This is a review and detailed measurements of the Rega IO stereo integrated amplifier with phono input. It is on kind loan from a member and costs US $649 on Amazon including Prime shipping. It is designed and built in UK and price there seems much more reasonable (379 pounds).
The front panel doesn't do much for me:
View attachment 162324
It is function though with a simple input switch and power. The inclusion of remote control is a nice touch:
View attachment 162325
Courtesy of the company heritage in building turntables, it has phono input built-in. No digital inputs which is an odd omission in this day and age.
Rega IO Amplifier Measurements
With power amplifiers I let them run at about 5 watts into my 4 ohm load and watch their distortion+noise to see when it stabilizes. It did not in the case of Regao IO and contrary to audiophile belief, kept getting worse!
View attachment 162329
I watched every video review of this box while waiting but it would simply not stabilize. At around 23:00 minute, I started to sense the smell of electronics running too hot so I put my hand on it. That was a mistake as it darn near burned it! The sides were quite hot. I took an IR picture of it:
View attachment 162330
As you see the left and right bars run much hotter with the back end being at around 45 degrees C. This is in open air in cool weather where we live. Imagine what it would do at higher power delivery and when put in a cabinet. Not good. Company provides lifetime warranty but says it won't include wear and tear. Wonder if it cooks itself whether they repair it under warranty.
Anyway, let's get on with our testing starting with our dashboard:
View attachment 162332
A lot of things stand out. For starters, the channel gain is not matched. The mismatch seemed to be volume pot independent. Then there is the matter of very high levels of mains hum and harmonics. No matter what I did with grounding, it would not make any difference whatsoever. The mains noise is actually higher in energy than the harmonics. That is not a bad thing in that our sensitivity at lower frequencies is much lower than at higher ups.
SINAD sums all the noise and distortion and lands the IO in the "fair" category:
View attachment 162335
This is well below average of nearly 79 dB.
Signal to noise ratio as a result is nothing to write home about:
View attachment 162333
I was surprised that despite being a simple class AB design, it doesn't have flat response in audible band:
View attachment 162334
Most shocking measurement was that of crosstalk:
View attachment 162336
Here is our multitone test showing the impact of distortion:
View attachment 162344
Company specs the amp at just 30 watts into 8 ohm and good news is that it delivers that:
View attachment 162337
But this is not much power. Here is what we get into 4 ohm:
View attachment 162338
Thankfully being a class AB amplifier with unregulated power supply, it does better in burst mode:
View attachment 162339
Modern speakers are built in compact enclosure that reduces their efficiency greatly. I am not sure this is enough power.
Here is our frequency stepped response:
View attachment 162340
Class AB designs sport clean transfer functions and the Rega is no exception. Typical of all amps though, you lose power at very low frequencies. Usually you have a lot to loosing some is not super painful. Here though, you don't so that is not good news.
Phono Stage Measurements
There is no preamp output so I decided to use the headphone output to measure the RIAA equalization:
View attachment 162341
Good showing here assuming you prefer less bass to LP rumble.
Headphone Output Measurements
Company specifies the headphone output as having an impedance of > 100 ohm which is massive. It will cause frequency response error in vast number of headphones which have variable impedance. And on those flat ones which tend to be low, it will dissipate a lot of power internally:
View attachment 162342
View attachment 162343
This is basically a checklist feature and not something that you want to use for any serious headphone listening.
Conclusions
I have a soft spot for western companies trying to compete with Asian ones in budget audio products. Alas, performance has to be there to do the job and for the most part, it is not with Rega IO. Capability is poor as far as power output. Measurements like crosstalk are horrid. Headphone output is years behind times with super high impedance. And then we have the large amount of heat this generates. If this were a powerful amplifier I could understand idling high but not when all you have is 30 watts into 8 ohm. Amplifiers have a tough life and you want them to be reliable. I am not sure how long the IO will last given the elevated temps under which it operates.
I don't know that this is a terrible amplifier but when test after test makes me cringe, I have no choice but to withhold recommendation for Rega IO.
Edit: see
teardown here:
https://www.audiosciencereview.com/forum/index.php?threads/rega-io-amplifier-teardown.27735/
------------
As always, questions, comments, recommendations, etc. are welcome.
Any
donations are much appreciated using
: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/