Projects => Build Reports => Topic started by: yomanfree on July 10, 2011, 03:51:34 PM

Title: Chunk chunk
Post by: yomanfree on July 10, 2011, 03:51:34 PM
Hi guys
second time that I do the famous Dr Boogey .....
But even with shielding technics, not possible to have an acceptable noise at high volume ...
Therefore I've tried several transistors config even if it decreases slightly the disto.
Quickly, exit the mpf102, I've found it too much muddy (even when replacing just one J201). The sound is darker.
Then I've tried the 2N5457. From my opinion this is a good choice even if I prefer slightly the J201. In fact, it sounds differently to my ears.
- the noise strongly decrease  ;D.
- the gain remains at a high level even if not at the same high level than with the J201.
- The sound has a bit more bass, is "hoter"
- With the J201, the pedal sound is sharper ....

I would have prefered to keep the J201 to keep the sharp, but for the noise control it is from my opinion a requirement to use 2N5458. But it remains a quite good pedal even with this transistor.
To be noticed: I've changed the 2 first J201 (2 first stages) + output buffer, because I've found it gives a good balance in term of bass-treble.

I have had one regret with the PCB: it just misses 1mm between pots to be able to mount them straightly on the PCB (and saves a lot of wires). But this mm cannot be added (if it was, it could not be possible to use a 1590B enclosure). One good idea could be to have 2 different lines of 16mm pots across the PCB, solded back side (I've already done that for a 5cm = 2 inches PCB).


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Title: Re: Chunk chunk
Post by: Haberdasher on July 10, 2011, 06:05:08 PM
Nice job on that!  I like the subtle look of those letters.

Another jfet to try is toshiba 2sk117, tayda has them for 24 cents.  You just have to switch the source and gate pins around, and then it faces the same way as j201 or 2n5457.

I used them in my rump roast build and they sounded better than the other 2 in my opinion.
Title: Re: Chunk chunk
Post by: nzCdog on July 11, 2011, 12:32:53 AM
If you had problems with the pots I can't tell...
That layout is awesome man, nice job! 8)
Title: Re: Chunk chunk
Post by: yomanfree on July 11, 2011, 07:45:32 PM
for the pots, I've tried to show the idea in the picture attached. The red circles show where the 6 pots 16mm can be solded (but bottom side) .....
The PCB is 5cm x 5cm (roughtly 2inches x 2inches).
Seems to me the cheapest solution which removes a lot of wires (when the number of pots is high and pedal is noise sensitive, like in the Dr Boogey).
Good night (in France)


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