Tube Monoblocks for heavy music on Khorns

The complexity will kill the impact. With K-horns you want things as simple as possible.

Stimbo22, most horns (Khorns included) have high efficiency drivers that, because of their efficiency, are also highly reactive. Such drivers have a lot of back EMF because of the greater precision and efficiency of their magnetic motors.

The back EMF really messes with amplifiers have a low output impedance. However the passive crossover of the speaker is helpful, because it is a series element in the speaker, and so allows you to use amplifier with a moderate output impedance (at least) without too much trouble.

If you get rid of the passive crossover, the only amplifiers that will work well without being excessively shrill (due to the interaction with the back EMF) will be ones that have a high output impedance.

The S-30 is one of these, as are a number of smaller SETs. So you *could* make that work, but OTOH you could have a slightly larger amplifier and the passive crossover, and it might work every bit as good, with a lot less complexity and a lot less invested.

BTW if anyone has ever wondered why transistors are often shrill and honky with horns, this back EMF issue is why. I should point out though that the back EMF will mess with any amplifier that uses a lot of feedback.

Stimbo22, I've used active crossovers quite a bit. They are very tricky to say the least. For the most part though, at least so far anyway, I have seen better results using one amplifier to drive the speaker while using a passive crossover.

One thing you want to consider is that nearly all drivers have nuances, odd little peaks and dips in their response. The designer of the crossover, if he is worth his salt, will accommodate these variances. Unless the active crossover is specifically designed for that speaker, it will only provide general curves with no accommodation for actual driver behavior.

I suspect this is why the best systems I have heard have all had passive crossovers.

Right.

I've spent a lot of time in the recording studio. I think you will find that the more you process the signal digitally, the less musical the final result will be.

An fact the more you process the signal, analog or digital, the less musical the result.

IOW, that is why most passive crossovers work better than active ones, unless the speaker designer designed the speaker for a particular active crossover.

Stimbo22, Brian seems to have designed his speakers so that he can use an active crossover. I suspect that if you were to open the cabinets, you would find some minor compensation components to deal with the characteristics of the drivers. The MA-2s were used to drive the midrange and ribbon tweeters, but IMO the amplifiers were overkill! They had *way* more power than was ever needed.