MP
2379 posts
Jul 30, 2012
12:31 PM
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hey all,
wanted to put a uf cap on a 151 element to roll off
the highs.
i can't remember the value of the cap.
Anyone know the capacitor value for this mod?
thanks, Mark
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MP
affordable reed replacement and repairs.
"making the world a better place, one harmonica at a time"
click user name for info-
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tmf714
1198 posts
Jul 30, 2012
1:15 PM
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Rod used a 500pf cap- here is the diagram-150 is the voltage,not the cap value-
Last Edited by on Jul 30, 2012 1:16 PM
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dted
21 posts
Jul 30, 2012
6:07 PM
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Rod's mod is NOT to roll off highs, but to preserve the highs as you turn down the 5M volume pot. This is a guitar volume pot trick.
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1847
99 posts
Jul 30, 2012
6:33 PM
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i am not an electrician
the cap is sang cmo5fd
151-j03
as i understand it... 150 pf
500 volts
Last Edited by on Jul 30, 2012 6:43 PM
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barbequebob
1995 posts
Jul 31, 2012
8:16 AM
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Dted's description is on the money and that cap works when you turn the volume pot down and is not supposed to do anything when the pot is turned all the way up, and with most volume controls, when the pot gets rolled down, many times the extreme lows and highs overtakes the mids too much and the cap keeps it working like the pot is tuned all the way up. It's a trick that was used on pre-1956 Fender Telecaster guitars (as well as it's predecessor, the Fender Broadcaster).
If you expect anything to get boosted when the pot is turned all the way up, it ain't gonna happen because it only kicks in when the pot is rolled downward.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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MP
2380 posts
Jul 31, 2012
12:59 PM
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well thanks everyone!
i was under the impression that the mod did the opposite.
and not only that, it only works in tandem with a 5 meg VC.
cool. mark
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MP
affordable reed replacement and repairs.
"making the world a better place, one harmonica at a time"
click user name for info-
|
Greg Heumann
1725 posts
Jul 31, 2012
1:09 PM
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no passive (unpowered) component can ADD anything. It can only take it away. In this circuit, it takes away highs at full volume, but the effect is reduced as you lower the volume.
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/Greg
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MP
2381 posts
Jul 31, 2012
2:00 PM
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so greg,
will adding this component to my crystal reduce some highs in a mic without a volume pot?
i hadn't planned on a VC. unless it was a 5meg inline thing added later on.
EDIT: the reason i'm asking is that i used to buy MC-151 NOS crystals from Angela Instruments. $18..those were the days!
they [Angela] had all kinds of mic tips, from the wacky "roll your own" beer can mic- i made one :-)- to soldering a component to the hot and not terminals on your element to roll off some high end.
after Angela sold all their good stuff, that was that. oh well...
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MP
affordable reed replacement and repairs.
"making the world a better place, one harmonica at a time"
click user name for info-
Last Edited by on Jul 31, 2012 2:59 PM
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MP
2382 posts
Jul 31, 2012
3:12 PM
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BOb,
interesting trivia on the tele and broadcaster.
which reminds me of a story....
a friends wife saw a Fender Squire in a Goodwill store
and told him about it. he goes to the Goodwill and it is NOT a Squire. it is an Esquire! and not only that, it is a lefty!
long story short, the guitar was sold for a pretty penny to SouthPaw Guitars.
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MP
affordable reed replacement and repairs.
"making the world a better place, one harmonica at a time"
click user name for info-
|
1847
101 posts
Jul 31, 2012
4:02 PM
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mouser makes a 5 meg pot
that will fit right in the front
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MP
2383 posts
Aug 01, 2012
12:16 PM
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thanks 1847,tmf,and dted!
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MP
affordable reed replacement and repairs.
"making the world a better place, one harmonica at a time"
click user name for info-
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