Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => AmpTools/Tech Tips => Topic started by: jjasilli on October 13, 2012, 08:59:53 pm

Title: Eico Signal Tracer Follies
Post by: jjasilli on October 13, 2012, 08:59:53 pm: Love vintage test equipment. Finally got around to updating this Signal Tracer. Replaced the obsolete test-pin input jacks with an RCA jack & a Phono jack. Right now I'm playin' electric guitar through it. Not enough input gain for that. But I actually need it as a "listening amp" to trace signal!

Photo's: http://www.facebook.com/media/set/edit/a.4453901342206.185007.1129726131/ (http://www.facebook.com/media/set/edit/a.4453901342206.185007.1129726131/)
Title: Re: Eico Signal Tracer Follies
Post by: John on October 14, 2012, 02:56:50 pm: I've tried several times but that page won't come up for me (I'm logged in). I'd love to see it though! What am I doing wrong?
Title: Re: Eico Signal Tracer Follies
Post by: jjasilli on October 15, 2012, 10:30:03 am: Don't know about the Facebook log-in issue, but here's the pic's:
Title: Re: Eico Signal Tracer Follies
Post by: Willabe on October 15, 2012, 05:38:58 pm: Looks very cool jj and in very clean shape.

What's the tube line up? It looks like the seeing eye tubes socket (top left) clips in place?

Brad :icon_biggrin:
Title: Re: Eico Signal Tracer Follies
Post by: jjasilli on October 15, 2012, 10:34:27 pm: I have this thing for a few years when I had GAS for this stuff. Now it's handy to trace a lack of signal in my home theater system.

It's an Eico 140a. The The Boat Anchor Manual Archive has the manual w/ schematics and layout here: http://bama.edebris.com/manuals/eico/147a (http://bama.edebris.com/manuals/eico/147a)

Tubes: 1X 12ax7 voltage pre-amplifier; 1X 6AQ5 power amp; 6X4 rectifier; 1X 1629 eye tube; 1X 1N48 germanium diode for watt meter. Yes, the eye tube socket is mounted sideways in a clip. I see this in older equipment that uses such tubes, like my Eico 950B Reistance - Capacitance comparator, and even Fisher stereo receivers like the Model 400 I'm refurbishing.
Title: Re: Eico Signal Tracer Follies
Post by: John on October 17, 2012, 05:58:19 am: Thanks for posting those. I've got a Heathkit that I still haven't tried out (2 yrs ago). It does light up and appear to work. I've got a thing for old meters, but have managed to stop myself at 6. I dunno why, but it's so cool watching the (big) needle swing when taking voltages and stuff.
Title: Re: Eico Signal Tracer Follies
Post by: jjasilli on October 18, 2012, 01:41:18 pm: I like analog meters for monitoring key voltages in an amp under test: plate; screen, whatever. I've got 4 working Heathkit VTVM's model IM-18. So I can constantly monitor plate & screen voltage on 2 power tubes while working on an amp. You can tell if the analog meter's needle is in a good place out of the corner of your eye. Digital readouts are not as useful for that particular purpose. I've also got 2 beautiful old Eico VTVM's with real glass face meters- they need rebuilds. Also have 3 vinatge Fluke 8000A digital multimeters and a cheap Radio Shack palm size digital multimeter. The Radio Shack is the most handy.

The Eico signal tracer does not have a meter. The black circle is a speaker. The eye tube functions as a sort of meter for some puposes.
Title: Re: Eico Signal Tracer Follies
Post by: John on October 19, 2012, 06:18:07 am: Quote
The Eico signal tracer does not have a meter. The black circle is a speaker. The eye tube functions as a sort of meter for some puposes.

Oh, I know. I veered off from one vintage piece into vintage meters, that's all. My mind does that som -- hey, is that a squirrel??
Title: Re: Eico Signal Tracer Follies
Post by: jjasilli on October 19, 2012, 08:37:20 am: You're not the only one! :laugh: http://www.el34world.com/Forum/index.php?topic=3045.0 (http://www.el34world.com/Forum/index.php?topic=3045.0)