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MOX-like crossover and discrete opamp group buy

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I understand where Jens is coming from, but for the majority of people I think the E96 values will be more than adequate. If your design is so refined that there is a difference between the xover point being at 2000Hz or 2040Hz, then you should already be putting "tweak" values in that allow you fewer choices but a finer adjustment range.
 
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tiroth said:
........I think the E96 values will be more than adequate......
Hi,
I agree. E96 is just fine. Anyway, caps have bigger tolerances (from Jens's parts list caps tolerances are 10%).
For example, if one cap has tolerance 10% and is on edge, frequency will drift for 10% too what isn't so good (from let say 1k to 900Hz).

Maybe is good idea buying few pieces extra and selecting with C-meter those with best values.
Regards
 
2SK389 'V' group have arrived!

grataku said:
are they the real deal?

Yes! I could find no evidence online of 2sk389 ever being faked, but I wanted to take no chances. I measured several samples finding

VGS matching: < 1 mV
DC offset at 15V in opamp: < 1 mV*
Square wave response: good**

*Over a voltage range of 5-30V the offset is within 10mV. If you desire different rails and 0V offset, just trim appropriately.

**this is NOT a small signal measurement, the square wave is 4Vpp!

I am also happy to report that the OPA boards have shipped (to me, orders will go out when the MOX arrive). I have no updated estimate on the MOX boards, so don't count on them coming early. 😉
 

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Parametric EQ as mox sidekick

Hi,

As some of you may know, I have been working on an adjustable EQ as a sidekick to the Active filter two boards. I think I have found a way to make a real parametric EQ, with completely separately adjustable Gain, Q and fc. If anybody is interested I’m offering to create the artwork for this module also, and later there can be a group purchase.

Let me know what you think and what the options on the boards should be

Thanks
 
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