I used to build Heathkit test equipment. The scope died a long time ago but I still have the voltmeter and audio generator. The voltmeter is currently dead but I still use the generator. I still have the manuals so I may trouble shoot the voltmeter
Lots of vintage gear here, I recommend checking out a youtube channel "The Museum of Everything Else", some cool stuff in there if you're into pre-computer age electronics and synthesizers.
Those Heathkits tug at my heart! They got me started in electronics: in Jr. High I built a Heathkit VTVM (Vacuum Tube Voltmeter) and a shortwave receiver.
Ron - very cool! I have fond memories of using that same signal generator in high school. I also remember using the HV power supplies that shared the same case.
@Ron_E said:
I used to build Heathkit test equipment. The scope died a long time ago but I still have the voltmeter and audio generator. The voltmeter is currently dead but I still use the generator. I still have the manuals so I may trouble shoot the voltmeter
Ron
Ron, Is that the IG-18? In 1971, there was a modification article in Audio Amateur Mag on significantly improving the distortion and meter accuracy of the IG-18. Bill
Finally got around to restoring my Heathkit TT-1a tube tester. This was Heathkit's flagship mutual conductance tester, which they sold from roughly 1960 to 1973. Before powering up, I tested all caps for leakage and measured all resistors against the schematic. All caps still measure good with no visible signs of leakage or bulging. A few of the 1% precision resistors were slightly out of spec, but not too bad (2-3% or so). All diodes checked OK, so I powered the unit up very slowly with a current limiting variac. I did this in stages to protect the transformer and to give the old electrolytic caps plenty of time to re-form. No smoke or strange smells.
I then went through the complete step by step assembly manual testing and calibration procedure. Everything checked out good! No wiring errors found. And I was able to set all adjustment pots fairly close to the middle of their ranges, which is a very good sign.
In the next few weeks, I plan to order all new electrolyics, film caps, close tolerance resistors, and diodes. Should be about $50 or so from Mouser. After installing the parts, I will have to go through the entire testing and calibration process again. As a backstop, I kept a detail record of all my initial measurements, so if a problem occurs during final parts replacement, I should be able to track it down quickly.
That's in beautiful shape! It looks like it had a pretty pampered life. Much cleaner inside than my old Hickok. I'll have to keep my eye out for one of those. Have you come across any tubes in your collection that aren't listed on the roll?
@Ron_E said:
I used to build Heathkit test equipment. The scope died a long time ago but I still have the voltmeter and audio generator. The voltmeter is currently dead but I still use the generator. I still have the manuals so I may trouble shoot the voltmeter
Ron
Ron, Is that the IG-18? In 1971, there was a modification article in Audio Amateur Mag on significantly improving the distortion and meter accuracy of the IG-18. Bill
It is an IG-18 and I am familiar with the mod. Not having a distortion meter I never bothered with the mod and I was never worried about the meter accuracy.
@Tom_S said:
That's in beautiful shape! It looks like it had a pretty pampered life. Much cleaner inside than my old Hickok. I'll have to keep my eye out for one of those. Have you come across any tubes in your collection that aren't listed on the roll?
Yes, I've only had this tester for a couple years, but when working on an old 1930's radio, I noticed that the old 4 pin style radio tubes (27, 47, 80, etc) were not on the roll chart. I think Heathkit removed older tube types from the roll chart to make room for newer ones. A note at the end of my roll chart shows a date of 1969 and I have Heathkit supplemental update sheets that include old as well as new types out to 1978.
One of the downsides of this tester is the meter. From what I have read, it can be a real problem because there are a few small parts (precision resistors, diodes, and inductors) inside the meter case that can go bad or drift out of tolerance. If they do, you will never be able to calibrate the tester. And fixing the meter is extremely difficult because you have to completely disassemble the tester to dig the meter out. Then you have to be very careful not to damage the meter movement when you tear it apart. Luckily, my meter seems to be OK.
Time for another Heathkit. Here is my model IG-72 audio generator, which I built from a kit in 1974. It uses 3 tubes and produces sine-waves only (1Hz-100kHz). I used it for years to measure woofer T/S parameters before getting a Dayton WT3. Nice little unit; I still use it for woofer break-in's. I also have a BK function generator for radio work, but it looks very bland compared to the Heathkit.
This isn't a piece of test equipment, but I built an extension for the back of my desk and included this little cubby to hold plano 3700 boxes.
I thought that a modified version of this idea may work for for someone else's storage needs.
Roughly 20 years ago, I built Joe D'Appolito's Mitey Mike. I mounted a Panasonic WM-60AY mic cartridge on the end of a long brass tube and bolted the tube to the end of a small aluminum box. I then mounted the mic preamp circuit on a small perf board and powered it with a 9 volt battery.
I had it hooked up to an M-Audio soundcard, feeding Speakerworkshop on an old Windows XP machine. It did not work very well at all. I spend most of my time fighting with the software, adjusting and re-adjusting the volume. Most of the time my measurements came back completely garbled. I finally gave up and bought an OmniMic. I still have the mic, but it no longer works because I borrowed the battery holder for another project.
So I got scammed on eBay 2 weeks ago when I bought an E-Mu 0404 audio interface. Ebay is no help, so I'm out $80 on that deal.
But sometimes karma has a way of throwing you a bone - I found a used Digilent Analog Discovery for much less than what others were asking. It arrived today and it's clean and working fine! This weekend I'll be running the same Audio Analyzer Suite that I've seen on quite a few hifi restoration videos.
I looked at one of those and even signed up for academic pricing on it. But the Analog to Digital converter on it is only 14 bits. So it is helpful for many things but not sensitive enough for definitive evaluations of electronics. It is probably sufficient for speakers.
Comments
I used to build Heathkit test equipment. The scope died a long time ago but I still have the voltmeter and audio generator. The voltmeter is currently dead but I still use the generator. I still have the manuals so I may trouble shoot the voltmeter
Ron
Lots of vintage gear here, I recommend checking out a youtube channel "The Museum of Everything Else", some cool stuff in there if you're into pre-computer age electronics and synthesizers.
https://www.youtube.com/c/THEMUSEUMOFEVERYTHINGELSE/videos
If you're really into analog synthesizers, this guy's main channel is "Look mum no computer". Lots of cool stuff in there.
Those Heathkits tug at my heart! They got me started in electronics: in Jr. High I built a Heathkit VTVM (Vacuum Tube Voltmeter) and a shortwave receiver.
Ron - very cool! I have fond memories of using that same signal generator in high school. I also remember using the HV power supplies that shared the same case.
Ron, Is that the IG-18? In 1971, there was a modification article in Audio Amateur Mag on significantly improving the distortion and meter accuracy of the IG-18. Bill
Finally got around to restoring my Heathkit TT-1a tube tester. This was Heathkit's flagship mutual conductance tester, which they sold from roughly 1960 to 1973. Before powering up, I tested all caps for leakage and measured all resistors against the schematic. All caps still measure good with no visible signs of leakage or bulging. A few of the 1% precision resistors were slightly out of spec, but not too bad (2-3% or so). All diodes checked OK, so I powered the unit up very slowly with a current limiting variac. I did this in stages to protect the transformer and to give the old electrolytic caps plenty of time to re-form. No smoke or strange smells.
I then went through the complete step by step assembly manual testing and calibration procedure. Everything checked out good! No wiring errors found. And I was able to set all adjustment pots fairly close to the middle of their ranges, which is a very good sign.
In the next few weeks, I plan to order all new electrolyics, film caps, close tolerance resistors, and diodes. Should be about $50 or so from Mouser. After installing the parts, I will have to go through the entire testing and calibration process again. As a backstop, I kept a detail record of all my initial measurements, so if a problem occurs during final parts replacement, I should be able to track it down quickly.
Way cool.
That's in beautiful shape! It looks like it had a pretty pampered life. Much cleaner inside than my old Hickok. I'll have to keep my eye out for one of those. Have you come across any tubes in your collection that aren't listed on the roll?
It is an IG-18 and I am familiar with the mod. Not having a distortion meter I never bothered with the mod and I was never worried about the meter accuracy.
Ron
Yes, I've only had this tester for a couple years, but when working on an old 1930's radio, I noticed that the old 4 pin style radio tubes (27, 47, 80, etc) were not on the roll chart. I think Heathkit removed older tube types from the roll chart to make room for newer ones. A note at the end of my roll chart shows a date of 1969 and I have Heathkit supplemental update sheets that include old as well as new types out to 1978.
One of the downsides of this tester is the meter. From what I have read, it can be a real problem because there are a few small parts (precision resistors, diodes, and inductors) inside the meter case that can go bad or drift out of tolerance. If they do, you will never be able to calibrate the tester. And fixing the meter is extremely difficult because you have to completely disassemble the tester to dig the meter out. Then you have to be very careful not to damage the meter movement when you tear it apart. Luckily, my meter seems to be OK.
Time for another Heathkit. Here is my model IG-72 audio generator, which I built from a kit in 1974. It uses 3 tubes and produces sine-waves only (1Hz-100kHz). I used it for years to measure woofer T/S parameters before getting a Dayton WT3. Nice little unit; I still use it for woofer break-in's. I also have a BK function generator for radio work, but it looks very bland compared to the Heathkit.
This isn't a piece of test equipment, but I built an extension for the back of my desk and included this little cubby to hold plano 3700 boxes.
I thought that a modified version of this idea may work for for someone else's storage needs.
Roughly 20 years ago, I built Joe D'Appolito's Mitey Mike. I mounted a Panasonic WM-60AY mic cartridge on the end of a long brass tube and bolted the tube to the end of a small aluminum box. I then mounted the mic preamp circuit on a small perf board and powered it with a 9 volt battery.
I had it hooked up to an M-Audio soundcard, feeding Speakerworkshop on an old Windows XP machine. It did not work very well at all. I spend most of my time fighting with the software, adjusting and re-adjusting the volume. Most of the time my measurements came back completely garbled. I finally gave up and bought an OmniMic. I still have the mic, but it no longer works because I borrowed the battery holder for another project.
This is my newest toy, a Levear (Panasonic) am/fm stereo signal generator. I have been wanting one of these, and I took a chance on an Ebay find.
Nice! Aligning tuners has become a lost art these days. Are you getting set up for a retirement gig?
So I got scammed on eBay 2 weeks ago when I bought an E-Mu 0404 audio interface. Ebay is no help, so I'm out $80 on that deal.
But sometimes karma has a way of throwing you a bone - I found a used Digilent Analog Discovery for much less than what others were asking. It arrived today and it's clean and working fine! This weekend I'll be running the same Audio Analyzer Suite that I've seen on quite a few hifi restoration videos.
Let us know how that works out, I don't really care about the oscilloscope function, but the spectrum analyzer looks interesting.
I looked at one of those and even signed up for academic pricing on it. But the Analog to Digital converter on it is only 14 bits. So it is helpful for many things but not sensitive enough for definitive evaluations of electronics. It is probably sufficient for speakers.