the D90SE at -20 dB on its screen means that I have degraded the sound purity by 20 dB?

IMD does not get worse, regardless of what volume you set your D90SE to. Neither does THD.

Only the signal level decreases.

 

[SashaR]

most (or all) of the loss in Sinad, comes from the reduction of SNR

IMD does not get worse, regardless of what volume you set your D90SE to. Neither does THD.

That is, my ears are not deceiving me and the sound quality has NOT deteriorated from changing the LA90 regulator to the D90SE regulator? And I don't need to add a regulator and cables between D90SE and LA90?


Hooray! Thanks to both of you! Maybe you know the answer to one more question: how to make LA90SE not notice (not decode) MQA tracks? (I listen to classics from Tidal using the UAPP Pro application).

 

[staticV3]

Maybe you know the answer to one more question: how to make LA90SE not notice (not decode) MQA tracks? (I listen to classics from Tidal using the UAPP Pro application).

Try disabling MQA Passthrough in the UAPP settings.

 

[SashaR]

Try disabling MQA Passthrough in the UAPP settings.

I'm not familiar with this option for this Android application. In addition, even a Windows application (in which such a switch exists) will not be able to solve this problem: LA90SE autonomously and independently responds to commands in the file and switches itself to execution (execution the filters?) the MQA. (Note, Even decoding the MQA with an application does not prevent D90SE from seeing that it is receiving an MQA file).

Yesterday for the first time I came across an album that was simply spoiled by MQA processing (Tidal has both the original and its MQA).

I again expressed myself inaccurately. I don't want ANYONE to execute MQA commands - neither the application nor D90SE.

 

[staticV3]

I again expressed myself inaccurately. I don't want ANYONE to execute MQA commands - neither the application nor D90SE.

In that case, I think that your best options would be to either wait for Tidal to complete its migration to FLAC, or to switch to Qobuz.

 

[SashaR]

either wait for Tidal to complete its migration to FLAC, or to switch to Qobuz.

I don't know who continues to create MQA versions of classical music albums. Typically, without comparison to the original album, I don't hear anything terrible about MQA albums - and there's almost always, to my ears, no very noticeable difference between the editions.
I still haven't found a way to persuade Qobuz to sell me his service: he doesn't sell it to my country...