SE Electronics Z3300a

[Emmathom]

32,80v > R5 > 20,54v

 

[micolas]

61,65v

how much is R13//VR?

 

[Emmathom]

how much is R13//VR?

0,5Ω (installed)

 

[micolas]

32,80v > R5 > 20,54v

put a VR=25....47k in parallel across R5 and adjust to get after R5 21.45v

 

[Emmathom]

put a VR=25....47k in parallel across R5 and adjust to get after R5 21.45v

the VR does not act on the voltage : I turn it CCW and the voltage stays at 20,96v

PS : on the Orig-mod we have 19,38v after R5 !

 

[micolas]

the VR does not act on the voltage : I turn it CCW and the voltage stays at 20,96v

PS : on the Orig-mod we have 19,38v after R5 !

voltage before R5 and after R5?

 

[Emmathom]

voltage before R5 and after R5?

32,43 / 20,96
Orig-mod is 31,42 / 19,38

 

[micolas]

32,43 / 20,96
Orig-mod is 31,42 / 19,38

adjust R5//VR and R13//VR to get voltages as close as possible
in all important points
But has polarized U decreased in Mod mic?

 

[Emmathom]

adjust R5//VR and R13//VR to get voltages as close as possible
in all important points
But has polarized U decreased in Mod mic?

R5//VR > VR seems to be full CCW and so is R13//VR
Polar 61,10v / after R5 21v

edit : RV // R5 reads 4KΩ (so RV must be at 28KΩ)

 

[micolas]

R5//VR > VR seems to be full CCW and so is R13//VR
Polar 61,10v / after R5 21v

You now have 3 adjustment points for:
U polarized capsules
U after R5
R9 for jFET BIAS
From these points you adjust patiently until you balance both microphones.

 

[micolas]

I'm sorry, I have to go to the hospital, I started physiotherapy, medical recovery 2 days ago.
We'll talk in the afternoon
I hope you balance the mics!

 

[Emmathom]

Polar +61,13 / - 61,17
Fet D 16,20
after R5 20,96

 

[micolas]

Polar +61,13 / - 61,17
Fet D 16,20
after R5 20,96

adjust the voltages as close as possible in both microphones.

 

[micolas]

Make a table to compare visually, it's easier than mentally.

 

[Emmathom]

Make a table to compare visually, it's easier than mentally.

I note each value

 

[Emmathom]

Following tests where I realized that I had to increase the R put in series with the one in // I ended up removing all the // and returning to the base values.
(RV100KΩ + 300KΩ) = 400KΩ in // with R13 and I would have to increase the value to lower the polar.
Same for R5 (RV50KΩ+33KΩ) = 83KΩ in // with R5 that was not enough.
Confirm that if I have to level up a full CW R in // with R1 that means that R1 si too small, correct ?
So the deal was not to lower the R but level them up ? because of the 9.1v zener maybe... ?

Measurments with original values :
R5 (4.7KΩ) = 20.50v after R5 (19.38v Orig-mod)
R13 (27KΩ) = 58.40v polar (57v Orig-mod)
Fet D = 15.78v (14.35v Orig-mod)

 

[micolas]

Hi, I'm on a break now.
Let me understand exactly:
with R13 27k stock (no VR), R5 4.7k stock (no VR) and 9.1v Zenner in series with D1 and D2, what voltages do you have, with the Presonus interface?
For both microphones

 

[Emmathom]

Hi, I'm on a break now.
Let me understand exactly:
with R13 27k stock (no VR), R5 4.7k stock (no VR) and 9.1v Zenner in series with D1 and D2, what voltages do you have, with the Presonus interface?
For both microphones

Measurments with original values :
R5 (4.7KΩ) = 20.50v after R5 (19.38v Orig-mod)
R13 (27KΩ) = 58.40v polar (57v Orig-mod)
Fet D = 15.78v (14.35v Orig-mod)

 

[micolas]

Measurments with original values :
R5 (4.7KΩ) = 20.50v after R5 (19.38v Orig-mod)
R13 (27KΩ) = 58.40v polar (57v Orig-mod)
Fet D = 15.78v (14.35v Orig-mod)

With Presonus?

 

[micolas]

what phantom voltage do you have without load in Presonus?