The right brite cap

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Andy Le Blanc
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The right brite cap

Post by Andy Le Blanc »

Just buttoning up a mod thats based on a JCM 800.

I happened to try an old SANGAMO TYPE 33 .001 as the
brite cap over the first volume control in the circuit,
exploring parts and voicing......
I'm blown away it makes the tone of the rig.

I picked the cap out of a box of junk and glad I tried it.

Whats the preferred cap? Mustard?
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Firestorm
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Re: The right brite cap

Post by Firestorm »

Did you measure it?
Andy Le Blanc
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Re: The right brite cap

Post by Andy Le Blanc »

Ya.... Its .0014. It wasn't the low end. Its the top that gets me.
Smooth smooth smooth. That circuit can be very aggressive.
The top can be harsh a bit hot with a ceramic or mica.
Somthing about it... Smooth and complex.
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Andy Le Blanc
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Location: central Maine

Re: The right brite cap

Post by Andy Le Blanc »

I bet its because theyre old leaky crappy parts.

Seems miraculous where its applied.
Cheep poly nichicon for the signal path. No odd values.
One other mica after the clip stage but run of the mill otherwise
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Stevem
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Re: The right brite cap

Post by Stevem »

I like a oil cap for those uses, but keep in mind that placing a cap where you have will only provide added briteness up until the pot gets mid way open, after that the cap is out of the circuit!
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!
Andy Le Blanc
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Location: central Maine

Re: The right brite cap

Post by Andy Le Blanc »

Yes yes... Im just stunned that the tone structure seems so reliant on one cap.
It seems to pass just the right portion of the upper mid and not the harsh high mids.

I've had some traynors over the bench with the same value cap in the same position
In the circuit. On a brite switch... Really changes the structure.
But it tends to be harsh... Other lead master rigs... even modern production amp

It might come to cap testing and selection. Be nice to have a criteria for parts selection,
especially after stumbling upon what seems to be just so.

Preferred caps for old Marshall amps?
Cap tester? Test results?
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Stevem
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Re: The right brite cap

Post by Stevem »

You could also be hearing for lack of a better word the unintentional smoothing of that amps circuit layout and it output transformer in regards to the lack of harshness!
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!
Andy Le Blanc
Posts: 2582
Joined: Sat Dec 22, 2007 1:16 am
Location: central Maine

Re: The right brite cap

Post by Andy Le Blanc »

Thats a thought. The circuit is not much different as far as the
tone formation component goes... But to get both channels to
play nice and in phase I had to back up the mix component a gain
stage and reduce the drive channel output with a Pi attenuator.

So... Ceramic and mica's were OK... Poly OK... but that one old cap
was just so. I didn't try old molded paper....

Client loves it... I know its not just me.
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roberto
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Re: The right brite cap

Post by roberto »

Andy, have you used them in other circuits and positions?
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M Fowler
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Re: The right brite cap

Post by M Fowler »

I recently used a domino cap from my junk drawer measured 220pf as the bright cap and it was so smooth sounding, I'm a believer too.
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roberto
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Re: The right brite cap

Post by roberto »

I've done alot of tests years ago, when I wasn't abroad so often, and sometimes I found some reasons (caps' datasheets can hide interesting informations, not only to a ME like me, but for EEs too), sometimes I've noticed some tendencied to certain specifications (years ago Wima was more on the excess of capacity, rather than below the declared value), but I still keep some preferences for certain caps, and for some of them I'm still in the believer/dontwhowwhy stege.
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