Fuzzface q1 failure
I have a fuzzface on my breadboard, ge, and q1 keeps failing. I play the fuzz for awhile and the next time I use it, q1 is dead. I’ve had 3 transistors die.
Could q2 be the cause? Anyone have this problem?
Could q2 be the cause? Anyone have this problem?
- plush
- Cap Cooler
Which transistors do you useSmoky Black wrote: ↑14 May 2020, 04:38 I have a fuzzface on my breadboard, ge, and q1 keeps failing. I play the fuzz for awhile and the next time I use it, q1 is dead. I’ve had 3 transistors die.
Could q2 be the cause? Anyone have this problem?
Schematic you are using
How do you power your circuit
?
It’s the arbiter GE fuzz face, except I’ve replaced the fuzz pot with a bias control, the cap is wired as full on fuzz, and I’ve got a 1k pot with a 680 ohm resistor at the emitter of q2 to bias,
Q1 is a 2n2625, hard to read, I have a lot of these.
Q2 is a hitachi 2sb175 or 176. It’s powered with a battery.
Due to the direct coupling, I’m wondering whether a problem with q2 could cause a q1 failure.
Q1 is a 2n2625, hard to read, I have a lot of these.
Q2 is a hitachi 2sb175 or 176. It’s powered with a battery.
Due to the direct coupling, I’m wondering whether a problem with q2 could cause a q1 failure.
- plush
- Cap Cooler
I beleive it's simply because you got defective 2n2625s.Smoky Black wrote: ↑14 May 2020, 11:03 It’s the arbiter GE fuzz face, except I’ve replaced the fuzz pot with a bias control, the cap is wired as full on fuzz, and I’ve got a 1k pot with a 680 ohm resistor at the emitter of q2 to bias,
Q1 is a 2n2625, hard to read, I have a lot of these.
Q2 is a hitachi 2sb175 or 176. It’s powered with a battery.
Due to the direct coupling, I’m wondering whether a problem with q2 could cause a q1 failure.
Also, 2n2625 has a very low hfe for a FF. Why did you decide to use them?
I double checked and it’s a 2n2672 in q1, with 3 failures, and a Hitachi 2sa15 in q2.
The 2n2672 is still low hfe, I found them at an electronics surplus store many years ago and bought around 25 because they were cheap. I pick out the ones that are in the 60-70 range.
It’s real frustrating because I get this thing dialed in, and then the transistor fails.
The 2n2672 is still low hfe, I found them at an electronics surplus store many years ago and bought around 25 because they were cheap. I pick out the ones that are in the 60-70 range.
It’s real frustrating because I get this thing dialed in, and then the transistor fails.
- plush
- Cap Cooler
Have you measured their leakage? 60-70 is very unusual for 2672, they could be leaky as f and/or already dead.Smoky Black wrote: ↑14 May 2020, 13:56 I double checked and it’s a 2n2672 in q1, with 3 failures, and a Hitachi 2sa15 in q2.
The 2n2672 is still low hfe, I found them at an electronics surplus store many years ago and bought around 25 because they were cheap. I pick out the ones that are in the 60-70 range.
It’s real frustrating because I get this thing dialed in, and then the transistor fails.
No, I didn’t measure leakage. I thought the leaky ones were the ones that wander really high when testing hfe.
They seem to develop a short from base to emitter. A good one has over 4 meg resistance, and the failed ones 120 ohms at best.
Seems strange to have so many failures, but it could be they’re just messed up. I was just wondering if anyone had ever experienced anything similar. They sound good before they fail...
They seem to develop a short from base to emitter. A good one has over 4 meg resistance, and the failed ones 120 ohms at best.
Seems strange to have so many failures, but it could be they’re just messed up. I was just wondering if anyone had ever experienced anything similar. They sound good before they fail...