Pumpkin Preamp - Perfect for F4

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lykkedk

lykkedk

Member
Joined 2002
Thank you ZenMod for helping me out... I will never ask quistion that i allready know, but it's in my nature to ask, instead of be in doubt :)

with WR2 you can adjust currents through left and right output CCS-es (look at currents through R7 and R8) and - accordingly - offset between outputs AND GND
Click to expand...

Then when voltagedrop between GND and +out , GND -out are just the same, the pumpkin will have perfect match between +/- out ? I do not have to meassure voltagedrop on thoose resistors rihgt ???

You mentioned that the :Pumpkin: uses ~50mA each channel will that be 72v / 0,05 = 3,6Watt(1channel) = allmost nothing ??? then there will be need for small heatsinks only, as i see.

Ok.. I will soon be ready to fire 1. channel up, are there any other thing's to consider ?

Jesper.

Btw: My problem with the bosoz 36-/36+ psu was 2shorted zener's !
 
Zen Mod

Zen Mod

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lykkedk said:
Thank you ZenMod for helping me out... I will never ask quistion that i allready know, but it's in my nature to ask, instead of be in doubt :)



Then when voltagedrop between GND and +out , GND -out are just the same, the pumpkin will have perfect match between +/- out ? I do not have to meassure voltagedrop on thoose resistors rihgt ???

You mentioned that the :Pumpkin: uses ~50mA each channel will that be 72v / 0,05 = 3,6Watt(1channel) = allmost nothing ??? then there will be need for small heatsinks only, as i see.

Ok.. I will soon be ready to fire 1. channel up, are there any other thing's to consider ?

Jesper.

Btw: My problem with the bosoz 36-/36+ psu was 2shorted zener's !
Click to expand...


you must have connected two voltmeters during settings of offsets- one between any output and GND and one between outputs ;all that BEFORE output caps

goal is to have zero on both

regarding bosoz psu........... you make a mess asking (or not?) two questions in same post , so ( at least that was case with me) we have no clue what is wrong ..... +/- 60Vdc supply or +/-36Vdc supply ....or both

next time - when you have question , make little effort and prepare and post exact schmtc ; sometimes- even if you post url to file, someone capable of answering to your question mebbe have no enough time to download it and look.........

;)

this is not critic ,just a tip :clown:
 
lykkedk

lykkedk

Member
Joined 2002
It's fired up !

Well, i am doing something wrong... (or maybee setup wrong) let's see if i can explain excatly this time :)

Setup 1 as this :

+36 / -36 / gnd from psu attached to pcb.

nothing at input (nothing attached to +in / -in / GND)

Voltmeter 1 attached where R13 meet's C11/C4 and where R18 meet's C12/C5. Also right before output caps (WR1 adjustment)

Voltmeter 2 attached where R18 meet's C12/C5 and GND Also right before output cap (WR2 adjustment)

Led D1 / D2 / D3 / D4 light's up now (1,8v voltage on each of them 4) Led D5 / D6 nothing (1,5volt on each on them 2)

Voltmeter 1. = ~0,2mv nothing happens when adjustning WR1.
Voltmeter 2. = 34V nothing happen's when adjustning WR2.

Is this the right way to setup adjustment. ?


Setup 2 as this :

OK I tried to attach 1000hz sine 1vpp at input +in / GND then this happens :

Led D5 / D6 light's up too now.

1000hz 1vpp at output between +out / GND. So no gain, except that the sinewave has moved a little up on the scope.

No adjustment's on WR1 / WR2 possible either now. (Voltmeter 1/2 still attached where i did at setup 1...)

Schematic http://www.diyaudio.com/forums/attachment.php?s=&postid=1247745&stamp=1183490665

Jesper.
 

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Zen Mod

Zen Mod

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lykkedk said:
It's fired up !

..............

Jesper.
Click to expand...


all leds must glow in same intensity ;

they must have 5mA through them ; for that check voltage across R24 ; 5mA across 270E is ~1,35V ; double check polarity of leds

for start - WR1 on mid position ; same for WR2 ; WR2 is first thing you need to winkle ;) ...chase zero DC from any output to gnd

in your case - you didn't biased CCS output mosfets ( Q6 and Q8) so you have full positive on output ........... I think so :devilr:

add: my mistake - one channel current consumption is in range of ~70mA , not as I wrote previously
 
mpmarino

mpmarino

Member
Joined 2004
but ya can't be crazier than I am
Click to expand...


....then I will stop worrying :clown:


....... where's Lucky Luke when man in trouble needs him .....
Click to expand...

We had a DOLL session this morning, you missed it. :clown:


OT: I gutz dem little speaks I built into the house. Biamp w/ Klone and mini A thru a DCX2496 off a Sony ES pre for now. Um, I think you can hurt yourself with these:D

If you look real hard you can see the speakers...
 

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mpmarino

mpmarino

Member
Joined 2004
Re: according to thread's title

Zen Mod said:



ya don't need F4 to drive that drek
Click to expand...

Your right. I'll keep the Klone on the woofers, I think. The Klone into the 4 ohm drivers in this app seems to work better than expected. I think it could actually cause a heart attack... or maybe restart a heart. Good and tight at lower levels too. The horns are as expected - phenomenal.

The tough part is the integration between the two.

I might need to get some rta stuff together to pull it off tho. I think I'll tweak it up with the DCX2496 and then design analog stuff based on those results. Suggestions ??
 
Zen Mod

Zen Mod

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Joined 2003
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Re: Re: according to thread's title

mpmarino said:


Your right. I'll keep the Klone on the woofers, I think. The Klone into the 4 ohm drivers in this app seems to work better than expected. I think it could actually cause a heart attack... or maybe restart a heart. Good and tight at lower levels too. The horns are as expected - phenomenal.

The tough part is the integration between the two.

I might need to get some rta stuff together to pull it off tho. I think I'll tweak it up with the DCX2496 and then design analog stuff based on those results. Suggestions ??
Click to expand...


rta?

ya need Hiraga's xover schmtc for A7 , just as idea?

btw , "Klone " is as "Gainxxxxx"?
 
lykkedk

lykkedk

Member
Joined 2002
in your case - you didn't biased CCS output mosfets ( Q6 and Q8) so you have full positive on output ........... I think so
Click to expand...

ZenMod ? I don't understand this :xeye:

Well, i will give up for today. This is how far i am now.
I can make all led's light up now(Suddently D5/D6 light up, when i adjusted a little).... voltagedrop below R24 is 1,2v.

DC between GND and +out is ~12vdc and the same on GND to -out (adjusted to this value's by WR2) If i go lower on e.g -out the value raises on +out... With WR1 i can set offset between +out / -out to near zero, but it seems to pendel a little up/down.

Still no gain, when attaching 1kHz sine 1v on input, the same wave appears on output.

Could you perhaps give me some meassuring point or any thing i can chase for :D
I now have no clue where to look.

Jesper.
 
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