All things Green Pre

[kato]

[quote author="sunyata"]

Here is a short sound-clip recorded with two mics in stereo:

http://goto.glocalnet.net/lars_wallgren/mp3/green%20inspiration%20clip.mp3
[/quote]

It sounds great!!
I love the scrap box. To me, that is what mic preamps should look like!

 

[sunyata]

[quote author="kato"][quote author="sunyata"]

Here is a short sound-clip recorded with two mics in stereo:

http://goto.glocalnet.net/lars_wallgren/mp3/green%20inspiration%20clip.mp3
[/quote]

It sounds great!!
I love the scrap box. To me, that is what mic preamps should look like![/quote]

Hahaha! Thanks for your support! I have one more box like that. I'm thinking of building a 1176 with it.

/Sunyata

 

[kato]

[quote author="sunyata"]

Hahaha! Thanks for your support! I have one more box like that. I'm thinking of building a 1176 with it.

/Sunyata[/quote]

That would be so cool.
It gives your studio a mad scientist vibe.

 

[sunyata]

[quote author="kato"][quote author="sunyata"]

Hahaha! Thanks for your support! I have one more box like that. I'm thinking of building a 1176 with it.

/Sunyata[/quote]

That would be so cool.
It gives your studio a mad scientist vibe.[/quote]

Yeah, maybe something like "Frankenstein Studios - creating life from left-over parts" - haha

 

[tonebucket]

Peter

What type of resistor is the 3 pin 20k component????

 

[peterc]

The 20k is a 10 or 20 turn trimmer. It has a square body & all the pins are in a straight line. Some of the sqaure trimmers have the pins offset.

The reason I used this part is because of the fine adjustment & the length of time they stay within calibration.

Peter

 

[grebdnul]

I finally got my dual green pre running but ran into a small PSU problem. After 10min it said "fjoff" and started smoking. One of the capacitors in the PSU, C10 i think, was all black. So i changed it for another one, same model. Worked fine for another 35 minutes then the same thing happened.

What shall I do? The capacitor I used is this (ceramic 35 volt):
http://se.farnell.com/jsp/search/productdetail.jsp?SKU=9708480

replace it with a higher voltage rated one?
can I replace it with a polyester wima 50v that i have extra? do I have to change the others then to or does it matter if they are different types? Voltages are perfect, apart from this. 15.2 volt and 48 on the phantom.

/Philip

 

[Ptownkid]

that's a tantalum cap, which means it's polarized, and you're most likely putting it in backwards

 

[grebdnul]

Aaa.. Jesus.. i didn't realize.. I thought it looked like a ceramic.. well.. that solves it.
Thanks a lot!

/Philip

 

[peterc]

Philip

You can actually see the "+" sign next to the "35" marking on the cap. They sometimes mark them with the tiniest of tiny polarity markings.... Does not make a lot of sense.

Peter

 

[grebdnul]

Yeah.. I did'n know about polarized tantalum capacitors.. I thought they were ceramics. Hate them already :wink: All 4 0.1uf in my PSU are now tantalum, but i will replace them with ceramics.. just to be sure.

But I did record some vocals before it startes smoking.. and boy it sounds great!! really good! compared to my EMU 1820M preamps there were huge differences.. The green pre sounds so much more clear. I'll post some comparsions later for those who want to listen..

Anyway.. Thanks for the help.

/Philip

 

[Ptownkid]

It's funny, because I learned about tants the hard way too...you could also use poly caps where you have those tantalums. However; afaik, the tantalums are fine as long as they are in the right way.

Now only if every circuit problem were that easy! It's good that it happened though, now you've learned something new.

 

[kato]

If it makes you feel any better, I learned about tantalums the hard way too.

Back when I started with audio DIY - mostly stompboxes - I amassed a little junkyard of projects that wouldn't work.

Only years later did I learn that tants are polarized. And I was putting them in backwards exactly 50% of the time. It explained a few non-working stompboxes.

 

[grebdnul]

Ha.. that's funny.. well at least you learn something along the way. Yeah I'm glad that's my only problem with the preamp.

 

[grebdnul]

Finally my dual green pre is all set and works just fine. Thanks to everybody for helping me out and answering all my questions, especially to PeterC, of course, for this preamp. This forum is really great. I've also learnt a lot during my way. Hope I can contribute some day. The preamp fired up at the first try and the only problem I had was a smoked cap in the PSU. Turned out I used a polarized tantalum cap and had it turned the wrong way. Switched to a ceramic, then it worked just fine.

Some info:
-Home etched pcb's
-Bought most of the parts from Farnell, UK
-Case is Adam ordered from thomann.de (didn't like that one. Next time I'll order a better one. This one was cheap but needed a lot of extra metal work)
-Front panel designed in "Front panel designer" and then etched and coloured by NEriks audio here in Sweden. Unbelievably nice work, I really recommend Nerik. 20% cheaper than Schaeffer too.

The preamp sound really nice and is extremely clean and also super quiet. Sounds so much fatter and better than my Emu 1820 preamps. I'll post some democlips once I have some good recordings/comparsions

Here's a link to some images and test measurements. The test was made at 6dB gain.

http://www.monsterljud.se/Uploads/Phil/greenpre.htm

/Philip
Sweden

 

[Ptownkid]

wow! neatest wiring ever!

 

[lofi]

[quote author="Ptownkid"]wow! neatest wiring ever![/quote]

QFT!!!

amazed and just a little envious.

 

[peterc]

Well done Phillip. Great wiring.....

Peter

 

[Ptownkid]

for those not up to speed, qtf means quoted for truth.

 

[sunyata]

Hi ya'll,
I'd like to share some results of an A/B test I did at a friends studio. He's an experienced sound engineer, with more than 25 years in different pro studios here in Sweden. We tested the Green Pre against a Focusrite Liquid Channel (approx § 2.500), set to the most neutral type of mic-pre (I'm not very familiar with the Liquid Channel). We used a Röde NT1 (or maybe it was a NT2, can't remember). First we recorded speech (with pronounced nasty consonants like P, T, F, S, K). Then we recorded a snare drum, in order to test transient response, beating it in diffent ways (hard, soft, rimshot etc.) We also recorded a sinuswave and then silence in order to evaluate the noise level of the two pre's.
We were both amazed that the Green Pre easily matched the Liquid Channel, we even found that the Green Pre had slightly more/better clarity and brightness. The speech test was in favor for the Green Pre. Speech was perceived "clearer". When we compared the two regarding noise, the Green Pre had slightly more noise in the higher regions. This could maybe be explained by the difference in brightness. There was also a tiny bit more hum from the Green Pre. It might be explained by the fact that the gain was maxxed, and that I adjusted the CMRR at 12 o'clock medium gain. Then again the levels of noise/hum was so low that we could regard it as negligible.
So this was a truly interesting/enjoyable experience. My friend asked how much I would charge for an 8 channel Green Pre...I said I didn't know.
Has anybody sold a Green Pre? And for how much?

Thanks for this forum

Lars