What an interesting old instrument. I just finished restoring and calibrating a nice surviving Heathkit model AA-1. Didn't know they also made a THD analyzer. Thanks Jeff. Keep 'em coming. I'm a "Benton Harbor Lunchbox" addict!
These Heathkits were commonly found at smaller radio stations that could not afford the HP 334 distortion analyzer series. The expensive HP essentially works the same way. At one time a FCC requirement for radio stations required an annual “audio proof of performance”. I spent many hours after midnight using the Heath and HP distortion analyzers. Those days are long gone now. I still have my HD-1 and HP 334A. Pretty much useless on today’s high quality audio gear.
Very enjoyable Jeff. I picked ip an IM 12 today for what will be my first Heathkit restoration of 2018. First thing I do is run to your channel for an intro
Hi there, thanks for a great video. I have one of these which I need to repair and although I have the circuit diagram, I'm still struggling to find the original manual for download. Did you ever locate one? Can anyone else help?
Hi there, Based on the schematic, what will be the output of the HDM if I feed audio. would it be distorted due the tubes in it?.. Thanks in advance =)
If you were to feed in a pure sine wave and adjust for a null, any output would be distortion from the unit itself, such as noise from the tubes and power supply.
Thanks for the prompt answer Jeff. It is appreciated. I would like to feed a sine wave from the audio output of a PA (music). any other tip you may want to share for my "experiment" looking for 2nd harmonics addition to the input wave?. thanks again
Great video Jeff.
What an interesting old instrument. I just finished restoring and calibrating a nice surviving Heathkit model AA-1. Didn't know they also made a THD analyzer. Thanks Jeff. Keep 'em coming. I'm a "Benton Harbor Lunchbox" addict!
These Heathkits were commonly found at smaller radio stations that could not afford the HP 334 distortion analyzer series. The expensive HP essentially works the same way. At one time a FCC requirement for radio stations required an annual “audio proof of performance”. I spent many hours after midnight using the Heath and HP distortion analyzers. Those days are long gone now. I still have my HD-1 and HP 334A. Pretty much useless on today’s high quality audio gear.
Very enjoyable Jeff. I picked ip an IM 12 today for what will be my first Heathkit restoration of 2018. First thing I do is run to your channel for an intro
Love your videos. If you have a Heathkit Audio Analyzer it would be great if you did an in depth demo of it.
I have a HD-1 and this video has been very helpful. It would be great if you could do a simlar video on the AA-1 Audio Analyzer
I don't own an AA-1, but if I acquire one I will make a RUclips video about it.
I was tempted to get one , but the 20K range was insufficient for me
Well done. I just subscribed.
Hi there, thanks for a great video. I have one of these which I need to repair and although I have the circuit diagram, I'm still struggling to find the original manual for download. Did you ever locate one? Can anyone else help?
I have not found a full manual available as a free download. You should should be able to buy one from here though: www.manualman.com/index.cfm
ever wonder where all those EE's graduating from U of M went to work ? here is your answer.
Hi there, Based on the schematic, what will be the output of the HDM if I feed audio. would it be distorted due the tubes in it?.. Thanks in advance =)
If you were to feed in a pure sine wave and adjust for a null, any output would be distortion from the unit itself, such as noise from the tubes and power supply.
Thanks for the prompt answer Jeff. It is appreciated. I would like to feed a sine wave from the audio output of a PA (music). any other tip you may want to share for my "experiment" looking for 2nd harmonics addition to the input wave?. thanks again