Topping Pre90 Review (preamplifier)

[misterdog]

Easy to fit XLR plugs on an RCA cable...

 

[Geared4me]

auronthas, yes and yes. There hasn't been any word yet about a multiple rca input extension unit. I suspect Topping is waiting to see what actual sales figures look like for the pre90 and the current add on input unit.

 

[DHT 845]

Hello to everybody. This is my first post.

I have question for the manufacturer and designer of Pre90. The case: power amp has only RCA.
From the sake of internal topology of the unit is it better to use RCA in / RCA out connections or better use XLR in / RCA out?

My tube power amp (monoblocks) has only RCA input (100 kOhm, 0,75V sensitivity) so I have to use RCA output from the preamp (I'd rather not using XLR to RCA transformer). My DAC has both, RCA out (35 Ohm), XLR (70 Ohm) so it is pretty current efficient.

I noticed that there are differences in parameters:
SE IN / SE OUT: SNR 141dB, channel crosstalk -130dB
BAL IN / SE OUT: SNR 137dB, channel crosstalk -137dB

So it is kind of mixed bag. If SNR is better then crosstalk is worse and vice versa (if I understand correctly).
And my question has 2 aspects. What is best in general when power amp has RCA only? And what is best in my case (tube monos and DAC of these parameters)?

Maybe with tube power amp above SNR differences are less important that channel crosstalk (especially with monoblocks, tubes have lower SNR anyway)...

Of course it's true balanced...

 

[misterdog]

With monoblock amplifiers I assume you have fairly long cable runs and also running the signal cable parallel to the power cable.

I would use DAC > XLR >Pre > XLR >RCA Amp.

The XLR to RCA cable, ground connected at the XLR end only. The pre is transparent whichever way you use it. I use Van Damme Quad core cable and Neutric XLR connectors.
This company or similar will make any cable you like.
https://www.designacable.com/musici...le-xlr-lead-pair-van-damme-neutrik-cable.html

 

[DHT 845]

With monoblock amplifiers I assume you have fairly long cable runs and also running the signal cable parallel to the power cable.

I would use DAC > XLR >Pre > XLR >RCA Amp.

The XLR to RCA cable, ground connected at the XLR end only. The pre is transparent whichever way you use it. I use Van Damme Quad core cable and Neutric XLR connectors.
This company or similar will make any cable you like.
https://www.designacable.com/musici...le-xlr-lead-pair-van-damme-neutrik-cable.html

Thanks. I use 1m RCA cables to monos and 1m speaker cables so pretty short. From DAC to Pre I intend to buy a cable as short as possible, like 0.5m max. Of course if preamp improoves sth. in my case (so far I prefer direct DAC-monos connection).

 

[Harmonie]

@DHT845
Cant you use your DAC directly into your poweramps ?
Just wondering your need about a preamp at all ?

 

[DHT 845]

@DHT845
Cant you use your DAC directly into your poweramps ?
Just wondering your need about a preamp at all ?

Yes. So far it was the best directly (I tried expensive preamps) but maybe with pre90 will bring improovement. From the reviews they say it is transparent and remain the character of the source. The improovement is in sounstage and dynamics. And there is great PRAT which is important for me. I will test pre90 to decide whether to buy it or not.

 

[auronthas]

@DHT845
Cant you use your DAC directly into your poweramps ?
Just wondering your need about a preamp at all ?

Most of Poweramps only have single XLR or RCA input only and binding posts to speaker. That's why Pre-Amps come into play, it's like a selector with multiple sources (digital or analog). Unless your DAC is direct connect to integrated amplifier (Pre & power amp in our chassis).

In this case Topping Pre90 is pure analog pre-amp. If your external DAC comes with multiple digital/analog input (Coaxial/USB/RCA/XLR) and single analog output (RCA/XLR) , you can connect the analog to PowerAmp direct with RCA interconnect (single ended) or XLR interconnect (balanced)

 

[Harmonie]

Most of Poweramps only have single XLR or RCA input only and binding posts to speaker. That's why Pre-Amps come into play, it's like a selector with multiple sources (digital or analog). Unless your DAC is direct connect to integrated amplifier (Pre & power amp in our chassis).

In this case Topping Pre90 is pure analog pre-amp. If your external DAC comes with multiple digital/analog input (Coaxial/USB/RCA/XLR) and single analog output (RCA/XLR) , you can connect the analog to PowerAmp direct with RCA interconnect (single ended) or XLR interconnect (balanced)

Don't understand what you are saying.
My point is that if you just have a DAC as source, you can drive your amp directly with it and do not need any preamp at all.
Nothing more.

 

[misterdog]

Though my SMSL M400 DAC has least distortion at fixed maximum output, so if I have to attenuate using the DAC in Pre -mode I'm loosing performance.

Though I also use other sources.

 

[auronthas]

Don't understand what you are saying.
My point is that if you just have a DAC as source, you can drive your amp directly with it and do not need any preamp at all.
Nothing more.

In short, this Pre90 is designed for owners with multiple analogue sources like CD player, Network media player, turntable, etc. If you have only single source, forget about the preamp.

 

[DHT 845]

I would use DAC > XLR >Pre > XLR >RCA Amp.

What is the point of using XLR->RCA cable from the Pre90? I have great RCA cable for my SE amp.
Just wander whether use XLR in to the pre to have lower channel crosstalk. This should result in wider soundstage.
Could designer of the Pre90 answer my question?

 

[misterdog]

What is the point of using XLR->RCA cable from the Pre90

Possibly none since you clarified that your cable run to your amps is only 1M. Though only by trial and error can you see if there is any gain.
No one has your exact set up so no one will know.
If your RCA runs parallel with the mains supply to your amps then a shielded XLR cable may reduce noise pick up, even as a pseudo balanced cable.

 

[misterdog]

In short, this Pre90 is designed for owners with multiple analogue sources If you have only single source, forget about the preamp.

Though as I pointed out in post 490 that if you have to attenuate your DAC you could be loosing performance. So purely as an analogue gain control it could have benefits.

 

[zachery2006]

Just ordered Pre90 from Hifigo. I'm currently using the preamp mode of Singxer SA-1 as my temp preamp. Hope I will identify any difference.

 

[auronthas]

Though as I pointed out in post 490 that if you have to attenuate your DAC you could be loosing performance. So purely as an analogue gain control it could have benefits.

Right sir, two days ago, I tried to set -6dB on D90 Pre mode with XLR out to A90 with pre-amp mode at medium gain and full volume pot, I could sensed loosing little dynamic and punch (not loudness) from my speaker has been degraded compare to D90 Pure DAC mode.

 

[PaulD]

Right sir, two days ago, I tried to set -6dB on D90 Pre mode with XLR out to A90 with pre-amp mode at medium gain and full volume pot, I could sensed loosing little dynamic and punch (not loudness) from my speaker has been degraded compare to D90 Pure DAC mode.

Was the test properly done? Double blind and with levels matched to 0.1dB? If not, this will be expectation bias influencing your perception. When I have done similar tests, I cannot hear a difference when the test is properly conducted.

 

[DHT 845]

I tested digital volume control on Accuphase power amp with gain settings and I heard no degradation on dvc from double ES9038Pro dac even with -12dB. As far as "expectation bias" I expected that DAC with max out and Accu with -12dB analog gain will sound better than DAC -12dB and Accu set on 0db Gain. And I was surprised that not. Opinions about digital volume control degradation are exagerrated IMO.

But there is ather aspect, the additional gain from the preamplifier (that is not only input selector). The question is whether additional gain is needed in particular system.

 

[misterdog]

I expected that DAC with max out and Accu with -12dB analog gain will sound better than DAC -12dB and Accu set on 0db Gain. And I was surprised that not.

Unless distortion rises on your amp with increased power, as with todays tested Class D Amazon amp.

 

[auronthas]

Was the test properly done? Double blind and with levels matched to 0.1dB? If not, this will be expectation bias influencing your perception. When I have done similar tests, I cannot hear a difference when the test is properly conducted.

I have few selected tracks which was sound harsh at Pure DAC mode of D90 to my Class A Krell int. amp.

After attenuate DAC to - 6 dB at Pre mode, with A90 medium gain, max volume to Krell int. amp. The sound harshness is gone but the punch and dynamic are gone little as well.

Both sound tests with SPL meter at 80dB with short time laps as need to swap cables and fine tuning.