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Topping Pre90 Review (preamplifier)

JohnYang1997

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Best measuring preamp indeed and credit to where credit is due. But unfortunately not for me. I will not use a preamp where I will need to cycle through inputs with a tiny button, be it on the unit itself or the remote. And I will not apologize for nagging about this with the hope that manufacturers such as Topping would eventually listen.

Because of ASR, manufacturers such as Topping have become obsessed with measurements and it has become a product drag race. Yes, it's awesome to have a car that does a quarter mile in 10 seconds, but I need it to have AC and automatic transmission too. Yes I am belaboring this and have started to use car analogies so I better end here.
What's wrong with selecting input with a remote?
 

win

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quick note on the oled thing -

topping is not manufacturing their own oled screens. if the prospect of burn-in really concerns you, you can buy the oled module for cheap on an electronics website
 

PeteL

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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.
Good, but, maybe some answer has been given and missed it in the tremendous anthusiasm this great product rightfully triggered, it's a lot of posting. So, a simple one. What is the input impedance? "No penalty", we don't know from this alone, there is a voltage drop of 0.4 dB for a 1k tone, trough 200 ohm that's what we have. Then again, I would agree with something in the lines of "no penalty for the vast majority of balanced sources out there", yep nitpicking I know, but in all cases, input impedance is not a non-significant metric, knowing it is useful in more precise term than "lower than normal". Might had missed it tough. Was not clear to me on a first read, or a quick spec review.
 
OP
amirm

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I don't recall who asked for RCA dashboard but I just added it to the review:

index.php
 
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amirm

amirm

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Then again, I would agree with something in the lines of "no penalty for the vast majority of balanced sources out there", yep nitpicking I know, but in all cases, input impedance is not a non-significant metric, knowing it is useful in more precise term than "lower than normal".
Unfortunately there is no mechanism in Audio Precision to measure the input impedance of the device being driven. I know, shocking but true. I need to build a fixture to measure it. It is a simple one but I don't know that I have enough XLR connectors to make one and at any rate, it takes time. Really, I don't have a reason to doubt the 2 k ohm spec from the company.
 
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amirm

amirm

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@amirm Thank you, for this extensive review. Would it be possible to add Topping A90 measurments in preamp mode for Crosstalk, Intermodulation distortion and SINAD vs frequency. So anyone can compare it directly to Pre90?
I ran two of the tests, didn't remember crosstalk. Here they are:

Topping Pre90 Measurements Preamplifier SNR Balanced IMD Distortion vs Topping A90.png


Topping Pre90 Measurements Preamplifier SNR Balanced THD+N vs Frequency vs Topping A90.png


Note that I had to put the A90 in medium gain to match the output of the Pre90. In its low gain mode it would likely do better. But even as it is, its performance is still excellent.
 

nobody

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Their upcoming Empire Streamer looks promising and quite affordable for 20.000 USD (doesn't come with Car though).
If they can sell it, good for them, more money to R&D.
But they still maintain pro line of DACs/ADCs with pricing in line with Benchmark.
 

nobody

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I ran two of the tests, didn't remember crosstalk. Here they are:
....
Note that I had to put the A90 in medium gain to match the output of the Pre90. In its low gain mode it would likely do better. But even as it is, its performance is still excellent.

Thank you armirm. I like A90 as preamp, I will definitely buy Pre90 due to added comfort and move A90 to my headphone rig to replace SMSL SP200.
 
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