Not pretty, but I want it sorted once and for all...
#002 Steel String Singer - almost there
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Re: #002 Steel String Singer - almost there
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- martin manning
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Re: #002 Steel String Singer - almost there
If everything is good up to the points where the red/green/white leads connect to the filters (but check that), then the problem must be within the R and C arrays and/or switches. There is no way the effect should be barely audible.
Re: #002 Steel String Singer - almost there
I've checked everything. I get the exact pf and resistance values on from common to the white or red board connection when I rotate the switch.martin manning wrote: ↑Mon Mar 11, 2024 1:53 pmIf everything is good up to the points where the red/green/white leads connect to the filters (but check that), then the problem must be within the R and C arrays and/or switches. There is no way the effect should be barely audible.
Do you know someone else who used this filters with Erwins boards?
Cheers
Gerhard
- martin manning
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Re: #002 Steel String Singer - almost there
That's a good question, since some of the filter components are on the boards. Maybe Erwin can look into that? I would be happy to check for problems, but I don't have his pcb files or even a picture of the traces and component positions. Maybe they are the same as Ryan's eyelet board layout?
- Raja_Kentut
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Re: #002 Steel String Singer - almost there
you lose always power...and heat the atmosphere the MOV only active in case of a open load condition which won't last for a long time, normally.bepone wrote: ↑Mon Mar 11, 2024 11:29 amand what about this simplicity, R=47R 5W permanently soldered to the output jack?Raja_Kentut wrote: ↑Sun Mar 10, 2024 2:44 pm a cheap way to protect the OT against secondary open condition is a MOV (metal oxyd varistor) just solder it directly over one of the output windings.
and the MOV is small...and a part that could have been used since the 30's so its "authentic"
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- erwin_ve
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Re: #002 Steel String Singer - almost there
Ill do a screenshot of the pcb, they are the same as Ryan's tho.martin manning wrote: ↑Mon Mar 11, 2024 5:35 pm That's a good question, since some of the filter components are on the boards. Maybe Erwin can look into that? I would be happy to check for problems, but I don't have his pcb files or even a picture of the traces and component positions. Maybe they are the same as Ryan's eyelet board layout?
Edit; see below
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Re: #002 Steel String Singer - almost there
Thanks Erwin.erwin_ve wrote: ↑Mon Mar 11, 2024 6:34 pmIll do a screenshot of the pcb, they are the same as Ryan's tho.martin manning wrote: ↑Mon Mar 11, 2024 5:35 pm That's a good question, since some of the filter components are on the boards. Maybe Erwin can look into that? I would be happy to check for problems, but I don't have his pcb files or even a picture of the traces and component positions. Maybe they are the same as Ryan's eyelet board layout?
Edit; see below
I have a 1 M instead the 470k after the 1nf. And the 3nf over the 100k to ground after the 820k. I took it off the switch today for testing. The inductor is jumped. That's all.
Cheers
Gerhard
Re: #002 Steel String Singer - almost there
I used Erwin's boards and Martins filters and the difference between switch positions is easy to hear.Maybe I'm expecting too much. I can measure different values, but I can barely hear any difference, when I switch the positions.
Shouldn't your first cap on the switch (orange drop) be connected to the rest of the capacitor "commons" white wire? Yours is grounded.
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Re: #002 Steel String Singer - almost there
No, it's the 3nf that is parallel to the 100k to ground at the green line.award70 wrote: ↑Mon Mar 11, 2024 7:35 pmI used Erwin's boards and Martins filters and the difference between switch positions is easy to hear.Maybe I'm expecting too much. I can measure different values, but I can barely hear any difference, when I switch the positions.
Shouldn't your first cap on the switch (orange drop) be connected to the rest of the capacitor "commons" white wire? Yours is grounded.
Cheers
Gerhard
- martin manning
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Re: #002 Steel String Singer - almost there
Marked up layout is here: https://ampgarage.com/forum/viewtopic.p ... 79#p463579
Re: #002 Steel String Singer - almost there
Thanks Martin.martin manning wrote: ↑Mon Mar 11, 2024 8:26 pm Marked up layout is here: https://ampgarage.com/forum/viewtopic.p ... 79#p463579
That's exactly what I've done. Except some small value differences 1n instead 1.5n, 1m, 100k...
I think, somethings wrong with that switches and everything on it. Time to start from scratch.
I'll order the right switches from Mouser and do it again.
Cheers
Gerhard
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Re: #002 Steel String Singer - almost there
If you are going to change the switches i can recommend using 11 position switches (blocked at 7 positions) like the original hand drawn schematic.
This way you can make a common bus for the capacitors
like the original schematic is drawn and as is visible on the gutshot of SSS001. (But if you measure the right values, i dont think new switches will make a difference.)
This way you can make a common bus for the capacitors
like the original schematic is drawn and as is visible on the gutshot of SSS001. (But if you measure the right values, i dont think new switches will make a difference.)
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Re: #002 Steel String Singer - almost there
I don't know what else to do. The only thing thats left are the switches.
Re: #002 Steel String Singer - almost there
I've found it and it's a shame:
4k7 instead of 470k at the LNFB. What a bummer, so stupid
Now the filter works as expected. I think, I'll change the switches anyway. These are so bulky and hard to rotate... like an old oven...
The amp sounds totaly different now. It had a lot of sag with the 4k7. Now it sound really big and responsive. I need to explore it some more the next few days, but I'm sure I will not be disappointed at all.
Again, thank you all for your support, I really appreciate it. Special thanks to Martin for his effort with the drawings.
Cheers
Gerhard
4k7 instead of 470k at the LNFB. What a bummer, so stupid
Now the filter works as expected. I think, I'll change the switches anyway. These are so bulky and hard to rotate... like an old oven...
The amp sounds totaly different now. It had a lot of sag with the 4k7. Now it sound really big and responsive. I need to explore it some more the next few days, but I'm sure I will not be disappointed at all.
Again, thank you all for your support, I really appreciate it. Special thanks to Martin for his effort with the drawings.
Cheers
Gerhard
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