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When tying a knot solves most of the hum issue!
When tying a knot solves most of the hum issue!
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Old 16th October 2019, 12:22 PM   #31
Galu is offline Galu  Scotland
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Originally Posted by mondogenerator View Post
Ropey* Adjective also used to describe bacterial infected fermentation.
Are you saying my sense of humour is infectious?
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Old 16th October 2019, 12:27 PM   #32
mondogenerator is offline mondogenerator  England
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Well... something is catching
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Old 16th October 2019, 10:14 PM   #33
kodabmx is offline kodabmx  Canada
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When tying a knot solves most of the hum issue!
Quote:
Originally Posted by DF96 View Post
Maybe a slight difference in valve capacitance meant that the other valves tuned to a different station? Parasitic oscillation? Alternatively, maybe you were hearing some residual AM on the carrier.
Any number of things really, but my construction technique has vastly improved from those days. I didn't even use shielded wire from the RCA to the grid... (Neither did my commercial "Belcor" receiver though).

Speaking of shielded wire... You only connect the shield/ground at one end, yes? I connect it only at the RCA end of the link.
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Old 16th October 2019, 10:20 PM   #34
cal3713 is offline cal3713
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Originally Posted by DF96 View Post
If the knot is actually solving the problem, then the problem is due to quite high frequency RF. However, more likely that the knot is a coincidence.
I'm sorry, but I believe "more likely than knot a coincidence" is proper usage here.
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Old 18th October 2019, 06:43 PM   #35
nezbleu is online now nezbleu  Canada
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When tying a knot solves most of the hum issue!
Quote:
Originally Posted by kodabmx View Post
Speaking of shielded wire... You only connect the shield/ground at one end, yes? I connect it only at the RCA end of the link.

You need a signal and a return to complete a circuit. One way to do that is to connect the RCA outer conductor to chassis, and connect signal ground of PC board to chassis at some point, and that completes the circuit. It also makes a big loop and the shield (connected at only one end) does next to nothing because return current does not pass through the shield. Alternatively, isolate* the RCA from the chassis and run a shielded cable with shield connected at both ends, which completes the circuit, reduces loop area, and makes the shield much more effective.


*but with a small cap from RCA outer connector to chassis to make a shorter path to ground for very high frequency noise.
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Old 19th October 2019, 07:10 PM   #36
KaffiMann is offline KaffiMann  Norway
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When tying a knot solves most of the hum issue!
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Originally Posted by cal3713 View Post
I'm sorry, but I believe "more likely than knot a coincidence" is proper usage here.
Indeed!

Whoever said that the occasional bend in the inductor was knot important?
https://pdfs.semanticscholar.org/004...69d66feb3c.pdf
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Old 19th October 2019, 07:15 PM   #37
mchambin is offline mchambin  France
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The knot makes a spintronics effect like in Bybee products.
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Old 20th October 2019, 07:34 PM   #38
KaffiMann is offline KaffiMann  Norway
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When tying a knot solves most of the hum issue!
Quite so! It does certainly put a new spin on tying the knot.
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Old 24th October 2019, 09:56 PM   #39
kodabmx is offline kodabmx  Canada
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When tying a knot solves most of the hum issue!
Knot V2.0... Even better hum rejection...

Now I just need to chase the hiss (brown noise actually). I have a LOT of gain so if I crank the volume without signal I hear noise...
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Old 25th October 2019, 07:29 PM   #40
Vovk Z is offline Vovk Z  Ukraine
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When tying a knot solves most of the hum issue!
Quote:
Originally Posted by lcsaszar View Post
Don't stop here. Some of these must improve the sound:

Knot table - Encyclopedia of Mathematics

But be careful - some of them definitely can summon the devil!
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