This is a review and detailed measurements of the Parasound Zamp V.3 stereo power amplifier. It is on kind loan from a member. The version I have is a revision or two older than what Parasound builds (I think). The latest version is being sold on Amazon for US $277 including Prime shipping. Considering this is a brand name company and we have a class AB amplifier, this seems like a reasonable price.
The Zamp V.3 comes in a tiny and rather cute, half-rack package:
In addition to power button, you also have a headphone jack. From the bit I have read, the output is just the amplifier with a resistor inline. This means its output impedance is high (not good) and likely noisy as well. I did not test it.
The back panel exposes good bit of control not seen on "normal" hifi amplifiers:
Parasound has a leg in two industries: the Custom Integration (CI) channel and hifi. The former is for companies who install these amplifiers in hide-away places to for example power a couple of speakers for a bedroom TV. The gain controls and such give flexibility to this kind of installation as does the small form factor (the amp could be hidden behind a flat panel TV. Being part of this channel means that when the automation is redone in a home using it, these units are ripped out and put on sale at low prices. I see this amp advertised for as little as $149 on ebay.
I was shocked when I read that this amp was class AB and after I looked inside and saw a heavy and large pancake toroidal transformer. How the heck did they put in inefficient class AB amp in there with no heatsinking that was visible? The answer came to me after I let the unit warm up for a little over 5 minutes at 5 watts being output from each channel. The amp went dead and displayed a thermal overload! It can't produce just 10 watts for five minutes? No, it can't. I touched the bottom of the amp and it nearly burned my hand. A narrow painted strip of metal fastened to the chassis carries the brunt of heat generated. Being on the bottom and having no fins means that the heat is not spread at all resulting in overheating. I put a cooling fan on it and it took a good 2 to 3 minutes to come back to life. And I ran the rest of the tests that way.
Amplifier Audio Measurements
Well, this ain't a pretty sight. One channel is much worse than the other. No amount of playing with the grounding, or messing with the switch in the back helped with any of the mains/power supply related tones either. The averaged ranking is below mean of all of the amps tested so far (77 amplifiers to date!):
Crosstalk was poor, matching a $25 amplifier I tested:
Frequency response is OK:
Noise performance as you can predict from the dashboard is not fantastic:
Amplifier Power Measurements
Let's get into the most important bit which is power capability starting with 4 and going into 8 ohms:
Weird how one channel goes crazy at just 1 to 2 watt. Specs are matched though.
Allowing for higher distortion of 1% doesn't help with max power but does give us more burst power:
Thermal Stability
Here is the test that resulted in the shutdown:
I was messing with grounding and caused that little blip so ignore that.
Conclusions
I really like the cute and small form factor of this amp for desktop use. Alas, with a weak thermal management, it won't produce much volume before shutting down. Used ones have probably had a hard life due to this reason as well. If you are going to play with one and want to shy away from the million switching amplifiers out there in this price range, go ahead. But I can't recommend the unit.
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As always, questions, comments, recommendations, etc. are welcome.
Drove back and forth through traffic all day to drop off tested gear and picking up new (nearly 200 miles). The struggle I go through for you all! I hope you reciprocate by emptying your pocket change by donating using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The Zamp V.3 comes in a tiny and rather cute, half-rack package:
In addition to power button, you also have a headphone jack. From the bit I have read, the output is just the amplifier with a resistor inline. This means its output impedance is high (not good) and likely noisy as well. I did not test it.
The back panel exposes good bit of control not seen on "normal" hifi amplifiers:
Parasound has a leg in two industries: the Custom Integration (CI) channel and hifi. The former is for companies who install these amplifiers in hide-away places to for example power a couple of speakers for a bedroom TV. The gain controls and such give flexibility to this kind of installation as does the small form factor (the amp could be hidden behind a flat panel TV. Being part of this channel means that when the automation is redone in a home using it, these units are ripped out and put on sale at low prices. I see this amp advertised for as little as $149 on ebay.
I was shocked when I read that this amp was class AB and after I looked inside and saw a heavy and large pancake toroidal transformer. How the heck did they put in inefficient class AB amp in there with no heatsinking that was visible? The answer came to me after I let the unit warm up for a little over 5 minutes at 5 watts being output from each channel. The amp went dead and displayed a thermal overload! It can't produce just 10 watts for five minutes? No, it can't. I touched the bottom of the amp and it nearly burned my hand. A narrow painted strip of metal fastened to the chassis carries the brunt of heat generated. Being on the bottom and having no fins means that the heat is not spread at all resulting in overheating. I put a cooling fan on it and it took a good 2 to 3 minutes to come back to life. And I ran the rest of the tests that way.
Amplifier Audio Measurements
Well, this ain't a pretty sight. One channel is much worse than the other. No amount of playing with the grounding, or messing with the switch in the back helped with any of the mains/power supply related tones either. The averaged ranking is below mean of all of the amps tested so far (77 amplifiers to date!):
Crosstalk was poor, matching a $25 amplifier I tested:
Frequency response is OK:
Noise performance as you can predict from the dashboard is not fantastic:
Amplifier Power Measurements
Let's get into the most important bit which is power capability starting with 4 and going into 8 ohms:
Weird how one channel goes crazy at just 1 to 2 watt. Specs are matched though.
Allowing for higher distortion of 1% doesn't help with max power but does give us more burst power:
Thermal Stability
Here is the test that resulted in the shutdown:
I was messing with grounding and caused that little blip so ignore that.
Conclusions
I really like the cute and small form factor of this amp for desktop use. Alas, with a weak thermal management, it won't produce much volume before shutting down. Used ones have probably had a hard life due to this reason as well. If you are going to play with one and want to shy away from the million switching amplifiers out there in this price range, go ahead. But I can't recommend the unit.
------------
As always, questions, comments, recommendations, etc. are welcome.
Drove back and forth through traffic all day to drop off tested gear and picking up new (nearly 200 miles). The struggle I go through for you all! I hope you reciprocate by emptying your pocket change by donating using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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