Pumpkin preamp - ordered by Steen , official making thread

[Zen Mod]

I was measuring resistance and found on the board that works
R5=R6 =16k measured across each in circuit and

on the board that doesn't R5=R6 =100k

????

Thanks

tomorrow evening I'll be at home , capable to see all those funny schematics ...

 

[flocchini]

Measured again D-S for Q6 and Q8
Good board .55V
Bad board .38V
Q10 is the same for both boards .55V

Resistance for both boards is in the*Mohm range for neg rail to ground

R5 R6 100k for the bad board and 16.6k for good board

Thanks again for all the help and of course a big thanks to Nelson and the gang for supporting DIY

 

[breizheau]

i received my components (except heatsink....) last week.

i hope to start to populate the Shunty PCB next w-e and to solder all the parts on Pumpkin.

 

[flocchini]

Choky

Me very bad !!!

The difference in resistance measurements that I mentioned across R5, R6 is because I forgot to remove shorts from pos inp to gnd and neg input to ground when I was doing DC setup Sorry !!!!!

The neg voltage still drops to 18V when connected to Pumpkin. I have measured all resistors and I have touched all solder points.

I put Q6 and Q8 back in because without them voltage still dropped. I will replace Q10.

Best

Bob

 

[flocchini]

All FETs on heatsink seem to be about same temp.

Q3/Q4 seem to be hottest components

 

[generg]

go on the sound is as hot as the Qs!

 

[flocchini]

Am pulling fets one at a time to see what is drawing the neg voltage down.

 

[flocchini]

No I am stuck. I have pulled all transistors Q1 to Q11 and I still get the negative voltage dropping to -20V

Ideas?

The power supply with the 400 ohm resistor reads -36V

THANKS

 

[Nelson Pass]

Choky will be my guest early next month. Maybe he would like to fix it
personally.

 

[flocchini]

I would be forever grateful. I don't see any solder bridges - maybe my eyes even with magnifier are too old.

THANKS!!!

 

[Zen Mod]

Choky will be my guest early next month. Maybe he would like to fix it
personally.

if you say that's arrangeable , I'll be glad to do this

 

[audiok]

No I am stuck. I have pulled all transistors Q1 to Q11 and I still get the negative voltage dropping to -20V

Ideas?

The power supply with the 400 ohm resistor reads -36V

THANKS

Hi Flocchini,

Have you connect the input volume ? If not, please try connect it and measure again.

 

[flocchini]

Hi Flocchini,

Have you connect the input volume ? If not, please try connect it and measure again.

I will try this Thank you

 

[Zen Mod]

I presume that can't be a culprit

 

[flocchini]

if you say that's arrangeable , I'll be glad to do this

Many, many thanks to Nelson and Choky !!!

Nelson knows I live just a short drive away. I will keep looking but really appreciate the offer.

 

[Zen Mod]

naah .....

just chill and find some other way to enjoy

we'll sort that right after BAF

edit :

even if I'm confused now ; I understood that I'll be dragged to Ocean , and now I see that you're ~100km from Papa's Ark

 

[Nelson Pass]

Many, many thanks to Nelson and Choky !!!

Nelson knows I live just a short drive away. I will keep looking but really appreciate the offer.

I'm at the coast right now, but you can give it to Kent (Cyclotronguy) at
Pass Labs as soon as you like.

 

[flocchini]

Thanks Nelson

As you know Kent and I go way back and I always enjoy seeing him

Best

Bob

 

[Abraxas336]

I am looking to buy a "A" or "D" package since Zen Mod has some problems with his PCB supplier and I am waiting for a very long time already. If anybody has A or D for sale please let me know.

Thanks
Sven

 

[Bksabath]

Waiting for my package as well

But problems somewhere else not PCB as I was given reason to believe

Hope it get sorted as realy looking forward to build one .

Yess I know I could make my own PCB but do not think it would be a fair thing to do to Zen.

So I shall be patient for a while longher and waith for my messages / prays to be answered.