Pumpkin preamp - ordered by Steen , official making thread

believe me - that cap is beneficial only if smallest one is used

ceramic is perfect , but use whatever you have in drawer

as I said - start from 1nF upwards

regarding visit to Italia .......... who knows ...... all roads are heading to Rome , anyway :clown:

Ok tomorrow it will be the first thing I do.

I recently live near Milano,so you should consider the idea to visit the next TOP AUDIO nex September.

But this is an other story😀

Thanks and good night!
 
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Hello Alex! the stuff may you seem strange, but I tried using a 4.7 nF
and I got a result slightly inferior that obtained with 1uF.
Logically, I carried out an analysis of all the frequency range Hz kHz MHz and found that in the range of kHz 1uF gives better results than 4.7 nF.
So now i decided to leave 1uF.😱
Now i need a good layout cables assembly.
Please can you give me same good link or informations, if you prefer, also in Private Post.

Thanks
 
Hi Alex i will use the input selector and volume control showed in pictures attached (red pcb).
I had to change a few things to be able to make it suitable for balanced use . I also have replaced its original pot with a four-way 10K Alps (much better than the original).
In this way i will get the same functionality of the input selector shown in the last picture more the possibility of remote control.😉
In the third picture the last pcb on the right will serve to keep the outputs to ground for a few seconds (about 10) to avoid bump input to the power amp.
What do you think of this device?
 

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COMPARE
the input signal to the output signal using a twin beam or dual trace Cathode Ray Oscilloscope (CRO).
Use a variety of signals, including sine, triangle and square, 10Hz to 50kHz, at a variety of levels.

"Compare" is the really important part of the technique.
 
Tony

for start - if you're not having enough praxis with CRO , just connect this (attached) across spk terminals,of course - with amp powered on
in silent , then with some light level muzak

if LED's are silent , you're good to go , without those two 1nF caps
 

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Cathode Ray Oscilloscope (CRO) ...Good to know,thanks Andrew!

About CRO use...i can try to find the power switch🙂 and after i can try also to do something more...but Alex i have to tell you ..."you know always something more of Devil" What mind had designed this circuit..almost doubt (for its simplicity) that will work!😀

Thanks Alex and Andrew!
 
About shunty heatsink temperature

Hi at all! Please is normal about 70° measured on heatsink of shunty (no load connected and cover open ) ,or i have to add more alluminium sink?
Thank in advance

Antonio
 

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