Topping LA90 Review (Integrated Amplifier)

[DrSpan]

This is a review and detailed measurements of the Topping LA90 integrated amplifier. It was sent to me by the company and costs US $800.
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I must say, this is one interesting industrial design. Everything oozes style despite the diminutive package. This aspect continues in the operation of the unit with the sound of the relays solidly clicking indicating something good is going to happen. Here is the side view:


Due to more power available now, we cross the amazing 140 dB SNR threshold. What this says is that even if you play at 140 dB, the noise level will be at or below threshold of hearing! Of course there is not enough power there to do that but basically you know that noise is not part of the equation with LA90 as even 5 watt measurement hits below threshold of hearing.

We want to know the power increase though so here it is (with 8 ohm which is the minimum impedance):

Amazing. Also funny format. It looks like someone took an Spl Volume 2 and put an amp inside.
This site is amazing. If it was easier to send things ot the U.S but….customs. I would have send you the Tangent Powerampster 2 i had for a few days. Felt very well build
but i send it back cause i had no way of testing it since my speaker died one day before it arrived.
Keep up the good work Amir!

 

[Ziofrenko]

To be clear; when you talk about dB SPL you talk about dBC -right?

If you are, I agree with you. Having a system capable of high SPL and low distortion is something everyone should try. But it's not exactly the same to say you want the levels that are present on the stage. The musicians are wearing hearing protection (I hope).

A drummer wear ear protection (now, non in 70' or 80' or 90').
A symphony orchestra, no, it seems banal to me... The orchestra can reach 120dB, but it doesn't maintain it for 10 minutes.
And I would also like to remind you that there are tables on hearing damage based on pressure... They depend on the amount of time clearly.

 

[glorei]

I have just one question. Its a good choice (L90) for B&W 683 S2? Now i have dac Topping DX3 Pro+, but amplifier (receiver) Yamaha RX V 659. Thank you

 

[antcollinet]

I have just one question. Its a good choice (L90) for B&W 683 S2? Now i have dac Topping DX3 Pro+, but amplifier (receiver) Yamaha RX V 659. Thank you

What do you expect to get from the change.

If it is sound quality there is a good chance you won't be able to hear a difference from the Yamaha in pure direct mode. The Yamaha is already very good.

 

[Ziofrenko]

As always it depends on how sensitive the speakers are, the maximum SPL you expect and the listening distance... And clearly from the environment!

 

[nagster]

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

 

[staticV3]

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

Thank you for the measurements!

So basically, the LA90 has an effectively un-clippable input. Nice!

Also relevant to @babadono I believe:

Also anybody know the maximum input level before clipping the input stage?

 

[babadono]

Please educate me... how does this show that the input is unclippable? Do you mean that it is always the output section that clips before the input? The input still must have a limit though, correct? All I want to know is the maximum signal input say +20dBu or whatever it might be. On the semi pro gear that I am interfacing with these type of specs are given. Both input and output.

 

[babadono]

Oh and an input impedance spec would be cool too.

 

[staticV3]

Please educate me... how does this show that the input is unclippable? Do you mean that it is always the output section that clips before the input?

Correct.

The input still must have a limit though, correct?

Not necessarily. A simple passive attenuator has no clipping point as-such.

All I want to know is the maximum signal input say +20dBu or whatever it might be.

With the LA90's volume control bypassed, you can input 6.9Vrms (=19dBu) in Low gain, or 2.2Vrms (=9dBu) in High gain, before the Amp's output clips.

With the volume control engaged however, even 25Vrms (=30dBu) is not enough to cause clipping, provided that you set the LA90's volume knob low enough to avoid clipping the output.

 

[babadono]

So the "volume" knob is a dual differential passive attenuator? Now I REALLY want to take one apart

 

[nUUK25]

I've had just one LA90 for some time (July) and realized that with two the sound might be less constrained. Two month ago I've bridged (mono) two amps, one for each speaker and it works wonders in terms of the past 'constrainment'. Definitely an audio quality ascent ! Now I'm thinking I might gain some improvement with another two LA90 in the setup as my Martin Logan Electromotion speakers are bi-amp capable. I doubt the improvement will be proportional; two to four, but even less are welcome ! The fact that one amp will be dedicated to the electrostatic section and another amp to the dynamic section in itself might reveal more clarity. If I do go for it I will report back here !

A lot of time has passed - Well, not a surprise ! 4 are better than 2 - it is worth it !!