Pumpkin preamp - ordered by Steen , official making thread

Thank you very much. I've been missing you too:)
I made a few mods on my Pumpkin, and reading through the Pumpkin manual, it dawned on me that 10 years had passed..... Chocking. BTW the child drawing puts a smile on my face, every time! Anyway, going through my stash, i found a few 2sk369V's, that needed a good home, so good old Pumpkin was in for a little surgery. I also made a few more mods, like the inputcap subboard, with provision to short -IN to GND via a jumper and some other small tweaks...
An externally hosted image should be here but it was not working when we last tested it.
 
damn ..... that big pcb , with selector and everything onboard (maybe just mono ) and with servo to avoid all caps ........ it's always on back burner .....

:)

Pumpkin V2.0, count me in :) Not sure about the servo, though. Input caps might be a better solution, if good caps are used (just some polyprops) Pumpkin has an extremely good definition and soundstage as is. Topology and Shunty, are probably main reasons for this.

One more pic:
Pumpkin has to be taken out, and put on top shelf for extended listening periods. You might want to take a look at the dissipation, for environmental reasons:cop: :)
An externally hosted image should be here but it was not working when we last tested it.
 
Hi Zen Mod,

I have been thinking of making a universal attenuator board to be controlled by an arduino. I like the ap1.7 design and would like to use it for other amps, like the pumpkin.

Can I use an ap1.7 type attenuator (schematic from ap1.7 service manual), replace the attenuation resistors with 50k, 100k, 200k, 400k, 800k, 1M6 and 3M2 (I think this would give a 25k input impedance) and place before input of the pumpkin? Or is a different type of attenuator better?

Thanks,

Albert
 
Official Court Jester
Joined 2003
Paid Member
ZM , here ..... to serve and protect ..... with all usual consequences :clown:

250px-Dredd_Apocalypse_War.jpg
 
1. yes - one Shunty for two Pumpies , with better heatsinking than for 2+2
4E7 is old European trick to confuse boyz from other side of Big Splash :clown: ........ same as you boyz wrote uuF , driving us nutz :rofl:

Hi,
I am prepping a parts order (the boards have now reached suffienct age) :D

I am thrown by the 4E7 notation as well. Can someone confirm my understanding below:
4E7 = 4.7 Ohms
390E = 390 Ohms

Thanks!