The official G9 help thread

[leanlowkey]

im sure im missing it. but where can I get a faceplate done at? thanks

 

[evil grill]

Collective Cases have what you're looking for.

 

[leanlowkey]

I have a few quieston about the g9 build..

will it still work if you dont install the instrument jack to the board?
as well as the input select. Im basicically going to run this at line always so was just curious if there is an easy way to "bypass" all the extra controls so to speak that im not going to ever touch.

thanks yall

 

[gyraf]

Yes, just hardwire

 

[Clbraddock]

Coming back to this after a few months, and still having the same issue of channel one barely amplifying. Channel 2 works perfectly.

The issue is in the output tubes. Performing a signal trace with a sine wave I get pretty much identical results up to the grid of V2B. The output from the plate of V2B is the first place the signals differ. On the defective channel doing a signal trace the output of the V2B plate is about two clicks of the gain knob quieter. This (logically) is also true of the grid of V2A. The cathode of V2A there is an even more significant difference in volume between the channels.

I've 100x checked that the components around the tube are correct, that there is continuity where the should be, that there are no shorts. I have also tried swapping tubes, swapping output transformers, swapping control pcbs. Nothing makes a difference. Cathode voltage drops are roughly the same between channel one and two. Plate Voltages are are also the same.

I am just at a loss.

 

[rock soderstrom]

I've 100x checked that the components around the tube are correct, that there is continuity where the should be, that there are no shorts. I have also tried swapping tubes, swapping output transformers, swapping control pcbs. Nothing makes a difference. Cathode voltage drops are roughly the same between channel one and two. Plate Voltages are are also the same.

I would replace the V2 tube socket if everything else has been checked.

 

[rock soderstrom]

I would swap C11 and C12 beforehand as a test. Desperate times call for desperate measures, take off the kid gloves.

 

[patzo]

Here is my single channel version of the preamp I made a few years ago. I changed some things like the power circuit and some other things. I replaced 3 custom toroidal transformers before I found the quietest one. ECC82 Input Tube, E88CC Output Tube, Lundahl LL1538 Input Transformer, Carnhill Output Transformer. The preamp is extremely quiet and sounds great. I intended to make 2 of them, but I never finished the second one, I have many hobbies and music and electronics have already been displaced by other hobbies

 

[thelivingroom]

Here is my single channel version of the preamp I made a few years ago. I changed some things like the power circuit and some other things. I replaced 3 custom toroidal transformers before I found the quietest one. ECC82 Input Tube, E88CC Output Tube, Lundahl LL1538 Input Transformer, Carnhill Output Transformer. The preamp is extremely quiet and sounds great. I intended to make 2 of them, but I never finished the second one, I have many hobbies and music and electronics have already been displaced by other hobbies

View attachment 135332
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Beautiful work!

 

[michinger]

Here is my single channel version of the preamp I made a few years ago. I changed some things like the power circuit and some other things. I replaced 3 custom toroidal transformers before I found the quietest one. ECC82 Input Tube, E88CC Output Tube, Lundahl LL1538 Input Transformer, Carnhill Output Transformer. The preamp is extremely quiet and sounds great. I intended to make 2 of them, but I never finished the second one, I have many hobbies and music and electronics have already been displaced by other hobbies

Wow, what a beauty! The nicest design I´ve ever seen!
Are you sure you do not want to sell it ?!?!
How did you made that front-panel? Because the wood is not just glued on, it is "in" the front -right?

 

[patzo]

Hi, thanks for the nice words. Yes, the wood on the front panel is not on top. The metal part is laser cut to the shape of the wood and the wood is built in.

 

[leanlowkey]

could anyone help me with where to start on why channel 1 is quieter than channel 2? its about one "number" lower in level. I have to have channel 1 around 8.5 to match channel 2 at around 7.. any help would be great thanks

 

[gyraf]

have you tried swapping the tubes to see if it's about those?

 

[leanlowkey]

have you tried swapping the tubes to see if it's about those?

thanks that seems to be the issue. when swapping tubes I have to readjust the levels to make them even so I ordered some tubes. thanks again!

 

[leanlowkey]

does anyone have a picture or diagram of which way the resisteors have to be on the gain switch board? or does it matter which way they face long as their in the right location

 

[gyraf]

Resistor orientation does not Matter

 

[sarakisof]

Found a 19' 2U chassis to properly fit my G9 finally. Did it's job nice since 2019 but was poorly located in a raw aluminum shelf I'd salvaged back then just to quickly use it & never looked back.

So as long as I'll be there it's an opportunity for me to make some layout & orientation I always wanted but was too lazy to do so.

The other day found a nice quality bulk wire probably from 80/90s in different colors old stock from a shop closure and would like to use this.
It's Sunitomo - Y XLPVC 20AWG 300V Double Insulated tin coated & it really feels quality stuff.

Can I use this for all secondary transformer (HT & 15V windings) to board & filter caps wiring?

 

[gyraf]

..yup, 20AWG is plenty..

 

[sarakisof]

..yup, 20AWG is plenty..

Now I saw it's 22AWG actually. My apologies Jacob. I guess nothing changes, I'm pretty safe to go right?

This is the wire

 

[gyraf]

Yes, no worries