Topping LA90 Review (Integrated Amplifier)

[tritopia]

The LA90's power inlet and 12V trigger terminal are located close to each other. Those who use AC cables with thick housings, be careful.

 

[restorer-john]

Those who use AC cables with thick housings, be careful.

Just use a normal IEC lead- problem solved.

 

[tritopia]

Just use a normal IEC lead- problem solved.

Yes, that's right.
When I used the power cable of the other preamplifier that was there, I found that problem.

Typical power cables, bundled cables are fine at all.

 

[Laserjock]

The LA90's power inlet and 12V trigger terminal are located close to each other. Those who use AC cables with thick housings, be careful.

View attachment 216996

LA90 uses an external power supply and has a DC inlet next to the 12V trigger I thought, what unit is your picture of?

 

[tritopia]

LA90 uses an external power supply and has a DC inlet next to the 12V trigger I thought, what unit is your picture of?

Oh... Sorry. It was about the location of the AC cable inlet of the A90D and the 12V trigger.

The picture above is of the A90D.

 

[manisandher]

As this is an integrated amp, tell us more about the volume control. You said lots of relays clicking - does the volume control use relays to change resistors in the gain-feedback loop? Or is it a conventional pot? How does the SNR change with volume control, like when you turn it down to some reasonable level like -20 dB?

Did anyone ever respond to this? (I looked, but couldn't find a response in this thread.)

@JohnYang1997 could you perhaps enlighten us please?

Mani.

 

[edwardgrey]

Would it be safe to run 2x LA90’s bridged to power Focal 948s?

The Focal 948 are 8Ω nominal but 2.5Ω minimum

 

[peng]

Would it be safe to run 2x LA90’s bridged to power Focal 948s?

The Focal 948 are 8Ω nominal but 2.5Ω minimum

It depends on how close you drive them to their limits. It only takes 1 W to produce 92.5 dB at 1 meter, that is 86.5 dB at 2 meters without room gain.

The manufacturer specifies a wide range or recommended amp output:

• Recommended amplifier power: 40-350 Watts

So better check your requirements using an online calculator if you want to be sure. Keep in mind music contents vary all the time, the 2.5 ohm minimum is just the minimum point. If the dip is of short duration then it obviously won't be as bad as if it is for a longer duration and that again would depend on the music contents and the impedance as well as phase angles vs frequency characteristics. Have you seen any measurements for the 948? I did a search but could only find one for the 936.

 

[edwardgrey]

It depends on how close you drive them to their limits. It only takes 1 W to produce 92.5 dB at 1 meter, that is 86.5 dB at 2 meters without room gain.

The manufacturer specifies a wide range or recommended amp output:

• Recommended amplifier power: 40-350 Watts

So better check your requirements using an online calculator if you want to be sure. Keep in mind music contents vary all the time, the 2.5 ohm minimum is just the minimum point. If the dip is of short duration then it obviously won't be as bad as if it is for a longer duration and that again would depend on the music contents and the impedance as well as phase angles vs frequency characteristics. Have you seen any measurements for the 948? I did a search but could only find one for the 936.

Thank you for the reply. Generally I would listen at lower volumes. I have not yet found any high quality measurements, there is a grainy scan of one on the last page of this FOCAL shared PDF review, from a French magazine: https://www.focal.com/sites/www.focal.fr/files/shared/catalog/presse/1311_Aria948_FR.pdf

Image also attached below for my best guess of the numbers from the PDF review, unfortunately not a very clear source.

Do you expect at lower/low-mid volumes the 2xLA90 might be ok in mono mode? Seating is ~3m from speakers.

 

[delta76]

It should be ok, no problem. The power required to drive floorstanding speakers are usually overestimated, given that they generally are more sensitive than bookshelf.

But, for 2xLA90 you can easily buy hypex or purifi amp with 250x2 into 8ohm. So why bother

 

[edwardgrey]

It should be ok, no problem. The power required to drive floorstanding speakers are usually overestimated, given that they generally are more sensitive than bookshelf.

But, for 2xLA90 you can easily buy hypex or purifi amp with 250x2 into 8ohm. So why bother

Thank you for that! Fair question: In Korea due to shipping and import costs the pricing is similar to the 2x hypex or purefi builds. I was planning on putting together an all-Topping kit, 2x LA90's, D90SE and Pre90.

 

[delta76]

I see. A few more things to consider: while la90 can be measured marginally better, you won't hear it. Hypex/purifi are tried and true design, and you can reasonably expect them to serve you 5+ years. Topping reliability, however, is questionable, and you might have trouble getting support even within warranty period.

If you are buying one la90 (which should have enough power to drive your 948s) it is one thing, but to buy two. Well, the economy does not work well with me.

My 2 cents

 

[peng]

Thank you for the reply. Generally I would listen at lower volumes. I have not yet found any high quality measurements, there is a grainy scan of one on the last page of this FOCAL shared PDF review, from a French magazine: https://www.focal.com/sites/www.focal.fr/files/shared/catalog/presse/1311_Aria948_FR.pdf

Image also attached below for my best guess of the numbers from the PDF review, unfortunately not a very clear source.

Do you expect at lower/low-mid volumes the 2xLA90 might be ok in mono mode? Seating is ~3m from speakers.

That review is extremely useful, hard to read because of the poor resolution, but if you try hard enough you can figure it out for the most important parts.
The following information should be applicable to answer your question "Would it be safe to run 2x LA90’s bridged to power Focal 948s?"

Assuming the 85 dB 1 kHz indicated on the graphs below refers to 1 meter distance, then you can safely assume it will apply to 79 dB at 2 meters and 71 dB at 4 meters as that would be with just one speaker and zero room gain.

The graphs show the following worst condition in terms of loading:

At 100 Hz:

Current: 0.361 A
Output voltage: 1.46 V
Power: 0.52706 (W), Note that the unit is W, that is, watt, is only correct for resistor test load otherwise it should be VA for speaker load that is reactive.

So if you bridge two LA90, the current would increase to 0.722 A and the output power would be 1.05412 W
Since you know your distance, speaker sensitivity and the spl you need, you should be able to figure the current required for your worst case condition.

The LA90 specs say:

• Output power
  • Stereo
    • 90W x 2 @4Ω THD+N<1%

So when bridged, it should be able to handle 45 W X 2 safely, assuming the amp does not have current/impedance sensing protection schemes to trip it most likely will be fine because Amir did test it for 2 ohm and said:

Topping LA90 Review (Integrated Amplifier)

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. I must say, this is one interesting industrial design. Everything oozes style despite the diminutive package. This aspect continues in the operation of the...

www.audiosciencereview.com

Edit:
Power Tests at 2 Ohm (Stereo) and 4 Ohm (Bridged)
Requests were made to test the amplifier beyond its minimum load impedance specs. Let's start with 2 ohm load while driving one channel in stereo mode. Dashboard still shows superb performance:

 

[nemanja_t]

Thank you for the reply. Generally I would listen at lower volumes. I have not yet found any high quality measurements, there is a grainy scan of one on the last page of this FOCAL shared PDF review, from a French magazine: https://www.focal.com/sites/www.focal.fr/files/shared/catalog/presse/1311_Aria948_FR.pdf

Image also attached below for my best guess of the numbers from the PDF review, unfortunately not a very clear source.

Do you expect at lower/low-mid volumes the 2xLA90 might be ok in mono mode? Seating is ~3m from speakers.

You have great speakers, do them a favour, and get a better amplifier. 2x200 W 8R, 2x350W 4R.

 

[delta76]

I recall the measured sensitivity of 948 to be 88.5 or 89dB. If you are sitting 3m away, that would mean it only draw 10w for 88-89dB (which is very loud, and not recommended for long listening session). La90 should be handle that with ease.

 

[peng]

I recall the measured sensitivity of 948 to be 88.5 or 89dB. If you are sitting 3m away, that would mean it only draw 10w for 88-89dB (which is very loud, and not recommended for long listening session). La90 should be handle that with ease.

The French review he linked shows 91.8 dB/2.83V/1m, that is a little closer to the manufacturer's specs 92.5 dB/2.83V/1m

 

[edwardgrey]

The French review he linked shows 91.8 dB/2.83V/1m, that is a little closer to the manufacturer's specs 92.5 dB/2.83V/1m

I found two other reviews that I google translated with some measurements, linked below.

As long as there are no issues, I'll test out the LA90. I may regret it later due to future issues and need to look for a purefi/hypex system as advised, but quite curious to run a full topping combo if it's possible! Have been running an E50/PA5 combo since launch on my PC, which has been ok so far.

 

[delta76]

Check out HPA-S400ET before purchasing your la90 . I think from a purely technical measurements, la90 is a great amp, one of a kind even, no denying that. But measurements alone are not everything

 

[edwardgrey]

Check out HPA-S400ET before purchasing your la90 . I think from a purely technical measurements, la90 is a great amp, one of a kind even, no denying that. But measurements alone are not everything

Ok will do! Price difference would be + ~10% / €150 for the HPA

 

[PH14]

And you have that large external power supply. My wish is another version of this amp with built-in power supply, motorized volume control with bridge mode standard.

I'm sure it's been said already, but I'm not going over a 78 page thread. THIS! Topping, Sabaj, SMSL, Loxjie, Schiiiiiiitt, JDSlabs and all that ilk, are you paying attention? Stop using those idiotic elephant bricks and learn how to make good integrated power supplies! There are some good devices out already (though I'm still waiting on Amir's judgement) like the Sabaj A10/20a, SMSL A300 etc, but it is still way too common for manufacturers to take the easy cheap route. Oh, and while on the subject: include a hard power switch on the back or front please! I'm not too lazy to walk over to the amp to switch it on (I have to work to pay for electricity, good training for not being lazy).