T.Bone SCT800 modifications - C12 and other type circuits.

[ln76d]

Desafortunadamente 

Su PCB es diferente, sin estos valores y las indicaciones.

Everything should be clear now 

 

[ViciusbeatZ]

ooooo
jajajaja
entonces la dejo como esta?

 

[ln76d]

Medir voltajes en R1, R2, R3 (measure voltages ) y escriba aquí.

 

[ViciusbeatZ]

R1--34,8v
R2--33,9v
R3--34,1v

 

[ln76d]

No

Not literally on resistors.

PSU with connectors on the front as on the pictures.
You need to measure one leg of resistor  (from the right) referred to ground.
One probe to the right resistor leg, second to the ground - can be XLR metal housing.
You should measure something like 150-170V at the first resistor.

 

[ViciusbeatZ]

aaaaa  jajajaj ok


R1---270
R2---236
R3---200

;D ;D

 

[ln76d]

Whaaaat?

Measure voltage on the left leg of 47k (first resistor).
Did you changed zener diodes?

Ok, i forgot that these are 300V not 200V.
Sorry, my mistake.
Change also  R2 and R3 for 47K (1-3W) and measure again.

 

[ViciusbeatZ]

jajajaja okkk

me estoy volviendo loco

 

[ln76d]

Really? With two diodes and three resistors?

 

[ViciusbeatZ]

I dont change de diodes!

I change de R2 and R3, and the results:

R1 280v
R2 240v
R3 200v

 

[ln76d]

Change diodes, these are most important.

 

[ViciusbeatZ]

I change the diodes and the results:

R1-- 260v
R2-- 180v
R3-- 120v

:-\

 

[ln76d]

So why you are sad?

You need 120V - now is ok!

Check are the resistors and diodes are not hot (don't touch metal leads).

 

[ViciusbeatZ]

ok!
Finally the diodes is changed.

And the R2 and R3 is changed for 47k.

The R1 no change? is correct 30k?

 

[ln76d]

Change also R1.

 

[ViciusbeatZ]

oak thanks in76d!!!!! 

 

[ViciusbeatZ]

ok with the 3 resistorsand the 2 diodes  changes the results is 240v 180v 120v .

The next week I change the circuit, capsule and transform and comment the results!!

Thank your

 

[ln76d]

Ok! Waiting then for results

 

[ELM]

I have a pair of sct-800 that i plan to rebuild. For me the only important thing is how it will sound. I'm pretty sure I will put  thierch m7s in mine, I've had it with bright mics...But Im not sure what to do with the cicuit yet more than the voltge lowering mod in the psu. I'm very curious about how your "maliq" mod afected the sound! Have you tested before/after?
Another thing I wonder about is the stock transformer. I read at Brian Fox site that the aurucle a5500 transformer also is doing some filtering and needs to be replaced if you look for a flat response. The sct800 seems to be identical but do they share the same x-former?
Is the stock 1:10 btw?

Brian Fox:
http://www.foxaudioresearch.ca/47gold.htm

 

[ln76d]

I didn't make Maliq mod so i can't say how it exactly sounds, i can only suppose, judging on my previous builds.
For overall microphone sound is responsible not only circuit but (the most) capsule type and in many cases headbasket (this is most noticable with bright capsules)
Anyway it's a safe mod, there's nothing inside which could make sound worse. There are some points to make minor improvements.
You will definately notice huge (positive) difference due to different input topology than in original circuit.
Original transformers are flat. Didn't read Brian Fox articles about it but i measured these trannies.