"I'm using Robert's modded Boss SD1 with Marshall JCM 800 100watt heads and Gibson Les Paul guitars.The SD1 is pushing an already driven amp into overdrive meltdown.

Robert has done a variety of mods to this pedal giving it a clearer tone,more juice under the bonnet and a very musical grind. Every note sings out - no mud, no extra noise - if anything considering the extra poke the unit has it's actually quieter than stock.

Very little tone sucking in bypass not that I'm gonna be bypassing this one much and a huge yellow LED that you could spot from the moon to let you know status.

I got into SD1's because of Zakk Wylde and have had stock units and one modded by Analogman. Robert's work blows them all away, believe me I've a/bed them all and the improvement in tone is as clear as black and white.

If you're after a full, defined overdrive tone this is for you. It'll wind down and do subtle, break up, and also go all the way up to sonic meltdown. Dare I say something for everyone?

I play in a professional Ozzy Osbourne tribute band and have been a pro player for almost 20 years.I know what I like and Robert Keeley's work is amongst the best I've heard,tried and used.

The SD1 is a personal favourite of mine but I have also gor several of Robert's TS9 808 mods too - all excellent tones and workmanship.

This pedal is awesome. I've tried and/or owned just about every overdrive unit out there, boutique and stock. This is the one. Robert Keeley is the tone master... thankfully!" - Tim Mills, on Harmony Central