Integrated Amplifiers

Arcam’s amps haven’t changed much externally since the introduction of the ‘Full Metal Jacket’ range several years ago, but their internal design has seen a fair bit of evolution.

In its description of the A38, Arcam draws special attention to the output stage design which, it says, is much less sensitive to thermal conditions than traditional output stages. The issue of ‘warm-up’ of audio electronics is a long-standing bone of contention, some saying it’s of little importance, while others maintain it’s crucial for proper performance. What’s often forgotten, though, is that the temperature of the output transistors can vary by many tens of degrees during the course of a track, as the music goes from soft to loud and back.

As a result, we’ve seen amplifiers whose measured performance differs markedly before and after a burst of loud music. Tackling this is possible by various means and many designers are aware of it, but Arcam’s approach is one of the most thorough we’ve seen, using special output transistors which include on-chip temperature-sensing components, thus allowing very rapid response to thermal changes.

Those transistors are fixed to a substantial heatsink which ensures safe operation at high power: this is quite a meaty amp as integrated models go and it has a large mains transformer to support that. Opposite that, on the preamplifier side of the chassis, there’s ample evidence of care taken in the handling of small signals. The main input switching uses reed relays (generally considered the audiophile’s switch of choice), which subsidiary switching uses solid-state devices. The volume control is electronic, with step size selectable at 0.5, 1 or 2dB. A phono stage is an option.

With very little said against it and lots of points in its favour, this was one of the best-liked amps of the group among our panel of ‘blind’ listeners. Two indeed specifically mentioned that it was their favourite or joint favourite.

The A38 also achieves an excellent balance between voices and instruments, something our listeners identified as a tricky area to get right, particularly in the Otis Redding track we used as part of the listening programme. If there’s a slight weakness in its presentation it’s in the resolution of small incidental details, which can at times seem subsumed into the whole.

On the other hand, resolution is generally very good, in terms of hearing what’s going on within a large and complex body of sound, so one might choose to express things in a more forgiving way and way that this amp is simply not over-fussy.

It’s certainly not fussy about the music it plays. In terms of specifics, it has particularly good bass, strong, rhythmic and with good definition of pitch. The midband is neutral and treble is clear and extended, with just a hint of dryness on violins, always one of the hardest sounds to keep really pure.

LIKE: Excellent bass, good resolution and clear, neutral midrange
DISLIKE: Can occasionally seem a little casual with fine details
WE SAY: A fine all-rounder with a well- judged balance of sonic and practical virtues

DETAILS
Origin: UK/China
Weight: 9kg
Dimensions: (WxHxD) 430x110x370mm
Features:
• Inputs: 7 line level
• Optional phono stage
• Separable pre- and power amplifier
• Dual switched speaker outputs
• Headphone output
• Nominal output: 100W
Distributor: Arcam
Telephone: 01223 203200
Website: arcam.co.uk