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Zen Mod 20th October 2007 07:29 PM

Synopsis of Pumpkin preamp - ordered by Steen , official making thread
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This thread is a subset of is a synopsis of the thread: "Pumpkin preamp - ordered by Steen , official making thread"

I have removed all of the off topic posts so it is less entertaining but possibly more useful to learn about the Pumpkin


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well ...... seems ages ago ,buried in some obscure DiyA Pass thread , after few quickie (on back of napkin) modifications of XYWZwhatever BOSOZ , my budy Lucky Luke (AKA steen) , demanded one little preamp with balls ....

few posts later , LL have some ideas about topology, perfectly good for me , just because I'm good at paper (napkin) and hand calc almost as he is good in making amps ........

little later - I already have some quickie quickie drawn , but somewhat flipped in regard to LL's idea,with added output stage(s) etc.

main reason why I flipped it is because I feel ( well - I rarely think,anyway) that's smart to use some non-audio-fancy-schmanzy Jfet , which is easy to find in near tobacco store, with all other parts .....

well - result is here (lookie lookie schmtc)

crazy process of :Pumpkin: delivery is also crazy documented in THIS
thread .........

I can just say tnx to entire OFF TOPIC MOB , just because they make my life miserable with regular questions "will it drive F4 " etc . :devilr:

anyway ......... for first post is 'nuff

(next post -The Shunty)...........

lykkedk 20th October 2007 07:40 PM

2 Attachment(s)
:Pumpkin: setup in my livingroom... Swinging so easily 40v with 1,8 on input !!!

Thank's for all the help ZenMod... Maybee it will be a while before finishing it up...

I made a :Pumpkin: from scratch, designing my pcb (clumsy i know) myself... but the thing is playing really nice, not to mention very relaxing too. All diy'ers, which life depend's on the F4, really should consider the :Pumpkin: to drive it wild an mad...

ZenMod :devilr: :devilr: :devilr: nice weekend...


Zen Mod 20th October 2007 08:01 PM

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crazy danske was fast almost as his country man LL :clown:

lykkedk earned his right to post piccies of his own :Pumpkin: because he is first who actually made non-prototype version ..........

first official pair of main :Pumpkin: boards are happily arrived at first BAF in history....... we'll hear more about Smashing and Barking :Pumpkin: tomorrow......

well- steen ordered :Pumpkin:, but he didn't count on my everlasting love for shunt regs .
as result of that love there is The Shunty ........ simply - proper reg for any eeny weeny preamp ........

my friend Oly (AKA Vangelis on DiyA) is responsible for stunning pcbs for both :Pumpkin: and Shunty ; btw. "The Shunty" is his name for that simple reg . you'll see pcb piccies in later posts.

he is also responsible for keeping me in sane boundaries ; well - almost keeping me ;)

when I drew series reg, in front of already drawn and tested shunt part of now existing Shunty, his only (and last ) comment was "that's pure demonstration of force....... why you need that ?" :clown:

I also wanna say many tnx to Off Topic Mob , which constantly make my life miserable with repetitive questions as "will it drive F4?" etc .......... :devilr:

anyway - this was (is) open source project ......... my intention to make decent preamp for regular DiyA members, without braking leg and arm to find obscuremadeofpreputium audio parts (read - toshiba 3 or 7 legged fuses) ...

both schematics are here ; I intend to sell pcbs along with matched crucial parts , in several levels ........ just main boards with parts, just Shunty with few important parts (if they exist at all) , complete package, main boards with just one Shunty ( if you are bean counter) etc.

to cut a story..........

here is The Shunty schematic:

Zen Mod 20th October 2007 08:13 PM

main boards piccies

Zen Mod 20th October 2007 08:20 PM

The Shunty pcb piccies

Zen Mod 21st October 2007 01:30 AM

for all greedy boyz without missus's Iron to make own pcbs
The Pumpkin preamp package(s) for sale...............


Zen Mod 27th October 2007 01:03 AM

The Shunty - BOM and schematic
2 Attachment(s)
as in subject

if anyone see mistake , let me know ;)

mpmarino 27th October 2007 02:11 AM

Page 3 is most informative.

RKH 27th October 2007 06:32 AM


The Pumpkin is the actual pre-amp

Shunty is the regulated power supply for the Pumpkin pre.

Hope that helps.


Zen Mod 27th October 2007 07:46 AM


Originally posted by mpmarino
Page 3 is most informative.
agree ...........
you can't so easy find schematic of INT-150 ........


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