G7 PSU +160V ?

hi !!

i have finish my g7 psu !! :grin:

i have a perfect 6,3v with my pot

but the 160v DC slowly oscillate in an hour
between 156, 160, 158, 164, 162 etc... :?

it's normal to not have a fixed voltage ?

PS : i don't have plug anything to the psu
just the psu alone

thank u

It's an unregulated PSU so yes, fluctuations (sp?) is to be expected. Your AC line voltage is probably also jumpy.. If it's not (more) stable during load something is wrong.

thanks :grin:

so i just have to finish my mic !! :twisted:

Hi
I finished G7 PSU. Now I have 163VDC unload with 10K resistor in RC circuit.
With 5K (two 10K in paralel) I saw 168VDC.
I used transformers like in part list 220V/9V and 220/15V.
Does anyone know what DC unload voltage I must have to got 160VDC onload?.
I am not still finished mike.
Duka

hi!!

i don't understand why there is a so big difference
between load et unload voltage :?

if Jakob say 10k resistor, Jakob know !!! :grin:

but here

http://www.omnipressor.com/Other/G7mics/Comments.html

the difference between load and unload was 40v !!!
184v -> 144v with a lower resistor of 5k

:?

What makes the difference between load and unloaded is with no load no current travels in your circuit. Loaded, the mike draws current so you have voltage drops in your circuit.

so...

and what are your voltage in your copper g7

[quote author="Jazzy_Pidjay"]hi!!

i don't understand why there is a so big difference
between load et unload voltage :?

if Jakob say 10k resistor, Jakob know !!! :grin:

but here

http://www.omnipressor.com/Other/G7mics/Comments.html

the difference between load and unload was 40v !!!
184v -> 144v with a lower resistor of 5k

:?[/quote]

OK
But I used right parts. I can decrease a 220V/15V to 12V and because this transformer work in wrong way I will got higher AC voltage.
Is it mean that I must have about 200V unload?
Duka

[quote author="thomasholley"]What makes the difference between load and unloaded is with no load no current travels in your circuit. Loaded, the mike draws current so you have voltage drops in your circuit.[/quote]

Hi Thomas
How much voltage drop I can expect. Curent is no higher than 1mA.
Thanks
Duka

Lowering the voltage also has the effect of lowering the current a bit as well. In my circuit I start with about 200V out of the choke. This is so high because the transformer has poor regulation. I lowered this recently to about 170V with an 18k resistor. My current draw is about 1.7mA. These are power supply valuse going to the mike.

[quote author="thomasholley"]Lowering the voltage also has the effect of lowering the current a bit as well. In my circuit I start with about 200V out of the choke. This is so high because the transformer has poor regulation. I lowered this recently to about 170V with an 18k resistor. My current draw is about 1.7mA. These are power supply valuse going to the mike.[/quote]

Hin Thomas
Is it mean about 10V higher than when mike is connected?

If I recall correctly Duka, these are the values I get with the mike connected. I will get over to my friend's studio and remeasure things this week and let you know.

thanks thomas :wink:

OK, B+ unloaded is 213VDC, loaded is 169VDC. Any other measurements?

[quote author="thomasholley"]OK, B+ unloaded is 213VDC, loaded is 169VDC. Any other measurements?[/quote]

It is for first OK. I have know unload 163V and I must increase voltage.
I will need 160V how Jakob recomended.
Thanks
Duka

A lot of the jump in voltage for my power supply is due to my Hammond transformer. If you are using a better one you will have less of a jump.

The mic works fine a bit below 160V. Mine run at about 145V with the mics connected & sound very good.

aaahhh that's a good news :grin:

so, a 160v average voltage unload is good

and it sound good !!

thanks

Hi!
Short question:
When monitoring the B+ voltage under load, it fluctuates around 160 volts.
Sometimes higher than that. Would it be OK to use zener diodes to clamp the voltage at 160 volts so that it ca't get any higher or is there something to be aware of?

Thanks,
Stefan