The official G9 help thread

[Dokdude]

Hi everybody, and my best wishes for a great 2023.

I finally completed my G9 unit. Things were a little bit weird when i built the unit, about 10 years ago. A lot of noise, crackling and hum, expecially on channel 2. But i decided to open the unit once more and have the final battle with it. So just to say what i have done to accomplish the mission.
- i desoldered OEP's from the board: the plates were unstable because the first soldering points were broken. So i soldered the plates to their screens all around. And soldered again to the board.
- replaced all signal caps and two electrolytics caps of the second channel
- replaced channel 2 tubes (both 12au7)
- replaced the C14-C15 220 uF 350V with 470uF 450V.
- cut GND from/to xlrs except one and rewired to star ground accordingly.
- installed a metal plate to segregate the 220 trafos and power switch wires.
- moved the power switch to the right (as the original Gyraf design) instead of the center of the front panel. Of course i had to make another front panel with my CNC (first time i engraved aluminium, so im very proud of it).

The unit now is very quiet. Low noise, transparent, powerful and rich.
There is a 100Hz hum @ -81dBFS (mics connected, output at zero) which is acceptable. I suppose that to get rid of it i need to move the PSU outside of the main board (?). Maybe a job for the future. For now i can live with it because nobody would notice.

Here two pics of my G9 (alongside with my Gyraf-based SSL diy buss compressor).

I thank everybody in this group since every post in this long thread is invaluable.
My compliments to Gyraf. I also noticed that his boutique units are now on sale on Thomann

 

[Icegoldnixon]

Sorry if this is clearly printed somewhere, but does anyone have part numbers for the all of the rotary switches needed for this project? Thanks!

 

[thelivingroom]

Hello everyone! I’ve been the beneficiary of these forums for years for various purposes, but this is my first post on here. I had done my own maintenance on the gear in my studio for years and put together a couple of full kits like the Hairball 1176, and made some DI boxes in the past, then as my confidence grew I pushed myself to build this G9 and audiox’s W492 EQ simultaneously as my first two more involved DIY builds about five years ago. Doing some of these builds on here like this, and having several others in various stages waiting to be finished, has injected a new and different love for recording for me in my 25+ years of being in my studio. It’s safe to say I now have an addiction haha.

Before I ordered any parts and got started I read every single post, printed out the important ones, took my time once I got going, and it worked perfectly on first fire up. I’ve waited this long to post my build because I initially stubbornly put the power switch in the center with a pretty neon light above it, due to my desire for panel symmetry, causing a lot of buzz on channel 2 (I know, I know haha). I made it a lot better by making an ugly metal shroud around that and the mains wiring, but always wanted to redo the front panel correctly, use shielded mains wire, and change the tubes from whatever JJ’s I had laying around at the time to get it going to something that may be a little better. I recently redid all of that and now love this thing even more. There’s still a little buzz on channel 2 if I turn my monitors all the way up, and I may eventually pull it one more time to add a divider plate next to the power switch and wiring, but for now I’m gonna enjoy it for a bit.

Thank you Jakob for your generosity and knowledge, Gustav for the pcb’s, and everyone who has posted useful information in this thread.


(Updated photos in post #2435)

 

[thelivingroom]

Sorry if this is clearly printed somewhere, but does anyone have part numbers for the all of the rotary switches needed for this project? Thanks!

I used the following Lorlins:

SW1, 3, 101, 103 (Input select and HPF): CK1057
SW2 & 102 (Gain): CK1054
SW4 & 104 (Phase): CK1047
Power: RMS1100

All of those are 1/4” D-Shaft and long, but they’re “plastic” and easy to cut down.

 

[Icegoldnixon]

I used the following Lorlins:

SW1, 3, 101, 103 (Input select and HPF): CK1057
SW2 & 102 (Gain): CK1054
SW4 & 104 (Phase): CK1047
Power: RMS1100

All of those are 1/4” D-Shaft and long, but they’re “plastic” and easy to cut down.

Thanks so much!

 

[Clbraddock]

Question on switch orientation. I have and am planning to use Lorlin CK1050 for the switches other than the gain. The CK1050 is 2 pole 6 position, but I can use the stops to make it 2 or 3 position. There’s 2 different ways I can fit the switch in the pcb. Does the orientation make any difference?

 

[Clbraddock]

Should I bin the CK1050 Lorlins and just reorder the switches suggested by thelivingroom?

 

[thelivingroom]

Should I bin the CK1050 Lorlins and just reorder the switches suggested by thelivingroom?

Just glancing at the schematic it looks like it may work for one of those (per channel), but in the BOM on the Gyraf site it calls for two of them to be MBB, and one BBM (per channel). The CK1050 is BBM, so you should get the correct MBB for the others. Also, the 1050 is 6mm shaft, so if you still want to use two of those then I’d look for MBB version with 6mm shaft. The ones I listed are all 1/4” shaft.

 

[Clbraddock]

Thanks thelivingroom. Sounds like the ones you listed might be a simpler solution than trying to make the ones I have work. Appreciate your help!

 

[thelivingroom]

Thanks thelivingroom. Sounds like the ones you listed might be a simpler solution than trying to make the ones I have work. Appreciate your help!

You’re welcome! Good luck; it’s a fun build, not too crazy, and sounds great!

 

[Clbraddock]

So, I'm finally down to the last phase of construction and was about to wire up the power transformer, but I'm worried don-audio may have sent me the wrong transformer. The markings on it are not correct. It is the don-audio G9230Sp but instead of secondary voltages of 230, 15, 12 the label shows voltages of 275, 12, 12. Did they send me the wrong transformer? The transformer pictured on their website shows the correct voltages on the label: G9 Audio Power Trafo Sec: 230V, 15V, 12V Integrated Shielding, 153,23

 

[gyraf]

..you should probably ask Don what this is about?
(note that with 275VAC, you will need 400V-type HT PSU electrolytics, 350V types won't cut it)

/Jakob E.

 

[innercityman]

So, I'm finally down to the last phase of construction and was about to wire up the power transformer, but I'm worried don-audio may have sent me the wrong transformer. The markings on it are not correct. It is the don-audio G9230Sp but instead of secondary voltages of 230, 15, 12 the label shows voltages of 275, 12, 12. Did they send me the wrong transformer? The transformer pictured on their website shows the correct voltages on the label: G9 Audio Power Trafo Sec: 230V, 15V, 12V Integrated Shielding, 153,23

View attachment 108657

Just connect you primary to your IEC socket and measure every secondaries. I've used same trafo in my build.

 

[Clbraddock]

Measuring the secondaries unloaded they are even higher than what’s on the label. Of course, the voltage will drop a bit under load but I’m afraid to connect it if it’s going to be too high for some components.

Was your transformer marked the same as mine 275, 12, 12? Did it measure correctly under load?

 

[innercityman]

Measuring the secondaries unloaded they are even higher than what’s on the label. Of course, the voltage will drop a bit under load but I’m afraid to connect it if it’s going to be too high for some components.

Was your transformer marked the same as mine 275, 12, 12? Did it measure correctly under load?

I've checked old pics of my build and yes, it has the same label informations than yours. Check that !

 

[Clbraddock]

I've checked old pics of my build and yes, it has the same label informations than yours. Check that !

Thanks man!

Still annoying (if not fraud) they seem to be shipping a different transformer than what they advertise.

Guess I can run a space heater when I connect it to drop the voltage coming from the wall a bit and then measure. Maybe that will save the caps. Looks like in your build you have a lot beefier power supply capacitors. Mine are rated 350 volts which Jakob indicated is not enough for this transformer.

 

[thelivingroom]

I've checked old pics of my build and yes, it has the same label informations than yours. Check that !

@innercityman and @Clbraddock, this looks incorrect to me. The connections for 48v should be the blue (.5A) and the yellow (3.0A) should go to the 15VAC/1A spot. If I remember correctly the transformer is just mislabeled, but is actually 15v/.5A Blue and 12v/3.0A Yellow.

 

[gyraf]

again - isn't it better just to ask Don?

 

[thelivingroom]

again - isn't it better just to ask Don?

Yes, but in the meantime my point was that they should be more concerned with making sure the correct current ratings are in the correct spots than whether it’s actually 12v or 15v…

 

[Clbraddock]

again - isn't it better just to ask Don?

I sent an email yesterday. My experience with don-audio e-mail support has been pretty bad in the past though. Maybe I’ll hear something in a few weeks.