I ended up rebuilding my SSS and upon finishing have been testing it with the current limiter where I've had a few instances of blown fuses. 3A fuse ended up blowing with a spark at the bias pot, resoldered the joint at the bias pot and the fuse is fine now. I then had the 1A fuse blowing which was due to a mistake with a backwards diode on the bias board. Fuses aren't blowing now but I've noticed with the current limiter that when turning the amp off of standby it increases in light until its stable but there's slight flickering of the bulb almost like a pulse. Before the tubes were in I didn't see the flickering. It's a 150W bulb and definitely isn't glowing at the maximum compared to plugging it directly into an outlet. Is the slight flickering to be expected or should I be worried about a short somewhere? I haven't biased the tubes yet
Attached a video for reference and tried capturing the flickering by changing the exposure mid video but you can't really see it unless you're directly looking at it.
https://streamable.com/awqj47
Current Limiter Flickering
Moderators: pompeiisneaks, Colossal
Re: Current Limiter Flickering
Don't think I can tell anything from the video. I usually use a clear 150w bulb and I would expect a fairly subtle glow from that amp. Not entirely sure what you mean by flicker, could be an oscillation from some kind of wiring error, power supply problem, lead dress issue, or bias irregularity. The amount of glow is directly proportional to the amount of current the amp is drawing, so a pulse could be a problem, or it could be any signal through the amp. Check the bias before you take it off the limiter. Expect lower numbers while it is on the limiter, but biasing the power amp cold while testing is perfectly fine. It is a lot faster to go slow in these situations.
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Stevem
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Re: Current Limiter Flickering
It sounds like when you had that bias diode in wrong you where feeding positive voltage into the negative end of the bias filter, so I would replace that cap just to be on the safe side.
Do not put the output tubes back in until you confirm the needed negative bias going to each tube.
Do not put the output tubes back in until you confirm the needed negative bias going to each tube.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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nwilderman
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Re: Current Limiter Flickering
Hmm thats a good point, I'll take them out and order this morning.Stevem wrote: ↑Tue Aug 08, 2023 10:30 am It sounds like when you had that bias diode in wrong you where feeding positive voltage into the negative end of the bias filter, so I would replace that cap just to be on the safe side.
Do not put the output tubes back in until you confirm the needed negative bias going to each tube.
Also ended up testing without the current limiter last night and all the tubes were on, but there turned out to be no sound at all, even with a cable connecting the FX loop. Transformers, tubes, and chassis scraped from original SSS build, v2.2 boards except for the power board v1.0
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Stevem
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Re: Current Limiter Flickering
On your left most output tube socket ( the one next to the red and black bias test sockets) the lead on the left side end of the 500 ohm screen resistor is super close to shorting on the heater wire.
Can you post a schematic for this build?
Can you post a schematic for this build?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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nwilderman
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Re: Current Limiter Flickering
Late response but ended up having a short on the terminal next to the reverb board. Limiter dimmed to almost nothing when I fixed it, plugged the amp into the outlet and didn't have any smoke or signs of shorting on the PCBs. Replaced my old OT and choke while I was at it too.
No sound unless I'm plugged directly into the FX loop in though. Going off of Ryan and Erwin's SSS schematic and eyelet layout I attached. Here's the voltages I'm getting
No sound unless I'm plugged directly into the FX loop in though. Going off of Ryan and Erwin's SSS schematic and eyelet layout I attached. Here's the voltages I'm getting
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Last edited by nwilderman on Mon Sep 25, 2023 7:20 pm, edited 3 times in total.
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Stevem
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Re: Current Limiter Flickering
That's not a schematic, it's a wiring layout, and providing folks you want to help you out with that only cost them a lot more time as compared to viewing a true schematic.
I guess that since you have had other errors in this build caused by you yourself that this is the case again and the wiring layout you are working off of is correct.
I suggest you look for errors back on up stream from the power amp in jack of the effect loop back to the first gain stage.
I guess that since you have had other errors in this build caused by you yourself that this is the case again and the wiring layout you are working off of is correct.
I suggest you look for errors back on up stream from the power amp in jack of the effect loop back to the first gain stage.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Current Limiter Flickering
Assuming your circuit is the same as the schematic I have for SSS #2 (just one I found on here, which is different than what your layout shows but appears to have the same output section), I'd want to know if you're getting anything out of the effects loop if you run that into an effects return of another amp. That'd help isolate the problem as a preamp or power amp problem. Zero sound at all after having positive bias voltage due to the reversed bias diode makes me think something might have died in the power amp during the initial test, but without a schematic and without knowing where the problem localizes, it could be something as innocent as a bad solder joint in the signal path.
What did you find when you removed the first OT?
What did you find when you removed the first OT?