Blue Bottle Power supply

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RuudNL

Well-known member
Joined
Apr 26, 2009
Messages
3,106
Location
Haule / The Netherlands
Does anyone have a schematic of the power supply for a Blue Bottle microphone?
The one I have here only supplies 2 volts of anode voltage...
I do however have about +245 volts right after the bridge rectifier. (So: probably a trasistor or a problem in the regulator circuit.)
Heater voltage starts at about 1 volt and increases very slowly to 5.5 volts.

(The designer must have thought: why do it the simple way if you can do it a more complicated way too!)
 
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I found that there are four(!) bridge rectifiers... Two with 'fat' diodes, two with small signal diodes.
One 'small' bridge rectifier goes to a 78L05/79L05 stabilizer pair, connected to a 5534.
The 78L05 gives 5 Volts, the 79L05 has an output of 0.5 Volts. Not good!
Is it the 5534 drawing too much current from this voltage, is it a capacitor or is the 79L05 'dead'?
It looks like the +5 V. is going to a 330K resistor with a tantalum capacitor at the other side.
Is this maybe a timer circuit, that should give the 'GO!' signal for the +HT?
 
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It is a shunt regulator on the B+. Should adjust 120-160v? Some versions did have a timer on the xlr3 as well.
Oddly, the heater is not capable of much current, unless there's a resistor to change....
 
Does anyone have a schematic of the power supply for a Blue Bottle microphone?
The one I have here only supplies 2 volts of anode voltage...
I do however have about +245 volts right after the bridge rectifier. (So: probably a trasistor or a problem in the regulator circuit.)
Heater voltage starts at about 1 volt and increases very slowly to 5.5 volts.

(The designer must have thought: why do it the simple way if you can do it a more complicated way too!)

This may help

Duke
 

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  • DA_POWERSTREAM-SCHEMATICS.pdf
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Many thanks! Interesting information.
As far as I can see the power supply that I repaired at the time was different.
That one had a 78L12 and a 79L12 regulator, that I don't see in this schematic.
What I find very annoying in the 'Blue' power supplies is that it takes "ages" before the relay clicks and the tube is powered. But maybe that's just me... :)
 

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