Topic: AD-20 Knob Mod?

[MPB]

Saw these pictures of an Ad-20 in the ys with a Knob Mod

Anyone know more details of what knobs to use, how they attach (remove original or fit over the top).


Unit was bought from redbook member aprox. 1 year ago, in perfect working condition, some minus scratches of use, and I've recorded 20-25 shows with this great pre. The unit has the mod for the gain pots (they were replaced into bigger ones)


Pictures:
 
     

[Church-Audio]

Saw these pictures of an Ad-20 in the ys with a Knob Mod

Anyone know more details of what knobs to use, how they attach (remove original or fit over the top).


Unit was bought from redbook member aprox. 1 year ago, in perfect working condition, some minus scratches of use, and I've recorded 20-25 shows with this great pre. The unit has the mod for the gain pots (they were replaced into bigger ones)


Pictures:
 
     

If you can tell me what size the shaft of the potentiometer is I might have some that you can have for free.

[MPB]

Hi Chris

I can't get the old knobs off by tugging on them & don't want to force them. Haven't opened it up yet either as I'm waiting on advice from someone who has done this mod already.

The original knobs are small so the shaft would be tiny if there is one. I am thinking new knobs go over the top & are held with a grubscrew.

Martin

[musicsherlock]

http://www.radioshack.com/product/index.jsp?productId=2103790&cp=&sr=1&origkw=knob&kw=knob&parentPage=search

[Church-Audio]

Hi Chris

I can't get the old knobs off by tugging on them & don't want to force them. Haven't opened it up yet either as I'm waiting on advice from someone who has done this mod already.

The original knobs are small so the shaft would be tiny if there is one. I am thinking new knobs go over the top & are held with a grubscrew.

Martin

Ok sorry I could not be of any help but keep me in mind if you need the knobs ok. I have lots of them and need to get rid of a few lol.

[MLKLuke]

I found this description on an old DAT-HEADS digest:

"Denecke AD-20 modifications. Date: Mon, 2 Sep 2002 02:40:13 -0400 I'm starting to get mail in response to my for sale post. Sounds like a few Denecke AD20 users may be interested in increasing the size of their knobs. Sounds like the penis enlargement spam email... anyway... back on topic... Here's how I got READABLE gains on my AD20 that I could also easily manipulate. At your hardware store they usually have a bunch of drawers or boxes filled with small parts. Cotter pins, rings, special washers. I bought two knurled knobs that were made to press fit onto the heads of cap screws. They are used to make your own "finger tight" fasteners from cap screws. If you dont know... a cap screw has a cylindrical head that is usually knurled on the outside and is used with an "allen wrench", "hex key" tool. The knobs on the AD20 look just like the heads of cap screws, minus the hex socket. Since cap screws have a hex socket, these knobs have a plug that fits into the hole. You need to remove the plug, using the tool of your choice :-). The knob will now slide onto the AD20 mini gain knobs. You need to glue them on. The knobs are about 1/2" dia. Maybe 5/8". I printed gain markings "0 thru 9" and "hash marks" onto some adhesive backed labels using AutoCAD. Turned the gains all the way down.. and applied the adhesive labels aligned to 0. Remember that the gains dont turn a full 360. Using AutoCAD, it was relatively easy to configure the spacing. Now I have easily read gain pots on My AD20. Sounds like a lot of work. It was really quite easy... takes a long time to explain."

I'm interested in this mod too...are your knobs just like the ones of the radioshack link in this thread Church?

[kskreider]

http://www.radioshack.com/product/index.jsp?productId=2103790&cp=&sr=1&origkw=knob&kw=knob&parentPage=search

These are the knobs that most folks use.  There is just a small brass set screw on the side to hold it in place.  One thing that most folks DO NOT talk about it how these really need to be ground down to fit flush on a AD-20.  I just used a bench grinder and they are fairly fragile, but it worked fine...

[MLKLuke]

can you explain what a bench grinder is please? sorry english is not my language 

[oscoastierob]

I put those knobs on my AD20 as well, I got tired of those microscopic knobs that were stock. Basically all you need to do is cut or grind approximately 1/16-1/8" off of the bottom of the knobs before you try to screw them on otherwise it won't work since the knobs are too deep stock. The screw that you use to tighten the mod-knob onto the stock knob won't have anything to tighten down onto since its too deep out of the package. After you get rid of that 1/16-1/8" it should be good to go. I used a dremel tool to grind mine down, but even a hack-saw would suffice.

[kskreider]

Bench Grinder

[mattb]

I did this mod to my old AD-20 with stuff from the hardware store, and then did the markings with a little model paint. It worked well for me.

I just found knobs I liked at the hardware store, and then using a product called plastic weld, I sanded the tops of the old knobs (to roughen them up) and glued new shafts on to extend them. The shafts were also from the hardware store. I didn't have to grind the knobs down, but I may have had to shorten the shafts, I forget now (been a couple of years). The set screws on the knobs held well and I never had a problem with slipping.

[ArchivalAudio]

nice knobs!

no really
I just slipped some small O-rings 
over my knobs (oh that sound a bit ...)
but really it made them  easier to grab
and it was cheap
+ it kind of helped to "lock" them in place so they would'nt get bumped and slip to a new setting...

but I like those big knobs