This is a review and detailed measurements of the Teac AX-501 integrated power (speaker) amplifier. It is on kind loan from a member. The AX-501 is part of the reference series from Teac so doesn't come cheap as desktop products go. I see the price at USD $999 on Amazon plus $35 shipping. There is a discount for silver a USD $899 but Amazon doesn't sell it for some reason.
When I reviewed the Teac HA-501 Headphone Amplifier, I heaped praise over its modern retro look. The AX-501 takes that to an entirely different level with addition of a couple of super cute, yellow background VU meters:
What is that? I should have took the shot with the VU meters working and the light turned on? Well, the owner played a cruel joke on me by not supplying me with the remote and leaving the setting to off for the VU meter!!!![Big Grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
The controls are almost as nice of the HA-501 with the exception of the volume control which feels a bit stiff and has some slack in it. Otherwise, there is nothing to fault it as far as I am concerned.
Here is the back panel:
XLR inputs should be mandatory in this price range and I am glad to see then included here (that is the way I ran all of my tests).
The AX-501 uses a class-D amplifier and runs as cool as you could get in my testing. I don't think it ever got even warm.
Class D also means light weight and that is NOT the case here. The AX-501 is a very hefty unit for its size. This means it stays put no matter how heavy your cables are.
Notice the lawyers getting their hands on the unit as to indicate the class of speaker wiring you are supposed to use! But hey, it is good to know the unit has been through corporate filter of certification and regulation.
Even though Teac is a Japanese company, the AX-501 is made in China.
Power Amplifier Measurements
Let's start with our usual 5 watt dashboard view using XLR inputs:
Even though Teac specs the AX-501 at 1 watt, we see the same performance at 5 watts which is nice. Distortion and noise as stated in SINAD dB puts the AX-501 above average (of 74 dB):
It loses to SONOS Amp using its digital input and ever so slightly outperforms the Amazon Link Amp.
Signal to noise ratio matches company spec:
Frequency response shows identical output for both channels which is a relief as poorly made class-D amps differ in this regard:
Roll off is early for my taste. I like to see flat response to 40 kHz. That said, early filtering seems to help bring stability to performance of the low cost class D amps and I saw that here as I measured power output:
There is a broad operating range where performance is good between 1 and 30 watts. We then run out of juice and clipping occurs at 88 watts. Rated output is 100 watts although higher resolution measurement may have gotten us closer.
The Amazon Link Amp has more power and SONOS even more. You are guaranteed to hear distortion when an amp reaches its max power rating so on this all important metric, the Teac AX-501 loses to its cheaper rivals. And of course we are worlds away compared to reference amps like those based on Hypex NC-400.
I have added a new test to my power amplifier suite and that is intermodulation distortion relative to measured power. I ran it against the recently reviewed Klipsch PowerGate Amplifier:
We see more evidence of the stability and clean performance of Teac AX-501 as switched/class D amplifiers go. The IMD graph is also more revealing of distortion set it around 7 to 8 watts and climbing before final clipping.
Headphone Amplifier Measurements
I ran a sampling of my headphone tests starting with power versus distortion using 300 ohm load:
Wow, this is impressive amount of output power at such a high impedance. I wonder if we are just looking at the output of the power amplifier, reduced with an in-line resistor. Here is the results with 33 ohm load:
Oh, this is not nearly as good. The reason is this:
Sadly, we have a high value resistor in series with the output to the tune of 58 ohm. I don't like to see a value much more than 10 ohm and ideally, down to 1 to 2 ohm.
Best use would be high impedance headphone with relatively flat impedance graph versus frequency. Otherwise some "color" will be imparted on the sound (for good or bad).
Conclusions
Personally I think Teac has nailed the look and feel of such a desktop product. The AX-501 is in an entirely different class, rivalling Nagra when it comes to switch-gear and meters. In that regard it is a "bargain."
The power amplifier seems competent without hairy corner cases. It is above average in performance but not rising up to the levels I like to see for $1,000. As I noted in the review. power is everything and there are much better choices in that regard such as SONOS Amp. At nearly half the price, it delivers more than twice the power plus a bunch of other features such as included streaming/DAC. It doesn't look nearly as nice as Teac AX-501 though.
The headphone output is a checklist item although it should sound very good with high impedance headphones (I did not test).
The AX-501 runs cool and should be quite reliable and safe giving its pedigree.
Overall I 'like" the Teac AX-501 but can't recommend it on performance or value. We should be able to do better for $1,000 so the search continues.
------------
As always, questions, comments, recommendations, etc. are welcome.
Major issue: my pink panther models have given me notice that they like to go on strike if I don't increase their pay. They say the original agreement did not at all call for daily reviews. Apparently they go through a lot of work with make up and such to look good on camera. So let's raise some funds so that I can pass on the same to my "talent" using:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
When I reviewed the Teac HA-501 Headphone Amplifier, I heaped praise over its modern retro look. The AX-501 takes that to an entirely different level with addition of a couple of super cute, yellow background VU meters:
What is that? I should have took the shot with the VU meters working and the light turned on? Well, the owner played a cruel joke on me by not supplying me with the remote and leaving the setting to off for the VU meter!!!
The controls are almost as nice of the HA-501 with the exception of the volume control which feels a bit stiff and has some slack in it. Otherwise, there is nothing to fault it as far as I am concerned.
Here is the back panel:
XLR inputs should be mandatory in this price range and I am glad to see then included here (that is the way I ran all of my tests).
The AX-501 uses a class-D amplifier and runs as cool as you could get in my testing. I don't think it ever got even warm.
Class D also means light weight and that is NOT the case here. The AX-501 is a very hefty unit for its size. This means it stays put no matter how heavy your cables are.
Notice the lawyers getting their hands on the unit as to indicate the class of speaker wiring you are supposed to use! But hey, it is good to know the unit has been through corporate filter of certification and regulation.
Even though Teac is a Japanese company, the AX-501 is made in China.
Power Amplifier Measurements
Let's start with our usual 5 watt dashboard view using XLR inputs:
Even though Teac specs the AX-501 at 1 watt, we see the same performance at 5 watts which is nice. Distortion and noise as stated in SINAD dB puts the AX-501 above average (of 74 dB):
It loses to SONOS Amp using its digital input and ever so slightly outperforms the Amazon Link Amp.
Signal to noise ratio matches company spec:
Frequency response shows identical output for both channels which is a relief as poorly made class-D amps differ in this regard:
Roll off is early for my taste. I like to see flat response to 40 kHz. That said, early filtering seems to help bring stability to performance of the low cost class D amps and I saw that here as I measured power output:
There is a broad operating range where performance is good between 1 and 30 watts. We then run out of juice and clipping occurs at 88 watts. Rated output is 100 watts although higher resolution measurement may have gotten us closer.
The Amazon Link Amp has more power and SONOS even more. You are guaranteed to hear distortion when an amp reaches its max power rating so on this all important metric, the Teac AX-501 loses to its cheaper rivals. And of course we are worlds away compared to reference amps like those based on Hypex NC-400.
I have added a new test to my power amplifier suite and that is intermodulation distortion relative to measured power. I ran it against the recently reviewed Klipsch PowerGate Amplifier:
We see more evidence of the stability and clean performance of Teac AX-501 as switched/class D amplifiers go. The IMD graph is also more revealing of distortion set it around 7 to 8 watts and climbing before final clipping.
Headphone Amplifier Measurements
I ran a sampling of my headphone tests starting with power versus distortion using 300 ohm load:
Wow, this is impressive amount of output power at such a high impedance. I wonder if we are just looking at the output of the power amplifier, reduced with an in-line resistor. Here is the results with 33 ohm load:
Oh, this is not nearly as good. The reason is this:
Sadly, we have a high value resistor in series with the output to the tune of 58 ohm. I don't like to see a value much more than 10 ohm and ideally, down to 1 to 2 ohm.
Best use would be high impedance headphone with relatively flat impedance graph versus frequency. Otherwise some "color" will be imparted on the sound (for good or bad).
Conclusions
Personally I think Teac has nailed the look and feel of such a desktop product. The AX-501 is in an entirely different class, rivalling Nagra when it comes to switch-gear and meters. In that regard it is a "bargain."
The power amplifier seems competent without hairy corner cases. It is above average in performance but not rising up to the levels I like to see for $1,000. As I noted in the review. power is everything and there are much better choices in that regard such as SONOS Amp. At nearly half the price, it delivers more than twice the power plus a bunch of other features such as included streaming/DAC. It doesn't look nearly as nice as Teac AX-501 though.
The headphone output is a checklist item although it should sound very good with high impedance headphones (I did not test).
The AX-501 runs cool and should be quite reliable and safe giving its pedigree.
Overall I 'like" the Teac AX-501 but can't recommend it on performance or value. We should be able to do better for $1,000 so the search continues.
------------
As always, questions, comments, recommendations, etc. are welcome.
Major issue: my pink panther models have given me notice that they like to go on strike if I don't increase their pay. They say the original agreement did not at all call for daily reviews. Apparently they go through a lot of work with make up and such to look good on camera. So let's raise some funds so that I can pass on the same to my "talent" using:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).