Stereophile tested a Topping Pre90

[MakeMineVinyl]

2kohm input impedance is a major drawback of the Topping preamp.

If it is really that low, that certainly could be a problem for some upstream gear such as a vacuum tube component. Most op-amps however are perfectly happy driving 2k continuously. Actually it takes some degree of effort to design something with an input impedance as low as 2k!

 

[sarumbear]

A preamplifier traditionally is a multi input buffer and gain stage that allows various capability ancillary sources to perform to spec and not be negatively affected in terms of degradation of THD, level, or deviations in frequency response.

2k ohms input impedance is a ridiculous burden on upstream devices.

I can’t imagine a modern source output impedance to be more than 100 Ohm. That’s 26dB deviation on load. Is that ridiculous?

 

[Robin L]

Someone asked before, didn't see an answer so far: Is there a link?
Is this never going to appear in the online version of Stereophile?
Seems like the kind of article J. Gordon Holt would publish and that the current powers that be would tend to bury, if possible.

 

[Kal Rubinson]

Someone asked before, didn't see an answer so far: Is there a link?
Is this never going to appear in the online version of Stereophile?
Seems like the kind of article J. Gordon Holt would publish and that the current powers that be would tend to bury, if possible.

Almost all reviews will appear online at www.stereophile.com However, they appear in print first for our subscribers and there is a delay before the online posting.

 

[Axo1989]

Almost all reviews will appear online at www.stereophile.com However, they appear in print first for our subscribers and there is a delay before the online posting.

Thank you, I'll stop looking for now.

 

[Blumlein 88]

I tried the Topping Pre90 with the RME ADI-2 DAC FS. The Pre90 colors the sound compared to the crystal clear sound of using the RME ADI-2 alone. With the Pre90 in the chain the sound is a bit more harsh and offers less clarity. I won't be using the Pre90 with this setup. Those that think the Pre90 doesn't add color should compare it directly with the RME ADI-2 DAC FS. The difference is amazingly easy to notice.

It would be interesting if someone had the RME ADC and could do the RME DAC with and without the Topping P90 in circuit to see what the differences were. You would think the Topping to be audibly transparent. I also agree that for home hifi a 2 kohm input impedance is low.

Also wondering did you match levels when you did this comparison? Sorry, I end up asking this like over and over, but it is such an easy thing to mess up comparisons if not done.

 

[Kal Rubinson]

Thank you, I'll stop looking for now.

I am sure someone will post here when it appears.

 

[Kal Rubinson]

Also wondering did you match levels when you did this comparison? Sorry, I end up asking this like over and over, but it is such an easy thing to mess up comparisons if not done.

That is pretty simple because you can easily set the Topping for 0db gain. Most other preamps, too.

 

[Robin L]

Almost all reviews will appear online at www.stereophile.com However, they appear in print first for our subscribers and there is a delay before the online posting.

Thank you.

 

[PatentLawyer]

Can’t wait for my issue to arrive….. but I’m almost more curious in what “class” it will land in the rankings. My guess is that inertia (metaphorically speaking) will keep it out of Class A, but I’d love to be surprised.

 

[amper42]

It would be interesting if someone had the RME ADC and could do the RME DAC with and without the Topping P90 in circuit to see what the differences were. You would think the Topping to be audibly transparent. I also agree that for home hifi a 2 kohm input impedance is low.

Also wondering did you match levels when you did this comparison? Sorry, I end up asking this like over and over, but it is such an easy thing to mess up comparisons if not done.

I have two RME ADI-2 DAC FS units. I ran one with the Pre90 and the other alone. I used them on two BMR monitor speaker setups with a MacBook Pro feeding each RME via Audirvana. All I do is mute one system and unmute the other. Same sound level. You can easily tell the unit without the Pre90 is crystal clear while the RME with the Pre90 is significantly coloring the sound. They don't sound anything alike. It's an easy test. Just mute/unmute each setup.

 

[JRS]

I have two RME ADI-2 DAC FS units. I ran one with the Pre90 and the other alone. I used them on two BMR monitor speaker setups with a MacBook Pro feeding each RME via Audirvana. All I do is mute one system and unmute the other. Same sound level. You can easily tell the unit without the Pre90 is crystal clear while the RME with the Pre90 is significantly coloring the sound. They don't sound anything alike. It's an easy test. Just mute/unmute each setup.

Of course it begs the question whether that is something that would hold up to double blind testing. Not doubting your perception, but also confused as a transparent device should be well, transparent.Is it possible one of the RME's is out of spec?--you could try switching the feed to the Topping from one RME to the other. Groping for explanations here.

 

[Blumlein 88]

I have two RME ADI-2 DAC FS units. I ran one with the Pre90 and the other alone. I used them on two BMR monitor speaker setups with a MacBook Pro feeding each RME via Audirvana. All I do is mute one system and unmute the other. Same sound level. You can easily tell the unit without the Pre90 is crystal clear while the RME with the Pre90 is significantly coloring the sound. They don't sound anything alike. It's an easy test. Just mute/unmute each setup.

Yes not a bad arrangement, but it would be nice to see what is different.

 

[BillH]

I have two RME ADI-2 DAC FS units. I ran one with the Pre90 and the other alone. I used them on two BMR monitor speaker setups with a MacBook Pro feeding each RME via Audirvana. All I do is mute one system and unmute the other. Same sound level. You can easily tell the unit without the Pre90 is crystal clear while the RME with the Pre90 is significantly coloring the sound. They don't sound anything alike. It's an easy test. Just mute/unmute each setup.

Do I understand this correctly? You’re using two different sets of speakers located in different places in your room and you attribute the difference in how they sound to a preamp in one signal path?

 

[dshreter]

Let's be serious, Topping just put some chips on the board. The credit goes to those who created the chips. Topping didn't invent anything in audio. It is absolutely normal to be cheap at what components it has in it. Topping, SMSL and others like them are just a few computer engineers and that's it. They probably weren't able to make a motherboard and reoriented themselves to audio because it's easier to stick 3 chips. Well, does Topping compare to Nelson Pass? Be seriosus... I bought four Topping products and two SMSL because are cheap and for me are enough but that doesn't stop me from seeing who's Topping and who's Nelson Pass

This impressively one of the yuckiest takes I’ve seen ever on this site. I’m not sure why you would trash a company making products that integrate the technology effectively, offered at a fair price, and aiming for objective outcomes.

 

[amper42]

Do I understand this correctly? You’re using two different sets of speakers located in different places in your room and you attribute the difference in how they sound to a preamp in one signal path?

Nope...Same place

 

[BillH]

Nope...Same place

Are they two separate BMR setups? If so they don’t create the same sound at a given listening location.
Also, The frequency response differences between the two sets of speakers will dominate over any signal chain differences.

 

[amper42]

Nice theory but with the Pre90 removed both BMR's setups sound identical. The noticeable coloration only appears once the Pre90 is re-inserted in one of the configurations.

 

[Galliardist]

I have two RME ADI-2 DAC FS units. I ran one with the Pre90 and the other alone. I used them on two BMR monitor speaker setups with a MacBook Pro feeding each RME via Audirvana. All I do is mute one system and unmute the other. Same sound level. You can easily tell the unit without the Pre90 is crystal clear while the RME with the Pre90 is significantly coloring the sound. They don't sound anything alike. It's an easy test. Just mute/unmute each setup.

Of course it begs the question whether that is something that would hold up to double blind testing. Not doubting your perception, but also confused as a transparent device should be well, transparent.Is it possible one of the RME's is out of spec?--you could try switching the feed to the Topping from one RME to the other. Groping for explanations here.

And here's our standard ASR answer set - blind testing needed and something's "broken".
Of course, we shouldn't doubt perception, and we can go further to the point that the Topping doesn't fit @amper42's use case. But can we even assume that the RME is the "crystal clear" device in this situation? All we have is a fairly crude description of a subjective difference.

At least with a Stereophile review, we have disclosure of the full system in use, and the language is usually chosen to represent that the reviewer is giving a subjective review or comparison in a specific setup. I can (if I can be bothered) check out each other item in the system - they are often reviewed already - and look at impedence matching of components, calculate system gain and power, see that the amplifier can drive the speakers, etc.etc.

I would hope that paid reviewers actually do all of that work anyway, even if such minutae is way too boring to be in a published review.

We don't know enough about the setup @amper42 is using, or the test protocol, to go beyond it not working in that particular setup (so don't use it there).

 

[mcdn]

Nope...Same place

That;s impressive, how do you get two speakers to occupy the same physical space?