The official G9 help thread

[gyraf]

No - there is no 12'th position on the gain switch. The switch must be limited to 11 positions by the "programming pin" under the lock nut.

Jakob E.

 

[ognam2]

haha.... what a stupid fault....
Thanxs!
But there is another problem. At the 11 Step of the right channel There comes something out of the box that I can´t hear but see at the meterbridge of my mixer. seems to be very lout, but I can´t hear it. Is that an oscillation issue? It is only there if a microphone is connected. With a condenser it is also at the 10 position.

Oscillation?

Thanx Jonas

 

[gyraf]

is that an oscillation issue

It might be - but it should not only occur with a mic connected. Maybe ultrasonic feedback? Does it still do this with mixer full-muted?

Jakob E.

 

[ognam2]

I fixed the issue with alex´method... cut the trace and use a shielded cable instead. This thing is working fine now... sounds very sweet!
Only one question:
I trimed the phantom to exactly 48V, but when I connect a Mic it goes down to 35V. Is this normal?
Thanx Jonas

 

[gyraf]

I trimed the phantom to exactly 48V, but when I connect a Mic it goes down to 35V.

Measured where?

The voltage after the 6K8 resistors is supposed to drop when loaded with a mic..

Jakob E.

 

[ognam2]

measured at the xlr´s ... so it´s normal right?
Thank you for this awsome project!



Jonas

 

[gyraf]

:thumb: :razz:

 

[ognam2]

finally the knobs arrived....

 

[gyraf]

Nice! :thumb:

Jakob E.

 

[microc]

Hi
Got a bit of an issue. I wonder what PSU transformator to choose. I looket at an  Avel Lindberg Toroid transformator P/N Y236003, the I go from 230/ 15+15. but I also need to go 15/230. Could I just use a 1:1 transformator parallell with the other one? then I get 15+15+230. Any better ideas?
Or two of 9531785 (Nr in Farnell, basic 50VA 230/15+15)

And also for the voltage regulators. I've bought a regulator for the 12V but I'm not sure what to do with the 245V and 48V

Thank you for Your time!
Best Regards
Jens, Norway.

 

[CurtZHP]

Can you go with the Amveco transformers in Norway?  They make exactly what you need for this.

 

[microc]

Can you go with the Amveco transformers in Norway?  They make exactly what you need for this.

Thanx. Do you have any product name else then Amveco ? Or do you order a custom design. Then I could order a two in one transformator.

I'm a bit nuuubie. lol

 

[CurtZHP]

If you've got the time to look at this entire thread, there is another product name that some here have used.  I don't recall what it is.

I ordered the Amveco transformers through a US company called Digikey.  I'm sure they handle international orders.  Or you could e-mail the company (www.amveco.com) and see if they have a European distributor.

 

[microc]

Allright, Thank You CurtZHP  8)
This is really cool!

 

[Stagefright13]

I know it's not just me but everything sounds WAY bigger thru the G9. I use it in line mode during mixing alot. I pipe it in using a protools insert at the front of the track. Of course everything can't be big lol. But this has a special sound and use it tons.

Thanks so much Gyraf!!

I know this is a little late but Holy Cow ognam2 that's a nice looking G9!!

 

[gyraf]

 

[Stagefright13]

Pic of my G9 after MU mod :

From http://www.lessemf.com/mag-shld.html Cheap and virtually silent! Giving away my secrets. But I was actually copying Jakob! The G9 was pretty quiet except a small amount of noise on the right channel. But it interfered with equipment bolted next to it. No longer any problem. And I have enough MU metal left to isolate alot of other projects if need be... It's a "Mac Daddy" pre or line amp!

 

[caseyc]

Hi people!

Have been building pro audio gear for a long time (build a lot of ssl clones and all the other great gyraf stuff, EXCEPT the G9).... until now! Had some parts over and put one together.

It works fine, nu hum what so ever. BUT, ok i have read this thread and cant access oscillation problem thread for some reason....but on the the three last gain settings it both channels it totally goes too high...screaming/distorsion. I just wanted to ask here about the oscillation issue before making the cuts on the board?

/regards



Btw, if you have hum in a DIY project and you have checked every soldering etcetc and properly grounded it but still got a 100 hz hum....measure the resistance between to points on the pcb (example from one side to antoher) when its off (should be zero) if the value changes when powering it up (lets say above 1 ohm) well then your pcb tracks are so thin that they have become a resistance. Just a tip from me.

 

[gyraf]

If you have the oscillation problem, you need to cut the traces just beside the input transformer:

http://www.gyraf.dk/gy_pd/g9/G9-EDIT.GIF

1) Cut the two traces that comes from the input transformers and goes to the instrument jack.

2) Cut the two traces that goes to the 220nF input capacitors from the instrument jack.

3) Mount four shielded cables to/from the instrument jack, wireing directly to the transformer and to the input capacitor, using shield-ground from the transformer ground that is found close by your cuts.

..good tip about finding high-res ground loop problems..!

Jakob E.

 

[caseyc]

If you have the oscillation problem, you need to cut the traces just beside the input transformer:

http://www.gyraf.dk/gy_pd/g9/G9-EDIT.GIF

1) Cut the two traces that comes from the input transformers and goes to the instrument jack.

2) Cut the two traces that goes to the 220nF input capacitors from the instrument jack.

3) Mount four shielded cables to/from the instrument jack, wireing directly to the transformer and to the input capacitor, using shield-ground from the transformer ground that is found close by your cuts.

..good tip about finding high-res ground loop problems..!

Jakob E.

Hi Jakob, Did this modification right now, problem solved  Thanks a lot! It sounds veryvery good

And many thanks for sharing these really great DIY projects

/C