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Replacing D type Knobs

tubatodd

tubatodd

Oct 31, 2004
2,456
4,424
Birmingham, AL
#1
I have a Carvin BX250. It's a decent no-frills amp. I was interested in replacing the current knobs with with either a) the same type of knobs but in a different color or b) different style of knobs in either white, silver or colors.

BX250-1_large.jpg


The knobs that are on the amp are the push on variety for solid a D shaped potentiometer. The knob would need to have the flat spot line up with the position marker and not a rotated orientation.

Has anyone replaced similar amp knobs? If so, what did you get and where?
 
#3
agedhorse said:
Sure, all the usual hobby DIY pedal supply companies.

They are not as common however.
Click to expand...
Thank you for your reply and information. You are correct on both accounts. D-shaft knobs are more rare and because they are directional, there is the added headache of knowing where the flat side is. I did some browsing of several pedal supply shops and they have great selections, BUT alas no D-shaft knobs (ok not exactly true, but I didn't care for the 1 I found). Would using a knob for a smooth shaft with a set screw be acceptable? Based on the orientation of the D shape, the set screw would hit the curved back side (that sounds wrong).

D <-- screw

Something like this seems like a decent compromise as long as I set the screw dead center.

Invalid Link Removed

At $0.85 a knob, I suppose it could be worth the experiment.

Edit:
Or these??
Brutalist Knob (18mm OD)
 
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#6
Keep in mind that some potentiometer shafts are 1/4", or 6.35mm, and some are 6mm.
The difference is important!
If you put a 1/4" knob on a 6mm shaft, it'll be loose and won't turn...and if it has a set screw and you tighten it, it'll still visibly wobble.
Obviously a 6mm knob won't fit at all on a 1/4" shaft.

1/4" / 6.35mm is more common for discrete components, and 6mm is more common for PCB mount components, but there are plenty of exceptions.
 
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#7
tubatodd said:
Thank you for your reply and information. You are correct on both accounts. D-shaft knobs are more rare and because they are directional, there is the added headache of knowing where the flat side is. I did some browsing of several pedal supply shops and they have great selections, BUT alas no D-shaft knobs (ok not exactly true, but I didn't care for the 1 I found). Would using a knob for a smooth shaft with a set screw be acceptable? Based on the orientation of the D shape, the set screw would hit the curved back side (that sounds wrong).

D <-- screw

Something like this seems like a decent compromise as long as I set the screw dead center.

Invalid Link Removed

At $0.85 a knob, I suppose it could be worth the experiment.

Edit:
Or these??
Brutalist Knob (18mm OD)
Click to expand...

You would need the 6mm - 6.35mm adapter sleeve to go over your 6mm D shaft. One trick is to then fill the void with a little epoxy, but be sure it doesn't wick down past the D cut. Then it becomes essentially a 6.35mm round shaft.
 
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#8
I'm still somewhat undecided about the color scheme but this is what I was thinking.

Option 1: Same style as the original
Carvin Knobs.png


Option 2: These knobs are 2mm wider. They may cover some of the control markings. I really like the style of them
upload_2022-3-6_8-18-47.png


Best I could do as a mockup
Carvin Knobs2.png


For those who are curious, I used the Google Drawing web app to mock these up. For something called "Drawing" the drawing options are almost non-existent, but the shape options were decent.
 
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#9
Ordered some Davies 1611 (original style) knobs with set screws from Love my Switches. I ordered almost all of the funky colors for the trio on the left side. Asked my wife which group of colors she would recommend......and here you are. The colors not used were red, green and royal blue. I'm digging it. I can always swap out colors if the mood should catch me. The black knobs pictured are the originals. As you can see they all match. I added the brass inserts and the set screws tightened very snug.

IMG_20220311_145714710.jpg
 
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#10
tubatodd said:
Ordered some Davies 1611 (original style) knobs with set screws from Love my Switches. I ordered almost all of the funky colors for the trio on the left side. Asked my wife which group of colors she would recommend......and here you are. The colors not used were red, green and royal blue. I'm digging it. I can always swap out colors if the mood should catch me. The black knobs pictured are the originals. As you can see they all match. I added the brass inserts and the set screws tightened very snug.

View attachment 4617595
Click to expand...

The nice thing about that type of knobs is that you can feel with your fingers the position set without looking. I use chicken head knobs when I mount a pot on the back of a chassis so I can tell with a touch where it's set rather than going around and looking.
 
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#14
Here is another question on knobs: These D-shaft knobs are mounted on my 1991 Ampeg SVT-II non pro. They have an aluminium cover with a dot glued on top of the plastic barrel. Can anyone tell where I can buy these?
 

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#15
LowBonito said:
Here is another question on knobs: These D-shaft knobs are mounted on my 1991 Ampeg SVT-II non pro. They have an aluminium cover with a dot glued on top of the plastic barrel. Can anyone tell where I can buy these?
Click to expand...
Unfortunately, the aluminum cap is a custom part. You may be able to buy similar knobs at fliptops.com, or get lucky and find something close at least.
 
#17
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#19
beans-on-toast said:
The nice thing about that type of knobs is that you can feel with your fingers the position set without looking. I use chicken head knobs when I mount a pot on the back of a chassis so I can tell with a touch where it's set rather than going around and looking.
Click to expand...
I put them on all ('cept the latest one) my basses, as well. :)
 
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