Discovered a way to customize cap values

AJAR1958

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Hello all, thought I would share something that I've had good success with lately. I have a Heathkit DC-1 Decade Capacitance Box ( in a wood casing no less ) and I have been using it to customize cap values on my Burny/Greco/Tokai vintage LP's. It's quite interesting ( and a little noisy ) to switch the values from .010uf up to about .050uf or higher and playing for awhile. Helps to decide which value works the best for a particular pickup/pot combination ( and different wood quality/construction for the very particular ). I have one Tokai that actually sounded the most versatile with a .047 in the neck and a .033 in the bridge, which was weird, but it works on that particular guitar. I also managed to improve the tone of a Chinese made Bacchus which had pickups that sounded kinda awful - reducing the value in that case worked well. Generally 500K pots are the way to go, although those values vary quite a bit from guitar to guitar, which also affects the slope, as most of you know.
How do I do it ? Well I start with the pickups positioned level with the mounting rings, no closer than 4 to 5 mm to the strings, depends where you have your action set of course, with no polepiece adjustment. I remove the existing caps and attach a locking type set of clips you get with a multimeter to the decade box ( very important - you dont want to woof out your expensive Celestion when trying a high volume powerchord if the connection comes loose ). One you are in a seated position to limit the possibility of a an untimely disconnection, dial the decade box to .010uf and start playing using the pickup you are connected to while adjusting the tone control all the way up and down . Increase the value after a while and play some more, and then....well, you get the picture...once you find the tone you are happy with for each pickup make a note of the value and find the cap that most closely matches that and solder it in. Use decent quality caps of course, but no you don't have to spend a fortune on them either.
The decade box I'm using is from the 60's so yes there is that caveat - meaning the accuracy was probably very good when new but time does alter the value a bit - and there is the capacitance that is added from the connector you use running from the decade box to the pots, but I have found it is still a reasonably accurate method for testing how the values affect the tone. And its kinda fun too...
As always, YMMV....
 

Knoby

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Good stuff :yesway:

Do you have pictures of the box and connections?
 

AJAR1958

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Sure, here is the photo of the box plus the connectors I use. It was fortunate for me that the two multimeter probe wires fit together so I didn't have to solder anything up in this case. Main thing are those sprung locking probes, and having wire long enough to have the box beside you on a little table or something so it doesn't pull on the connectors.
 

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