New bench test equipment!

daddyjt

I’ve been using and Atten signal generator and an HP 339A for the longest time to measure distortion on amps and preamps before and after mods. The combination has been effective, if a bit cumbersome. I have also wanted to be able to measure distortion below 0.1%, however the 339A did not go lower than that.

A couple days ago I snagged this nice HP (Agilent) 8903B formthe crazy price of $450. This incorporates a signal generator and distortion analyzer in one, and reads distortion down to 0.001%. The unit was calibrated only a year ago, and is very clean inside and out. I always marvel at the build quality of these old HP units - actual internal frames, removable PCB cards, and clean, efficient designs. This stuff was built to last - I’m very happy to add t to my bench.

Clipdat

Very clean indeed, looks like a nice piece. Congrats!

[Deleted User]

I use the venerable 339A as well as a Sound Technology distortion meter and an older Heathkit IM distortion meter. If you don't mind, where did you find the 8903B?

daddyjt

KennethSwauger wrote: »

I use the venerable 339A as well as a Sound Technology distortion meter and an older Heathkit IM distortion meter. If you don't mind, where did you find the 8903B?

I got it off “KSL Classifieds”, which is kind of like Craig’s list in the greater Salt Lake City area (except WAY better, because you can narrow the categories a lot more than CL - here’s a link https://www.ksl.com/classifieds/search/?keyword=&zip=&miles=25&priceFrom=&priceTo=&city=&state=&sort=0 ). The guy was listing an older Tektronix oscope and a benchtop DMM, saying he was selling off some older test gear. In the photo for the oscope (which I do not need, but can’t help looking anyway), I saw the HP 8903B, with an Audio Precision analyzer sitting on top of it. Seeing that he had th3 Audio Precision, I took a gamble that he wasn’t using the HP, so I called him and asked if he wanted to sell the HP. The rest is history:-) Now I just have to do the studying to figure out how to use it properly (These are the times when I am most thankful for YouTube!)

[Deleted User]

Beautiful piece of gear. I found my H-P on Craigslist along with a signal generator and other stuff. One guy was a serious German Shepherd trainer and he needed to sell some stuff to enter a dog competition. I met him and his dog, General, and he showed me what the dog could do. I have always loved shepherds and this dog was absolutely amazing. He could respond to dozens of commands in both English and German. If this guy had said the dog flies his own plane I would have believed him.

pitdogg2

very nice should suit you well.

daddyjt

Thanks, Ken - it’s good to know that there are a few of us that still like to work on gear. I find it a very gratifying hobby, and there is SO MUCH to learn. The guy I bought it from has his own company making guitar and microphone cables for stage use.

Those dogs are incredible - I am convinced they are smarter than a lot of people walking around today. I’ve seen some that take all their commands in a different language, which I find fascinating.