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General NewsMastermind PBC/6XTech Tips

The Lowdown on Input Impedance

It was recently announced that we were going to produce a batch of Mastermind PBC/6Xs with a modified buffer circuit for Mason at Vertex Effects. This unfortunately became a source of confusion to some, leaving people wondering what it’s all about. So, I felt the need to explain what’s going on.

Buffers (and all circuits) have an important characteristic called input impedance. This is how much the circuit loads down or “pulls on” the circuit before it. The lower it is, the more the circuit affects the circuit before it.

We’ve been using the same buffer circuit for almost 15 years now, starting with our RG-16 rack switcher unit and continuing on to the products we’re making today. We’ve been using a 500k input impedance since the beginning. We feel it gives the most “natural” sound, and the majority of our customers I’ve spoken to are quite happy with the buffer. We have a lot of world touring customers, and no one’s ever asked me to change the input impedance on one of our units.

That said, this is a very subjective thing, and personal taste factors in a great deal. Mason prefers a 1Meg (or 1000k) input impedance. The main difference is that you’re going to hear a bit more treble with this configuration. For some people, it’s exactly what they’re looking for. For others, it’s too much – it’s brighter than they’ve ever heard their guitar. For many, they can go either way, it’s not enough of a difference to matter. And, tone controls can do a lot more tone modification than input impedance can.

This is probably a one time thing, I don’t expect that we’ll be doing more of these modified units. We’re not able to do one-off customizations either, we have enough work just keeping up with our regular production products. If you’re still feeling like you missed out by not getting one of these modified, a qualified electronic repair tech would be able to do the modification – it’s quite easy, and I’m happy to give the information needed. Just make sure the person is qualified – we can’t provide warranty coverage if your unit has a botched repair job.