Pumpkin preamp - ordered by Steen , official making thread - Page 338

Itsmee · 12th February 2012, 09:32 AM

Hi BKsabath,

These are the transformers I bought for my Pumpkin, not too expensive

Buy Chassis Mounting Transformers Frame mount transformer,75VA 2x50V o/p RS 10-5879 online from RS for next day delivery.

Bksabath · 12th February 2012, 10:30 PM

Tanks Itsmee

I belive AC V rated X 1.471 = 73 V DC
100V capacitors then.

Bksabath · 13th May 2012, 08:51 AM

It has been A long time since last post

I got a Shunty working fine yesterday the other just wont have it.
I have most probably messed up the PCB when desoldering components for the third time.

I am going to start and probably bench test Pumpkin today.

Questions
What gain you use for F5?
I am thinking 4 may be the best compromise so R5 R6 at about 47K
As those are about 1/2 then C1 C2 = 10P ?

Zen Mod · 13th May 2012, 09:39 AM

yup

Bksabath · 13th May 2012, 01:00 PM

TA

Bksabath · 12:00 PM

Long time since
Got my Pumpkin getting there.
Got same truble with setting up ofset sems to go from +3 to - X V as WR1 turns atiny winy fraction so I put on same red and green components.

Did I do this right (please remember I have attention span of Dodo site of Trillobite and move swings that would make Marvin estatic)
so when one vrites turn pot to zero it takes me quite a lot to decide to ground the imputs and still wonder if is right.
So question :

Are green and red componets in right place?
And by the way
Prety crappy square
Prety good square
Prety nasty mod (green and red dudas)

Bksabath · 1st July 2012, 01:11 PM

And another thing

Crappy square is on crappy scope at 200 KHz so

Zen Mod · 1st July 2012, 09:06 PM

sorry

will look tomorrow

me brain is on 10% of usual 10%

had 560km of driving today , with air conditioner on all the time

it would be more enjoying that I took bicycle for that trip , instead of car

in any case - whatever you do , that devily vegetable must be in final case , with lid on

usual drill as with any Papa's creature - temp equilibrium is 70% of story

Bksabath · 2nd July 2012, 07:27 AM

WHAT VEGETABLE?

Fruty thing work first time preaty steady out of box down to cuple of millivolts between T1 an T2 just sitting on bench.

Can't wait for second chanell to mesure up and then in the box

PS you yes quite right...
Take your time me going for spatcha now.

jacco vermeulen · 2nd July 2012, 08:40 AM

I take it you cook better than the average Englishman too.

13th May 2012, 09:39 AM	#3374
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	yup __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

1st July 2012, 09:06 PM	#3378
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	sorry will look tomorrow me brain is on 10% of usual 10% had 560km of driving today , with air conditioner on all the time it would be more enjoying that I took bicycle for that trip , instead of car in any case - whatever you do , that devily vegetable must be in final case , with lid on usual drill as with any Papa's creature - temp equilibrium is 70% of story __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

2nd July 2012, 08:40 AM	#3380
jacco vermeulen diyAudio Member Join Date: Oct 2004 Location: At the sea front, Rotterdam or Curaçao	I take it you cook better than the average Englishman too. __________________ Not so much,.......if it says "ZM" in the corner.

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12th February 2012, 09:32 AM	#3371
Itsmee diyAudio Member Join Date: Feb 2009	Hi BKsabath, These are the transformers I bought for my Pumpkin, not too expensive Buy Chassis Mounting Transformers Frame mount transformer,75VA 2x50V o/p RS 10-5879 online from RS for next day delivery.

12th February 2012, 10:30 PM	#3372
Bksabath diyAudio Member Join Date: Dec 2007	Tanks Itsmee I belive AC V rated X 1.471 = 73 V DC 100V capacitors then.

13th May 2012, 08:51 AM	#3373
Bksabath diyAudio Member Join Date: Dec 2007	It has been A long time since last post I got a Shunty working fine yesterday the other just wont have it. I have most probably messed up the PCB when desoldering components for the third time. I am going to start and probably bench test Pumpkin today. Questions What gain you use for F5? I am thinking 4 may be the best compromise so R5 R6 at about 47K As those are about 1/2 then C1 C2 = 10P ?

13th May 2012, 01:00 PM	#3375
Bksabath diyAudio Member Join Date: Dec 2007	TA

1st July 2012, 01:11 PM	#3377
Bksabath diyAudio Member Join Date: Dec 2007	And another thing Crappy square is on crappy scope at 200 KHz so

2nd July 2012, 07:27 AM	#3379
Bksabath diyAudio Member Join Date: Dec 2007	WHAT VEGETABLE? Fruty thing work first time preaty steady out of box down to cuple of millivolts between T1 an T2 just sitting on bench. Can't wait for second chanell to mesure up and then in the box PS you yes quite right... Take your time me going for spatcha now.