Saturday, December 10, 2011

Last time I put the King under the knife, let's move on to the Knight.

Faux hide, from what I can tell.

Nice and compact speaker case..

..with an amp on board.

Allied Knight Model 93 SX 350. I think this qualifies as "cute as the dickens".

Single ended 6L6 amplifier, puny output transformer behind Coke Bottle 6L6.

Classic labelling on the AC mains cord, sometimes that specifies the quieter of the two positions, other times it's an effort to keep phasing unified across multiple electrical units (reducing the chance of two chassis being hot in relation to one another). This all becomes moot with a proper 3 prong plug.. which is a baseline standard in my world view if reviving an old amp.

Looks like a late (early December) 1954 Quam driver. The seven pin Amphenol connector seems a bit overkill compared to modern speaker connectors, multiple output taps to match the output with the load was more commonplace in that day. However, the neat element of a speaker being wired up to reflect the correct load when plugged into the amp is shot down when you factor in the fact that the amplifier manufacturers didn't standardize anything, as "universal" means "bad for business". [Deep breaths and good hot coffee, helping to stave off a rant..] So, we essentially wind up with a lot of various set ups here, sluicing our way to separate "matched" systems. If you're say, putting together a collection of goofy old amps and speakers for something like a recording studio, where the widest range of intermingling is preferred, you'll either have to punch a 1/4" (or some other standard simple format) output in there, build and live with a mess of pigtails or decide on a wide hole multipin format and build it in all the amps. So, you'll have to choose your point in the balance between invested work, hassle of operation and original appearance (AKA, condition). I realize that functionality trumps originality in terms of value, currently, but 50 years from now?

Now THIS is a clean interior.

Multi-purpose of unallocated 5Y3 socket pins to select primary taps to reflect mains voltage. I'm excited about the 130 volt tap, that'll go easier on all involved components.

Printed schematic in the bottom of the enclosure. Simpler times.

Union built. Doesn't seem like the unions succeeded in retaining the wide spread production of electronics on a domestic front. Shame that. Though, clearly it wasn't in their control, nor was it really their battle alone. I'm not in the mood to chase that subject (Mmmmm, coffee), as it tends to end up to heavy on the pointing of fingers and too light on the sucking it up. I really added that because I like the illuminated fist. Nothing like a fist logo to really drive your point.

In other news, I'd like to know why hammertone finish isn't more popular on automobiles. I'd love to have this finish on the VW.


peter Moore said...

Where is the fuse in these amps? I can't find mine. Also, did you remove the "death cap"?

crochambeau said...

I think this amp predates UL requirement for fuses as IIRC mine doesn't have one either. I like to correct that with the little inline fuse holders. Death caps are either snipped completely out or replaced with an X1Y2 across the hot/neutral pair - I don't favor the death cap referencing chassis configuration, even though these are designed to fail open.

Nice little amp, I still need to recap mine.

peter Moore said...

OK, wow, thanks for the reply as this is an old post. I like the idea of the inline fuse holder as I don't have to drill a hole in the chassis.
The only other thing I need to do is find a 7 prong speaker plug and attach a speaker cable to it. I have seen plugs with a 1/4" female jack on eBay, maybe that will work. I plan to run 2x10" speakers as the amp gets pretty loud!
My amp is very clean and very little work is needed. At least two caps were changed in the past and it ran clean the other day with little hum noise. My tech gave a small discussion on the "death cap" to a few customers in the shop as part of his "don't try this at home" lectures!
My next project is a Bogen HE-10 amp that will require a little more work.

peter Moore said...

Oh yeah, how big was the inline fuse you installed? Thanks.

crochambeau said...

I'm somewhat unscientific when it comes to fuse selection (runs for cover), 1 amp seems fine. If you can, it's nice to be able to meter over all current and observe the amplifier in it's natural habitat, so to speak and adjust from there. The Fender Champ, which is a somewhat similar tube configuration runs a 2 amp, which I feel is overly large, but would probably open up fast enough to avoid catastrophe. I wouldn't go larger than 2 (and again, that seems too much to me, probably reaction to reduce non-essential service calls).

Downside of the inline is that you need to crack the case to change it, but I like looking at the innards..

Speaker plug to female 1/4" is nice to have (that's increasingly my preferred method to allow for mix & match). If you have the cabinet, and are not too squeamish about originality, lopping a foot off the OE speaker cable and setting those ends up with a female & male 1/4" might be a cheaper option. Down the road you could return to original at the expense of about a foot of speaker reach.

crochambeau said...

I guess it could be reasoned that "if the fuse blew you should have a peek at the guts anyway".