Blackstar Series 1 S1-100 head review

  • £849
  • $2129.99
Tame this 100-watt beast with the onboard DPR control

MusicRadar Verdict

One thing that's missing from so many multi-function amps these days is character. The Series 1 amps have tons of it, with all the flexibility you need. It's been a very long wait for these amps to arrive, but it's been worth every minute!


  • +

    Fantastic tone. Great character. Lots of perfectly-useable features.


  • -

    Quite unbalanced when carried by its handle.

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It's only been around two years since its first products hit the shelves, yet Blackstar is already seen as one of the UK's top amp builders. However, it isn't just down to having good products and snappy marketing - an amp can have all the right features and styling, but within 10 seconds of plugging in, it will either connect with what makes you want to play music or it won't. So, after the long wait, do the Series 1 amps have that indefinable 'I want' magic? Let's find out.

The Series 1 range launches with three products: a 45-watt 2 x 12 combo, a 100-watt head and the KT88-powered flagship 200-watt head. We certainly like the attention to detail that's evident in the appearance of all three amps; cabinets are built to a very respectable standard, with super clean woodwork matched by flawless vinyl covering and sharp control panel graphics. No question about it, this trio certainly looks the part.

S1-100 head

Inside the chassis it's much the same story, with typically neat and robust PCB construction. There are boards for the front and rear panels, with three larger ones handling the power supply and main preamp components, all supported properly on robust metal standoffs.

The valve bases are all PCB-mounted, which is fine - the only practical drawback is that preamp valve replacement is trickier, as they're quite deeply recessed into the chassis. These aren't simple amps, so those PCBs are stuffed full of components, with several bundles of interconnecting wires all neatly terminated in plugs and sockets. The chassis is a tough steel box and needs to be, as the amp has substantial transformers.

"The crunch mode has some of the best tone and response we've heard from any amp in any price bracket for a very long time."

The S1-100 has two pairs of gain and channel volume controls sharing a single EQ network. One channel is dedicated primarily to clean sounds and can be switched between two modes - warm and bright.

The other channel is for overdrive and again there are two modes, called crunch and super crunch. Next to the conventional bass, mid and treble controls is Blackstar's now-familiar Infinite Shape Factor (ISF).

Put simply, this knob changes a classic British EQ network into its American counterpart, with an infinite range of subtle colours between the two extremes. The master section has global controls for volume, presence and resonance, which govern the output stage's high and low frequency response.

Lastly, perhaps the most powerful control on the panel is Blackstar's Dynamic Power Reduction feature, or DPR. This is a circuit that varies the power stage's output from maximum down to just 10 percent, so you can go from 10 watts to 100.

Rear panel features consist of a series effects loop with switchable levels, a speaker-emulated recording output with balanced and unbalanced connectors, speaker outlets with switchable impedance, a socket for the supplied footswitch, and a pair of MIDI sockets for channel switching using MIDI program change commands.

Overall, a very good-looking and highly specified amp, but what really matters is how it sounds and responds.


Check out a few audio clips. First, here's the clean channel in bright mode:

Now switched to warm mode:

Crunch mode:

Super crunch mode:

Finally here's a longer piece that shows off a range of the S1-100's sounds:

One cool thing about the S1's bright and warm clean options is that, behind the scenes, the power amp is also being reconfigured, going from Class A operation with no feedback in bright mode, to Class AB with feedback in warm mode.

This makes for a dramatic difference between the two clean modes. Combined with Blackstar's ISF control, the EQ is wide-ranging, yet easy to dial in, and the gain range for both clean sounds is perfectly tuned.

By just lowering the output power and raising the master volume, it is easy to nail that elusive sweet spot, where the amp just starts to naturally compress as you hit the strings harder, at any volume level.

While the bright clean setting will sound fantastic with effects, we preferred the warm's clean tones, rounder bass and generous mid-range for humbuckers and single-coils - there's plenty of range on the EQ to handle both.

Where the clean modes finish, the S1's crunch takes over and we'd have to say that the crunch mode has some of the best tone and response we've heard from any amp in any price bracket for a very long time.

Bold and very forward sounding with a fast attack, it's supremely responsive to player input and once again it is very rewarding to be able to tune in exactly the right output stage response using the DPR control.

"Unlike other manufacturers' power reduction features, ours doesn't sit between the valves and the loudspeakers," explains Blackstar's Bruce Keir. "A lot of the magic in a great amp happens in that chain from output valve to transformer to loudspeaker and you mess with it at your sonic peril.

"The DPR circuit reduces the output valve's voltages proportionally, maintaining that dynamic feel of power stage 'sag' and compression at any output level".

Switching to super crunch mode kicks everything up a gear for blistering solos, yet roll off the guitar's volume knob and you're back in Cleansville - it's very responsive.

There's plenty of headroom on tap if you need it. Hooked up to its matching 4 x 12 cab, this amp has real authority and power. For many classic rock and blues players, this amp will produce everything that's needed.

Blackstar's Series 1 range is going to find a lot of fans at all levels, from serious amateurs to top pro players. We like the care that's evident in every corner of the design. Cool 'secret' features such as digital valve monitoring (which automatically puts the amp into standby if you pull the guitar lead out) and MIDI channel switching are great, but let's be in no doubt about this, the bottom line is great tone and this amp has got bucketloads of it.

Thanks to Korean manufacturing, the price is better than you'd expect for such great performance and, if the whole range matches up to the quality of this, Blackstar's Series 1 amps are going to be very, very hard to beat. Sod the credit crunch - you need to try them....