Hi,I'm looking for a schematic for a pair of Classic IIs that have had the custom Jensen trannies replaced with reversed Lundahl 1538 transformers(not sure why?)
It doesn't stop there,one capacitor has been upgraded,a component that looks like it may have been a fet(PCB shows a small half mood shape and three empty holes) has been removed,and one resitor has been lifted at one end.
I didn't pay a ton for these mics cause I knew they had been modded,and waranties were void.I got them from a guy on Kijiji,who had them for a few years after purchasing them from a guy on ebay that does some DIY builds in the Victoria BC area(not sure who it might be).
One of the issues I am having,is the mics sound different from each other,other issues I had were rectified by cleaning cable contacts,and reattaching the lifted resistor(this was causing a pulsing thump in mic 1 when the high pass filter was disengaged,but made mic two sound more open and bright).
Mic one has about a 6dB lower output,but has a more buttery sound that I prefer,Mic two has more midrandge punch,a higher output,but not as pleasing of a sound when tested in cardiod(sounds very similar to My K2).
After having swaped tubes,power supplies,cables,recording samples of my voice testing fronts and backs of the capsules.I've noticed, after cleaning and inspecting the capsules,on mic 1s capsule,the back plates are more easily visible,and more gold is missing from the diaphrams(not flaked off,but worn looking.)Mic 2s capsule looks newer,and in better condition.Could this be the reason for the higher output??
Both capsules are edge terminated,and more or less look to be of the same construction.Should i swap the capsules to see if the output goes up in mic 1?
I taked to Dave a AA Microphones ,and he offered to get the mics to match up as a stereo pair for a very reasonable price,possibly some component and capsule replacement.
The issue here is that I don't really want to put much more money into them,I can't really sell them for what I paid for them($1,400.00 for the pair),because now I am aware of every issue with these mics that I would feel obligated to disclose to the buyer,although some issues have been resolved.
While I do like the sound of the mics,(although they are different,they are still very useable,but some applications are more suited for one over the other)I would still like to resolve the issue at hand,but good luck trying to find a schematic for ANY Rode mics.If some one has a schematic that they would like to share for the Classic,or Classic II,please?just so I can see what has been done.Perhaps a conversion to a U47 like plate following mod has been attempted?
If nothing else,this is a cautionary tale for those fooling around with a perfectly good mic design,and then having to pawn their F.U. off on someone else,and that someone else things they are getting a good deal.