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Rega IO Review (stereo amplifier)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 262 88.2%
  • 2. Not terrible (postman panther)

    Votes: 20 6.7%
  • 3. Fine (happy panther)

    Votes: 3 1.0%
  • 4. Great (golfing panther)

    Votes: 12 4.0%

  • Total voters
    297

amirm

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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:

Rega IO Review Integrated stereo amplifier.jpg


It is function though with a simple input switch and power. The inclusion of remote control is a nice touch:

Rega IO Review back panel Integrated stereo amplifier.jpg


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!

Rega IO Measurements Warm up Integrated stereo amplifier.png


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:

Rega IO Measurements Thermal Integrated stereo amplifier.jpg


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:

Rega IO Measurements Integrated stereo amplifier.png


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:

Best budget amplifier reviewed 2021.png


This is well below average of nearly 79 dB.

Signal to noise ratio as a result is nothing to write home about:

Rega IO Measurements SNR Integrated stereo amplifier.png


I was surprised that despite being a simple class AB design, it doesn't have flat response in audible band:

Rega IO Measurements frequency response Integrated stereo amplifier.png


Most shocking measurement was that of crosstalk:

Rega IO Measurements Crosstalk Integrated stereo amplifier.png


Here is our multitone test showing the impact of distortion:

Rega IO Measurements Multitone Integrated stereo amplifier.png


Company specs the amp at just 30 watts into 8 ohm and good news is that it delivers that:

Rega IO Measurements Power into 8 ohm Integrated stereo amplifier.png


But this is not much power. Here is what we get into 4 ohm:

Rega IO Measurements Power into 4 ohm Integrated stereo amplifier.png


Thankfully being a class AB amplifier with unregulated power supply, it does better in burst mode:
Rega IO Measurements Max and Peak Power into 4 ohm Integrated stereo amplifier.png


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:

Rega IO Measurements Power into 4 ohm vs frequency Distortion Integrated stereo amplifier.png


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:

Rega IO Measurements Phono Input Integrated stereo amplifier.png


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:
Rega IO Measurements Headphone 300 ohm Integrated stereo amplifier.png



Rega IO Measurements Headphone 32 ohm Integrated stereo amplifier.png


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/
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As always, questions, comments, recommendations, etc. are welcome.

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polmuaddib

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Could it be that they intentionally deisgned it to be bad just so that their more expensive models be audibly better?
Do companies do that? Or they just can't design a solid product within a price range?
 

Tangband

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Isnt this a clear case of trying to make an amplifier that , for the ears, sounds more ”analog” and maybe more pleasant to listen to in a complete Rega system? Makes me think about PS audio when I read about this Rega.

I also think that the amplifier fits in the sound filosofy of a Rega setup with a Rega record player, amplifier and a Rega loudspeaker.

I have had a Rega planar 3 record player a long time ago and later had a Rega dac. Im sure they were measuring terrible but I listened to a lot of music during this time, so its a paradox.
 

Doodski

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It appears that Rega is using some sort of IC for the output amplifier devices.
EDIT: Are those even output devices? Are there transistors mounted on the side heatsink(s)?
Do I have the correct pic?
@amirm can we please get a tear down of this Rega IO amp?
io_gallery_04.jpg
 
Last edited:

Koeitje

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fordiebianco

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I always thought that Rega would value excellent engineering and this is disappointing to see. Their video factory tours are interesting though: https://www.rega.co.uk/about/factory
 

DS23MAN

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It appears that Rega is using some sort of IC for the output amplifier devices.
EDDIT: Are those even output devices? Are there transistors mounted on the side heatsinks?
@amirm can we get a a tear down of this Rega IO amp?
io_gallery_04.jpg

Looks like a conventional Class AB design.
 

batfunk

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Little brother of Rega Brio(2×73 watts 4 ohms). Very popular brand in France, specially for vinyl playing. Brio could have been my first "audiophile" integrated amp in 2013,with Nad c326be.
Well, another one bites the dust:facepalm::facepalm:
 

DanielT

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Thanks Amir!

Looks sad. The development engineers at Rega should know better, you might think. Maybe a way to get money, profit from the brand Rega? What about the financial status of the company Rega? New owners who want to "cream" out as much money as possible and do not care what Rega pours out on the market?

Note speculation on my part!
 

KSTR

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Looks like a conventional Class AB design.
Yep, a pair of SANKEN STD03N+STD03P Darlington power transistors in discrete output stage.
And given a bloated circuit with all those features, crammed into that poor tiny little sheet metal case, no wonder it doesn't perform well wrt mains interference, crosstalk and power dissipation. It could have been done better in this form factor but that would have required a much greater effort in many regards, actually a true design challenge... at significant cost increase.
Overambitious Product Managers at work, pushing for goals impossible to realize?
 

jrosser

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It appears that Rega is using some sort of IC for the output amplifier devices.
EDIT: Are those even output devices? Are there transistors mounted on the side heatsink(s)?
Do I have the correct pic?
Some fancy output transistors have more than 3 pins, see https://www.onsemi.com/pub/collateral/and8196-d.pdf as an example. Don't think those exact onsemi parts are used here though as theres still a manual bias adjustment and only 4 pins, but you get the idea.
 

respice finem

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IDK what they thought, but probably "nobody's going to notice"... Way to spoil your brand reputation.
 
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DS23MAN

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Yep, a pair of SANKEN STD03N+STD03P Darlington power transistors in discrete output stage.
And given a bloated circuit with all those features, crammed into that poor tiny little sheet metal case, no wonder it doesn't perform well wrt mains interference, crosstalk and power dissipation. It could have been done better in this form factor but that would have required a much greater effort in many regards, actually a true design challenge... at significant cost increase.
Overambitious Product Managers at work, pushing for goals impossible to realize?

NRND:

 
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