Topping Pre90 Review (preamplifier)

[Cujobob]

It now remains to combine these three devices D90, A90, Pre90 into a single standard of 43 cm. I will agree to pay in advance.




View attachment 98664
like that

You’d only be saving some build costs, but they’d have to manufacture a brand new enclosure which also adds to the cost (instead of using one already available). There’s no real advantage to making this product except form factor (which isn’t a plus for everyone because it’s just height vs width).

 

[bungle]

You’d only be saving some build costs, but they’d have to manufacture a brand new enclosure which also adds to the cost (instead of using one already available). There’s no real advantage to making this product except form factor (which isn’t a plus for everyone because it’s just height vs width).

Yes, Pre90 + n-number of different chainable expansions would be good enough to me. NAD does it with cards. The main point is that volume and input selection you will need always. EQing or room correction is more a static thing, that can be done later in output chain. Splitting inputs across separates, will hurt usability.

 

[amirm]

Yes, that's why we need the complete set of standard parameters and not only the cherry-picking.

Watch your tone. There was no cherry picking. I ran the same tests on this unit that I have run on every other one. As a rule, I don't measure impedances on anything other than output of headphone amplifiers. So no cherry picking whatsoever.

I have never measured the input impedance device of any device and so this review is no exception. Indeed I went out of my way to characterize this aspect by changing the source impedance and showing the effect on both level and distortion. So if anything, this device was tested more thoroughly than any other.

 

[RigorDude]

This is a review and detailed measurements of the Topping Pre90 balanced and unbalanced preamplifier. It was kindly sent to me by the company. The base preamplifier with ability to switch between RCA and XLR inputs costs US $599. There is an extension that gives you four (4) more inputs (three balanced and one unbalanced) for another $250.

Splitting the functionality into two boxes is rather unique:

View attachment 98412

Unfortunately there is no immediately switch to select an input. You have to cycle through them using the "SEL" button on the left.

Remote control is provided for volume which in turn mandated relay based stepped attenuator which is quite a "high-end" feature. For any kind of home system use remote is mandatory in my book so it is great to see it implemented here. There are other cool features like setting a pre-input gain or maximum safe playback level.

The back panel shows the unusual configuration with the umbilical cord connecting the two:

View attachment 98413

As you see mains power supply is built-into it as it should in this price category.

Overall fit and finish is very good.

For my testing I exclusively focused on XLR input and output.

Topping Pre90 Measurements
As usual I setup preamplifiers for "unity gain" meaning what voltage I put in, is what comes out. On Pre90 that meant setting the volume to -6 dB instead of zero. That gives us this eye popping output:

View attachment 98414

Distortion is whopping -25 dB lower than best case threshold of hearing. Combined noise+distortion as represented by SINAD is 5 dB better than said threshold. And this includes the noise from my analyzer. Likely the actual performance is fair bit better.

Suspecting some of the good noise figure comes at the expense of lower than normal input impedance, I jacked up the default 40 ohm output impedance of my Audio Precision analyzer to 200 ohm. The result was that the output from the Pre90 dropped down to 3.6 volts (instead of 4). One click on the volume control compensated for that nicely and give me the same good performance just as well:

View attachment 98416

So there is really no penalty to the lower input impedance.

I wanted to test the effect of the external box so I selected one of its inputs and ran the dashboard again (with 40 ohm impedance);

View attachment 98424

As you see the external input works just as excellently as the internal input.

EDIT: here is the RCA performance:
View attachment 98630

Signal to noise ratio (combined with my analyzer input) is 21 bits and rises to almost 22 bits with full volume:
View attachment 98429

Note that Topping advertises much higher numbers. They do that by using a noise amplifier, measuring the results with AP, and then dividing the output by the gain of the noise amplifier. By doing so the remove the effect of Audio Precision analyzer's self noise and get much higher SNR. That is customary in chip industry. For us to keep things consistent we will continue to test as we have as any performance above what I am showing is academic anyway.

Note that the Pre90 can go up to +10 dB gain. Doing so though has a penalty in overall noise. To show the effect of output level/gain, here is a sweep:

View attachment 98435

As you see you can get to 8 volts while maintaining the full performance of the preamp. There is more gain left if you want to drive an amplifier like Benchmark AHB2 in low gain or Purifi without its input buffer.

Frequency response is almost flat to 80 kHz:
View attachment 98436

There is a bit more droop in my measurements vs Topping. Not sure why but it is immaterial.

Crosstalk was more than good enough for what we need but shy of the best that can be done:

View attachment 98438

Intermodulation distortion test is as good as the best I have tested, the Benchmark HPA4:
View attachment 98439

Same is the case for SINAD vs frequency:

View attachment 98440

Conclusions
Seems like the revolution we have had in high performance headphone amplifiers has bled into preamplifiers. I love it because I have a Reel Reel tape deck that I like to use occasionally in my system along with my usual DAC. Sadly hardly any premplifier could keep up with said DAC so I was degrading the performance of it to have the ability to play another analog source. With the Pre90, that compromise is no more. It is an instrument grade, more transparent than transparent, preamplifier. Other than Benchmark HPA4, I don't think it has an equal no matter how much money you spend. In that regard, it is quite a value as well although obviously not "cheap" as compared to desktop products.

It is my pleasure to strongly recommend the Topping Pre90. If you needed to have another source beside your DAC to play in your system, you now have a wonderful way to accomplish that with zero impact on performance.

------------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Which balanced input was used for the test? Seems like the inputs on the second box might have a bit more noise.

 

[preload]

You’d only be saving some build costs, but they’d have to manufacture a brand new enclosure which also adds to the cost (instead of using one already available). There’s no real advantage to making this product except form factor (which isn’t a plus for everyone because it’s just height vs width).

I'd totally pay extra for an enclosure that matches the quality and performance of its internal design. Slap in some thicker gauge steel, a thick faceplate, beefier RCA/XLR connections on the rear, and now we're talking. Design matters. Look at Apple products.
Plus, Topping could sell a "VTL edition" and drill some random holes in the bottom cover.

 

[amirm]

Which balanced input was used for the test? Seems like the inputs on the second box might have a bit more noise.

I tested both the internal and external XLRs against each other. Both data is in the review showing no degradation from external box.

 

[Labjr]

I wonder if any of these companies are interested in selling kits or bare boards like Hypex and Purifi?

 

[Prutser]

Now I know for sure this forum is sponsored by Topping.. time to leave ..

 

[Prutser]

Now I know for sure this forum is sponsored by Topping.. time to leave ..

But how do I delete my account ?

 

[Veri]

Now I know for sure this forum is sponsored by Topping.. time to leave ..

But how do I delete my account ?

Some kind of existential crisis there that you're having?

 

[Guerilla]

Sadly, as well as this preamp measures, I feel that we are in a race to the bottom aiming for the best specs by introducing unnecessary compromises.

Douglas Self has said that balanced connections are rarely necessary in a domestic environment - he has also pointed out that balanced connections are inherently noisier* than unbalanced connections, and require a lot more silicon to even match the noise specs of an unbalanced input (let alone better it).

What we have here IMHO, is the MQA of preamps - it's a solution to a problem that doesn't exist.

It is possible to build a very low noise preamp without the input impedance compromises. Even 10k is too low for non DC coupled sources, unless they have large (=>47uF) coupling capacitors in the output stage.

*electronically noisier - the balanced connection does offer improved noise immunity to EMI etc. which is a different type of noise.

Some of us really needs ballanced inputs for various reasons, so its a solution for a need. Most people would be waisting money going ballanced, but not all. I will buy if i dont find a good reason not to. I wish it had adjustable loudness though

 

[Guerilla]

A lot of people are missing the point that this is a reference level product. Asking them to worsen their performance so that it’s more flexible with poorly designed products isn’t fair. Use this preamp with a modern high end amplifier and DAC for state of the art sound. That’s it’s use case and what it was designed around. I get that people have devices they’d like to use with it, but in order to do so it makes this product worse in performance and cost. I don’t see that making sense at this level.

I’m picking one up because I was actually in the market for a stereo preamp, nearly went for tubes, but I’ll try this first and check back.

Products arent poorly designed just becaus the dont fit this preamp

 

[Cujobob]

I'd totally pay extra for an enclosure that matches the quality and performance of its internal design. Slap in some thicker gauge steel, a thick faceplate, beefier RCA/XLR connections on the rear, and now we're talking. Design matters. Look at Apple products.
Plus, Topping could sell a "VTL edition" and drill some random holes in the bottom cover.

I’m sure a small group would, but as the cost goes up, the audience shrinks. Not everyone needs a ton of inputs or wants to use the Topping DAC. This preamp is cheaper than an all-in-one and allows me to upgrade my DAC as I please. I truly wonder how long someone buying a D70 (I think that’s their DAC) is keeping it before moving on to the new flavor of the month.

My criticism of the unit is that I think the price is a bit high for what this is. I paid it anyways and look forward to testing it out. This is a companion piece for their power amplifier that I also intend to purchase and compare with the Purifi based amplifier I currently own.

As for room correction, I’d prefer a company dedicated to such a thing handle that anyways. I also prefer as little room correction as possible as that should be handled with the speakers and room and then only adjusted if absolutely necessary. Controlled directivity speakers are absolutely crucial to a good experience.

 

[TimF]

It now remains to combine these three devices D90, A90, Pre90 into a single standard of 43 cm. I will agree to pay in advance.




View attachment 98664
like that

Virginia Slims.

 

[ElNino]

I'd totally pay extra for an enclosure that matches the quality and performance of its internal design. Slap in some thicker gauge steel, a thick faceplate, beefier RCA/XLR connections on the rear, and now we're talking. Design matters. Look at Apple products.

There’s probably no issue with the enclosure quality. If this is anything like the D90 (and it probably is), the enclosure is very heavy weight, at least partially milled and largely seamless. Just as an example, I own both the RME ADI-2 and the D90, and the D90 chassis feels and looks much more premium. It’s also a lot heavier. The ADI-2 is nice too but most of the chassis is just painted folded sheet metal. The D90 also comes in a much nicer box, reminiscent a little of Apple and Sennheiser’s packaging.

Where Topping’s industrial design falls a little short IMHO is just the visual aesthetics, the combination of font sizes on the faceplate and the blocky inconsistent fonts used on the display, the TOPPING logo that flashes briefly when you first turn it on, etc. That’s where they’re weakest at the moment IMHO, not the physical chassis itself and certainly not the sound quality.

 

[Guerilla]

https://parasound.com/p6.php

Crossover goes between pre- and poweramp

 

[Guerilla]

This preamp is obviously without any noise issue. There is EMI, yes, but now more than ever balanced line level connections are relevent IMO. The way I see it is an insurance policy. Thing is, unbalanced connections work well, for gear that talk well to each other.
Over the years, the manufacturer's practices regarding audio ground scheme varied quite a bit. Even the AES modified their guidelines and standards. Most audio gear enthusiasts that I know that use equipment from different manufacturers and different era have had to deal with a hum in their system at one point or the other. Troubleshooting is a pain, ground loops can comes from anywhere. It's time consuming, can be intermittent, can be faulty cable, can be gear incompatibilities, can be defective equipment, can come even from gear that is currently unused and powered off, it's a pain. Going balanced mostly fix the issue of swearing a lot an costing time. That's the most obvious reason.

Going ballanced connecting different diferent brands of gear often cause hum,hiss and sometimes no sound

 

[Guerilla]

No chance of Topping ever making a home theatre processor ?

No need. Just let the topping do frontchannels wherr it counts. No reason for high performance on the other channels. You wont hear it

 

[maxp779]

Is the pre90 display an OLED or regular LCD?

 

[Guerilla]

Next design a pre with ballanced turntable input please
Cheers!