The 865 amplifier might be one of the most expensive ever to grace our testing labs, but it’s also the most affordable in the entire Boulder range.
To put this into perspective; Boulder’s ‘entry- level’ 810 and 860 pre/power pairing retails for £11,400, while at the other end of the scale, the 2008 phono stage costs £22,000 and the 2050 monoblock power amps are £49,000 a pair! The 865 is, therefore, a keenly priced component in the general scheme of things.
While the 865 is still expensive, the fact that its design and construction comes from the same stable as the distinctly ultra-fi kit should be a definite advantage. The 810 preamplifier and 860 power amp mentioned earlier are the ingredients that go into making up the 865, which is why the integrated looks like a higher version of an 810. According to the company literature, the 865 can deliver 150 watts into both four and eight ohm loads. This is quite unusual for a solid-state design. As a rule, valve amps have the same power regardless of load and, up to a point, transistor designs increase output as impedance decreases – see our interview with Jeff Nelson on the next page for more on this subject.
As is nearly always the case with high-end American products, this is a fully balanced component. Where Boulder take this a step further is in the use of exclusively balanced XLR input and output sockets. If you have a source component that only has single-ended phono sockets you will need a cable that has XLRs at one end and phonos at the other, or a converter plug such as the Boulder ones that UK distributor Metropolis loaned us for this review. There are four inputs and one auxiliary output that can be used in a fixed or variable form. In other words, it can be an output to a recorder or processor, or to a second power amplifier for bi-amp operation.
Each input can be named, but the sheer range of characters including upper and lower case letters, numbers and an assortment of ‘runes’ and symbols, complicate the process somewhat. A list of these in the manual would have been useful.
Input gain can also be adjusted so that different sources can be matched as much as possible. Difference in recording levels tend to be the dominant factor, but older components can have much lower output levels than modern ones. Integration with what Boulder calls ‘home theater’ [sic] is aided by a bypass mode that you can assign to an input from a multichannel processor. This uses the power amplifier side of the 865 to drive front left and right channels.
Boulder is unusual among the high-end companies for making extensive use of surface- mount components. These are chosen because Boulder considers them to sound better as a result of reduced capacitance and inductance: the fact that they don’t have ‘legs’ in the same way that regular capacitors and resistors do, being a factor here.
A discrete-resistor stepped volume control, developed for the 2010 preamplifier (£30k), allows half-decibel increments in level via the large rotary on the amp, or the attractively curvy remote handset (which probably accounts for £250 of the retail price alone). The volume range goes from 0 to -100dB in half-decibel steps, but in practice, you are unlikely to need more than twenty per cent of this, although this may vary according to speaker sensitivity. The switches on both amplifier and remote are interfaced with ball bearings, which is a neat, albeit expensive way of doing things.
All Boulder power amplifiers include circuits to protect against defective cables, damaged loudspeakers, crossovers, or ‘operator error’. Designed not to activate unless absolutely necessary, these circuits in the 800 series are indicated by the amplifier muting for three seconds and then retrying for 1/10 second. There are no fuses and thus, theoretically, no user frustration — the circuit is designed to recover and allow you to go on listening.
This feature is also said to make Boulder power amps virtually indestructible.
We were surprised to find that we could hear the volume changing through the speakers. This is only apparent when there is no signal and is probably due to the design, but there is an audible clicking. Once you are in the zone, however, this becomes irrelevant as you don’t need to change level that much (we stayed within 10dB for most of our listening). Metropolis leant our test team a pair of Boulder SE to balanced XLR converters so that our largely single-ended sources could be used. These plugs cost around £100 a pair, however, and the extra level and dynamics you get from a direct balanced connection would suggest that the 865 is best suited to all balanced systems.
Hooked up to the Resolution Audio Opus 21 CD player and B&W 802D loudspeakers, the Boulder delivers phenomenal low-level resolution from our test discs. The new Manu Katché album Playground on ECM revealed extremely fine detail right down to the sax player’s breathing. The sound is super-smooth, ultra refined and, perhaps, a little smooth at high frequencies. There is a noticeable loss of ‘air’ and sparkle in the uppermost registers, which is surprising given that you can hear so much through the midband. It’s possible that speaker cable choice might be an issue here, but when we asked Jeff Nelson what he recommends, his specification was almost an exact description of the Townshend DCT used.
The bass on the other hand, is remarkable in its extension and resolve. One male voice choir was utterly convincing, but Diana Krall’s All Or Nothing At All reveals a small but clear shortage of snap: the track didn’t really gel in timing terms, which is surprising given that the timing seems pretty decent, if not remarkable. The sheer detail on offer, though, is so strong, we are happy to let this pass. Unfortunately, when Rage Against the Machine hits the turntable, the situation became more problematic because the music didn’t have the drive and energy that it usually does.
Naturally, it became necessary to find something suitably appropriate with which to compare the £7,750 Boulder. So we phoned B&W and requested a Classé CP-700 preamp and CA-2200 power amp, knowing from experience that this class-leading combination would work nicely as a reference. This pairing retails for £9,400 and needs an interconnect that warrants another £250 at least, so is clearly the next step up. This combo does not produce as smooth and creamy a midband as the 865, but it can deliver considerably greater energy and a more open top-end.
We started to wonder whether the SE to XLR converter might be part of the problem and compared the sound of the two different connections from a Cairn Fog 3 CD player reviewed last month (HFC 302). With the levels matched, balanced connections are 6dB louder than single-ended ones. It was a close call, but the balanced option does get you that much closer to the music. This particular source is not well suited to the Boulder, however, because the combined sound is distinctly edgy. Which is okay with relaxed material whereby it adds electric realism, but with music that’s already energised it’s plain uncomfortable.
The energy factor is seemingly irrelevant when it comes to more relaxed music, which is delivered with such incredible transparency and delicacy that it brings a lump in your throat. Gillian Welch’s 14th Day Of April Part One, has the power to do this, which means that any system with this amp in has the potential to be great. Metropolis had also delivered a set of Hansen’s The Knight loudspeakers for us to test drive with this amp.
These £11,000 floorstanders produce a sound that’s remarkably close to the larger 802Ds but have, perhaps, a little more swing, if less firepower. This similarity did not transform the Boulder into an amp to rock out with, rather it continued to revel in the incredible finesse and subtlety that it extracts from familiar records. We also tried some KSL SPC speaker cable to see if that would suit the amp’s balance better and found that it served to improve the realism of voices and acoustic instruments, the combination proving highly engaging with more intimate pieces.
The Boulder 865 is an incredibly smooth and revealing amplifier. It may lack a little speed, but its resolving power is quite remarkable. Head down to the superb dem-rooms at Metropolis and see if you agree.