Pre/Power Amplifiers

In this era of all-in-one amplifiers and ‘crossover’ products, where even a tube amp might come to market with a built-in USB DAC, there’s something refreshing about Californian brand Pass Labs. Now approaching 35 years in business and named after founder and chief designer Nelson Pass (also the man behind Threshold in the 1970s), the company has long been known for its focus on frill-free, performance-first designs. Yes, its current product catalogue spans 18 amplifiers, but all are analogue-only. If you’re interested in digital inputs, network audio and touchscreen controls, you can move along. But stay, in the words of Pass Labs, for ‘simplicity and power’.

Selling for £7850, in just the one (very smart) silver aluminium finish, the XA30.8 auditioned here is a power amp from the manufacturer’s Class A range. It’s a stereo design, positioned above the entry-level XA25 at £5595. Also in the lineup are no fewer than six monoblock amps, from the £15,700-per-pair XA60.8 to the dual-chassis Xs300 flagship, a set of two costing £92,500. Meanwhile, there are two mono and three stereo options in Pass Labs’ Class AB series, plus three integrated amps, including the INT-25 [HFN Dec ’20].

First class act

Nelson Pass’s penchant for Class A goes back to Pass Labs’ debut model, the Aleph 0 of 1991. This almost cube-shaped 75W/8ohm-rated monoblock operated as a single-ended, solid-state Class A amp, switching to a conventional push-pull topology toward its maximum output. Next up, beginning in 1998, were the X series amplifiers, with their patented ‘Super-Symmetry’ circuits enabling higher power outputs. These two families were then effectively merged to make Pass Labs’ XA series, now into its third generation.

The XA30.8, which the company says has been engineered to strike the ‘optimal balance between performance and cost’, is rated at 30W per channel. Both PM’s boxout [see] and [Lab Report] cover off why no one should take that specification at face value. And to this I will add that – just by looking at it – the XA30.8 appears destined to deliver a healthy dose of power. While certainly more ‘compact’ than Pass Labs’ top-flight monoblocks, measuring 483x191x540mm (whd), it is still the sort of amplifier that is likely to be mounted on a platform between the loudspeakers rather than in a hi-fi rack.

Above: An Avel Lindberg toroid [bottom] feeds linear PSUs for the balanced line in/voltage stage [top] and Pass Labs’ favoured current feedback power amp based on ten pairs of (20A) FETs per channel [on heatsinks, left/right]

There’s also its 40kg mass to consider, which comes not only from a large toroidal transformer centrally mounted between the XA30.8’s two banks of ‘high-biased’ MOSFETs [see pic, above] but the amp’s solid casework, heatsinking, and machined aluminium fascia.

The last of those has a lush hairline finish, but more eye-catching is the porthole display, which is not a traditional power meter but an indication of output stage bias. Subsequently, don’t expect to see its black needle ‘jumping around’. Oh, and its blue illumination cannot be dimmed.

There’s nothing else on the XA30.8’s front apart from an on/standby button and company logo, and there’s a similar fuss-free feel to the amp’s rear.

Heatsinks ’n’ links

Indeed, a glance around the back reveals two useful carry handles, single-ended and balanced XLR inputs, a 12V trigger (for automated switch on via a connected preamp), a mains socket, and an on/off rocker. Improved over previous XA amps are the speaker binding posts, which are now widely spaced and feature a locking mechanism that makes it impossible to over-tighten – good news for owners of spade-terminated cables.

Pass Labs suggests a clearance of around 6in is necessary to manage heat dissipation from the XA30.8’s side-mounted heatsinks. These large, sculpted patterns of metal do a good job. After a couple of hours’ usage, the amp was running reasonably warm, but without any discernible hotspots, though the power consumption when idling was more than 250W…

For a partnering preamp, Pass Labs sells four line-level models and three phono units. Of the former, the entry-level XP 12 is perhaps the XA30.8’s most obvious companion, a single-box model available for £6595. Step up to the £10,895 XP 22 for a twin-chassis preamp, with dual mono power supply housed in an external chassis. For our review, however, BAT VK-90 [HFN Jun ’25] and Constellation Revelation 2 [HFN Jan ’25] preamps were used, with the flagship dCS Varèse DAC/streamer [HFN Feb ’25] and Marantz SACD 10 [HFN Jun ’25] as sources.

No strain, all gain
Anyone sniffy about the XA30.8’s modest 2x30W rating will soon have their nose wiped. In the HFN listening room, with both DALI Epikore 11 floorstanders [HFN Feb ’25] and B&W 801 D4 Signatures [HFN Sep ’23], there was no sign of strain at the levels needed to ‘fill’ the large space. Just the impression of ample power, married to sweetness and warmth. It’s a moreish sound that steers clear of brightness and glare, but not so soft as to miss out on transient attack and musical drama. The XA30.8 also digs deep with relish, sounding rich and weighty in the bass. That £7850 asking price looks like a bargain.

Felix Laband’s ‘Black Shoes’ [Dark Days Exit, Compost Records; CD resolution] begins with a metronomic, two-note bass line that acts as the building block to a sparse, minimalistic instrumental. There are tinkling bells in each channel and stylised, electronic percussion. Delicately resolved effects, including splashes of water, sent the music skywards. But really notable here was the bounce that the XA30.8 brought to the bottom octaves, ensuring the track sounded both large and alive.

Previous experience of Pass Labs amplification has shown the brand has a way with the low-end and throughout the listening sessions, the XA30.8 delivered big drums, electronic swells, and electric and acoustic bass guitars with ease.

From pluck to pummel

The upright bass that kicks off Rickie Lee Jones’ ‘Easy Money’ [eponymous; Warner Bros. Records 256 628] was precisely drawn, with clear plucks and a gentle resonance, to match the smooth vocals and fine-as-you-like guitar strings.

With Judas Priest’s ‘The Serpent And The King’, from Invincible Shield [Columbia; 48kHz/24-bit], the amplifier gave a display of controlled aggression. Drummer Scott Travis opts for an all-guns-blazing approach to match the lightning-fast guitar riffs, and the clear beats of his kick drum(s) enjoyed solid – if not quite gut-punching – slam. Listening at a volume level suited to this legendary rock band, the XA30.8 didn’t appear to be out of its comfort zone.

Widescreen wonder

The Pass Labs amp also impressed with its soundstaging. Playing Fleetwood Mac’s ‘Gold Dust Woman’, performed live at LA’s Fabulous Forum in 1977 [Rumours Live, Rhino Records; 96kHz/24-bit], it was a doddle to visualise Stevie Nicks standing front and centre, her vibrato vocals ahead of keyboards and bass as Lindsey Buckingham chopped out chords on his guitar. There was an airy, deep feel to this rendition, while switching to the in-the-studio original tightened yet widened the stage.

The XA30.8 confidently replicated the wide view of the orchestra in the Berliner Philharmoniker/von Karajan recording of Ravel’s Boléro [DG; 96kHz/24-bit], and the timbral differences between the woodwind instruments that carry its jazz-like melody. The crescendo, with blasts of brass and snare drums, sounded big and thrilling – words that also fit the amp’s handling of ‘Seven Angels Of Vengeance’, from James Horner’s suite for the 2016 remake of The Magnificent Seven [Sony Classical 88985346202]. On this piece the staging was again superb, evoking the wide, open plains of the Old West. In other words: Yee-haw!

Above: The XA30.8 is equipped with custom 4mm speaker outputs that apply a pre-set torque to spades and bare cable. Inputs are on RCAs and balanced XLRs

What Pass Labs’ XA30.8 offers is a performance both big-hearted and enveloping, yet able to accentuate finer details. It sits well off ‘neutral’, but remains vivid in the midrange. The vocals of London Grammar’s Hannah Reid, during the perennial hi-fi demo ‘Hey Now’ [If You Wait; MADART1], were clear and nuanced, even with the track’s generous reverb. The amp dug deep into the dual vocals in Hans Theessink and Terry Evans’ ‘Got To Keep Moving’ [Visions, Blue Groove; CD res], Evans’ baritone in particular being packed with inflection and character.

In a section of the XA30.8’s manual, Nelson Pass explains that a good deal of his company’s evaluation processes are based around listening rather than measuring. If you wanted an amplifier that’s an utter pleasure to listen to, while not warranting the term ‘transparent’, then this is it.

The sound of Theessink and Evans’ guitars sent me off on a country-blues tangent, so Tony Joe White’s ‘Polk Salad Annie’ [Black And White, Rhino Records; 96kHz/24-bit] was soon tumbling from the DALI Epikore 11 speakers, followed by The Nitty Gritty Dirt Band’s ‘Tennessee Stud’ [Will The Circle Be Unbroken, Capitol Nashville; CD res] with its beautifully recorded vocal and thick instrumentation. And this might be the Pass Labs amp’s vital attribute – it puts nothing between you and the music, while the sound, sweet but with a steely spine, is ripe for listening long into the night.

Hi-Fi News Verdict

Nelson Pass’s reputation as an amplifier designer par excellence isn’t threatened by the XA30.8. This near ‘entry-level’ stereo amp offers the finely detailed, approachable sounds expected of Class A operation, without shying away from the business of driving your speakers. It’s a performance that should put a smile on the face of all audiophiles, bar those obsessed with ‘clinical neutrality’, and for a sane price.

Sound Quality: 90%