Review and Measurements of Topping TP60 and FX Audio FX502SPro Amps

[strumf666]

I just bought a fx502s pro (it is fed by SMSL SU-1) and it appears the output of the dac is too strong for this amp? Volume control is pretty much useless as is, in 4 step it gets from silence to too loud. Any suggestions how to fix this?

 

[strumf666]

Swapped the pot for 100k logarithmic and I have a proper volume control

 

[Toku]

Swapped the pot for 100k logarithmic and I have a proper volume control

I have been pointing out the incorrect use of volume pots in Chinese audio products for over five years. I contacted the manufacturer's engineers directly, but they couldn't understand what they pointed out at all. I also didn't know that taper A and taper B existed in the volume pot.
However, recently, perhaps because of the understanding of the volume pot characteristics, the number of cases where tapered A is used has gradually increased.
The volume pot for adjusting the volume of an audio device must use the log curve characteristic of tapered A. Many audiophiles don't understand this.

 

[milosz]

Would the levels of noise and distortion from the TP60 actually be audle on a pair of modern speakers with an 87 dB / 1 m / 1 w efficiency in a normal listening room?

A normal room typically has 40 dB or more of background noise... a library is 30 dB....so you're telling me you'd hear noise from the SINAD of 70 dB from the TP60?

Audio gear is for LISTENING not just for measurements to impress engineers.

I have a TP60 laying around. I'll hook it up, adjust the gain for normal decently loud listening and report back if I can hear any noise when there is no input.

Measurements do matter, and better measurements are desirable - but one has to have SOME perspective!

 

[drewdawg999]

Would the levels of noise and distortion from the TP60 actually be audle on a pair of modern speakers with an 87 dB / 1 m / 1 w efficiency in a normal listening room?

A normal room typically has 40 dB or more of background noise... a library is 30 dB....so you're telling me you'd hear noise from the SINAD of 70 dB from the TP60?

Audio gear is for LISTENING not just for measurements to impress engineers.

I have a TP60 laying around. I'll hook it up, adjust the gain for normal decently loud listening and report back if I can hear any noise when there is no input.

Measurements do matter, and better measurements are desirable - but one has to have SOME perspective!

From my experience with the TP60, there's an electronic whirring sound that's audible when no music is playing. The low SINAD figure seems dominated by noise. But once music starts playing, the noise can't be heard, and my ears hear beautiful music. I'm using it with efficient speakers (old Tekton 4.5) and I'm getting good synergy. The TP60 outperforms a Rega Mira3 integrated and an OEM Tube Cube in this system. Maybe that's not saying much, but I've been happy with the TP60 for many years of service.

 

[Jimster480]

Would the levels of noise and distortion from the TP60 actually be audle on a pair of modern speakers with an 87 dB / 1 m / 1 w efficiency in a normal listening room?

A normal room typically has 40 dB or more of background noise... a library is 30 dB....so you're telling me you'd hear noise from the SINAD of 70 dB from the TP60?

Audio gear is for LISTENING not just for measurements to impress engineers.

I have a TP60 laying around. I'll hook it up, adjust the gain for normal decently loud listening and report back if I can hear any noise when there is no input.

Measurements do matter, and better measurements are desirable - but one has to have SOME perspective!

Depends on the speakers and room and volume.
You would lose micro details. There is an undertone / hiss / hum associated with this amp.

 

[milosz]

Depends on the speakers and room and volume.
You would lose micro details. There is an undertone / hiss / hum associated with this amp.

I built one of these into a little project for my bedroom system. I'm using this amp to drive ScanSpeak Revelator 18W/8531G-00 (7" mid-woofer) in a 1.5 cu ft sealed enclosure with a MiniDSP 48 dB/ 8ve xover at 1100 Hz. Other amplifier drives the Bozhen tweeter above 1100 Hz. In my fairly quiet - but not silent - bedroom, with no signal coming in to the TP60, I can't hear any hiss, hum or whine from these Revelator drivers with my ear right against the drivers. The amp seems to have enough power for my needs in this case - a small room but there is some low frequency EQ so some power demands are placed on the amp, which it doesn't seem to have a problem with.

As to the "micro details" - how do I set up a listening test to try to discern if those are present or lost? I have not seen an actual definition of "micro detail" though I have seen the term used in reviews, so I would like to know how what they are and how to listen to see if they are being lost. (And it seems to me that any such sonic subtleties might be coming through the tweeter anyway, making "loss of micro details" by the TP60 moot in my case as it is only driving the woofer.)

I can certainly see from the test that this amp is adding noise and distortion to the sound, but if I can't HEAR that coloration no matter how hard I try - is it REALLY a problem?

 

[Jimster480]

I built one of these into a little project for my bedroom system. I'm using this amp to drive ScanSpeak Revelator 18W/8531G-00 (7" mid-woofer) in a 1.5 cu ft sealed enclosure with a MiniDSP 48 dB/ 8ve xover at 1100 Hz. Other amplifier drives the Bozhen tweeter above 1100 Hz. In my fairly quiet - but not silent - bedroom, with no signal coming in to the TP60, I can't hear any hiss, hum or whine from these Revelator drivers with my ear right against the drivers. The amp seems to have enough power for my needs in this case - a small room but there is some low frequency EQ so some power demands are placed on the amp, which it doesn't seem to have a problem with.

As to the "micro details" - how do I set up a listening test to try to discern if those are present or lost? I have not seen an actual definition of "micro detail" though I have seen the term used in reviews, so I would like to know how what they are and how to listen to see if they are being lost. (And it seems to me that any such sonic subtleties might be coming through the tweeter anyway, making "loss of micro details" by the TP60 moot in my case as it is only driving the woofer.)

I can certainly see from the test that this amp is adding noise and distortion to the sound, but if I can't HEAR that coloration no matter how hard I try - is it REALLY a problem?

Micro Details are very low amplitude sounds in songs or background tones in the beat/melody depending on the type of music. They are not present in all music, so it depends on which music you listen to. In Jazz and Classical; there are usually lots of Microdetails on a good recording especially with full Orchestra's / Bands and even more so in Live recordings. In electronic music; there are lots of songs that have undertones to the main beats or other supporting sounds which are not at the same amplitude because of layered audio.
As a person who regularly listens to live recordings; they are important to me to get the "feeling of being there". When I drive in a car I don't typically listen to music like that as the noise floor in a car is too high (and usually car audio quality isn't the best) so those details are lost.

 

[milosz]

Please suggest a piece of music I can try to test this with. Seems so subjective that it's not really any kind of test but an opinion. If it's real there ought to be an objective way to test for it.