Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

hand making inductors
hand making inductors
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 8th May 2013, 04:49 AM   #1
Dan Moos is offline Dan Moos  United States
diyAudio Member
Dan Moos's Avatar
Join Date: Mar 2013
Location: Lynden, WA USA
Default hand making inductors

Is it common for DIYers to hand wind there own inductors, such as the one on the output of a lot of amps?

If so, is there a guide somewhere for "how many turns at what diameter for what gauge of wire for how many henrys" out there?

Or is it more common to order them commercially?
  Reply With Quote
Old 8th May 2013, 04:54 AM   #2
Mihkus is offline Mihkus  Estonia
diyAudio Member
Mihkus's Avatar
Join Date: Jul 2012
I do it randomly but accurately and measure them over.
Simple task.
  Reply With Quote
Old 8th May 2013, 05:00 AM   #3
Dan Moos is offline Dan Moos  United States
diyAudio Member
Dan Moos's Avatar
Join Date: Mar 2013
Location: Lynden, WA USA
If I don't have a tool to measure inductance, is this not a good idea for me?
  Reply With Quote
Old 8th May 2013, 05:11 AM   #4
sofaspud is offline sofaspud  United States
diyAudio Member
sofaspud's Avatar
Join Date: Nov 2005
Location: San Antonio
Many amplifier projects will specify the wire gauge and turns for the inductors.
You can calculate the inductor characteristics and be reasonably certain of its electrical properties. This will help do that.
It is error only, and not truth, that shrinks from enquiry. - Thomas Paine
  Reply With Quote
Old 8th May 2013, 05:19 AM   #5
dchisholm is offline dchisholm  United States
diyAudio Member
dchisholm's Avatar
Join Date: Mar 2011
Location: St Louis, Mo
Several incarnations ago I made a few inductors for production test jigs. At that time, "Reference Data for Radio Engineers" and the ARRL "Radio Amateurs Handbook" included graphs, nomograms and formulas for air-core inductors. The folks who sold magnetic cores (e.g., Amidon, Fair-Rite, Micrometals, et al) were pretty good at publishing design aids for their particular products. Typically you had to add or remove a few turns from the calculated value to get the inductance you wanted, but once this was done the unit-to-unit repeatability was good if you took care to construct them identically. I suspect that design information is squirreled away on the 'net someplace, and I wouldn't be surprised if it has been implemented in online calculators.

If you don't have access to an LCR meter - or your LCR meter doesn't cover the range you need, or measures at a frequency far removed from the actual application - you can make reasonable inductance measurements by resonating the device with a known-value film capacitor, using your 'scope in X-Y mode to detect resonance.

  Reply With Quote
Old 8th May 2013, 06:05 AM   #6
RJM1 is offline RJM1  United States
diyAudio Member
Join Date: Jan 2010
Location: Titusville, Fl.
Online coil inductance calculator.
Coil Inductance | Electrical Engineering Tools | EEWeb
  Reply With Quote
Old 8th May 2013, 06:59 AM   #7
Ian Finch is online now Ian Finch  Australia
diyAudio Member
Join Date: Apr 2010
Location: Coffs Harbour
At the accuracy required for output chokes, messing around adjusting inductors for precision better than 10% is really only gilding the lily. Other uses for inductors in solid state audio may be in small signal LR, LC or RLC filters but these became redundant with the development of opamps.

Considering that audio DIYs often modify output filters with choke increments of x2, x3 or a half or quarter value, it seems a waste of time and money precisely measuring a damped output choke any more than you need to accurately specify main rail smoothing caps. For typical output use, general coil winding guidelines from a trusted source will give more than adequate accuracy. From my perspective as a making one for each amplifier completed, and that's well over a hundred, I've never had a need to measure, even with repair work.

Curiosity and collecting a pile of instruments as an expression of our serious interest in electronics is another matter. Some of us like to do this and others don't understand circuit requirements and fret about things that aren't professionally made, labelled with certain values and with overkill levels of precision to aid our sense of security, too. Those are personal issues.

There are occasional designs like Quad power amplifiers, that use an RLC bridge for feed-forward error correction and this does require better precision than the simple, first order filters we usually refer to. Those, I would probably purchase with a kit or individually with the specified accuracy in any case, considering the likely one-off nature of the purchase and also the mounting requirements.

This little calculator is so easy and there is a multi-layer version on the site too: Pronine Electronics Design - Single-Layer Air Coil Calculator

Last edited by Ian Finch; 8th May 2013 at 07:14 AM.
  Reply With Quote
Old 8th May 2013, 12:52 PM   #8
lcsaszar is offline lcsaszar  Hungary
diyAudio Member
Join Date: Mar 2004
Location: Budapest, Hungary
Look for the J.A.E.S. article from A. N. Thiele: "Air-cored Inductors for Audio". I made several inductors for loadspeaker crossovers in the 10mH order, and all measured within 1%.

  Reply With Quote
Old 8th May 2013, 01:24 PM   #9
wintermute is offline wintermute  Australia
just another
diyAudio Moderator
wintermute's Avatar
Join Date: Aug 2003
Location: Sydney
hand making inductors
I like this site for working out air cored coils... --> Mark 2 - Inductor Sim

I was winding coils for crossovers, but should be still applicable. I found I needed to up the inductance 10% on what the calulator stated to get the right value, but I was using 14Gauge wire (which is hard not to get kinks in) so using thinner wire it may work out more accurate.

Any intelligence I may appear to have is purely artificial!
Some of my photos
  Reply With Quote
Old 8th May 2013, 02:30 PM   #10
djoffe is offline djoffe  United States
diyAudio Member
Join Date: Oct 2008
There's also the famous Wheeler formula for inductors. Wheeler developed inductor formulas for the National bureau of standards in the early part of the 20th century.

Wheeler Formulas for inductance

Update My Dynaco
Akitika GT-101 Audio Power Amplifier Kit
  Reply With Quote


hand making inductorsHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
need a hand with TPA3123D2EVM -works with hand on ground k2panman Solid State 0 16th September 2012 06:11 AM
Second hand in Amsterdam - where? tonto The Lounge 1 1st October 2009 08:20 AM
inductor winder for making your own inductors pjpoes Multi-Way 10 6th July 2008 07:19 PM
Any tips for winding inductors by hand? 454Casull Parts 6 30th July 2006 06:03 AM
Making speakers cables and interconnects from foil inductors JCoffey Everything Else 4 5th February 2005 01:05 AM

New To Site? Need Help?

All times are GMT. The time now is 01:18 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio