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Topping Pre90 Review (preamplifier)

PaulD

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Yes, we fail to see how it is possible, which is why we need more science! Many people hear things we 'fail to see'. Nice to think it's all in our heads, but I really think that there are other things happening that we haven't figured out how to quantify. Or I could be wrong, but history shows us that the progress of science brings new discoveries where we thought we knew it all.
Yes indeed. Except that we also know that casual and uncontrolled listening leads to false conclusions. So whatever else there is to discover about audio reproduction, and yes I agree there are probably still some things to learn, will be:
a.) small in comparison to the large issues of frequency response and distortion, and
b.) not the result of casual listening.

So far the evidence is that the biases from sighed and uncontrolled listening FAR outweigh the other unknowns. That is why people making claims about what they hear at home via an uncontrolled test have no value. I am all for hearing evidence of things that actually exist, but to know that it is something audible a controlled listening test must be done. People who have never experienced a double-blind and well controlled test do not appreciate how it may change a person's life. It changed mine, and others I know, and I have a research background (teach postgrad research methods, double-blinding is a very basic experimental control). The sorts of areas where we still need a lot of research in audio are in proper soundfield reconstruction and room interactions - and this is the wrong forum to discuss that.
 

PaulD

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This is just my experience in my home with my own system. If you don't like it just ignore it. Telling people what they can and can not discuss is a bit immature. Did it ever occur to you that some people may find a discussion of audio perceptions useful? You may be fossilized in your own views but don't try to impose that on others.
Uh huh... But there are enough forums for discussion of uncontrolled listening tests and whatever you feel about a piece of equipment. This is Audio SCIENCE Review, so please present evidence of your listening tests to prove it is not just the result of sighted bias or uncontrolled listening. To quote Feynman, "If it disagrees with experiment, it's wrong." I am not imposing anything on others, this is a science-based forum, it seems that others are trying to validate uncontrolled listening tests. I know how real such uncontrolled tests can feel, we all do, but the experience of a properly controlled test is greatly illuminating to how the brain works an how biased we are - you should try it.
 

gentlejax

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can a different remote be used ? like a harmony or something? I am waiting on mine to arrive.
 

Peternz

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Uh huh... But there are enough forums for discussion of uncontrolled listening tests and whatever you feel about a piece of equipment. This is Audio SCIENCE Review, so please present evidence of your listening tests to prove it is not just the result of sighted bias or uncontrolled listening. To quote Feynman, "If it disagrees with experiment, it's wrong." I am not imposing anything on others, this is a science-based forum, it seems that others are trying to validate uncontrolled listening tests. I know how real such uncontrolled tests can feel, we all do, but the experience of a properly controlled test is greatly illuminating to how the brain works an how biased we are - you should try it.

Thanks for your opinion. If it helps, then I can mention that the reason passive preamps tend to sound dead is generally an impedance mismatch. To drive cables well and to avoid phase shifts and frequency response anomalies it is good practice for a source component to have a low output impedance and the component it is connected to should have a high input impedance. It could be a power amplifier driving speakers, a headphone amplifier feeding headphones or a preamp feeding a power amp. A passive pre amp will inevitably have an output impedance that is higher than optimal. This is well known and easily measurable.
 

JohnYang1997

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Thanks for your opinion. If it helps, then I can mention that the reason passive preamps tend to sound dead is generally an impedance mismatch. To drive cables well and to avoid phase shifts and frequency response anomalies it is good practice for a source component to have a low output impedance and the component it is connected to should have a high input impedance. It could be a power amplifier driving speakers, a headphone amplifier feeding headphones or a preamp feeding a power amp. A passive pre amp will inevitably have an output impedance that is higher than optimal. This is well known and easily measurable.
Easily measurable or measured?
 

Deki

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Yes indeed. Except that we also know that casual and uncontrolled listening leads to false conclusions. So whatever else there is to discover about audio reproduction, and yes I agree there are probably still some things to learn, will be:
a.) small in comparison to the large issues of frequency response and distortion, and
b.) not the result of casual listening.

So far the evidence is that the biases from sighed and uncontrolled listening FAR outweigh the other unknowns. That is why people making claims about what they hear at home via an uncontrolled test have no value. I am all for hearing evidence of things that actually exist, but to know that it is something audible a controlled listening test must be done. People who have never experienced a double-blind and well controlled test do not appreciate how it may change a person's life. It changed mine, and others I know, and I have a research background (teach postgrad research methods, double-blinding is a very basic experimental control). The sorts of areas where we still need a lot of research in audio are in proper soundfield reconstruction and room interactions - and this is the wrong forum to discuss that.
Thank you for your reply, I appreciate your experience in the matter.
 

Peternz

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I am enjoying the Pre90 very much, I must say, it is a superb preamp. There is nothing missing in my system, the bass is excellent. Many thanks to the designer and manufacturer, the performance at this price is a revolution.
 

ohnonate

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I am enjoying the Pre90 very much, I must say, it is a superb preamp. There is nothing missing in my system, the bass is excellent. Many thanks to the designer and manufacturer, the performance at this price is a revolution.
Just wondering what gear you have it connected to ? Thanks
 

Peternz

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Just wondering what gear you have it connected to ? Thanks

PC > Modified Oppo UDP-205, linear power supply mod > Pre90 > Western Electric 111c transformers > DIY power amp based on Burmester design > Dynaudio X18 speakers. All cables are premium quality and the AC power has minor tweaks. Minor upgrades here and there...
 

Kal Rubinson

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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.
This observation has an explanation.

According to John Yang, "When set to balanced/XLR output only, 0dB is 0dB. When set to RCA plus XLR, 0dB is referenced to RCA out, XLR is 6dB louder."
I have my Pre90 at XLR output only and XLR in-out is 0dB at -0.0dB. So, is it possible that you did your test with the device set to RCA plus XLR?
 

k525

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can a different remote be used ? like a harmony or something? I am waiting on mine to arrive.
Hi the one of mine arrived today, the remote is absolutely not usable, fortunately I was able to acquire all the codes with my Harmony (there is not a build in Harmony preset), note that the problem is not the transmitter but the receiver, in fact it works only keeping the additional Harmony transmitter very close to the Pre90
 

Kal Rubinson

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Hi the one of mine arrived today, the remote is absolutely not usable, fortunately I was able to acquire all the codes with my Harmony (there is not a build in Harmony preset), note that the problem is not the transmitter but the receiver, in fact it works only keeping the additional Harmony transmitter very close to the Pre90
I used a simple IR repeater to extend the range with the stock RC to useful distances.
 

Dgob

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Hi the one of mine arrived today, the remote is absolutely not usable, fortunately I was able to acquire all the codes with my Harmony (there is not a build in Harmony preset), note that the problem is not the transmitter but the receiver, in fact it works only keeping the additional Harmony transmitter very close to the Pre90
This might be obvious, but the Pre90's RC has directional (rather than 'functional') issues. If you point it below the obvious position, it functions fully - with the exception of the few keys which are noted in the manual as not being operational.
 

k525

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This might be obvious, but the Pre90's RC has directional (rather than 'functional') issues. If you point it below the obvious position, it functions fully - with the exception of the few keys which are noted in the manual as not being operational.

Well I am loving this pre and with Logitech Harmony I was able to get rid of this problem but I can assure this is a "functional" problem because at the distance of 3 meters I was completely unable to remote control the Pre90, they for sure committed big mistake, and let me say that I do not thing this is only a "directional" problem, in my opinion the problem is also due to the low sensitivity of the receiver (probably because it is behind an opaque plexiglass) take into account I was forced to put the Harmony IR extender very close to Pre90 otherwise neither Harmony will work
 

Kal Rubinson

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.......................... in my opinion the problem is also due to the low sensitivity of the receiver (probably because it is behind an opaque plexiglass) take into account I was forced to put the Harmony IR extender very close to Pre90 otherwise neither Harmony will work
My cheapy IR repeater adheres directly to the plexiglass.
 

Dgob

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Well I am loving this pre and with Logitech Harmony I was able to get rid of this problem but I can assure this is a "functional" problem because at the distance of 3 meters I was completely unable to remote control the Pre90, they for sure committed big mistake, and let me say that I do not thing this is only a "directional" problem, in my opinion the problem is also due to the low sensitivity of the receiver (probably because it is behind an opaque plexiglass) take into account I was forced to put the Harmony IR extender very close to Pre90 otherwise neither Harmony will work

I am sorry to hear that. However, I do sit more than 3 meters away from the receiver and find that by pointing my remote at the ground a few feet in front of the Pre90, I have no problems. Sorry that my suggestion did not help.
 

arcamfan1989

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There is no data because it would not look nice on the paper. Based on @amirm measurement, voltage drop from 4V to 3.6V when AP output impedance changed from 40 ohm to 200 ohm - results in Topping input impedance of 1.44 kohm - simple circuit maths.

This is very small input impedance. I would recommend nothing below 10 kohm. It affects distortion, and the low frequency corner, if the sound source has output coupling capacitor, which is very usual.

In my designs, I use 47 kohm or 100 kohm input impedance, very rarely 10 kohm.

I agree, I tested the Topping Pre90 with my Tube DAC and it gives lots of distortion in tweeter and **not recommended if you are running an Tube Dacs**. YOu can try on integrated DACS or R2R works fine on them.
 
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Dgob

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Tube dacs almost sounds like an oxymoron: at least in my set-up, where the last thing the Marantz CD63 KI Sig needs is sweetening! :)
 
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