The Mighty Messed UP Kay

:slight_smile:

Bill, here are a few pictures of the amp - not great, but you get the idea.

http://s1235.photobucket.com/albums…20Recon

I tried recording something with it. It wants to sound good, but it is really “squishy” and compresses like crazy, and there is no high end to speak of. The "contour’ knob is more like a gain than anything, although it does also cut out highs when it is turned up for distortion. Perhaps you can tell what it going on from the schematic, I certainly can’t! Should I ship it up to you to have you fix it for me? It still has the 2 prong plug on it…

Is part of the problem the speaker? There was a 4 amp speaker in there, when I bought it, and I think it needs 8 ohms - would that mess it up? I put all new tubes in it, and it really doesn’t have too many “cobwebs” when I turn it on. It does make a crackling sound when i first touch the strings with my fingers - that’s a ground problem, right? And I was not careful and got a small shock from the guitar when I touched the mic preamp. I should know better! Anyway, I won’t plug it in again until it is reconditioned. How much should it cost, I wonder?

I don’t like the way that wood crosses over the front of the speaker…I know, I know bass frequencies go through solid objects…it’s just the principality of it.

Do you mean a 4ohm speaker in there and you put in an 8ohm?
you said amp but that doesn’t sound right.


There is some equation or something you can figure that out by…as far as the amp is putting out and what speakers to put on it, if it was rated at 4ohms tho…makes you wonder if that is it’s design spec?

keep shinin

jerm :cool:

Yep, speaker is what I meant, not amp. Gotta proofread this stuff!!!

I think I remember looking at the schematic and it said 8 ohms. Also - yes - that wood is in the way. Weird looking. I wonder if whoever had this made the back the front? I seem to recall that the knobs were in the back on someone else’s picture. I gotta go check that out. Tomorrow I think I will in fact plug it in, and run it into an external speaker I have. It’s a Crate, no great shakes, but should give a better indication of what it might sound like. It really does want to sound good. I can hear that it wants to do the bell thing with my strat.

Judging from the position of the original speaker(s) mounting studs, I’d say it probably had two eight or two ten inch drivers in it. If the schematic says the amp was rated for 4 ohms, two 8 or two 10 inchers at 8 ohms wired parallel would yield four ohms nominal impedance.

Could have been even smaller speakers OR one oblong shaped driver.

UJ

I should scan the new topics before I post in what comes in my E-Mail, as replies…
Anyway, this is, the Amp…
I assume…
It looks like it has potential, just from it’s appearance…
I’m gonna see what information I have in my Amp Paper-back Books…
It should be in them somewhere… OR… I’ll google the model and see what comes up…
If there is some burned up resistors in-and-around the Output and power supply areas of the chassis, I would try not the keep the power on for long periods of time…
You;ll stress the output and power section of the amp and tubes…

You;ll be chasing good money after bad for those new output tubes…



I was telling Bob about your Kay Bass Amp…
and going on a House call…
He replied…
When do you want to go?

We both smiled and were quiet for a while…
Yea gotta know these freaks…



Seems when we talk talk , it’s at the same time…

Something two “Old Hens” talking over their knitting, or something…
You Know…
:p
:)
:laugh:
Gotta be Care FUL…
This is a Co-Ed Board…
these days…






Bill…

Hi TomS:
I saw the photos you’ve posted… Looks SwEET… Before I go google’ing I’d say that the speaker that’s in the cabinet is way too small for the amp… Nice Speaker, though… :agree: It should be an 18" speaker in it… Maybe… Can you measure the Diagonal distance between the Bolts ???? If it happens to be … Say some 17" -or-so… Then an 18" speaker would be Default, for that amp…

Gotta GO… We’ll be back… He Says… :) :laugh:

Bill…

Quote: (woxnerw @ Nov. 08 2010, 9:33 AM)

Hi TomS:

I saw the photos you've posted..
Looks SwEET..
Before I go google'ing I'd say that the speaker that's in the cabinet is way too small for the amp.. Nice Speaker, though..
:agree:
It should be an 18" speaker in it..
Maybe..
Can you measure the Diagonal distance between the Bolts ????
If it happens to be .. Say some 17" -or-so..
Then an 18" speaker would be Default, for that amp..


Gotta GO..
We'll be back..
He Says..
:)
:laugh:


Bill..

I believe you're right Bill. It does like a single 18 incher was the original speaker. After a closer look at the pics, I can sort of see the outline in the grill cloth and that bit of edge foam stuck to that upright.

What are the tubes Tom? Looks like 6L6GC for the output? Is that a 5AR4 rectifier sitting next to the power transformer (left-side in the pics)? Pair of 12AX7's for preamp most likely...

Neat, simple old amp. Probably 40 watts or so.

UJ

PS Be careful poking around that thing!

I snooped in the Gerald Weber Paper-back…
No-Go…
Gerrard is stuck on mostly Fender Amps…
sigh…
The other paper-back is over at Bob’s place… I’ll look in there the next day we get over there…


That rectifier tube looks like a 5U4 tube…
Most rectifier tubes with the correct pin-outs will power up the supply… However, a 5V4 or a GZ34 tube would be the correct one…
??
Anyway, a Bass amp should have Diodes in the power supply… That’s just my opinion…
You want the best rise-time, from a power supply, you can get for a Bass Amp…
AND… you don’t want the supply going “Soft” or “Brown-Out” when you put your Foot-in-the-Bucket… That’s O.K. for a Guitar Amp…

A tube Amp is naturally “Soft” anyway, in comparison to a Transistor amp…





Those 6L6 tubes look like Tung-Sol tubes, from what I can see in the Photos…
Maybe, I’ll go and google…
to see what I can see…





Bill…

FYI… you can buy solid-state rectifiers mounted on a tube base with correct pin-outs IF you want to convert it to solid-state rectifier operation.

UJ

AaHh…
Cheaper to build them yourself…
:)
:p
:laugh:
6 X’s 1N4007 diodes…
Three X’s Three…
in series…


Kay 720 Bass Amp…



Still Google’ing




Bill…

That photo. in that link explains how the BOLTS work… I would say the speaker in the 720 is a 15" speaker…

More photos…


:O :O :O :)

Quote: (woxnerw @ Nov. 08 2010, 10:30 AM)

AaHh..
Cheaper to build them yourself..

Not really. Especially if you don't have the tools already available. A 5AR4/GZ34 replacement for example is 20 bucks. Last forever... While the 1N004's are dirt cheap, my TIME is more valuable than 20 lousy bucks. So I'd just spend the 20 spot and move on...

Always attach a monetary value to your time. Once gone, you don't get it back. God said; "Here yarr! NO REFUNDS!" :p

UJ

Here Bill;

These are GREAT!

http://www.webervst.com/ccap.html

UJ

I like Calculator at bottom of the page…

That’s a whole lot better than buying number’d Groove Tubes… Always buy 10’s G/T’s for your amp… No Sag from the optput circuit… Get SAG from your power supply… IMHO… that is…

Bill…

I donna Know…
???

This says it’s the amp…
BUT…
IS IT ????




TomS…
Look up under the top Panel…
See if there’s any tubes in the control panel…
????






Bill…

What a wealth of KNOWLEDGE in

This Link…




Bookmarking this one… :)





Bill…

I’ll go look at the tubes and up under the chassis, but I promise I will avoid buckets into which I put my feet.
Based on those pictures, Bill, it looks like whoever had this amp put the front on the back and the back on the front.
The schematic you found is indeed it, at least it looks like it to me.


So, I’ve always understood tube rectifiers to be “better” than solid state, b/c of the effect when pushed, the “sag.”
I’m not at all averse to going to solid state, and was vaguely aware that this sort of thing was made, but never really thought about it.

Any idea what a reasonable cost would be to get this done by a pro?
I, personally, don’t really want to get electrocuted.
???

Oh - 8 ohm 15 inch. (The speaker, that is…)

This link is bookmarked AS Well

MaN…

It surprising what you find up here…

Bill…

Sorry…
I got sidetracked…






This amp can be fixed for next-to-nothing…


That’s just me seeing it on paper…
There is so little in the Box…
If the output transformer is not burned, and the voltages are close, I can only think that the bias supply is not correct…
and needs some components replaced…
to make the 6L6 output tubes idle correctly…

It’s like tweeking the air on that old Buick Carb… hehe… and regapin’ the plugs…

Maybe we can fix this amp over the internet…
Wouldn’t that be saomething…
:p
:p
:laugh:






Bill…