thread: ORBAN EQ ?!
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Old 22nd May 2009
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gwailoh's Avatar

Originally Posted by Jim Williams View Post
Orban EQ's tend to be noisy if you boost HF EQ. That is because the order of filters in this series connected EQ design. The hf section is last in the chain so any noise is boosted by the HF EQ.

642's can overcome that by the use of low noise opamps and clever users can remove the 4 cards and reverse the order. That way the HF EQ comes first and noise is lowered during boost.

Jim Williams
Audio Upgrades
I have the blue-faced 642B, and Jim has performed the mods which he describes here. Noise is no problem. But, it's a grainy-sounding unit with very restricted headroom. Clips easily, and sounds awful when clipped. You have to be very careful with your gain staging to get good use from it.

(Just want to emphasize that the graininess and lack of headroom are not related to Jim's mods. Was always like this. Jim's mods made it quieter.)