Topping Pre90 Review (preamplifier)

[delgesu]

Is the pre90 output stage strong enough to drive 5 meter xlr ->active speakers, or is 5m too long?
Thanks!

 

[staticV3]

Is the pre90 output stage strong enough to drive 5 meter xlr ->active speakers, or is 5m too long?
Thanks!

5m is fine.

 

[Jimbob54]

Thnx to all, although still bit confused, Topping says it converts, and for @ZestClub and me doesnt seem to work.

Yes i tested it, and it is not just a drop in dB but RCA in/XLR out sounds lot more dynamically constricted. Night and day to RCA all the way.
It makes me concerned if the amp's XLR input is ok. This amp has RCA/XLR switch and I actually 1st tried Pre90 XLR withouth switching to XLR on the amp. Thinking back it sounded similarly bad. With the XLR switch on amp it sounds bit better, more depth, but kind of too much - all is somehow quite in the background but bit more noisy than RCA.
I am about to sell the amp since i can't really test it cos I only have Pre90, and just sold the XLR cables today. (DIT) Ok i just ordered standard Amazon XLR to check what is the diff.

Someone asked about the remote - i had a (black) Pre90 before and sold it, remote was really bad, this Pre90 one is silver and remote is much better, the angle is greater compared to the previous one, although still not perfect, but i doubt this depends on the color of the Preamp

I wonder if the xlr level signal was exceeding the input sensitivity of the amp? Did you ever say what the amp was ?

 

[Kal Rubinson]

Is the pre90 output stage strong enough to drive 5 meter xlr ->active speakers, or is 5m too long?
Thanks!

5m is fine.

So is 10m.

 

[delgesu]

Thank you!

 

[tuannguyetxm]

i have Dac Teac NT505x (with volume ) and pre 90, which volume setup better ?

 

[wizardofoz]

You have both, try both and see which if any you prefer. Job done.

I really don’t know why people ask such questions when it’s their own ears and brain they need to satisfy.

 

[kolestonin]

I am noob and I am maybe entering in unknown territories so feel free to correct me.

My understanding is that almost all DACs(there are a few with analogue volume controls but most don't have) require full volume in order to get the best out of them.
Below maximum volume their ability to expose detail is reduced because they have digital volume control.
Meaning that the number of bits they output is only maximum at maximum volume and at low volume SINAD and dynamic range will be reduced.
I remember, when doing my research before buying Pre 90, I had read that each bit not used on the output reduces dynamic range by 6dB.
Above was the only reason, as I mostly listen in low volume, I added a preamp in my chain so I hope it's valid

But if it's valid, why you will want to use a DAC as volume control when you already have a quality preamp as Pre 90?

 

[tonapo]

I am still enjoying my pre 90, all apart from the remote which is not great. Its quite tricky to line up, and I think, not helped my set-up, as the right hand-side of the pre-amp is mildly obscured by the left speaker, so the signal does not get through. My solution, other than living with the remote, has been to use a logitech remote I had lying around. It works better, but it is not 100% a solution, in part because it is puppy chewed, and a whole controller just for volume feels wrong. Has anyone else use a different remote?

 

[DHT 845]

Has anyone else use a different remote?

Simple learning one for 5 bucks... It has greater strenght than original, but it's not ideal either...

 

[DHT 845]

Has anyone else use a different remote?

I suppose there is an easy way to additionally increase the power of such a remote control. The remote control has an IR diode emitting infrared light, invisible to the eye. However, despite the fact that it is invisible, there is some objective "brightness" of such a diode, which is crucial for the DAC's receiver. Therefore, the power of the diode in the remote control should be increased (current flowing through IR LED), most likely by reducing the series resistor connected to the diode (current limiting resistor). Maybe the remote control will run on batteries for a shorter time, but it will work much better... I'll try it with that cheap learning remote to father improove it's performance. Unless it turns out that the IR LED is connected without a resistor, but as far as I know, LED's are always connected via a resistor...

 

[Kal Rubinson]

You should try an IR extender to intercede between the Topping's IR remote and IR receiver.

 

[glc650]

You should try an IR extender to intercede between the Topping's IR remote and IR receiver.

This is what I (have to) do in order to use a lot of my devices (consistently without issues and not just Topping) with my Harmony Hub and iTach. There are all kinds of wired and wireless IR extenders and blasters you can get too. I use a wireless one to send signals across the room to a couple of IR devices. I use wired extenders with almost all of my other IR devices to ensure commands aren't missed.

 

[DHT 845]

There are 2 resistors on the RC, I am not sure which one is responsible for infrared LED current

 

[DHT 845]

...

 

[zengwendian]

Hey @amirm I'd like to know if the performance of the Topping A90 Discrete for preamp use is the same as the performance of the PRE90's? If I already own the A90 Discrete, would it make sense to buy the PRE90 or not? Also, would the sound quality be different?

 

[Rhamnetin]

Hey @amirm I'd like to know if the performance of the Topping A90 Discrete for preamp use is the same as the performance of the PRE90's? If I already own the A90 Discrete, would it make sense to buy the PRE90 or not? Also, would the sound quality be different?

Although I'm no Amir, the answer is 100% no. In terms of sound quality, the fully transparent Pre90 will sound no different than the fully transparent A90 Discrete serving as a preamp. Although the A90 Discrete's preamp performance wasn't measured in the review here, it should be very similar to the headphone amp performance in terms of SINAD and frequency response.

 

[amper42]

I have a Topping Pre90 Preamp for sale. In excellent condition. See details here:

For Sale: Topping Pre90 Preamp $399 - Shipped in USA

Topping Pre90 preamp along with remote, power cord and original small manual $399 shipped within the USA. This unit is in excellent condition. The ASR review can be found here: https://www.audiosciencereview.com/forum/index.php?threads/topping-pre90-review-preamplifier.18283/ If interested...

www.audiosciencereview.com

 

[atmasphere]

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/

Amirm, I don't see anything in this thread about AES48, the balanced line standard. It appears that its not supported. There's nothing in your tests that suggest one way or the other, so I thought I'd ask.

 

[Peternz]

Hey @amirm I'd like to know if the performance of the Topping A90 Discrete for preamp use is the same as the performance of the PRE90's? If I already own the A90 Discrete, would it make sense to buy the PRE90 or not? Also, would the sound quality be different?

It would not make any sense to buy the PRE90. Opinion as to the difference in SQ varies.