Those filter cap will become dead shorts if a.c. is applied to it. They may just explode or they could damage the power trans. Be careful.
And good luck getting it running.
Originally Posted by kstlfido
Those filter cap will become dead shorts if a.c. is applied to it. They may just explode or they could damage the power trans. Be careful.
And good luck getting it running.
In it's present condition, I'm not even thinking of plugging it in - even on a metered Variac! I'm very familiar with old components. Used my TO-4 to reform a few 'lytics. But these are probably beyond reforming judging by the general level of corrosion. Frankly, all the components are suspect, though I've had better luck with old resistors.
I'm not going to touch the components until I figure out what it is. Thank you for the heads-up though!
To-4, I'm not familiar with that except the semiconductor package. I'd bet you a couple buck that the iron is still good. The only thing that would kill them beside catastrophic failure is being submerged in water. It doesn't look like either of those problems have happened. No black tar leaked out on the underside of the chassis.
Anyway, sounds like you've got a plan. You have a pretty cool little project there. Keep us posted.
Nick
He's referring to the Sprague TO-4 Capacitor checker:
http://www.ohio.edu/people/postr/bapix/capchkrs.htm
I'm guessing this amp probably was stored near the waterfront, judging by the corrosion all over. Will be quite the project. Extensive pictures will be needed to document where everything goes on the wiring harnesses.
When faced with another JBL find, Good mech986 says
, JBL Fan mech986 says
Kstlfido, thanks very much for the additional pictures. It appears that your amp is virtually the same circuit as the Iconic amp, but installed in a rack mount chassis. Your silver power transformer doesn't match the others, but the installation looks original as best I can tell. One oddity with the Iconic amp and field supply iron is that all the end bells are stamped "Inca Transformer Co., Los Angeles" with the logo with the design of an Inca fellow in profile. Perhaps by this time Inca was building some transformers for Altec to their specs... hard to say.
At some point in the mid or late 1940s Altec Lansing purchased the Peerless Transformer Company, and Ercell Harrison became their chief engineer or at least contributed many significant designs to the new Altec division. He is credited with designing the Peerless 20/20 and 20/20 Plus audio transformers.
I recently visited my friend who got the Iconic amp and field supply running, and it sounds great.
NickH, you are correct that all Lansing Manufacturing Company products are now very rare, even here in the Los Angeles area. The Iconic amp and field supply are in another category, I suppose "beyond rare" as I have seen or known of perhaps thirty Iconics in the past dozen years, but only two of these amps and field supplies.
Make it so much more cool when you get it running again. It looks ruff but I bet it can be fixed.
Ah, a cap tester. I should have though of that. How much voltage does it apply when it tests the caps?
A capacitor checker is above my pay grade, but I think it's safe to say that any 70 year old electrolytic filter cap should be replaced with new in every case. These things have a designed service life of 15 or 20 years and anything beyond that is iffy. In this case iffy would refer to the future life of precious tubes, vintage transformers and chokes that should be protected at all reasonable cost.
Some friends and I built a dozen reproduction Iconic 330 VDC field supplies a few years ago and we bought the electrolytic caps from Antique Electronic Supply in Tempe, who apparently bought the old Sprague equipment and put a good portion of their old product line back into production. These caps have been perfectly stable and reliable in operation, and should be considered for installation before powering up any valued old gear that uses electrolytics.
Kstlfido you seem knowledgeable technically, and can no doubt upgrade your amp and get it up and running well yourself. If however you would like to be put in contact with my friend the restoration guru supreme, just let me know. I think you have a very significant amp, one of the very first Altec industrial power amps. I wouldn't worry too much about the rust; the Iconic amp and field supply is fairly rusted up but delivering beautiful sounds at present.
Nice find there Kent !
"James B. Lansing" = Lansing Manufacturing ~ Altec Lansing ~ JBL
Finally got the amp on the bench. Did a a small bit of cleaning- it came up a little bit but the rust is pretty extensive. Thanks, Steve for the Inca tip. I did get a *little* info on this power. All I could find was "1121" stamped on the top label.
Starting to map out the circuit. Took some transformer DCR readings. They seem to be OK.
Power-
Primary- 2ohms (110v tap- not used); 2 ohms (120v tap- used).
Secondary-
B+: 45---0---45 ohms.
5V for 5Z3: 0.4 ohms
6.3VCT for 6SJ7, 6L6: 0.4---0---0.4 ohms.
TU-504 Choke- 87 ohms.
TJ-151 Output transformer-
Primary- 4 taps. 151---0---0---150 ohms. 0 taps connected.
Secondary- 6 taps. 21.7---21.2---0---0---22---22.5 ohms. 0 taps connected. First and last taps unused.
Looks like the OPT is indeed line output, not voicecoil.
More info as I gather it!
Cheers- Kent
600 ohms, odd. What are the tubes, 6l6? One hell of a line out. You could probably get a matching transformer to get a more usable range.
Nick
Thanks for the transformer specs, Kent. I'm thinking your amp either drove a distributed line, like a bunch of transformer connected ceiling speakers, or perhaps drove the grids of a high power booster amp.
I have a book published by RCA Service Company in 1950 that has several pages listing the Altec transformers and chokes, updated as recently as 1946. The numbers on Kent's components do not appear, though there is an output transformer called a TJ-152A which may be a close cousin to the TJ-151. Here is a scan of that page:
Thanks, Steve. It does seem similar. Maybe the TJ-151 is similar to the 152, but without tertiary windings? Also, the secondary DCR's don't seem to be high enough for such high output impedance. But yes, seems to be a similar animal!
I cleaned it up. Just a mild detergent and a toothbrush. Careful brushing and compressed air. Then finished the outside with a light rub of beeswax. Looks a lot more presentable now!
-Kent
Wow, she cleaned up pretty good.
...and smells good! Howard's Feed N' Wax.
...and smells good! Howard's Feed N' Wax.
Ill have to check that stuff out.
Nick
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