Absolutely the best around, finally the right attenuator, he does his job perfectly,really really happy with it, the best purchase I could make, after having tried other 3 attenuators, cheaper, thinking of saving money, I just threw money instead. I should have bought it before. I use it with a jtm 45, and it works well even at very low volumes, of course it's always better to play loud at high volume, it doesn't heat at all. Probably with a 100 watt non-master volume head it could heat up more, and have a slightly different sound, I can't say. Used as an attenuator it is certainly among the best on the market, perhaps the best, but if you also want simulation of cabinets and other studio functions, you will have to spend even more for other products, but for how much it concerns the attenuation, to date, nothing is better. I really recommend not to throw money with attenuators that cost a lot less, the difference is really remarkable.