Heathkit IG-18 (IG-5218) Sine-Square Audio Generator: History, Overview, Demonstration, Theory

[@patthegunsmith]

Thank you for your effort and work to put this together. Most appreciated.

[@andymouse]

Just awesome tutorial regarding the switches, they always freak me out so much better to have someone like you to explain it carefully, complicated wafer switch assemblies also put the fear into me ! great work...cheers.

[@jenniferwhitewolf3784]

Had one of those IG-18 long ago, built it from kit. Got me started till I could a real pro by Wavetek, then HP, and finally multiple models of Tektronix generators which is what finally filled out the lab.. Nostalgia, in a way...

[@tomcroley7084]

Thanks for the very thorough circuit description. I'm currently restoring one so your video is very helpful. Nice paint job! I painted my covers with some flat black I had on hand. There are some mods on the web that you may want to consider. Mostly increasing capacitance and replacing R3 with a 56K.

[@jeditoto3441]

Fantastic video - thanks

[@braveheart9275]

Hello ... Thanks for thise great video.

[@jr4062]

Hoping one day you do some of the handheld radios, like the hw-24ht.

[@WestCoastDP]

Just bought an old Ig 5218. Adjusted the sine wave, looks good, nice slope but the lines look a little staticly/fuzzy. Wonder what's going on. I also just put in the meter board mod which works pretty good.

[@leonbaker1202]

Pretty sure the IG 1271 did indeed have offset control. I still have mine.

[@youtuuba]

leonbaker, if you still own an IG-1261, why not check it to see for sure? I looked at images online to verify that it had two knob positions. The left position knob was the frequency multiplier, with a red co-centric knob selecting the function (sine, square, triangle). The right position knob was the rough attenuator, with a red co-centric knob for fine attenuator/variable level adjust & power switch. No offset control. So I don't understand why you would contradict my statement of fact with a guess. Maybe you have a modified version. I recall that I modified mine with an extra small knob to give offset control, but it was awkward to use and had no detent for zero offset.

[@leonbaker1202]

​@@youtuuba thank you for the insight

[@neilkiots]

Hi- just stumbled on one of these today at a garage sale. had 2 questions: what kind of cable are you plugging into the sine and square wave jacks? and would I be able to plug this into a typical audio interface to record it into my computer? thanks

[@youtuuba]

Neilkiots, there is nothing special with the sine and square outputs of the IG-18. The connectors are just regular banana jacks, and I use regular banana-to-shielded cables. The only issue will be that the voltage levels of the signals will not be correct unless you can arrange to have 600 Ohm terminations on the cables. The IG-18 can optionally use its own 600 Ohm terminator for the sine output, but there is no equivalent to that on the square output. But if you don't need or care about the accuracy of the signal output levels, then none of the above matters. You should be able to connect up easily to any kind of single-ended (un-balanced) line level input on any audio devjce.

[@neilkiots]

@@youtuuba great, thanks for the response. i'm trying to record these sounds and create a sample library from them.

[@youtuuba]

@@neilkiots , a "sample library" of sine and square waves will be about the most boring 'sounds' ever. The IG-18 is not a music synthesizer......

[@neilkiots]

@@youtuuba haha maybe. trying to make some music inspired by early Stockhausen where he was using WW2 oscillators. another question about Ohms. i'm not sure what you were talking about- Is this 600 difference something that could damage my audio interface. i use a UA Apollo 8xp

[@neilkiots]

@@youtuuba kzbin.info/www/bejne/hafdZ5yqZ5ucidk this is the Stockhausen piece. one of the first of its kind

[@tylergilroy8894]

This is awesome and definitely helpful for things to be looking at when diagnosing the circuit. I have been trying to get the unit that I have up and running correctly, the issue I'm seeing it that the output is far too low. When I follow the calibration instructions, I can adjust it to where I measure a 1kHz sine between R13 and R14, but at 5.7Vpp. Not sure what the deal is 🥲