Topping Pre900

[PristineSound]

Supposed to drop tomorrow.

TOPPING

TOPPING Pre900 preamplifier is coming soon! ● Full-path balanced architecture Built around a four-channel reference-grade amplifier circuit, Pre900 is not only fully balanced, but fully differential...

www.facebook.com

Looking forward to one to go with my AHB2.

 

[da Choge]

Looks like a very nice minimalist preamp. Unfortunate that it has only XLR/TRS balanced inputs, but I imagine eliminating the single-ended inputs and their conversion to balanced allowed Topping to more easily pursue the "Holy Grail" of stratospheric SINAD/DNR/Crosstalk specs. Still, I'd be interested. I have the Topping Pre90/Ext90 in both black and silver and haven't really used them much except when testing out certain setups. Back when I got the Pre/Ext90s, my wishes for the combo were that it had 1) trigger in/out jacks, 2) discrete input selection, 3) home theater bypass/pass-through, 4) two more single ended and one-less balanced inputs, and 5) better IR range and pickup. The Pre900 doesn't seem to have any of these either except for the trigger jacks. It does seem to have a much superior IR remote unit, and, hopefully it will have better range and pickup. I'm impressed with its relay-controlled resistor-ladder volume adjustment, but 0.1dB increments do seem a tad excessive. However, still very anxious to find out more.

Topping Pre900

 

[welwynnick]

The Pre900 sounds lush, but despite being an overt Topping fan boy and loathe to criticise new products, I find myself a little disappointed.

Firstly, I hoped it would be the answer to how to drive the B100 in low gain (no gain) mode. Topping says the sensitivity is 26.6Vrms or 75.2Vpp, but the Pre900 max output in low gain is "only" 69Vpp (though strangely 65V in medium and high).

Secondly, the specs of the A900 and Pre900 are otherwise identical, yet the A900 is $300 cheaper, despite having a powerful headphone output.

The specs are epic, and I believe what they claim, but I'm struggling to understand why you would get this instead of the A900?

 

[PristineSound]

The specs are epic, and I believe what they claim, but I'm struggling to understand why you would get this instead of the A900?

Excellent point.

I just may get the A900 instead.

 

[JohnnyNG]

I've been an owner for four years now and love everything about my Pre90, including the per-input volume memory and RCA-balanced conversion. This one looks very nice but not sure I'd have any use for it.

 

[welwynnick]

Just a thought - wouldn't this thread be better off in the Amplifiers forum, where the thread topics tend to be specific rather than general in nature?

Amplifiers, Phono preamp, and Analog Audio Review

Reviews, tests, measurements and discussions of analog audio electronics.

www.audiosciencereview.com

 

[staticV3]

Firstly, I hoped it would be the answer to how to drive the B100 in low gain (no gain) mode. Topping says the sensitivity is 26.6Vrms or 75.2Vpp, but the Pre900 max output in low gain is "only" 69Vpp (though strangely 65V in medium and high).

The B100 output clips at 20Vrms into 4Ω and 23.7Vrms into 8Ω.

The Pre900 can output 23Vrms in medium/high gain, so you can easily clip the B100 in Unity gain when driving 4Ω loads, whereas with 8Ω loads you're merely 0.25dB (2% perceived loudness) short of clipping.

 

[JohnnyNG]

I notice that they publish an Input Impedance spec (used to be a bit of a mystery?) and that it's now 20kΩ (up from the 2kΩ of the Pre90). Doesn't phase my OG D90 but may help for some DACs.

 

[welwynnick]

The B100 output clips at 20Vrms into 4Ω and 23.7Vrms into 8Ω. The Pre900 can output 23Vrms in medium/high gain, so you can easily clip the B100 in Unity gain when driving 4Ω loads, whereas with 8Ω loads you're merely 0.25dB (2% perceived loudness) short of clipping.

Yes, I do maths too. I don't know where Topping get their 26.6V from, because it corresponds to a higher power output than the B100 can manage into 8Ω, even when they relax the THD threshold to 10% and assume it's still sinusoidal. I was just pointing out that Topping themselves specify a lower output from their new "ultra-flagship" preamp than they specify for the the sensitivity of the B100. Here's some gain staging calcs that I did a year ago for a variety of low sensitivity power amps:

"N" is output noise, and "Input" is Noise/Gain, or the input noise that corresponds to N, so it's the target for any preceding source or preamp.

 

[RetroStereo]

I've looked at the new Topping 900 series; but I just can't see the advantage. I already have the A90D, the EXT90 (for additional connectivity) and the D90 III discrete. I'm also using an Apt (Holman) model 1 preamp (I have a lot of vintage analog sources), two sets of power amps and three sets of speakers. The Pre900 doesn't give me any flexibility that I don't already have, costs more and, while its specs are better, the equipment I already have is so bleeding edge good that "better" is really pointless.

 

[RetroStereo]

I'm not a gamer so I'm no expert. And while better is always better, I doubt the need for the extreme specs of the Pre900 to significantly advance the immersive experience in "FNAF free" games. USB out, possibly through an isolation circuit to cut noise, into a high-quality DAC and headphone amp and a top notch set of cans is probably quite good enough.

My last several electronic equipment swaps have been because of features -- not because of changes in specs. There comes a point where the equipment is significantly better than our hearing.

 

[Sokel]

I notice that they publish an Input Impedance spec (used to be a bit of a mystery?) and that it's now 20kΩ (up from the 2kΩ of the Pre90). Doesn't phase my OG D90 but may help for some DACs.

That's really good news.

 

[welwynnick]

I've looked at the new Topping 900 series; but I just can't see the advantage. I already have the A90D, the EXT90 (for additional connectivity) and the D90 III discrete. I'm also using an Apt (Holman) model 1 preamp (I have a lot of vintage analog sources), two sets of power amps and three sets of speakers. The Pre900 doesn't give me any flexibility that I don't already have, costs more and, while its specs are better, the equipment I already have is so bleeding edge good that "better" is really pointless.

I think there is a point to recent amps like the A900 and Pre900, and it's this.

Topping partly get high performance by using nested feedback loops. They call it NFCA, Nested Feedback Composite Amplifier. It's one feedback loop inside another, and allows the use of more negative feedback to reduce distortion, but without becoming unstable. This particularly helps high frequency linearity, where conventional single-loop feedback is less effective because of decreasing loop gain at higher frequencies.

The A70, A900, Pre900 and B100 are different because they use triple-nested feedback loops, and this goes even further. Topping call it the T'ang-ku-la Module. When you look at Topping's distortion vs frequency measurement data for their lesser models, you see low distortion at 20Hz to 1kHz, but increasing distortion beyond that (like pretty much everything, to a greater or lesser extent). The A70, A900, Pre900 and B100 are different, and have flat distortion vs frequency characteristics.

 

[JohnnyNG]

That's really good news.

Maybe that's why they publish it now.

 

[RetroStereo]

I think there is a point to recent amps like the A900 and Pre900, and it's this.

Topping partly get high performance by using nested feedback loops. They call it NFCA, Nested Feedback Composite Amplifier. It's one feedback loop inside another, and allows the use of more negative feedback to reduce distortion, but without becoming unstable. This particularly helps high frequency linearity, where conventional single-loop feedback is less effective because of decreasing loop gain at higher frequencies.

The A70, A900, Pre900 and B100 are different because they use triple-nested feedback loops, and this goes even further. Topping call it the T'ang-ku-la Module. When you look at Topping's distortion vs frequency measurement data for their lesser models, you see low distortion at 20Hz to 1kHz, but increasing distortion beyond that (like pretty much everything, to a greater or lesser extent). The A70, A900, Pre900 and B100 are different, and have flat distortion vs frequency characteristics.

I concede your point. I didn't intend to imply that there is no reason for further innovation (which, upon re-reading my post, is exactly what I did imply). However, for my own system, I've reached a limit in quality reproduction where I doubt I can perceive the difference. Additionally, ignoring the tech specs, the A90D offers flexibility that the A900 does not (the EXT90 & RCA inputs).

Given that the specs for the A90D are only near SotA compared to the A900's pushing beyond the bleeding edge (true for the whole 90 vs 900 series), I'm sticking with what I have. Based on the feature set of the current 900 series, I could not accommodate some of the vintage elements of my system and that is more important to me.

 

[welwynnick]

Given that the specs for the A90D are only near SotA compared to the A900's pushing beyond the bleeding edge (true for the whole 90 vs 900 series), I'm sticking with what I have. Based on the feature set of the current 900 series, I could not accommodate some of the vintage elements of my system and that is more important to me.

I agree, I have an E70, L70 and PA5, and there are no rational reasons for getting a 900 series - only irrational reasons!

 

[RetroStereo]

I agree, I have an E70, L70 and PA5, and there are no rational reasons for getting a 900 series - only irrational reasons!

It's a mental disease called GAS - Gear Acquisition Syndrome. Something I have a very difficult time controlling. ;-)

 

[z624391]

I think the Pre900 will deliver a higher audio quality level. I am sure that upgrading from Pre90 to Pre900 will be noticable. The Pre900 will take place behind the ML No 632 poweramp and autostatic loudspeakers.

I also have the D900 which do his job quite well, exept the D900 pre-amp you must really skip that one because it terminates all sound quality.

 

[staticV3]

I am sure that upgrading from Pre90 to Pre900 will be noticable.

How are you sure?
That would go against everything that we know about human hearing.

 

[z624391]

That is just the same story as what people say about audio switches. The electronic signal is beyond imagination sensitive for distorions. Therefor specs are not telling the compleet story. Ultimo you have to listen to find out what is will bring.