DF-2 Super Feedbacker & Distortion MIJ vs. MIT (noise issue)

[Pepe]

I have owned five DF-2 pedals in total. Three were Made in Japan, two were Made in Taiwan. Right now I have these two (left: MIJ, right: MIT).



As I wrote here I ran into strange noise problems with a Taiwanese DF-2 in the past. That was long ago and for the last years I thought that a better power supply or a fresh battery could have resulted in proper operation.

So with the gathered knowledge of another twenty years and improved skills I bought another MIT DF-2 a few months ago. As soon as I plugged it in I rediscovered the undesirable noise: a constantly ticking sound whenever the pedal is engaged. A cycling "tic-a-tic-a-tic-a".

I found out that this noise vanishes when another buffered pedal is placed before the Taiwanese DF-2. So you always have to use two pedals if you want to use an MIT DF-2. I don't know if there are exceptions. My two Taiwanese models had this noise, whereas the three Japanese units were working flawlessly. All the DF-2 units are ACA models, no matter if MIJ or MIT.

So I wondered what might be the cause of this ticking noise. The circuit boards are the same in the two pedals that I have right now. In the Japanese unit the unused IC legs are soldered to the board, while the Taiwanese unit has no solder on these legs, but that is the only difference and of course not the cause of this behaviour.


(click on the picture for a photo in higher resolution)

So the reason must lie in the used components. All the ICs used in the MIJ and MIT units are the same. At first glance the only difference is the colour of the capacitors (MIJ: green, MIT: brown) and the diodes (MIJ: yellow ring, MIT: black ring). Another difference is that the transistors Q12 to Q15 are 2SC2603 (marked "603") in the MIJ unit, whereas 2SC945 transistors were used in the MIT version.


(click on the picture for a photo in higher resolution)

Could the differently coloured capacitors or the different transistors be the cause of the noise in the Taiwanese model?

[zentropa]

At first glance the only difference is the colour of the capacitors (MIJ: green, MIT: brown)
Could the differently coloured capacitors or the different transistors be the cause of the noise in the Taiwanese model?

My gut tells me the brown caps aren't original.

[Pepe]

Both pedals have not been modified. The solder joints don't look as if someone had tinkered with the board.

[bigtone23]

I used to have a very early MIT ACA DS1, when comparing it to my 86 DS1, there were similar differences. The MIT had brownish caps, MIJ green. My picture is not super sharp, but it also appears the diodes in the MIT are black band, the MIJ blue?

[Zerksies]

I've seen them caps in unmodded pedals

[Pepe]

I have just seen a Taiwanese DF-2 with PSA Sticker and Label in the internet. I wonder if these produce the ticking noise, too.