I have a serious problem... i read things and it makes me wanna do things haha.
I began floating around the internet last night and eventually started reading into varitones and how they work. I read that Gibson used to use a 1/4 inch bolt to make a 1.5 henry inductor. I'd like to try to copy this but i cant find any details on wire size or wraps or anything. Any calculator i try tells me quickly that to get anything around 1.5 henries is going to weigh 75 pounds so if anyone could give me a starting point id be very happy and share my results.
Also i messaged David Schwab as I've read he may know something on the subject, so if your reading this check the p.m.'s haha
Craig Anderton used 1/2 of a Radio Shack audio transformer in his 1st edition of Electronic Projects for Musicians, and I have had decent success using a matching transformer unsoldered from an obsolete computer modem. If you want to wind a bolt, have at it. But you'll get there faster if someone has already done the winding for you.
Alan Peterson
Name in Anagram Form: "Resonant Peal"
Leon, using these calculators, what DC resistance are you aiming for? From memory, most varitone inductors measure around 1k, because of the fine gauge wire used. I'm not sure exactly what gauge is used, but wouldn't be surprised if it was 42 or 43 gauge pickup wire.
I'm just looking to experiment a bit really. 1k resistance and fine wire is probably a good start to what I have to know. I thought I had a multimeter to test the inductors but it turns out it doesn't have that option. It wont stop me from trying though. I'll probably head to radio shack and get some magnet wire tomorrow and wind a bolt. I suppose if I shoot for 1k resistance I should get something to work from. How much magnet wire will I need to get around 1k ohms?
Leon,
The DC resistance is pretty meaningless unless you know the diameter of the wire used and the diameter of the coil core for starters. You can then look up resistance per foot of magnet wire and use Pi to figure out the approximate length of each turn of wire around your bolt. I doubt RS will have magnet wire anywhere near fine enough for this job. You can buy small spools of 42 or 43 AWG wire off ebay if you want to make your own. Keep in mind that inductance is effected by the permeability of your bolt.
In Anderton's book "Electronic Projects for Musicians" he has a project much like a varitone and in that parts list he lists a Mouser part that would work perfect, in fact I have built a few. It's a small center-tapped transformer. You might be able to find his "passive tone control" circuit on the web somewhere.
The Mouser part number is Mouser - 42TM019-RC and another alternate part number is 42TL021-RC, These are mini audio transformers. I did a google search for "craig anderton passive tone control" and got a link on the Telecaster guitar Forum that shows the full schematic and parts list.
Hi , for what it's worth there is a general purpose relay i've used to make p/u's.
Omron Electronics mfg part number GSR-1-S DC24---1K dc resistance and 2.25 H inductance.
Bought mine through RS Components $AU9.00. takes a few minutes to remove the coil , but hey worked for me.
Regards
Geoff
thanks for the part numbers and ideas on components guys. Although I am more interested in seeing if I can reproduce the Gibson creation of old for my own amusement. How ever if i can't get close after a while, I'll get one or two of those parts and see what makes them do what they do. I thought I had access to an inductance meter but it turns out I do not so it may be a bit trickier than I thought. I do have a bad strat knock off in need of a new wiring job so I may use it for some experimenting. Get the varitone to make the changes I like and call it at that.
The only thing holding me back at this point is that I have to rewire that guitar now before I get going. Maybe ill do er up this weekend...
An inductance meter will be fine, but lacking one, all you need is a signal source, a resistor of about 1kohm, and a decent accurate capacitor....to find the resonance point...
Halgeir, you need one more important thing- the know-how and the math to put those things together for testing. Why don't you tell us how to proceed, assuming you have everything in front of you?
This site gives a number of good ways to measure inductance without a specially designed meter, although you will need a function generator and oscilloscope.
I'll bet Gibson didn't bother with an inductance meter when they developed this thing. They just wound it with the wire they had until it "looked right" and moved on from there.
I'm sure once in production, that's true David, but I bet during the development stage they had some target value, it would have taken quite some trial and error to get something that worked based on what "looked right".
so if anyone could give me a starting point id be very happy and share my results. 
