Kay K-503A Combo

Thsi is a single channel tube amp. Volume and tone control, three inputs, that's it. As others have said of this amp, features aren't the point.

I use this amp with many different guitars(LP junior, 90's texmex strat, jackson sl2h, prs se). No matter what guitar I use ths amp sound amazing. The warmth, depth, and clarity of this amp are matched only by very expensive vintage or boutique amps. The breakup doesn't occur until about 7 or 8 on the volume knob and it is extremely organic and warm. Not heavy but extremely rich and full of overtones.

This amp is close to 50 years old, and mine is all original. I would never rely on this amp alone if my job or reputation was at stake. Better kept in the bedrrom or studio. Despite this I have never had the amp fail me.

Is Kay still around???

I have been playing for over ten years and have used plenty of amps including a JCM 800, Fender Champion, and an Orange Tiny Terror. This is my Favorite amp I own. Recently set out to buy something more feature rich and reliable but with same sound. Nothing comes close in normal human budget. Ended up with the Tiny Terror but for clean sounds it gets put to shame by this litle Kay.

Well, this is a budget practice amp from the 60's. "Features" are volume, tone w/integral power switch, and 3 jacks. I thought maybe the jacks would offer different volume levels, but no.
However, features aren't necessary on this amp.

The amp is mostly clean, even with both controls full up. I never adjust the controls (in fact, I disconnected the tone control. See below). With volume full up, "normal" strumming produces a dark clean sound with the slightest edge of breakup. If you strum harder you get a nice bluesy overdrive--but it's pretty "easy-going", nothing hard rock. It only has one pentode in the preamp, which explains the cleanness. I may try bypassing the volume control.
The amp is darker than I prefer. It sounds good with single coils but not with humbuckers. I tinkered with it a bit to try and brighten it. I disconnected the tone control. I also bypassed the volume control with a 250pf capacitator. I thought this might help even with the volume full up. These changes did help a little, to the point that I am now considering keeping it.
I have to stress: the "stock" tone is great--just not my cup of tea. For distortion, I like to get a Zeppelin/Wolfmother sound.
There is 120hz hum in the background. I need to replace the filter caps.

The tubes (12AU6, 50L6, 35Z5) appear to be original (they're so worn you can hardly read the names). The components inside appear to be the worst quality they could find, but aside from the filter caps, nothing needs replacing.

You're on your own! The company is out of business, but any tube amp forum could help you with problems, mods, etc.

I wrote a check for $100 for it, which was too much. After 5 months, I don't think the previous owner has deposited the check yet... if I end up paying nothing for it, I'll be quite happy. After having played it this much and tinkering with it, I might pay $40 for it. I've been playing for three years and I have other homemade tube amps that work better for me.
All said, this is a great practice/recording amp for any old-school blues man. And the clean tone with a bridge single coil is very good.

I got my Kay K503A used about half a year ago, to go with a Kay guitar, and I've just dug the hell out of it.

It's got 3 inputs, volume knob, and tone knob (includes the power switch). That's it. This amp maybe makes five watts on a good day, which makes it good enough for home solo use, or playing w/ another guitar. Unless the other guitarist wants to play loud.

If you try to push it with a lot of pedal/fuzz/overdrive, it can get a little bit 'farty' sounding as the speaker gets way overpowered. If you want tricks, gadgets, and features, you're S.O.L. But if you want real round, brown-tone breakup, and don't want to go deaf or meet cops, this is the real deal. And the mojo factor on this is off the hook. I wish my other amps had THAT feature.

Like I said about, this amplifier has the nicest 'bluesy' breakup you could ask for. With hot pickups, breakup starts about 4-5 on the volume, and is really 'brown' by 10.

The amp has a little bit of hum to it; not real bad. I think most of the noise is in the power transformer; it seems to do it even w/ the volume turned all the way down. But, I don't hear it while I'm playing.

I have a Squier Fat Strat, the Kay hollow body, a Steinberger Spirit (sounds soooooo good thru this amp!), and a custom solid-body made out of jelutong with a Jackson neck and onboard preamp. Any of these guitars sound good through this amp. It's one of those things where it just won't make a bad sound - unless you overdrive it ridiculously with a pedal or preamp. That'll make it squeak. But, ya' gotta' get nutty overdriving it before it gets noisy.

I also have a Silverface Champ, which uses three tubes (incl. rectifier), but sounds WAY different. My Champ is dead quiet at idle, way louder when cranked, and much, much brighter. But, it's not any better sounding.

The previous owner tells me that a couple of caps were replaced, but that's all I think has been done to it. It has tubes in it that look old enough to be original; I suppose if I wanted to use it to play live (I'd have to mike it), I'd carry some spare tubes.

But, I don't play in a band, so it doesn't really matter.

Way long out of warranty. But, there's a parts list & schematic in the chassis; any amp tech should be able to fix it.

I've been playing for a couple years, have the aforementioned Silverface Champ, and my daughter's 60W Behringer bass combo amp here.

I wouldn't change a thing about this amp; it's perfect at what it does.

Date on schematic suggests that it was made 2/16/62. limited features, on/off volume and tone with 3 count 'em 3 inputs into this .275 amp out- put powerhouse. It doesn't do much...but what it does do it does fantastic!! Sound is warm slightly overdriven at full volume(even at full volume you can have a conversation over it. Very quiet. HAs an odd assortment of tubes for a guitar amp. Basically set up like a champ with a set of tubes mostly used in a radio setup(12AU6, 50L6, 35Z5). I love this amp!! It's an old amp and so is a bit buzzy at times but so what!

Part of the beauty of this amp is that ytou can play at bedroom volumes and get an unbelievable great brown distortion. Imposiable to gig with, but would be a great recording amp.

I used to laugh at Jack White and Beck when I would see them playing this old Silvertone/Magnatone/Kay stuff. JUst thought they were trying to be too cool for school. Boy was I wrong. After I bought this I started looking into all the mid-century-cheap-crap-amp. and I love them!!! I also have a Mesa Boogie Blue Angel; I love it and it sounds awesome and is much more versitile then the KAY but to my ear I honestky like the $50 KAY to the $850 Boogie.