Nice ! Should I do the same mods DIY on my SC1100 ? increase polarization voltage of the capsule ? (I must mesure wich tension is there on the cardio pattern mode)SE microphones have been discussed here:
3300, 2300, 2200, X1, X1s
Here I added a DC/DC converter to an old SE2200
I increased the polarizing voltage of the capsule stock from 36v to 65v
It increased the output signal and dramatically decreased the microphone noise.(from 18..20dB to <13dB, compared with B1). I also got a nice magnetic saturation of the transformer, earlier, more harmonics, nice flavor.
I increased the capacitor in the de-emphasis circuit and from a too bright, sibilant sound, I got something in the vintage U87 style, warm, mellow and sweet.(maybe U67?)
DC/DC I made it p2p in my style on metal, without classic PCB. It also helps with electromagnetic shielding, reduces radio frequency interference (oscillator operating at 1.7...2.1 MHz depending on the components)
Sometimes I completely enclose the oscillator in a metal shield (see Z3300a DC/DC picture).
Of course I modified the supply of the audio circuit to compensate for the consumption of the Oscillator, from Phantom.
SE Electronics Z3300a
- Thread starter TornadoTed
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Help Support GroupDIY Audio Forum:
The SC-1100 already has a DC/DC converter and a polarizing voltage of the capsule close to 60v.You have to measure the Oscillator output voltage not on the capsule because of the high impedance, common multimeters have low internal resistance.
It can be increased, but it depends on the capsule and the effect on the sound, and the capsule can collapse faster and reduce the headroom.
The SC-1100 has no Treble de-emphasis circuit, although it is very bright and lacks a bit of bass.
We could add the NB circuit if you want to keep the stock capsule.
That would mean reverse-engineering the schematic, it would take me some time.
I draw your attention that the headbasket is not so good for this K67 type capsule, if you follow the character of U87.
I would rather leave the stock circuit and put an Arienne K47 flat, I guarantee it will sound excellent.
That old 2200 has a U87A-like circuit? The 2200A definitely doesn't.
Old SE2200 has similar circuit to ADK51s, Hansen, EG5014, MXLV67 etc.
jFET+BJT+Transformer
(1.87...2) : 1 ratio
It has a de-emphasis circuit (c*=220pF stock)
Without DC/DC converter
Attachments
great news ! I will soon replace the capsule and let you know guys...Thanks +++ for your help & advices
It is a wise decision.
Also inspect the interior of the one you bought now, which I understand you want to keep stock for comparison. See if it is identical to the other one.
For the microphones you modify, make recordings, comparisons, with each modification, one by one.
Don't make two changes at once, you won't know exactly what made the difference.
Make voice tests (it's a complex, relevant source, of maximum interest, spoken, sung) and steel-string acoustic guitar, different playing styles, it can give a lot of information.
If you have the opportunity, do comparative tests with pink noise and null tests.
Yes I will modift only one in the first time, for sure
I'll have a look inside to check the componants (the fets) > I bought a second one "first generation"
Unfortunately I've had a problem with my vocal cords so my voice is not the right one for vocal tests (but I'll speak anyway) but I have a folk guitar (steel strings) I can record
For tests, what I usualy do : I've edited a sound file with shorts passages (30-45sec) of : pink noise > jazz drumer playing alone > cello solo > fusion jazz "modern mix" > female singing (Spanich Harlem recorded by D. Chesky). I play this 4mn file on my system (JVC SX911 tweaked + Mosfet ampli) and record it for comparaison between my diff. mics. It's not perfect but as soon as it's always the same file recorded at the same distance with the same level...
I'm sorry to hear you're having trouble with your voice. I also had problems, after Covid I couldn't speak at all for a while and I was hoarse, with a distorted voice.
I wish you a quick recovery.
If you use this method, you must keep the same test conditions, distance, positioning, sound volume, etc. And in addition to audio samples, do tests with pink noise, it contains more spectral information, and you can compare (for example in Curve Eq Voxengo) including visually.
How could I add a de-emphasis circuit to keep the original caps ? does it worth the case ?
I have 2 of them : one is ok and the other worked for a couple of hours and then nothing...
I mesured voltage at the entry of polarisation board (a schematic of z3300 would be great !!!) and the good one has 28v on the first R of the circuit when the "off one" has only 1v... I see a transistor (bjt ?) C1008 • Y-705 and another one labelled K105
I mesured voltage at the entry of polarisation board (a schematic of z3300 would be great !!!) and the good one has 28v on the first R of the circuit when the "off one" has only 1v... I see a transistor (bjt ?) C1008 • Y-705 and another one labelled K105
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You need to look for the schematic of z3300 or sc-1100.
But, due to the way the patterns are switched, the de-emphasis circuit from the U87ai cannot be used.
Without an exact scheme it is difficult to do the treble attenuation at the circuit input.
You can attenuate the highs between the jFET and the BJT, but it can increase the distortion and shift the phase a bit.
I understand that you purchased 2 Arienne K47 Flat capsules.
The headbasket shape of the 3300/1100 is better suited to the K47 than the K67
Do some experiments.
Have you already tried the Arienne K47 flat capsule in the stock microphone that works well?
Did you measure the voltages at the important points in the defective microphone, compared to the good one?
That's what I measured yesterday...
I can't measure much more because of the very high impedance of the polarisation circuit... but I should have more-or-less 28v to feed the ploar board (and I got 1v !!)
First you need to measure the phantom voltage without load, with the microphone disconnected. Then in the good microphone you have to measure the polarization voltage on the voltage multiplier diodes in the DC/DC converter.
Then you deal with the faulty microphone.
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Voltage of Phantom with the mic disconnected of 44v is too low for proper mic operation. The normal value is 48v, sometimes it reaches 52v without load.
