Pumpkin Preamp - Perfect for F4

Zen Mod said:



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

clarify

six 12 volt battery supply. Ground reference in the middle of the six batteries. A charged 12 volt battery is really ~13 volts. This would mean +-39v instead of +-36v as spec'd. It would probably be a bit more if under a light charge during listening.

In your opinion, will the jfets handle the increased voltage ? Maybe I'd have to increase 27R R20 a bit?
 
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mpmarino said:


six 12 volt battery supply. Ground reference in the middle of the six batteries. A charged 12 volt battery is really ~13 volts. This would mean +-39v instead of +-36v as spec'd. It would probably be a bit more if under a light charge during listening.

In your opinion, will the jfets handle the increased voltage ? Maybe I'd have to increase 27R R20 a bit?


everything OK with that scenario with default values ;

+/-36V isn't carved in stone

leave gray cells on vacation and enjoy

:devilr:

edit:

call gray cells just for moment -

try to think about listening without charging in same time;
leave that just as emergency option
 
OH,

My supply will be 2.9ah, so I don't see it as a major issue. But, the charging circuit does seem to be the quandary. I could use some suggestions.

The psu case has 6 x 12v batts for the pre. This will do the Pumpkin or if I want to try the Xccsxxcxxwacsccssbosoz in the config. It also has 2 x 12v for the phono pre and possible DAC. Now, do you guys think I should 'relay' them all and charge in parallel or just charge them in groups in series? I'd like to use one of those TI SLA charger ICs......


I'm not gonna mention the 4 x 12v x 100ah batts for the amps. woops....
 
Official Court Jester
Joined 2003
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apassgear said:
Besides Choky, has someone else heard this elusive :Pumpkin: thingy?

How about you cookie boy?

Maybe the appropriate day will be by next hollowing…

:D


mpmarino said:


I don't think so.....




;)

ask Papa ;

whatever I bring with my limited mind , he already made centuries ago ;


not first and certainly not last time
 
Zen Mod !

Really looking forward to see picture's of pumpkin from 'Burning Amp'... Just hoping someone will post a few, while show goes on next month :) ...

What kind of attenuator are suitable for the pumpkin, i mean 4deck rotary switch? / relay attenuator? / impedance? / db step's? / ohm's, Kohm's? etc ???...
The thing is, that i just rebuild my bosoz for balanced out. While not having any balanced attenuator, i just put in my alps pot at the input. It's working good through it's not optimal... the bosoz swings 10v with 1v input now click on bosoz scope test on the link here , and my F4 are really coming to live now !!! :D Wooooow factor just showed up in my living room -- > not giving any more comment's now as i guess it's offtopic :cool: <--, i guess the F4 driving balanced now are up near(not all the way) to 2/3 of the max, compared to my LeachAmp125w...

So, what kind of attenuator should i be looking for ??? :D ofcause futureproof for :Pumpkin:

Jesper.:cool:
 

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