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WolfX700 Measurements of Topping Pre90/Ext90 Preamplifier/ Extender

WolfX-700

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#1
I'm back... Today I measured Pre90 Preamplifier and Ext90 Extender from Topping.

This is a set of equipment that I have been looking forward to for a long time...I have received the prototype a few months ago, but my audio analyzer was lent out. When the analyzer came back, unfortunately, the review time lock in the prototype had been activated-the entire device was locked and unusable.:facepalm:

I contacted Topping and got a "retail version" of this measurement.

Anyway, look at things first

Photo.jpg

Rear.jpg



Previously, Topping's A90 could be used as a preamplifier, but it was limited by the basic design (no remote control, only the volume can be adjusted manually). The preamp function of A90 is just better than nothing for me. (But it might be useful for desktop users) What I need is a preamplifier for "living room" or "audio room". So when I knew that Topping was going to develop a preamplifier with remote control, I looked forward to it and made some suggestions of my own.

First, it is almost completely transparent, almost as transparent as the signal cable measured by APx555.
Then, it must have enough volume adjustment range and very good channel balance:
ChannelBal.jpg


In addition, it can expand more input ports (actually, I originally recommended daisy-chain connection so that you can connect multiple extenders at the same time... but Topping rejected this requirement). This is for users with multiple audio sources The user is more friendly.

Then it is very important to use experience! First of all, there must be a volume memory function (different signal sources have different output levels, and a volume memory function can ensure a good experience when switching between different input sources.)

But is the volume memory enough? No, that's not enough... Let's assume a scenario (actually I have actually encountered it), when a source is not turned on or there is no sound from the source, maybe I unknowingly turned up the volume. Then I found that the source was not turned on, so I switched to another source. Two days later, I turned on the source that was not turned on before, and then switched. Due to the volume memory function...maybe I was deaf right away...so at my request, Topping added a safe volume function:
SafeVol.jpg

SafeVolSet.jpg


The logic of this function is that when the memory volume is called, if it is higher than the set safety level, it will be muted first, let you press OK to call it or press VOL + to gradually adjust it.

Okay, stop talking nonsense... Measurement is the most important thing...


XLRin 4V Dashboard
Dashboard4V.jpg



XLRin 5V Dashboard
Dashboard.jpg


RCA in Dashboard
DashboardRCA.jpg


EXT XLR Dashboard
EXTinDash.jpg



THD+N Vs Freq
THD+N-Ratio-@-4V-IO.jpg


FR:
Relative-Level-(1.jpg


Multitone
Multitone.jpg


And Output impedance:
OI.jpg


I know that for many users, the necessity of preamplifiers is debatable. But I believe that there is a certain market for pre-amplifiers with multiple inputs, good functions and user experience, especially if it has excellent performance and inexpensive prices.

This is exactly what I want.
 
Last edited:
OP
WolfX-700

WolfX-700

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Thread Starter #3
+1! That extender board looks hella clean/elegant. Great solution for those who need it. Excellent device!
Originally, Topping planned to launch an A90 without headphone output and using relay volume. What makes me happy is that they finally followed my advice and designed a combination of Pre/Ext.
 

mocenigo

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#6
Originally, Topping planned to launch an A90 without headphone output and using relay volume. What makes me happy is that they finally followed my advice and designed a combination of Pre/Ext.
Are they using relays or a potentiometer in this preamp?
 

garbulky

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#7
Originally, Topping planned to launch an A90 without headphone output and using relay volume. What makes me happy is that they finally followed my advice and designed a combination of Pre/Ext.
This is exactly what I want. If it's cheaper than the Schitt Freya S then this will be perfect.
Does topping have any other version of a standalone preamp?:
Is this a fully balanced XLR preamp?
What's the cost?
Do you have a pic of the remote?
What kind of volume control does it use? (Is it analog?) Is there any digitization?
How does the extender get the signal to the main unit? Using the EXT connector.
 

EdW

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#8
Looks to be a superb product for a high end preamp complementing the D90 and allowing the D90 to be operated in DAC mode for those who insist on max linearity - even if any distortion is very many 10’s of dB below any audible threshold. :)

Some questions
1. Are all analog I/Ps unity gain or there some gain options?
2. Overload point on preamp O/P. - might be of interest with some power amps where the first stage can be bypassed?
3. . . . And of course when will it be available?

Congratulations to John Yang and colleagues for another impressively executed piece of audio engineering
 

daftcombo

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#9
Hi Wolf! Thanks for the review.

Does that Pre90 actually amplifies the signal (and by how many dB ?) or does it just attenuate it?
 

Matias

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#13
Very nice linearity. Interesting proposition of pre-amp + input extender. Congrats.
 
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#14
Are both outputs active at the same time? In the picture, it looks like only XLR output is selected?

What are the options on the volume memory setting? On the picture, it shows a setting of "IN". What does that mean? What are the other options?
 
OP
WolfX-700

WolfX-700

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Thread Starter #16
Are both outputs active at the same time? In the picture, it looks like only XLR output is selected?

What are the options on the volume memory setting? On the picture, it shows a setting of "IN". What does that mean? What are the other options?
Output Select: RCA XLR RCA+XLR

You can use volume memory on the input or output interface
 
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#17
Output Select: RCA XLR RCA+XLR

You can use volume memory on the input or output interface
Can volume memory work on the combination of input and output?

Like, could it remember volume -10 for In1+RCA, vol -15 for In1+XLR, and vol -20 for In2+RCA?
 

NTomokawa

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#18
Another home-run product by Topping. Beautiful!

Meanwhile I'm still trying to decrypt Wolf's wolf-code. Amir's panther-code is clear enough...
 

JohnYang1997

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#19
Can volume memory work on the combination of input and output?

Like, could it remember volume -10 for In1+RCA, vol -15 for In1+XLR, and vol -20 for In2+RCA?
Either input or output. Can't work in combination.
 
OP
WolfX-700

WolfX-700

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Thread Starter #20
Any plans for multiple RCA inputs only version ?
The extender is an attempt. I believe that if this product sells well (Topping has always doubted whether the extender can sell well), more different versions of the extender may be developed.
 
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