The official G9 help thread

[innercityman]

Ok, Thanks TiIIM !

 

[innercityman]

Hi there,

I finished soldering every components. Is there a wiring guide somewhere ? I'm just wondering how the 2 big PSU caps are wired ? I'm using the don-audio's special designed single Power transformer.

 

[gyraf]

Then maybe ask Don-Audio how to wire it?

Jakob E.

 

[TillM]

It's easy to wire it !
It's all AC on the secondary.
He also has a wiring guide on this website.
But there a two on this website.
Do you have the cheaper one or the one with the white housing ?

 

[innercityman]

I bought the expensive one with white housing. Specially designed for the G9. But I can't find informations on how the two PSU caps are connected.

 

[TillM]

See at the schematic !
Or look at some photos.
The minus poles from the capacitors went to the middle on the pcb. The plus poles on left to it, from the other capacitor right to it.
Connect both minus poles to the middle.

 

[innercityman]

Not sure to understand but anyway thanks for your help. I'll check the schematic.

 

[TillM]

Hi,
I hope that this will help you.

 

[innercityman]

Thanks Tiim, I've already checked on Jakob's layout and found out.

I have another probably dumb question anyway... How do you set 2 positions on a Lorlin 3 positions switch. I mean, for the phase switch, there should be 2 positions right ? Normal or inverted. So is it possible to do that ?

 

[innercityman]

I found out, sorry. Needed to pull up the bolt of the switch to access the adjustment ring.

 

[gyraf]

edit

 

[dasnevestheo]

Hi, hope everyone's safe.
I've just finished a unit, OEP xformers, 60's Mullards tubes, DI jack mod, All cables shielded/twisted/crossing 90°.
The major issue is frequency response, i've never seen such curve on a unit 
I am aware of the small low-end loss using OEP and I am fine with it, but this is really something..
Any ideas ? I have to mention that the curve is the same for the L and R channels.

Sadly I don't have spare tubes to swap and see atm.

Thanks a lot for your help !

 

[shabtek]

-3dB @60hz ref1khz. 

 

[innercityman]

HI everyone,

Juste finished my G9, and started to take measurements, and I have an issue on Phantom power. I get something like 0.37v when I take measurement at the xlr input 10k trimmer at maximum, I have 51,9V at the tip121. I measured HT and I have 246V, At the 12V measure points I get 11.9. I'm using Don-Audio's G9 custom power transformer.

Any idea or help would be appreciated.

 

[innercityman]

I forgot to mention that I got a little smoke cloud at first start around D13 to D16. Don't know exactly which one has blown up.

And just to be sure... Do I need to measure 48V at xlr inputs or somewhere else ?

 

[innercityman]

I discovered that I've soldered Zener diode D6 upside down. That should be the reason.

 

[innercityman]

Hope this time I'll get some help or advices...

I've soldered back the D6 zener in the right orientation and replaced D13 to D16 diodes rectifiers. So all my measurements are good, including the 48V at mic inputs but... When firing up the unit, I got again a little smoke cloud coming from D17 to D20 diodes area. I couldn't determine which one has blown away, not even sure if it comes from a diode or resistor or a cap. Measured voltages from diodes  and all of them gives me around 600mv. I double checked the solder side with a minifying glass and was unable to see any short nowhere. So now, I'm afraid to power it on again, wouldn't want to damage more components.

Don't know which  direction I should investigate.

 

[TillM]

Check power  transformer wiring

 

[innercityman]

Hi TillM,

My power hook is ok, I'm pretty sure about that. I used the custom G9 transformer from don-audio, very simple to connect. And if the wiring was wrong, to you think I could have good voltages values everywhere ?

 

[TillM]

There a two options for g9 power transformers from Don-Audio.
I used the cheaper one for round about 85€.
I smoked up the diodes, when I used the wrong wires for the 12vac and 15vac connections.
If you use the "cheaper" audio transformer make sure, that you use the blue and green cable for the 12/15VAC connection.
The power transformer for 115€ used blue for 15vac and yellow for 12vac.
Check if you use the right wires for any connection.
When you see smoke in the Diode area, definitely change your diodes.
Sometimes its hard to see, whether the diodes blow up or not.
To be safe, change them in the D17 to D20 area.