Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => AmpTools/Tech Tips => Topic started by: billcreller on January 08, 2010, 05:51:48 am

Title: signal generator
Post by: billcreller on January 08, 2010, 05:51:48 am

  I was in my attic looking for stuff to toss out, and came across a signal gen that someone gave me a long time ago. Don't remember who it was, but it's a NRI (National Radio Institute I believe) Model 88. It has RF modulated, RF un-modulated, and audio, and six bands.
  It sez 170 KC to 60 MC, on fundamentals.  The faceplate doesn't say anything about the audio, so I guess its just a single audio tone generator (?)  Likely not much use as an amp tool. Haven't taken the cover off yet to see what's inside. Maybe it's tube powered.  Couldn't ring myself to toss it yet :undecided:

Title: Re: signal generator
Post by: PRR on January 08, 2010, 03:59:59 pm

http://www.radiomuseum.org/r/nri_signal_generator_88.html

Title: Re: signal generator
Post by: JayB on January 08, 2010, 07:30:57 pm

You could probably still make 50 - 100 dollars a week.

Title: Re: signal generator
Post by: jjasilli on January 09, 2010, 10:13:23 pm

Well it puts out a 400Hz signal, so it is useable! 

Those 6BE6 tubes look intrigung.  Heptode (but in "triode mode" so to speak with screen connected to plate) with a mu of 20 @ 25mA c athjode current.  With that, betcha Isotone & Buttery could wrangle-up a preamp stage or driving stage for tonestack, reverb or PI.

Title: Re: signal generator
Post by: sluckey on January 09, 2010, 11:26:20 pm

You can buy one on eBay (http://cgi.ebay.com/Vintage-NRI-Professional-Signal-Generator-Model-88_W0QQitemZ330364115904QQcmdZViewItemQQptZBI_Signal_Sources?hash=item4ceb3c5bc0) for $25. Good pics on the link...

http://cgi.ebay.com/Vintage-NRI-Professional-Signal-Generator-Model-88_W0QQitemZ330364115904QQcmdZViewItemQQptZBI_Signal_Sources?hash=item4ceb3c5bc0

Title: Re: signal generator
Post by: billcreller on January 10, 2010, 12:02:08 am

I have a younger brother who is restoring old radios. Maybe I can unload it on him!!  He has been restoring battery powered "farm radios" from the 30s, plus other old sets.  Maybe he can use it.