G9 ????

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Nono, the secondary is not in the signal patch.. have a look at just about any switched jack. This is very common on most preamps, even quite expensive ones. It's a bad idea, period.

Gyraf is doing it the right way, with a switch or a relay
 
Or so I thought :green: (Hell, I even think I did that same on the SlowBlow thingy :roll: )

I would advice Jakob to update the schematic to include a relay option, like the one he's using for phantompower. I really have seen quite a few preamps crap out this way..
 
Sorry, I'm confused here - how does a nonswitched jack after the TX (like mentioned above) get rid of the sec-winding ? Guess its switched, right ?

The G9 does use a switched instrument jack after the input-TX - if the contacts go wild the mic-signal path goes. But it'll be fine, if we can't trust switching jacks we can doubt a lot of other things as well.

Peter
 
All set, no confusion any more.


I just made a FET follower with it's own PSU. Unbalanced output that can drive a mic input. Works as long as the center tap isn't grounded!

I like the impedance balanced output of that Jensen-circuit: the mic-pre sees the same R_source on both legs and just the signal on one leg.

Peter
 
It may be bad wording on my part. Look at the G9 input section. This is the most common way to do it. When that jack craps out, like dust/shit between it's switching contacts, THAT will be in the signalpath when you plug in a microphone...

My argument is not to have a swithced jack, but a jack that's switched into the signalpath with a relay or a switch.. :? :grin: Makes sense?

The jacks most often have open contacts, they'll get poluted. Relays and encapsulated switches are much better...
 
I just connect pin3 to ground on the output XLR on the FET buffer. That's also why it won't work with grounded centertaps. Don't have any of those, so it's not a problem for me..
 
Our confusion is gone... Others reading this may get confused by the sequence of posts - DK & NL typing at the same time & both experiencing the inevit. posting delays :grin:

OK, I'm out, thanks for sharing the experiences.
If I ever come to soldering me a G9 I'll definitely include a Hi-Z input option to go through both TXs. And the G9 being double-channel, I may even be tempted to split the PU's of a passive Jazz and blend after going thru both channels- or even track them separately - but that's another story altogether.

Bye,

Peter
 
Regarding the Gyraf (or any other preamp using the same arrangement), the PCB doesn't really need altering as the relay could be mounted on a small PCB along with the jack. This little PCB could be controlled by the phantompower and thus be used in any preamp... just a thought..
 
sismofyt,

I understand your concern, but I have NEVER ad switching problems in the "Rean" brand switching jacks I use - unless someone by accident had stepped in the cable, bending the contacts. I find it quite safe to use jack-switching at this point in the G9..

Jakob E.
 
..or you hang around too many drunk musicians.. :razz: Do you also have the impression that the horn guys are always the worst when it comes to drinking too much and stepping in cables..?
 
Jakob, i had a musical instrument shop from 1987 til 1996. We also did repair/service and Marshall amps (mosfet series every single one of them) came in very often to have a repair on the Reans send/returns. All the ones i sold back then went out with an extra patchlead in case the reaninterupted in action.

i still like em though :roll:
 
A ? Again.----

Can i use this trafo 230 V ~ 2 x 15, [RS: 257-4979] from radioparts for the powersupply? Are there any specific demands for the powertrafo's
 
Gropies! :green: I kinda like 'em myself :cool:

Jazzy, those are 3amp diodes, they have fatter legs than the 1N4XXX and may not fit the G9 PCB. Groupies with fat legs are no good either..
 
Thanks J...

I think i have the last parts to the g9 preamp in place now. All i need now is the money for it... ;-) I can't wait.....
 

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