The series one 45 is medium sized combo containing two 12 inch speakers allowing up to 45 watts of power. This is plenty loud enough for the gigging musician. It does however still sound great at very low volumes.

The first thing you will notice is the front loading controls are very well organised. There is a good arrangement of tone options and the single row of controls means that this amp is very easy to use. As with all Blackstar amps it is well constructed and built to last. This particular range is also hand built in the UK.
I decided to try the clean channel first and add a small amount of gain. Using the bright clean channel gives a sparkling clean tone. The big USP (Unique Selling Point) for Blackstar amps is their ISF (Infinite Shape Frequency). This dial, found on all of Blackstars amps allows the user to create an American amplifier sound and a British amplifier sound. Whilst this may sound like a fad, the dial creates a noticeable difference in tone and becomes just as important as treble or bass for your sound.

On the clean channel with low gain, turning this control all the way to the 'British' side presented a ballsy tone which threatened to break up when pushed hard, whilst turning it all the way to the 'American' side gave an extremely noticeable bright twang sound, reminiscent of classic fender and mesa amps.With the gain at half way and the ISF set al the way to British, the neck pickup of my guitar gave me a deep, resonant, yet crystal-clear twang perfect for country music styles. Selecting the 'warm clean' channel and turning the ISF control to the American setting meant that the bright twang was retained, yet the switch to the 'warm' channel meant that a new dimension of bass and resonance was added.

Selecting the overdrive channel with a low gain setting meant that the warm twang was still readily available, especially when incorporating the British side of the ISF. Adding more gain made the tone thick and ballsy due to this ISF setting, and was perfect for re-creating any classic rock tone. However, this slightly dirty tone was cleaned and refreshed by turning the ISF to the American side.
Considering that the amp is all-valve, the Gain levels that could be reached were highly impressive. The tone was prefect for metal if the 'American' side of the ISF was incorporated, especially when the mid range of the equalizer was 'scooped' out. As were searing, high-register solos. However, turning the ISF control the opposite way meant that the same levels of gain and sustain were readily available, but with an extremely British influence, reminiscent of modern Marshall heads.

To conclude, it can be heard that the Blackstar has been developed and tweaked by engineers wanting to stay true to valve tone. To this end, it is easy to re create almost any classic amp sound, be it the bright clean of early Fender or Mesa combos, to the raw, dirty rock sound of early to modern Marshall heads. Modern tone players may find that the Blackstar does not deliver the compressed levels of sustain and gain as newer peavey and mesa heads, But from crystal clear clean to roaring, huge distortion sounds, the Blackstar will most definitely not dissapoint.