9K PSU transformer question/problem

[muadgil]

Hi to all
I'm finalizing a 9k BOM, and i was wondering if some of you used a fuse for the power. and which value should it be for 4 boards?
Thanks
Gillles

 

[Flatpicker]

[quote author="Svart"]two 15v zeners and some resistors ought to bring the 18v down to 15 for the tl0XX parts..[/quote]
All the TL0XX's I've seen will run on +/-18V max, so this is probably much ado about nothing. However, if you insist on playing it safe, ( :wink: ) I would either do what Svart says or take my super-simple route of just putting one or two 1N400X's in series between the +/-18V pads and the +/-15V pads (observing the correct polarity, of course!). Two diodes in series on each side will drop the voltage approx. +/-1.5V which is plenty safe for the TL0XX.

 

[drpat]

...

 

[muadgil]

Thanks for your answer Patrick :thumb:

To make sure i fully understood, i'll make a quick simulation. Would you tell me about mistakes?

I check all currents drawn by active components on my boards (ICs, diodes, LED...). I find these values on the datasheets (Input current, or Collector current, or supply, or quiescient, depending on datasheets), they are about 6mA for each. Sounds like the good value to you?
I use, for example, 20 ICs on the boards-->120mA
(i count nothing for capas and resistors, right?)

Then, my transfo is 2*18V/30VA, that's 15VA per winding.
-->they can deliver 0,83A per winding, or 1,66A if windings are in serie.

To sum up : i choose a 240mA fast fuse, and my transfo is ok for that application.

Hoping i got that fuse thing in a right way

 

[muadgil]

Hi
My newbie experience requires a little help from the knowing ones.
I made the math for a 9k preamp with : 2 pré boards, 2 PSU, 1 line balancer card, and 2 greenpre VU-meter.

The amount of current drawn i found is 184mA (->370mA fuse)
Does this value sounds like a possible one for a 2 channel Preamp??
I've got absolutely no idea...

Thanks

 

[Esset]

With 1pc 2x18V 50VA power trafo, can I power 8pcs SSL 9K's on 1pc 15V PSU and 1pc 18V PSU? Or do I have to have 2pcs of each PSU?

 

[zitoune]

you need 2 of eatch .... if you make +- 15 whith regulators..
other solution is drop down the -+18 with 2 or 3 diodes in serie...
on each pcb you put 2 diodes in serie between -+18 and -+15 (careful whith polarity) just plug -+18 V on pcb , and just use 2 -+18psu for 8 preamp

 

[king-rb]

hi,

i'm nearly finished with my ssl9k but i don't know if i
can use the 380/1,5A bridges for BR1,2 or should it be the 500/1,5A =?


greetings, ludwig

 

[basscakes]

[quote author="king-rb"]hi,

i'm nearly finished with my ssl9k but i don't know if i
can use the 380/1,5A bridges for BR1,2 or should it be the 500/1,5A =?


greetings, ludwig[/quote]
I think either is fine.

 

[basscakes]

Does this Toroid look like it will power 2 channels of 9k?

Digikey PN#
TE62064-nd

 

[RedNoise]

Hi there...
I tried to build the 9K , but I've some problem with the psu :


I have -19,90 and -19,90 either with the 7918 and the 7915...
May some of you have an idea of the problem??
Did I made a mistake with wiring??
thx.

 

[RedNoise]

other voltages are fine , +18V , +15V , and +44V ....

 

[marshman]

The negative voltages need a load to read correctly. Drop a chip or two in and see if that does not bring it into line.

mm

 

[RedNoise]

ok , thx marshman , I fear to burn some of them...
Also I was surprised to get exactly the same negative voltage behind 15 ans 18v regulators...
So , you think I can plug the préamp cards???
thx.

 

[mitsos]

You don't need to plug the preamp cards in.. Just take a 3k9 resistor from -18V to ground and -15V to ground and read the voltages.. That should do it.

 

[rodabod]

[quote author="mitsos"]You don't need to plug the preamp cards in.. Just take a 3k9 resistor from -18V to ground and -15V to ground and read the voltages.. That should do it.[/quote]

Yes, test it with a load resistor first and measure the voltage.

 

[RedNoise]

thx guys!!I'll try i'll try this solution tommorow!!!
Many , many thx!!

 

[geoff004]

On the PSU board - printed is 'IC2' 3 times.
where do IC1 and IC3 go?
I assume looking at the picture above IC 1 is on the right, then IC2 in the middle and IC3 on the left.
And what about strapping heat-sinks to those guys? Isn't that a necessity? Anyone have any suggestions as how to squeeze them in?

Finally, with the +48 - does that go directly to pins 2 (+) and 3(-) on the XLR input (switched of course)?

 

[RedNoise]

Hi Geoff !
Regarding the heatsink , IIRC Vertiges told me not to have a common heatsink on the regulators (in the gssl , but it's same type here)

Lm317 is the only regulator with resistor around him , if it could help you to locate him....It's just "inline" with the 220µ(the green one on the pic).The 7918 is in the middle , just in front of the "-18V" printing...

Regarding the 48V, it's a good question that I would have asked here in the next days! :green: But on several pics I've seen it seems to be something like that.

Hope I've helped a little!!
Cheers.

 

[MartyMart]

RE: Heatsinks
Nothing required on the 48v side (LM317) as it doesn't even get warm.
The other two can share a heatsink if you use those special insulator kits that
keep the bolt and the heatsink from touching either of the regs.
You can also use a small bit of heat-shrink on the bolt as it passes through to make
double sure that it's insulated.
Check for continuity - or rather lack of it - before a power up !!!

MM.