capnspoony

G9 issues for my first DIY
« on: September 02, 2006, 02:19:04 PM »
Hi all

I've just completed my first G9 and as I have expected I also have my first real problems.

They seem to be related.

When my gain lorlin is turned down from positions 1-4 it will clip over and over again at about 80bps .. when turned to position it sounds like I have a serious grounding problem .. when turned up further than that signal passes through fine but my gain does not increase or decrease.

My output pot also seems to do nothing.  I have checked the pinout on that and I have it wired correctly.  

Any help would be greatly appreciated so I can get my first pre up and running!  

 :oops:

Richie
defender of the ancients


capnspoony

G9 issues for my first DIY
« Reply #1 on: September 02, 2006, 02:20:48 PM »
I forgot to mention I don't have the Direct insert installed yet .. would that be the cause of the problems?
defender of the ancients

Svart

G9 issues for my first DIY
« Reply #2 on: September 02, 2006, 02:40:31 PM »
yep, could be. try it again after you have it installed.
Welcome to the GroupDIY leper colony! when something falls off, we just replace it with a tube!
occupation: General Electron Mayhem

Alesis X2 information repository:
http://www.theopiumdenproductions.

capnspoony

G9 issues for my first DIY
« Reply #3 on: September 02, 2006, 03:40:19 PM »
On the pcb itself there are three holes

To
From
Ground

My Trs jack only has 2 leads coming off of it...

I'm looking at the schemo for the G9 and I see a ground lead coming from J1
but I'm a bit confused how to ground that .. or do I just wire the ground hole to where I have grounded everything else?

And which are "to" and "from"  the tip or the ring?

thanks
richie
defender of the ancients

jdr

G9 issues for my first DIY
« Reply #4 on: September 02, 2006, 04:20:29 PM »
The instrument in jack on the G9 acts as a switch so that when a patch cord is plugged in it disconnects the balanced xlr input, and inserts the signal from the quarter inch jack and sends it to C2 and the first gain stage. When there is nothing plugged into the quarter inch jack, the switch is closed and signal from the xlr in (via the transformer) is passed on to C2 and the first gain stage.

If your TS jack only has 2 leads coming off of it, then it is a non-switching type. You need a switching type. When you lay hands on a switching jack, insert a quarter inch plug and the switching action will make more sense.


Good luck. You'll love the G9. I finished mine about a month ago and I use it all the time.


 :guinness:
John


(edit: Thanks Al)

alk509

G9 issues for my first DIY
« Reply #5 on: September 02, 2006, 04:22:47 PM »
Quote from: "jdr"
If your TRS jack only has 2 leads coming off of it, then it is a non-switching type.


It's also a TS (not TRS) jack.

Peace,
Al.

Lest laziness get the best of you!

capnspoony

G9 issues for my first DIY
« Reply #6 on: September 02, 2006, 04:40:02 PM »
I said before that it only had two leads coming off from it but it actually has 4
 
Its two ends to the same piece of metal .. i thought it was a pair of hookups to the same "TS" jack.  

Here is what I have:

http://www.mouser.com/search/refine.aspx?Ntt=NMJ4HCD2

if that's not what I need can someone tell me what switching TS to buy?

Or is there any way of bypassing the DI input?  

  :thumb:
defender of the ancients

Svart

G9 issues for my first DIY
« Reply #7 on: September 02, 2006, 05:13:21 PM »
to bypass go from the TO directly to the FROM with a jumper and you should be good to go.
Welcome to the GroupDIY leper colony! when something falls off, we just replace it with a tube!
occupation: General Electron Mayhem

Alesis X2 information repository:
http://www.theopiumdenproductions.

capnspoony

G9 issues for my first DIY
« Reply #8 on: September 02, 2006, 06:05:56 PM »
great I'll do that for the time being.. and report back with what happens
defender of the ancients

capnspoony

G9 issues for my first DIY
« Reply #9 on: September 02, 2006, 08:03:20 PM »
Svart:

wiring to to from .. made the gain pot act as a sort of beat box .. the more i turned the gain up .. the faster it clipped ..

I tried it with the "ground" hole in the pcb wired to ground which resulted in no sound passing through

and then again with nothing hooked to ground which made the beatbox error happen.  



Ive eliminated most of the hum I was talking about earlier but I still have no real control with the input gain lorlin.  It still pops in positions one through five and then in position 6 it reaches a max loudness and then 7 through the rest are about equal output.  

Has anyone had this problem before?

Thanks for the help thus far  :thumb:
defender of the ancients


capnspoony

G9 issues for my first DIY
« Reply #10 on: September 02, 2006, 11:38:23 PM »
So I've run a continuity test here and there to make sure everything is good and here's the question ive come up with:

When linking the smaller pcb boards to the main pcb I found that if i hold one end of my multi meter on one header and the other end on the other header, I don't always get a beep for just a pair of leads.  

For example. I'll hold one probe at the very end of the header on the main pcb and then match it to the other header on the smaller pcb.. it beeps.  

then when i move the probe on the smaller header it will still beep sometimes saying there is continuity.  Should each line only beep once to its matching side, or can it have multiple coninuity points?  I've tried looking at the schematic but I cant wind my head around it to figure it out.. This is the best I can do for my first trouble shooting .. Sorry for the length on probably a really simple question.. not sure how to word these things yet

thanks for all the help as always  :thumb:

best to DIY
richie
defender of the ancients

capnspoony

G9 issues for my first DIY
« Reply #11 on: September 02, 2006, 11:57:12 PM »
Well i snipped all the leads assuming this was the problem and then i cleared all the header holes and i plopped my probes on the solder pads and by following the tracks i see that some of these pads are connected via the transformers?
defender of the ancients

capnspoony

G9 issues for my first DIY
« Reply #12 on: September 03, 2006, 12:03:32 AM »
so on both large headers i found counting over from the left side solder pads 2 and 3 are connected via the transformers .. both sets of headers only had continuity on this one spot.  

but my wiring before was giving my more than just those two pairs.. so I think I still found the problem .. i'll be back with more after i re solder all the interconnecting wires to the lorlin pcb's  :shock:

i feel like this is my online diary  :guinness:
defender of the ancients

lofi

G9 issues for my first DIY
« Reply #13 on: September 03, 2006, 05:36:38 AM »
makes damn good reading too!! i am about to start on 2 G9's, so am reading all this avidley
Are you professionally stupid, or just a gifted amateur.

Iain Westland (UK)


capnspoony

G9 issues for my first DIY
« Reply #14 on: September 03, 2006, 03:35:23 PM »
So ive reworked all the headers for my first channel

Now my input gain and my output gain are working.  

My line/mic/48V switch works

My phase switch works

My bass roll off switch works

The only problem now is:

        The last three positions of my input gain lorlin make the circuit squeel like a tiny piggy.  I had my scope hooked up to my in/out to take a look at the waveform and when I plugged in a mic at the same time my mic would create a very high pitch noise.

any ideas?

 :?:
defender of the ancients

ioaudio

G9 issues for my first DIY
« Reply #15 on: September 03, 2006, 04:10:31 PM »
oscillation at higher gain settings, seems to be pcb - related.

solution (from the g9 meta):
http://www.groupdiy.com/index.php?topic=114787

capnspoony

G9 issues for my first DIY
« Reply #16 on: September 03, 2006, 04:24:20 PM »
well

it works

it sounds great

thanks to everyone who replied earlier

The only question I have left is .. what kind of DI inserts did anyone use?

I'm a bit confused by the "switching" type people are speaking of

 :razz:

I love the sound already

thank you gyraf and prodigy pro  :guinness:   :thumb:

I'll post pics as soon as I drill the front panel etc.
defender of the ancients

ChrioN

"All PCB traces are curved to emulate the electrical response of point-to-point wiring" -Drip

gyraf

G9 issues for my first DIY
« Reply #18 on: September 04, 2006, 02:17:33 AM »
Quote
any ideas?


Yes.

Make a search - and use the archives. Click on the link named

".:Meta-Meta:.
(Look here for an overview.)"

at the top of this (or any) page..

Jakob E.
..note to self: don't let Harman run your company..


 

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