All things Green Pre

[simoncastic]

First time poster and long time reader!

Enchilada - I'm looking at the Green Pre for my first DIY project (other than a few guitar pedals years ago), and I'm having trouble finding a consise list or kit for the green pre! I'd be keen to purchase some PCB's if you got some professionally manufactured, and I'm also in Australia (Melbourne).
How much would an 8 channel green pre cost, all inclusive? I've been searching for days but I can't really get any up-to-date info.

Cheers!

 

[swal]

I have put together two v14 Green pres. When I hook up the green pres the same thing happens on both boards. The two 10r resistors between the last 5532 and TL074, just under the jumpers get hot and burn up. Is this an issue with my 10 uf caps grounding out? Since this is happening on both boards I thought it was my psu. My psu is working great, Voltage 15.1 -15.2 -47.8, when the green pres are not hooked up. But when I hook up the green pres the voltages drop to almost half. I assume I've got something grounding out??
Thanks for the help.

 

[swal]

Simoncastic, all the info you need, including BOM and pcb pics are here (by the way its on the first page of the Meta): http://mhumhirecords.org/DIYpages/Green/Voltages.htm
Cost for me in Canada will come up to $100 per channel.
Best way to find a pre-made PCB is to post on the Black Market, thats how I got mine. Posting here wont help much, seems everyone is avoiding this thread like the plague.

 

[swal]

Wow, I'm an idiot, the ic's in the meter section were upside down, I didn't notice they were the opposite orientation from the 5532. Thats what I get for putting on the IC sockets first thing and not double checking the orientation, all it cost me were a couple 10r resistors. Both channels are working perfectly!! Thanks Peter for all your hard work on these pres over the years!!

 

[sunyata]

Peter!
I haven't received that PCB yet. Any news?

/Lars

 

[jwrightzz1234]

Hey pete, i am sure you may be sick of people asking, just wondering if you had any pcbs for sale for this project? Or anyone else for that matter.

 

[juanjovincenzo]

Hi jwrightzz1234 I self etched the PCB rev 14 of a file that I edited two years ago, but  I only put some components and never finish to populate this project. I have my pdf file.  if you dont get a PCB maybe you want etch the pcb.

 

[Luax]

Hi Guys,

I'm trying to prepare my green pre for the rack.( a project that has been lying around unfinished in my room for a shamefully long time)
But by trimming the 20k pot for the DC offset, there is no way that I get it down to -3mV It stays on around 10mV no matter what way I turn.
It also jumps around a lot. If any of you have some advice on how to tackle this. I'd be glad to hear it.

 

[peterc]

Luax

If there is no change on the trimmer, sounds like it could be faulty.

Unsolder and check the resistance with a multimeter

Peter

 

[Luax]

Hi Peter,

Thanks for your reply. I think the 20K trimpot is not faulty as the led meter is reacting to it. (although it's not the led trimpot)
When I turn all the way to the right the first and second led start to glow. Is this normal?
Also I get a lot of different and very inconsistent readings from the multimeter depending on were i put the ground.
Any suggestions are welcome.

 

[peterc]

When I turn all the way to the right the first and second led start to glow. Is this normal?

Yes, thats correct.

Anywhere on the ground track should be fine. Make sure the contact is good and the batteries in your meter are good....

Peter

 

[Luax]

Thanks Peter, (and fellow board members whom's posts I frequently read)
I was constantly measuring my -probe on the chassis. Finding another ground spot on the board immediately had positive results.
After some testing I finally racked it up! After years of head-scratching I'm finally to owner of a working and tuned Green Pre.  ;D

 

[jwrightzz1234]

I am lucky enough to have access to a PCB board printer! i was wondering if anyone had a Gerber file for the v14. I feel like i found one months ago, but after scouring the site i can't seem to locate it. Thanks!

EDIT: after doing some research on gerber files on this site, i didnt realize that it might be taboo to ask for them. I am just an EE student going for an associates degree. I guess i should just build the layout myself!

 

[PeteC]

Hi,

I have 2 green pre's which I use all the time in my project studio. They are really great preamps.

They are the early version without the LED bargraph displays.  V1 i think
same as on this link ...
http://www.intensemetal.com/~aortizjr/projects/ADA8000/green.htm

I'd like to add a 4 LED meter (or more LED'S if poss ) to these original green pre's but can find much documentation to help me.
Is there a board or something I can make up with the LED display to wore up to the V1 green pre's ?

Rgds
Pete

 

[joaquins]

Maybe out there somewhere but I can't find any data on ferrite bread used here... someone could help me?
Which core should I use? how much turns? how much inductance spected? can I use any choke inductor or it must be ferrite one?

Thanks...

JS

 

[peterc]

Joaquin

I used any small ferrite here. Also left them out with no change, but I suspect this would be different in a place with lots of interference.

Peter

 

[PeteC]

Hi again
ref my post 853 above ....

I found Keef's universal bargraph driver which I will build up on 2 boards fro VU metering

BUT - has anyone fitted a 4 LED meter to GreenPre V1 etc and if so is there a layout anywhere ?

- I'd like to try this out first if I can find a layout which works.

Cheers
PeteC ( coincidentally ! )

 

[sunyata]

Hi,
I just realized I get a digital noise/hum from the Green Pre into my Fireface 400. It disappear when I isolates the pre's 230V ground from the rest of my studio. I have come across similar problems with my guitarpedals (mixing digital and analog).
Is there something I can do? I built a ground lift for the mic inputs which doesn't help.

Best regards

/Lars

Btw, I recently recorded a Swedish/Macedonian/Brazilian jazz project with the GreenPre. The soundquality of the pre is really awesome. I will post some clips soon

 

[spase]

Hi,
I just realized I get a digital noise/hum from the Green Pre into my Fireface 400. It disappear when I isolates the pre's 230V ground from the rest of my studio. I have come across similar problems with my guitarpedals (mixing digital and analog).
Is there something I can do? I built a ground lift for the mic inputs which doesn't help.

Best regards

/Lars

Btw, I recently recorded a Swedish/Macedonian/Brazilian jazz project with the GreenPre. The sound is really awesome. I will post some clips soon

Macedonian ?? Want to hear that track ))

 

[peterc]

Lars

Sounds like it might be an earth loop.

Keep the mains earth connected and do not connect the signal earth between the pre and sound card.

Also, try isolating the pre signal earth from the mains earth with a 10R resistor.

Peter