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Post by rowmat on Oct 22, 2016 1:01:32 GMT -6
I fitted a pair of front panel toggle switches to our SCA N72's and J99's so I can easily change both the mic input transformer impedance and the output transformer loading without having to remove the modules to change the jumpers on the PCB's. (Haven't labelled them yet) I'm finding I often prefer the 300 ohm setting on the mic input transformer even with our LDC's as it warms and fattens up the lows and is usually a little less sibilant than the 1200 ohm setting and can provide more of a vintage vibe if that's what you're looking for. It also allows the singer to back off the mic without the low end getting too thin. For those who haven't tried the 300 ohm setting I can recommend it especially if you need to take the edge off a bright condenser and thicken it up a little. Don't worry too much about the 1 to 10 mic input impedance 'rule' just follow what sounds best. The N72 set to 300 ohms with the Flea 47 is FAT!
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Post by Guitar on Oct 22, 2016 9:21:40 GMT -6
Wow, nice!
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Post by ariel on Oct 22, 2016 18:33:24 GMT -6
Very cool ! 7th circle should add this mod onto the units. Great stuff !
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Post by rowmat on Oct 22, 2016 18:47:59 GMT -6
Very cool ! 7th circle should add this mod onto the units. Great stuff ! I had been contemplating this mod for sometime and then I saw someone post some pictures on the Seventh Circle Audio forum a while back. I've no doubt Ryan is aware of it.
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Post by EmRR on Oct 23, 2016 3:07:39 GMT -6
The actual EQ curve might frighten you if seen, don't look at it.
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Post by rowmat on Oct 23, 2016 3:47:58 GMT -6
The actual EQ curve might frighten you if seen, don't look at it. I'd call it the 'Bing Crosby' Probably something like the RIAA replay EQ.
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Post by p0llenp0ny on Sept 10, 2020 14:56:24 GMT -6
Would love to know how you performed this modification.
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Post by yewtreemagic on Sept 30, 2021 17:22:03 GMT -6
Would love to know how you performed this modification. I know I'm resurrecting a dead thread, but essentially you simply need to switch in an appropriate value resistor across the primary of the input transformer, such that the combined parallel value with its existing input impedance is the overall value you're after (in this case 300 ohms). If the existing input impedance is 1200 ohms then the parallel resistor would need to be 400 ohms (390 ohms is the nearest preferred value, and close enough). Peterson of DIYRE posted up a handy way to do this via an external box, for fully adjustable input impedance with any preamp here, which should give you the general idea: Hope this helps someone! Martin
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