Pumpkin preamp - ordered by Steen , official making thread

[Zen Mod]

what was the question ?

 

[Mr. dB]

what was the question ?

Whether or not Kristijan K ever responds to email inquiries? That question?

 

[Zen Mod]

what is having KK with this thread ?

 

[tonimxp]

Hi! Alex i assume kk is KK pcb.
However I do not understand what does KK PCB in this thread too.

what is having KK with this thread ?

 

[tonimxp]

Hi!Mr.Db.

I, too, initially was a little confused, but looking wiring diagrams also a child be able to
understand that the Pumpkin and Shunty topologies are significantly better.

After a number of weeks I'm inclined to give up. Unless someone knows different...

 

[didiet78]

My unfinished Pumpkin Clones. I hope Choky don't mind (It easy to ask forgiveness than ask permission)

An externally hosted image should be here but it was not working when we last tested it.

Didiet

 

[Zen Mod]

everything I could , I put in public domain .....

Lykkkkkdkkkkk was first , making his own pcbs ....

 

[didiet78]

Just finished populating pumpkin. Power Supply with standar LM3x7. When first power on, Led string doesn't light-up. I measured just 4.5V (Gate Q11 and V-). Can you help me?

Thanks

Didiet

 

[Zen Mod]

send me hi-res pics on >sasica5@gmail.com<

you are probably having some mistake on your pcbs , but I can't see anything on thumbnail attached in post #3406

 

[didiet78]

Email sent.

Thanks
Didiet

 

[didiet78]

Led string tested with voltage 11.8V, led light up, so i guest led orientation not wrong. Led Vf=1.97V.

Didiet

 

[AudioSan]

ZM. how was it with bords for dis thing?

 

[Zen Mod]

Led string tested with voltage 11.8V, led light up, so i guest led orientation not wrong. Led Vf=1.97V.

Didiet

I was looking last night at your pcbs and I still can't find what's wrong

will try harder

ZM. how was it with bords for dis thing?

still waiting for Paypal in Serbia

most probably in a month or two , but even then I can't be sure will they include receive money option from start

 

[didiet78]

If i change Led with higher Vf (maybe White or Blue Led) will it make Voltage higher (Gate Q11 and V-) ?
Thank for checking.

Didiet

 

[Zen Mod]

certainly ;

but - why doing that ?

 

[didiet78]

Because i just use LTSpice to sim Led String CCS, and i got 5V, maybe my sim not right.

Update : i lift Gate resistor of CCS output (Q6 and Q8), Led String light up, measure it 11,4V. Howto check mosfet, good or bad ? check with my ohm meter pin G-S i got 220 ohm ( on both Channel, Q6 and Q8)

 

[AudioSan]

I was looking last night at your pcbs and I still can't find what's wrong

will try harder



still waiting for Paypal in Serbia

most probably in a month or two , but even then I can't be sure will they include receive money option from start

aha. bummer. they need some😀

 

[didiet78]

Replace Q6 and Q8 (IRF610), LED string light up (just one channel). I guest Q6 and Q8 on the other channel need replacement too.

Didiet

 

[didiet78]

Q6 and Q8 are faulty. Replace quad of them. On one channel, i can set the offset betwen - gnd and + gnd to get 20mV. Betwen - and + i get 2mV.
On the other chanel i only can get - gnd, + gnd 16V. Betwen - + 2 Volt.

I think Q9 fault too. I'll check again tomorrow

Didiet

 

[tonimxp]

2sj310 matching

Hi at all! Please i just make the matching of 2sj310 (Q1 and Q2) jfet of Pumpink with Zen mod's circuit matcher.
I have found those values of Vgs:
180-184-(187-188)-(193-196) mV so i have match as in parenthesis.

I have to ask you your comments for results.
The current draw is set to 5mA for five minutes test time.

In addition I also bought some 2sj109 used (for future aleph j babbelfish project), can you suggest a method to test their genuineness?

Please can you let me know?

In attached some pictures please to know some comments for results.