Sugden Masterclass IA-4 Integrated Speaker Amplifier – Review

As you may  remember, Piega 5.2 are quite pretentious when it comes to the amplification. Knowing that I am a big fan of good Class A amplifiers,, gave me a Masterclass IA-4 to play with.

Introduction and Specs

This amplifier only has 33W into 8 ohms, but they are full Class A. Surprisingly, I don’t think I ever managed to go higher than 20% of its volume output with Piega Primium 5.2 . What I am trying to say is that an Class A amplifier capable of 33W is quite powerful.

The Sugden Masterclass IA-4 amplifier integrates a state of the art preamplifier and the classic Sugden Class A output stage, also including a MM phono stage.


Inputs Three line level, tape, MM phono, balanced
Outputs Variable pre-out, fixed out, loudspeaker out
Volume control Remote control RC5 compatible


Line Input sensitivity 125mV
Moving Magnet input Sensitivity 2mV
Power output 33 Watts per channel
Frequency response +/-1dB 14Hz-200kHz
Bandwidth +/-3dB 6Hz-300kHz
Signal to Noise 84dB
Gross Weight 20kgs
Dimensions 165x430x440 (hwd)

Sugden Mastarclass IA-4 Review (1)

Listening Impressions and Tests

The tests were performed with  AG500 Power Regenerator,  MSB Analog DAC with quad usb, Masterclass IA-4 Integrated AmplifierXindak A600 Integrated Amplifier, Piega Premium 5.2 Speakers.

Alison Krauss – It Wouldn’t Have Made Any Difference 

The first thing I noticed was a relaxed and musical sound signature. The artist’s voice was very nice with a very good presence. Actually it was brought forward in a natural and textured manner. The instruments around it were flowing with musicality.

Vivaldi – Autumn – Allegro (La Caccia)

The instruments were, detailed, full bodied and tube like. The plucks were strong but not aggressive showing strong attack and a little bit lingering decay. However the decay wasn’t making the sound slow, but rather musical and relaxed.The instrument separation was quite good and the soundstage was spacious but I would have wanted a little more depth to hear the instruments loosing themselves in a big room. Overall the presentation was tubey/analog, musical and very enjoying.

Hugh Laurie – Battle of Jericho

IA-4 has a very nice coloration that brings the voices in front, giving them good scenic and full bodied presence. The drum showed a deep bass that can go low, showing good depth and extension, but doesn’t hit too hard, making the sound a little romantic. The guitar plucks were quite nice, being an interesting combination of good but not very strong attack and a full but not slow decay.

Mamma Mia – I have a dream

This song was an interesting experience. With the guitars in this song, IA-4 showed a sparkly and playful energy that tickled my years. The voice was well extended showing very good extension and texture as you could feel the vibrations and subtle note changes. You can also feel the body attached to the voice.

Pink Floyd – Another Brick in the Wall ( Part 2 )

The drum had good impact and depth. I’ve heard many presentation here of many amps with Premium 5.2. Some were too aggressive, leading to a kind of dead sound signature. IA-4 handled this very well, showing good impact on the drums, but also a full bodied decay leading to a musical, analog presentation that was very pleasant to the ears. The electric guitars caught my attention with their extension and harmonics and helped me loose myself in the song. The voices had again a very strong scenic presence, extension and good textures.

Sugden Mastarclass IA-4 Review (2)



The bass on IA-4 was quite enjoy-full, showing a good balance between depth, control and punch. It has good impact and I didn’t feel that I needed more here, but also having a wonderful full bodied extension with decent control. While I’ve heard better bass control on other amplifiers, the presentation on IA-4 had it’s magic, giving a more musical pace to the songs.


This is another strong point of this amplifier. The midrage is very present and quite detailed. The voices are brought in front, near you, having a strong and full bodied presence and extension. The instruments are no exception and they present good detail and textures. I loved how the violins, cellos, pianos sounded on IA-4, as they had a vibrating presentation, leaving me thinking of the harmonics you usually find in tube amplifiers.


The treble was sparkly and detailed as well. While it wasn’t so opened on top as other amplifiers that help you hear the reflections in the room, it did behave quite well in this region as well.


I loved the voices on IA-4. I felt that they were brought in front near you, but in natural way. They were full bodied, very present, textured and extended. I felt the body attached to the voice as well.


The soundstage is quite spacious and naturally presented, but it could use a little more air on top and depth, to hear the instruments/voices loose themselves better in the scene.


The attack is good, but not too strong or aggressive, while the decay is a little tube like, it doesn’t make the sound slow. Overall it’s a very interesting balance between the two, resulting in an interesting sound signature that is relaxed & musical, having a good pace in the same time.


I found the details to be good on all the frequency range, especially on the bass-midrange area.


This amplifier has a relaxed sound signature sometimes making me thing of the word “effortless”, leading to a musical / analogical sound experience.

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I ended up liking this amplifier quite a lot. I think that it has a very nice sound signature that combines the best of solid state and tube sound. It has an effortless and musical sound signature that lets the music flow into your ears.

If you like this type of sound, I think that you should definitely give Masterclass IA-4 a chance.


  • Good build quality
  • Good bass that shows balance between depth, control and punch; full bodied experience. It gives a musical pace to the songs
  • Rich and detailed midrange, showing good textures and extensions that make me feel of tube like harmonics sometimes
  • Sparkly and detailed treble
  • Very present and extended voices
  • Spacious soundstage
  • Good transients with a nice balance between the attack and decay, leading to a relaxed/effortless sound signature
  • Good details
  • Musical sound signature


  • some may like a more energetic/faster sound signature
  • the soundstage could use a little more air on top
  • some may want a more neutral sound
  • pricey