Bauman PSU

[Greg]

To summarize:

If NOT connected to R1/C1, R10 is needed to drop the 48VDC down to <35VDC at the input of the 7805.

If connected to R1/C1, R10 is not needed because I'm getting right at 35VDC with a 24-0-24 toroid.

 

[louder]

alo
the tranny spec.,say:40va for each sec winding.
is it okay?
best regards
pedro

 

[louder]

alo
well,removed r10,and now i blew all my fuses.
please,merçy.
best regards
pedro

 

[louder]

alo
well,it`s getting worse:now the psu smokes.think it`s r1.
help
best regards
pedro

 

[Bauman]

DO NOT REMOVE R10 IF THE TOROID IS REALLY 80VAC!!!
Can you get a 24+24VAC one? Them you can throw away R10...

I told you Pedro! Get a 24+24VAC toroid instead of this 80VAC one...
the caps are not ready for a voltage that high!!!

cheers!
Fabio

 

[louder]

alo fabio
now i am lost.
w
the tranny it`s 12+12.isn`t va related to curent?
removed r10 to the 48v,and now i only get 36v of phantom power.
at 7805 vin i get 33,6v.
at r1/c1,i get 23v.
best regards
pedro

 

[robomatique]

We are a few people on a swedish DIY group that uses Fabois PCB, and we only get 44V out on the 48V.

Is R8 supposed to be 8K2? I am REALLY bad at these things, but I tried to calculate something acording to the datasheet of the LM317, and for me it seems that 9K1 should be a better value? But... I may be totally wrong... :?

Anybody that could calculate this and see if I am right? Or is it 8K2 it should be?

http://www.national.com/ds/LM/LM317.pdf

Robert

 

[Bauman]

I'm using R8=10k and R7=270R, it will take you near 48V... but 44V work ok as phantohm power so don't worry

:thumb:
Fabio

 

[datape]

I know this is an old thread but I may as well keep it all in one place...

The R10 issue...

I'm connecting the 7805 to the point where R1 should be, but I am using jumpers instead of resistors. Will this cause a problem to the regulator?

If I follow the JLM schematic there are no resistors at this point.

Are the resistors R1/R2 really necessary?

Using a -/+ 30V 160VA Transformer.

Also does the output of the 7805 need the LED and resistor across the output to act as a load or can I do away with this?

Schematic is here

http://www.braudio.com/product_files/CANPSU312_schem.pdf

Thanks

 

[JLM Audio]

You will still need a resistor to the 7805 input to lower the voltage to less than 35vdc. As using a 2 x 30vac is going to give you about 43vdc unreg at that point.

There are no 7805 on any of the JLM power supplies that would need them.

:shock: 160VA transformer is way over the top of a mic pre or two.

 

[datape]

Thanks Joe..

I know there are no 7805 on your PSU, but its just that at the point where R1 and R2 are on Fabios PSU there are is no resistors on the JLM. I know you said in a previous post they would improve smoothing, but I guess they are not necessary for normal operation.

I was wondering if I simply needed a reistor on the input of the 7805. I think you have answered that.....but.... I dont see how I will get 43vdc into the 7805 from the point where R1 is? R1 is on the positive rail. Wouldnt this just be a regulated +30VDC. (probably a slightly lower VDC with the voltage drop from the recifier?)

I guess theres no harm in firing it up and testing the volatge though so I'll try that out.

The 160VA should work though shouldnt?. It's overkill, but I'll be reusing if for a larger current supply later on.


Thanks!!

 

[bigwillz24]

I've read this thread twice and it might as well be in another language.

I keep burning up the resister at r4 when I try to adjust the trim pot. I took a voltage reading at the rail at the G and - and and keep getting somewhere around 30 -35 volt before adjusting the screw.

I give the adjustment screw about 10 turns and end up at about 29 volts with a fried resistor on R4 the other voltages seem correct. +15VDC , +44VDC +5 VDC.

I've tried replacing the resistor and the trim pot twice now any help appreciated.

Thanks

 

[AnalogPackrat]

Are you sure you've got D7 in the correct orientation? And D8, too, for that matter.

 

[bigwillz24]

Yes they are in the right direction. I just replaced the voltage regulator too. Still no dice. I'm running out of resistors.

 

[bigwillz24]

Okay Replaced diodes D3, D4, D7, D8, R4, REG- and ADJ_NEG and I'm still ending up with about 30 VDC before I even attempt to adjust the screw. I'm scared to adjust the srew now because I afraid I might burn up r4 again. That's everything in the signal path except for the capacitors i think according to the schematic.

This may be a stupid question but to check the VDC you check from ground to + or - right?

Please Help.

Will

 

[Arrigotti]

So I finally got my Bauman PSU up and running. It didn't explode....good so far. The postitive voltage was right around +15, and the Negative was right around -15. I chose to use 24V relays, so I used an LM7824, and I have aound +24V there. The shocker was the Phantom Power voltage. I have +77V there. I'm not sure what to make of it. Maybe my regulator isn't soldered correctly, or maybe it is just wrong altogether. I have an LM317 in that spot.

Any thoughts?

Thanks.

 

[Arrigotti]

Okay, I answered my own question: D13 was in backwards. I have +44.8V on the Phantom now, so I think I am good. All the other voltages are close or spot on as well.

I may just use this board to power the PM1000 I have waiting to be racked up. They need +44v, and if this voltage works for Phantom then I don't need to change anything.

 

[crisotop]

Is there anything else i need to pay attention when choosing which relay voltage to use? I'm not sure if I should use 5 or 24V?

Many thanks in advance
Christoph

 

[Greg]

Lower voltage relays typically draw more current. I used 5V relays to power a pair of Fabio's 312 boards (8 relays total I think), and when all are on the regulator gets extremely hot. If I were to do it again I'd use 12V or 24V relays.

 

[Jonkan]

I powered 10 or 12 of those 5v relays with my bauman psu, and things got extremely hot. It even killed the regulator once. Its working now that i have a bigger heatsink, but i wouldnt recommend it. Go for the 24v relays!

/J