finally went to OC139 germanium transistors
This cheap ass version came with BC549C transistors known as one of the common high-gain transistors. The original B&M fuzz seemed to come with BC184C silicon transistors from the many sources on the web. and, I believe there were few different transistors Sola Sound tried at 70’s for this fuzz.
I replaced the components one by one. Omeg pots and 470pf caps made a improvement while NOS 0.1uf Mullard trpical fish didn’t bring a noticeable difference.
Most of the resistors are staying on the circuit board except for 3 of them. cheap ass version came with 3 different resistors than the normal and expensive BUM fuzz. you’ll need each of 100 ohm, 100K, and 33K resistors to revert this circuit to 70’s style. (or expensive version of BUM fuzz). 100 ohm resistor can be replaced with 220 ohm or 0 ohm as well. I’ll check the resistors and update later.
ZTX109 brought a difference anyway. this bum fuzz sounds a bit older and bit alive than the original state with BC549C
This volume boost pedal has optical resistor instead of potentiometer. the pot on the side is for boost not the volume control.
the black taps are screening the light to the optical sensor. you can see how it works from this video.
Ever checked out their gear & accessories community: https://www.ultimate-guitar.com/forum/forumdisplay.php
Grabbed this off reverb.com recently. the seller believed it didn’t work while I believed I could fix it. the price was really good for the reason.
It was a luck. this little thing works fine without any issue. I see 4 Germanium transistors on the circuit board and expected a different sound than the current product. but it sounds pretty much close to the new ones.
According to the schematic I got from https://music-electronics-forum.com/showthread.php?t=8790 , it has 4 transistors.
Two of the germanium transistors (in the black housings) are sitting around the black hood which covers transformers. they seem to be 2SB324H. and I barely see 2SB172A and 2SB175B on the circuit board.
몇주 전에 소리를 들어보고는 마음에 들어서 빌려왔습니다.
리이슈라서 요즘 PCB입니다. 풋스위치 배선을 보니 트루바이패스네요. 예전 영국산 페달들은 Arrow H&H 풋스위치를 썼는데, 요즘은 대부분 미국회사인 Carling 스위치를 쓰네요. 어짜피 둘다 이제는 멕시코에서 만드니 품질은 같을겁니다.
멀라드 OC75 세개가 들어있습니다. 이 퍼즈 소리가 마음에 들어서 비슷하게 개조하려고 Bum Fuzz를 구했습니다. 세세하게는 다르지만 전체적으로는 비슷합니다. Bum Fuzz는 B&M fuzz의 복각이고 Jumbo Tone Bender 회로라서 그냥 대충 봐도 저항과 캐퍼시터가 두배쯤 더 많고, 얘는 상대적으로 단순합니다.
OC75는 유리관에 들어있는 게르마늄트랜지스터로 0.125W 저출력입니다. 60년대 게르마늄 트랜지스터는 용도에 따라 동작주파수가 다른데 얘는 0.1MHz로 동작합니다. 이 정도면 원래 오디오 신호용이 맞는 것 같습니다.
Youtube에서 샘플을 하나 찾았습니다.