All things Green Pre

[clintrubber]

[quote author="Freq Band"]
Analog Devices-nada
National Semi-nada
ST Microelectronics-BC550 ="BC547B" only....no result for BC560
[/quote]
"Straf moet zijn" we say here in the Netherlands :twisted:
I mean, what's your excuse for looking at IC-manufacturers and some non-descript Eu-company ?

You should have looked here: :wink:

http://www.semiconductors.philips.com/cgi-bin/pldb/pip/BC550C.html

http://www.semiconductors.philips.com/acrobat/datasheets/BC549_550_4.pdf

BC550/560-types shouldn't be hard to locate - at least not here in Europe.
Note that the BC560 for the LED-bar is not critical, just use an ordinary PNP.

Bye,

Peter

 

[Freq Band]

Thanks clintrubber,
but I still cannot find it in Digikey...not listed under PHillips npn/pnp transistors....not showing up in a digikey search BC550, BC550n, BC550c...etc.

I guess if no one knows another company's cross #,

- I'll have to search each Digikey transistor vendor's website.....
- find their version...
-check datasheets/voltages....
-go back to Digikey and see if they carry it.
Pain in the ***.

=FB=

 

[dissonantstring]

hi freq band,
not sure where you are, but mouser has them:
512-BC550
512-BC560

clintrubber wrote:

Note that the BC560 for the LED-bar is not critical, just use an ordinary PNP.

i noticed on Frank's layout that the BC550 were "C" versions. is this necessary? the fairchild BC550 listed at mouser has an Vceo=45V and max hFE=800 which seems in-line with the philips data sheet. sorry for this newbie question.
thanks.
-grant
edit: hFE not mA as clintrubber said. sorry.

 

[enthalpystudios]

Hey guys, hooking up the transformer and power supply atm.... i'm looking around at some of the pictures, but basically....

I have my 120 and my 0 going to a power switch, and then to the transformer... which has 125/0 and 0/125....

This just gets one side hooked up, correct? And then, where does the ground from the power inlet go?

Then I've got the secondary side of the trannie. I've got 15/0 and 15/0.

I'll guess, and maybe somebody can help correct me if I'm wrong....

My guess is that I connect both 0's to the hole on the PSU that is labeled "G," and then a 15v connection to each of the other two 'ins' on the PSU.

Is this the way to do things?

Also, when I'm checking voltages, should I ground my DMM to the power ground, i.e. the third prong on the back of my power inlet?

Sorry about all the funny questions, I just don't wanna smoke anything. Or myself. Or have grounding issues. Still trying to wrap my head around the audio ground and the safety ground... different thread/question though.

Thanks ahead of time,

BIlly

 

[enthalpystudios]

bump








totally shameless

 

[dissonantstring]

hi billy,
take one side of the primary and connect to the neutral of the power inlet.
take the live side of the inlet and connect to one side of the fuse.
take the other side of the fuse and connect to power switch.
take other side of power switch and connect to the other primary wire of the transformer.

you've got the idea for the secondaries (tie 0Vs and connect to 0v on supply board, the two 15V wires go to the 15V pads on the supply board input).

ground your power inlet to the chassis along with the input XLR pin 1 of each channel. i think peter c. mentions that he also connects pin 1 of each output XLR to the star ground as well.

you can check voltages by placing one probe of your DMM (DCV) to the 0V and the other probe to one of the 15V pads on the PS board output. check polarity +/- on 15Vs.

does anybody know how much to fuse for 2 channels (315mA maybe)?

hope this helps.
regards,
grant

 

[clintrubber]

[quote author="Freq Band"]Thanks clintrubber,
but I still cannot find it in Digikey...not listed under PHillips npn/pnp transistors....not showing up in a digikey search BC550, BC550n, BC550c...etc.

I guess if no one knows another company's cross #,

- I'll have to search each Digikey transistor vendor's website.....
- find their version...
-check datasheets/voltages....
-go back to Digikey and see if they carry it.
Pain in the ***.

=FB=[/quote]

Hi,

Please check your Private Mail, I've mailed you yesterday about those BC550-types.


Bye,

Peter

 

[clintrubber]

[quote author="dissonantstring"]hi freq band,
not sure where you are, but mouser has them:
512-BC550
512-BC560

clintrubber wrote:

Note that the BC560 for the LED-bar is not critical, just use an ordinary PNP.

i noticed on Frank's layout that the BC550 were "C" versions. is this necessary? the fairchild BC550 listed at mouser has an Vceo=45V and max hFE=800mA which seems in-line with the philips data sheet. sorry for this newbie question.
thanks.
-grant[/quote]

BC550C indeed preferred as I was told also a while ago.

BTW, note hFE is dimensionless, not mA.

Bye,

Peter

 

[Kev]

[quote author="enthalpystudios"]bump[/quote]
:roll:
did you get an answer to your questions ??

 

[CJ]

Peter, you have someone close I can mail transistors to?
Need an new address.
package waiting.
if no need, i use somewhere.
cj

 

[enthalpystudios]

didn't mean to be pushy!

just was so amped about getting a psu board stuffed and a channel board stuffed..... first diy, that kind of thing....

but yes kev, I did get the answer answered....... thanks grant! Thats how I have everything, was just hesitant to get going... triple checking i noticed that I had the lm337 in backwards as well, so I wanted to be sure about everything first.

only thing is that I have dual primaries..... 115/0 on each. I'm guessing I'll just use one of them, and take the hot to 115, and the neutral to 0, right?

The grounding is all making sense now. Building these is totally helping me get around how I'm going to wire up these patchbays I have as well.

Got a lot of pots on the burner i guess, but I've recently lucked out with some time to work on projects of different nature...... diy, patchbay, some remodeling, a desk... built a foam core model today, felt like I was in art class again.

Thanks so much for help you guys, I really appreciate it all......

Oh, and good question grant, regarding the fuse.... I'm going to be running 4 channels off this one, but right now I'm going to just test 1..... I assume a 120v fuse, not sure of the current rating.

My power inlets say use a 250v fuse, but perhaps they're not actually for US? Or do they actually take 120v?


anyway... back to looking for sweet looking knobs (for cheap ;] )

thanks again

billy

 

[Kev]

[quote author="enthalpystudios"] didn't mean to be pushy![/quote]not pushy
I was just just checking that you didn't get forgotten

The grounding is all making sense now. Building these is totally helping me get around how I'm going to wire up these patchbays I have as well.

now that's what I like to hear
knowledge is the underlying benefit of DIY

... only thing is that I have dual primaries..... 115/0 on each. I'm guessing I'll just use one of them, and take the hot to 115, and the neutral to 0, right?
I assume a 120v fuse, not sure of the current rating.

IF you have 110 to 120 volts at the wall then parallel them together.
please tell me I'm right there
use the 120 volt fuse such that it will blow before the current rating of the trafo is exceeded.

IF you are 240volts like here in Melbourne then series is for you.

 

[enthalpystudios]

Sweet.... thanks so much kev, and everyone!


billy

 

[dissonantstring]

billy,
for future reference i found this page to be great (big thanks to mark burnley for the page and mnats for the link):
http://mysite.wanadoo-members.co.uk/deltaharmonic/Technical/Transformer_Connect.gif
-grant

 

[enthalpystudios]

Ok... so I have two 2x15 power trannies here. The one I was going to use is a transera encapsulated toroid like the one in peter's photo's of his dual green. When ordering, I figured I'd go for the same one, as not to mess things up...... It's 30va, 15v@2amp, 30v@1amp. Only thing is, as I started trying to connect things, I realized that this thing was just going to be a big pain to try and mount on perf board (I finally realized peter made up a pcb for his.)

Anyway, I also have a 2x15 that I bought for a future ssl project, it's 15va however, 15v@1a and 30v@500ma........ can I just use this guy? Will it have the mmmph? And how many channels could I power with it?

Thanks,

Billy

 

[peterc]

15v@1a and 30v@500ma........ can I just use this guy? Will it have the mmmph? And how many channels could I power with it?

Should do 2 channels easily, probably 4 as well but it will be borderline.

Peter

 

[enthalpystudios]

cool, thanks peter... I'll just use it for all my testing, and once all 4 channels are ready, and everything's a-ok, I can get in there nicely with a pcb for the 30va trannie when I rack it all up.

Thanks peter!

billy

 

[squib]

Just finished some Green Pre's.
These boards were purchased and loaded up with parts by Cactus who then sent them to me for installing in a rack case. I decided to try and lever the four channels into a one unit case...this was no mean feat. The clearance between adjacent modules and gain switches was only a mm or so and much time was spend double checking the layout before committing the front panel to the drill press.
The front panel is black anodised aluminium laser etched for the labelling.
I changed the design slightly: the gain control DC blocking cap was increased to 10,000uF, bypassed with a 0.1uF polypropylene. The audio path electros were changed to 100uF Bipolars and the output caps increased to 330uF Bipolars. The pcb around the level pot was cut and resistors added to make the pot work as a +/- 10dB trim control.
Blue leds were added to the phantom power switches to indicate when phantom is on.

The PSU is in an exernal case with the voltages set for +/- 18V and +48V, this runs the ICs at their safe maximum voltage rails and thus gives maximum headroom within the unit.

photos and info are here http://www.proharmonic.com/recent.htm

rock on

 

[clintrubber]

[quote author="CJ"]Peter, you have someone close I can mail transistors to?
Need an new address.
package waiting.
if no need, i use somewhere.
cj[/quote]

Oops CJ, I just caught your note. Sorry for not following this up more properly - I'll PM you right away.

Thanks,
Peter

 

[louder]

alo
good news:
all 4 greens work,first try.
all voltages on the spot.
now i need to calibrat the greens.
one question i have:
the output pot,when ccw should stop the sound,but it doesn`t.there`s some sound and a litlle distorted.when fully cw,there`s more sound,and not distorted.
the 12 pos switch work okay.
best regards
pedro