Thursday, December 08, 2011

While I'm digging through a bunch of neglected junk, I figure I may as well begin with the older, more attractive designs, then roll out the later uglier beasts until I reach a point where the units at hand do not merit my banging out a few words in their honor; they will then be quietly rendered into parts and no one will be the wiser.

Here's a Manatt-King Radio Company amplifier, with nothing else to go on I'm going to conclude this is a "KING" model and refer to it as such.

Half cage rear enclosure, I believe the selector dial at left is an output impedance selector to match up to whatever is plugged into those 4 pin Amphenol speaker output sockets, the loose trunk wiring of which we'll see in the upcoming gutshot.

It's hard to discern what's what here. Going left to right, I presume we're looking at a rectifier, pair of outputs, phase inverter and a trio of preamp tubes doing preamp and/or mixing duties. Come to think of it, I was just shuffling through a pile of amps without really digging into them, so chassis labeling may be evident underneath that carpet of dust.

More sign of post factory work. The series pair of CC resistors are clearly in a more modern package, and the PVC jacketed wire is also pretty suspect without a time machine. The tagboard circuit and over all layout is pretty clean though, so there's potential. What's this? I do say, we've had a cookout!

Wirewound B+ dropping resistor, a touch worse for wear..

..beyond which is an indicator this unit has had something of an electrical mishap in the past.

Smoke stains, never a comforting sign. When/if I get around to this one it'll entail spot checking everything down to the iron and more or less rebuilding it all. Pretty nice doorstop though.

7 comments:

I build these said...

If you don't have a home for or time for this one (or any other 30's/40's pa amps)I'd love to help you out there. Contact me at getchellamps@gmail.com.

crochambeau said...

This amp isn't slated for the gutting treatment, but I will contact you in the event it looks like it'll be nothing more than a dust catcher in my hands.

You're getchellamps.com, right? What is the little red amp on top of the stool situated in front of your Fairlane? (Nice wheels, BTW)

LarryInSF said...

I am currently restoring an amplifier nearly identical to the one you have on this page. Can you please let me know what the tube compliment on yours is? Mine is missing the rectifier tube (nearest in your photo) and the phase inverter (the middle tube). Both are the glass tubes in your photo. Any help would be very much appreciated. (:

crochambeau said...

Hi LarryInSF! I'm a bit confused, as you mention tubes in my photos, but the post this comment ties to is the Manatt-King KING p.a. unit which has no tubes in the pictures. I'm happy to dig and see what I can see, but I want to be sure we're talking about the same amplifier first.

LarryInSF said...

Sorry, I saw another photo online of this same amp w/the tubes. Can you please let me know if you were able to restore this PA, and, if so, what the tube lineup was for the unit? Mine uses 3 x 12SJ7, 2 x 6L6, and two unknown tubes (they were missing from mine) - the middle tube (phase inverter, I think it maybe a 6SL7, and the rectifier tube on the far left, which is most likely a 5U4 or a 5Y3. Any help would be most appreciated, thanks for your reply and Happy New Year! (:

crochambeau said...

I have not restored this amp, it's currently slotted in a storage position or I would have a look at it to see if I could discern anything. The 5U4 vs 5Y3 question would, at least to me, hinge on what the 5 volt filament winding on the transformer can handle (and of course, personal taste if it looks like either tube is compatible with the system.

The inverter determination could be narrowed down by measuring and mapping filaments, input, and outputs. I'm pretty sure there are no markings on the chassis on mine, but I did locate the bottom plate (which was missing at the time in which the photos were taken) so it's possible Manatt-King was kind enough to slap a schematic on the unit. I'll see if I can locate the amp and confirm or deny this..

Happy New Year! Here's hoping 2022 will treat us all much better than the last couple of years...

crochambeau said...

Hi LarryInSF, my amp turned up. There is no schematic pasted to my baseplate. However, someone did hand write the tube compliment on my chassis. The (unverified) tube markings are as follows from left to right: 5U4, 6L6, 6L6, 6SC7, 6SK7, 6SJ7, 6SJ7. It also looks like the two rightmost tubes were at one point labeled 6J7; I do have holes in the chassis for a wire leading up to a top cap on the three rightmost tubes.

Hope this helps!