Hello, all. I got tired of dreaming about it, so I went ahead and wired up a Tone Bender Mk.I. It's working and has plenty of sustain, but it's awful dark sounding. Are my transistors' hfe too low?

Hi, everyone. I recently purchased a bunch of AC128 transistors on eBay and I was wondering which fuzz circuits should sound good with them. The hfe on them varies. The lowest is 58 and I believe the highest is 75. The leakage on most of them is 0.06 ma with some having 0.12 ma. I used some in my Tone Bender mk. II clone, but it sounds too smooth. I also used them in a Tone Bender mk. 1.5 with slightly better results. I can't seem to get any of them to work in a fuzzrite circuit, though. I'm wondering if they're useable or if I just wasted my money. Thanks.

I've still been using the amp with no problems other than a mild hum. I played through it for over an hour earlier. I wonder where that hum is coming from. I don't think it's the filter caps because it seems to go away when the volume is turned down, I think.

Do you have a different speaker that you could try with it? I had an amp that started making a weird (but cool)  sub octave fuzz sound and it turned out the speaker was bad. Hope this helps.

Very sad news. Hang in there, Roly. Thanks for all your help. Situations like this are difficult and I never know the right things to say. You will be missed by everyone here.

Okay. Thanks again, Juan. I had been wondering if my old fans could be contributing, but maybe that's not the case. Could it be fluctuations in the mains voltage? I have come to suspect this by paying close attention to my vintage fans while running them. Also, there are times when the light in my room either dims or gets slightly brighter. I keep this amp plugged into a surge protector, but I don't know how much protection that actually offers.

Thanks, Juan. So, those antique fans of mine could be causing some of the noises in my amp? That's a shame. I guess I'll just have to live with it. I haven't noticed anything else that could be causing it.

I should also say that I don't live near any traffic lights, or anything like that. I live away from the city on a mountainside. Unless it's coming from the transformer outside, or the well pump, I don't see much anything else that would cause the interface.  I also try to keep my phone at least a few feet away from the amp. I'm really at a loss here.

Thanks. Maybe the problem is the diodes I used,  then. I don't know what they are. I just found some and threw' em in there.  My problem with it is that it sounds too smooth and dark. Sure, the ring modulation is strong and the octave- up effect is there, but where's the insane sounding fuzz that this circuit is so famous for?

Thanks for your suggestions.  I have never taken the amp anywhere, so I don't know how it would act in another house. There was one night when it started making those noises and I determined it was picking up interference from one of my antique fans. Lately,  there's been a faint buzzing noise that comes in after the amp has been on for about 10 or 15 minutes. Could that possibly be some kind of interference. We don't have a working furnace anymore, either, but we do use a submersible well pump. My brother also keeps an air conditioner running in his bedroom, which is less than 20 feet from where the amp is sitting. Thanks again.

Hi, everyone. That Kasino amp is still working, but occasionally makes odd popping sounds through the speaker. I have pulled it apart several times because the old solder kept coming loose in the power section, and there was some corrosion that had to be cleaned out. Is it normal for these amps to make the occasional odd noise, or do I need to start working on it again?

Quote from: teemuk on October 03, 2015, 11:27:47 AM


Final part of the full-wave rectifier made out of two forward biased half wave recitifiers (the diodes) and a differential amp (Q3 & Q4).

I think the point of that BJT differential is that it operates less ideally than a traditional FWR and somewhat "smoothens" the transitional region to cutoff state. If a sinusoidal input is fed to traditional FWR you get a "pulsating" output (IOW rectified sine wave) at 2x input frequency (IOW an "octave up" effect). When you feed the sinusoidal input to this circuit it tends distorts so much near the cutoff state that the output resembles more a sinusoidal wave (at 2x input frequency) than a traditional rectified sinusoidal wave.

Thanks for the explanation,  but I really don't understand what that means. Is the effect supposed to be smooth sounding?

I don't have any way of posting a schematic . I don't even remember the numbers on the transistors I used. I just measured a bunch and used the ones that had the highest gain. Q3 and Q4 are over 500 (Q3), and over 300(Q4). They're not darlingtons, but from the parts I had they had the highest gain.

Hello. I have a question regarding the ampeg scrambler circuit. I built one a while back and it has had many problems, most of which have been solved. The problem I'm having now is the overall smoothness of the effect . The ring modulation and octave up are there, but the overall tone is dark and the fuzz is weak. I've been running it through my Kasino u100-p amplifier , which all my other fuzzes sound great with. Has anyone else had similar problems with this circuit? What can I do to get this thing sounding as it should?

Very true. I don't play anywhere,  so I don't really have any use for any monitor.  I was just curious about it. My amps are actually overkill for my tiny bedroom, but they sound good.