Pumpkin preamp - ordered by Steen , official making thread

carpenter said:
Well now, guess what was in my mailbox.

Quick as a wink, I visited the local Post Office and now have the the package on my desk.

Its contents reminds me of some of the women I've loved: beautiful, impressive, and intimidating.:hbeat: :hypno2: :hbeat: :yes:


There will be plenty to do this winter!😀

You got your insurance bill?
 
quote from ZenMod:
dunno for your pcb - but for mine correct way is like this

Thank's for the correction on my attenuator schm.
Well i tried to hook it up, the way you suggested, and some hum dissapeared.

look at zenmod's attennuator schm. here

I made a 'star' connection in middle of chassis (not connected to that) from that 'star' connection wires are going into these point's.
1 wire ---> pwr gnd Right channel
2 wire ---> pwr gnd Left channel
3 wire ---> signal gnd Right channel
4 wire ---> signal gnd Left channel
5 wire ---> comming from input gnd

The god thing is, that now my 4deck work's as good as my 2deck-stereo pot. 🙂

But still having that strange -in to GND problem... If i deattach the -in wire comming from attenuator, the :Pumpkin: is dead-quiet! ... But when -in is attached to attennuator there is comming some humming... really annoying. Donno what the problem is. Seem's to me, that it's some grounding issue...
Because when -in is connected to gnd via attennuator the :Pumpkin: is becoming very sensitive.. e.g when i touch some part's you can hear it. All that dissapears when disconnecting -in... something i didn't noticed before. I must say, that i didn't try it on my F4's this testing is done with my LeachAmp, there is ofcause the possibillity that there is no humming when connected to F4... but i sure would like to solve that problem anyway.

Jesper.
 
gimme pics ,drawings , whatever ;

you must have ground loop somewhere .

Yep... groundloop it must be! --- but no piccie's today, cause children bring along digicam on a weekendtrip 🙂

I realise, that i did not use the 'coax shield' in coaxcable. it might be the problem.
The coax i use is a 3wire+shield cable, containing red, black, yellow. + shield.

I use the black wire as GND, red is for +connection's and yellow is -connection's. The shield connection, i just leave as it is at end of cable's... I just looked at your'e grounding schm. HERE
And see that the shield is connected at the PCB (which i didn't do so far)... this might could be it ???

Will be back when rewiring once more ! 😉 Not tonight for sure 😀

Jesper.
 
lykkedk said:


Yep... groundloop it must be! --- but no piccie's today, cause children bring along digicam on a weekendtrip 🙂

I realise, that i did not use the 'coax shield' in coaxcable. it might be the problem.
The coax i use is a 3wire+shield cable, containing red, black, yellow. + shield.

I use the black wire as GND, red is for +connection's and yellow is -connection's. The shield connection, i just leave as it is at end of cable's... I just looked at your'e grounding schm. HERE
And see that the shield is connected at the PCB (which i didn't do so far)... this might could be it ???

Will be back when rewiring once more ! 😉 Not tonight for sure 😀

Jesper.


if everything is wired OK - then shield is just a bonus , not necessity
 
if everything is wired OK - then shield is just a bonus , not necessity

If that's the case... i haven't no clue anymore... everything is connected proberly.

Will be thinking next few day's i guess... might be that i'll figure it out that way! 😉

Thank's for helping me out ZenMod... PS: check youre mail in few minutes... 🙂

Jesper.
 
lykkedk said:


If that's the case... i haven't no clue anymore... everything is connected proberly.

Will be thinking next few day's i guess... might be that i'll figure it out that way! 😉

Thank's for helping me out ZenMod... PS: check youre mail in few minutes... 🙂

Jesper.

gimme pics .


Magura said:



Remember, snaps December 8th Jesper 😀


Magura 🙂


whazzat now that dec. 8. ?