Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => AmpTools/Tech Tips => Topic started by: teisco88 on August 06, 2013, 05:42:16 pm

Title: Using Old Test Gear...and the occasional Bonanza!
Post by: teisco88 on August 06, 2013, 05:42:16 pm

I have been restoring some old boat anchor test equipment that's been laying around the shop for years--i.e., old signal generators, oscilloscopes, vtvms, etc.  I got my old Heathkit IO-18 'scope working again. It's perfectly adequate for working with amps.  Going to do the same with my even older Eico 460, just for giggles.  Anyway, I have some really old stuff that I decided not to restore, so I pulled it apart to see what I could salvage.  Whoa!  Christmas in August.  One old Heath Audio Analyzer contained nothing but old, essentially not used Mullard tubes.  12AX7, 12AU7, 12AT7, and a 6X4.  Another piece of gear that I had three of--a Heath signal tracer--also had a Mullard 12AX7.  Nice day for just popping open a couple of unused pieces of old gear.  The tubes test new on my gear.  Nice thing about old test gear--lots of guys built it and set it aside.  The "innards" are often _hardly_ used.  I don't need to tell you what those Mullard preamp tubes sell for, these days.  Hmm?  Maybe I will look inside some more of my old gear...

Say, does anyone else find it fun to work on vintage circuits _with_ vintage gear?  Now, if I could only find a way to purchase bottled Fullerton factory air to breathe while I build.  :think1:

Title: Re: Using Old Test Gear...and the occasional Bonanza!
Post by: jjasilli on August 06, 2013, 06:31:37 pm

 :headbang:

Title: Re: Using Old Test Gear...and the occasional Bonanza!
Post by: eleventeen on August 06, 2013, 08:41:23 pm

It's only fun if the old test gear works sort of well. It is true that a 500Khz o'scope is essentially overkill for audio use...and might have been chucked out 30 years ago!

Yep, all that old Heathkit stuff used Mullard 12AX7s almost exclusively. And you're right....much of it has 20-50 hours burn time on it, if that!

Title: Re: Using Old Test Gear...and the occasional Bonanza!
Post by: LHPcope on September 18, 2013, 03:27:03 am

I have a Eico 460 that gets daily use along with a Leader discrete transistor signal generator from the 1970s.  The 460 is great for audio use.  I also have a Hickok 539A Tube tester that gets a fair amount of use.  I just wish I could find a "boat anchor" audio spectrum analyzer.

I also have built my own Maxwell/Wien bridge for measuring low Q inductors and my own Gauss meter. Both of these get a fair amount of use also.