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Review and Measurements of Lyngdorf TDAI-3400 Amp & EQ (Part 1)

Juhazi

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I use B&O ICEPower 125ASX2 and 50ASX2 units and have a NHT Power2 amp that carries two heavier models (500?). These have been requested to be tested by amirm.

Does anyone have a link to independent measurements of them? Are they analog or digitally controlled class-D by nature? I have read comments of some models having noise issues, some others having too low and deep LP filter... I like the sound of them anyway and 4 units have been running practically 24/7 for over 5 years now. Datasheets look ok to me too. https://icepower.dk/products/amplifier-power-modules/asx-series/
 

Tip

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Lyngdorf have just announced a new product after the collaboration with I presume Putzeys,
https://lyngdorf.com/wp-content/uploads/2019/02/MXA-8400-fact-sheet.pdf
Keith
If you enlarge the drawing you'll see that the MXA-8400 has four pairs of bridgeable channels, and that it only has balanced analog (no single ended or digital) inputs. This obviously is the matching amp for the MP-50 pre-pro (http://lyngdorf.com/mp-50/) that they announced last year, which has only balanced analog outputs. The MP-50 is attractive because it has 16 EQ'd outputs that can handle 12 unique inputs. So Lyngdorf now has made a clean break from the all-digital signal chain.

I was looking at the MP-50 last year as a possible replacement for my TacT TCS mkIII pre-pro (for when it "bricks"), which has 12 EQ'd outputs (either analog or digital) that can be configured either as full-range or subwoofer channels, and can handle 8 unique channels (via either analog or digital inputs), plus a mixer to perform bass management (I'm running in 5.4) or additional zone(s). Unfortunately, only one of my five TacT S2150 stereo amps has analog inputs, but since they use the same technology as the Lyngdorf TDAI-3400, I'd be better off without them! ;)
 

March Audio

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I am not worried if I hear the US noise it's self but wonder how it effects the tweeters performance in the audible range... all that energy is doing something... what I don't know. Amir can you do some testing of something like a tweeter being fed a 12 KHz tone with and without US noise and see if there is any measurable difference?
If the tweeter has no response at the ultrasonic frequencies then there will be no in band intermodulation. Also as frequency rises so does inductive reactance of the speaker coil so any heating effect is minimal.

In reality speakers will have some response, but vastly reduced at US frequencies. What level and up to what frequency is obviously speaker dependant.

Don't get me wrong, I don't think this amp has acceptable performance and its US output is something you want to avoid. Its US noise is too high and too close to the audible band. An Fft will tell you what's going on. However I disagree with using a THD + N overall figure that's measured into the US range as an indicator of audible performance because it includes things that aren't reproduced or audible.
 
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Tip

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That maybe made sense 20 years ago. Today, people have high-resolution content and they like to think what they get above 20 kHz is what is in the music, not a heap of ultrasonic noise. Here is the fact sheet from Lyngdorf on TDAI-3400:

View attachment 22154

Over USB it supports sampling rates up to 384 kHz. That would give us a bandwidth of 384/2 = 192 kHz. Yes, usually that is more limited in practice so let's round that down to 100 khz. You are telling me that I am not entitled to any of that between 20 kHz and 100 kHz?

The notion that I should put filters in measurements to produce conditions that do not match what users have is just wrong in my book. I am not here to bend to what the product limitations are. I have tested many other switching amplifiers without the condition you mention.

In this day and age, high-end products must be able to reproduce high-resolution content. There is no reason to make excuses for it because the designer chose an architecture that doesn't work right there.

Even if I were to do as you say, there better be documentation to this effect. It needs to say that this product produces tons of ultrasonic distortion above 20 kHz so it is not suitable for high-resolution audio and such. If we are going to hide this, then the consequences are that reviews like mine come out and people are shocked to read it for the first time. As it seems to have happened.
OK, what's going on here is that Lyngdorf uses an ASRC to up/downsample all inputs to 96kHz because the room correction convolution is performed for a 96kHz sample rate. Otherwise, the Lyngdorf would have to calculate correction filters for each of the possible input sample rates (8?) and then load the appropriate correction filter for the input sample rate. BTW, the TacT RCS 2.0 did calculate a correction filter for each possible input sample rate and performed the convolution at the input's sample rate. But that was back when there were only three sample rates: 44.1, 48, and 96kHz. Tact went to the ASRC at 96kHz scheme with the release of the RCS 2.2X when more sample rates appeared. And a few years later, Peter left TacT Audio to start Lyngdorf Audio using essentially the same hardware at first but with a different room correction algorithm (not RoomPerfect -- that came later.) Even though the analog inputs maybe sampled at 192kHz, they also are downsampled to 96 kHz. And if you put the TDIA-3400 in Bypass mode, it still operates at 96kHz instead of the input sample rate, as amirm has discovered.

Amirm is right that people should know that they're wasting their money if they are buying high-resolution audio media above 96kHz to play on the TDIA-3400 (or any of the Lyngdorf products that have room correction.)
 
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I see your point. But I see no mention of that anywhere in the documentation or marketing material for the product. What you saying is that if I want to use external amplification for more power, I should not. This should be clear in the documentation. Seeing how the amplifier is the much weaker link than the DAC, that would be a bad thing in global scheme of things.

Also, what on earth is a cheap DAC doing in a $6,500 product? We have $99 DACs that run circles around it.
As I already stated in earlier posts, the TDAI's are not designed to use as a pre-amp to an analogue amplifier. In the past Lyngdorf produced the DPA-1 preamp/drc and the RP-1 room processor. These units were designed to use in an analogue chain. If you want to use the TDAI's as a pre-amp and room processor only and respect its design principles the only logical setup is with digital input power amplifiers.

It's like judging Usain Bolt's soccer skills...
 
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The ASRC chip in the unit I have is an AK4122. It is old, assume there are newer chips in the units available today. The limit is 96K with it. The Room Perfect is 96K also.
In my limited world that fine. All my files are either 44.1/16 from CD or 96/24 from ISO files.
I will get reprimanded for saying this, but I used software to feed the AK4122 with 96/24. Sounded better to me.
The spec sheet does not show the S/N and DR for 96k in and 96K out. At least I do not see it. It only references sample rate conversion specs.
 

restorer-john

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However I disagree with using a THD + N overall figure that's measured into the US range as an indicator of audible performance because it includes things that aren't reproduced or audible.
Whilst I partially agree with what you are saying, it does need to be mentioned and reported upon when any amplifier (or D/A converter) has significant noise and spuriae out of band, regardless of whether it is inaudible or not.

There are some Class D amplifiers dishing out multiple volts at AM frequencies out there... (not yours of course) :)
 

March Audio

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Whilst I partially agree with what you are saying, it does need to be mentioned and reported upon when any amplifier (or D/A converter) has significant noise and spuriae out of band, regardless of whether it is inaudible or not.

There are some Class D amplifiers dishing out multiple volts at AM frequencies out there... (not yours of course) :)
Sure, these things MUST be looked at, they are absolutely relevant, just saying caution should be exercised when trying to relate to actually audible issues.
 
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The out of band noise can create issues.
I built a phono stage one time that was picking up RFI from the four TV transmission towers about five miles away. Layout was terrible for a high gain amplifier. Loop area was not on the radar then. My cheap 12 bit scope could see it. Orientation and shielding effected it, but never eliminated issue.
The speakers were Lowthers, 8 inch, high inductance, limited top end. I could not hear the ultra sonic but it gave me headaches in five minutes. Phono stage lasted a week before ending up in the failed project pile. It is a large pile.
The high RFI level only effected this one source. Other phono stages, preamps, and amps did not cause the headaches. Main amp used then rolled off around 200 KHZ.
Those 15 ohm Lowthers were outputting something I could not hear, yet feel.
 
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Thank you for the informative posts. Let's go back to the first posting: the measurements.

With ICC engaged you should feed it only 44.1..

With 48Kh f.e. the signal clips [high freq]: This is audible when you do a sweep with REW.
 

maty

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LYNGDORF AUDIO TDAI-3400

[Polish] https://audio.com.pl/testy/stereo/wzmacniacze-stereo/3056-lyngdorf-audio-tdai-3400

to English: https://translate.google.com/translate?hl=&sl=pl&tl=en&u=https://audio.com.pl/testy/stereo/wzmacniacze-stereo/3056-lyngdorf-audio-tdai-3400







  • Rated power (1% THD + N, 1 kHz) [W] 8 Ω, 2x 210
  • Rated power (1% THD + N, 1 kHz) [W] 4 Ω, 2x 419
  • Sensitivity (for maximum power) [V] 1x 1.0
  • Signal / noise ratio (A-weighted filter, with reference to 1W) [dB] 62
  • Dynamics [dB] 85
  • Damping factor (relative to 4 Ω) 91
 
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Like $6,395 deniro'$ less.
Please do tell where one can get an integrated amplifier for $105 with the following features:

One of the best room correction systems on the market that also measures and corrects the sub + sat splice.
32 different voicing profiles, each with 8 slots and multiple types of filters.
2×400 W RMS @ 4Ohm / 2x200W RMS @ 8Ohm.
7 digital inputs including a balanced AES/EBU.
USB inputs connects to music stored external.
2 analog inputs for simple analog music sources.
Module with 4 high-end analog inputs.
Module with 3 HDMI inputs and 1 HDMI output
Digital crossovers and multiple customizable inputs.
Bluetooth and Wifi connectivity.
Built in streamer with Roon, Spotify Connect, and Airplay as well as internet radio.
Well designed app.

I've got my credit card ready to buy this $105 wonder amp.
 

amirm

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Lyngdorf TDAI models claim that no power filter/conditioner is required due to the proprietary PUS, is this true?
It is true of Lyngdorf and other audio gear you use. I have an AC simulator and last time I tested it on a proper amplifier, even when I severely chewed up the AC mains spectrum, not a hair moved out of place on the amplifier.
 
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As someone relatively close to Lyngdorf, who was considering a 3400 to run my Monitor Audio Platinums, which have a touted (and measured) flat response up to 100khz, this was a serious disappointment!
Having heard a Steinway Lyngdorf system, I can say it was absolutely one of the best sounding setups at the audio show I was at, which really got me intereseted... so I have no doubt it sounds good - but at the same time, knowing it measures this badly makes my objectivist mind rather upset...
 
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