Note on Porch Find & Free Monday-on-Tuesday

[Peter Wieck]

Free for Shipping: Eico Signal Tracer. Untested, no probe (looks like
it may not need one), Not stored well, but not bad either.

Free for Shipping: Tube Tester, needs a bit of help, but claims to be
"Dynamic Conductance". Banged up a bit but not overly so. If anyone is
interested, I will come up with the brand. It is not one of the top
brands, but not NRI either.

Now that is out of the way.

The Kenwood Receiver that wandered onto the porch over the weekend
turned out to be (once the lint was removed) a KW55a AM/FM Receiver, 17

or 18 tubes. Outputs are EL84/6BQ5 PP with 12AX7 drivers. It got
through all the passive tests OK, so when fired up and the meter on the

variac stayed steady, I ran it for a few moments.

Quite a sensitive front-end, the FM goes from 80.0 (!!) to 108.0.
LOTS of clicks and pops and wheezes that eventually steadied out...
definite candidate for capacitor replacement. But decent sound for all
that _when_ it steadied out.

http://radioatticarchives.com/images/k/Kenwood_KW-55A_Potter.jpg

is a picture of the unit I found at Radio Attic, but mine is NO where
near as nice as the one shown.

Questions for the assembled multitude, does anyone know:

a) The approximate year of this unit? It has dialable AFC, no mute
function, tape-head, Tape, and Mag. Phono inputs. Codicil: was it
top/middle/bottom of the line in its day?
b) There is a mysterious two-position slider switch dead-center on the
back of the unit, between the pairs of output tubes, unlabeled. Any
idea as to its function?
c) I am going to word this carefully. I will not flog this beast on
eBay, so I am not asking what it is worth. But, is it desirable to
someone who might want to trade for it for something that I am actually

interested in having? For instance, I would like an VINTAGE US-made
(solid-state) AR tuner. Or a similar Scott or Sherwood or Fisher
receiver, or some such. Suggestions welcome.
d) I am half-tempted to do the full monte on the thing, clean it up to
semi-pristine condition just to have a piece of Japanese Iron in the
inventory if only for comparative purposes. Is this a silly idea?

Pictures are available, of course, to the interested-in-trading.

Thanks in advance.

Peter Wieck
Wyncote, PA

[Arny Krueger]

"Peter Wieck" > wrote in message
oups.com

> The Kenwood Receiver that wandered onto the porch over
> the weekend turned out to be (once the lint was removed)
> a KW55a AM/FM Receiver, 17
> or 18 tubes. Outputs are EL84/6BQ5 PP with 12AX7 drivers.
> It got through all the passive tests OK, so when fired up
> and the meter on the

> variac stayed steady, I ran it for a few moments.

> Quite a sensitive front-end, the FM goes from 80.0 (!!)
> to 108.0.
> LOTS of clicks and pops and wheezes that eventually
> steadied out... definite candidate for capacitor
> replacement. But decent sound for all that _when_ it
> steadied out.

Probably needs a visit from a vacuum cleaner.

> http://radioatticarchives.com/images/k/Kenwood_KW-55A_Potter.jpg

> is a picture of the unit I found at Radio Attic, but mine
> is NO where near as nice as the one shown.

Those aluminum front panels like to oxidize, right?

> Questions for the assembled multitude, does anyone know:

> a) The approximate year of this unit?

I sold a jillion of these at that Lafayette Associate store I worked at as a
kid. Those were Lafayette branded. I'm going to guess around 1965.

> It has dialable AFC,

That would be diasableable.

> no mute function, tape-head, Tape, and Mag. Phono
> inputs.

Is the FM section stereo? I seem to recall that it was.

> Codicil: was it top/middle/bottom of the line in its day?

Near the bottom. The EL 84 output tubes are the tip-off. I don't know if
this was one of the Kenwood receivers with the *magic* output transformers
that generated a lot of nonlinear distortion around 7 KHz to "brighten up"
the AM.

Try listening to the FM with good (preferably SS) power amp attached to the
tape outputs. If that cleans up the FM sound considerably, then you've won
the booby prize. The FM section could sound good, but if you've got one of
the ones with *special* output transformers, the amp side is pretty nasty.

My recollection is that the FM section of this puppy is really pretty nice,
with good tubes and alignment. Lots of IF stages, and a FM RF stage as
well - Maybe 4 FM sections in the tuning capacitor?

> b) There is a mysterious two-position slider switch
> dead-center on the back of the unit, between the pairs of
> output tubes, unlabeled. Any idea as to its function?

Speaker phase switch?

[Peter Wieck]

Arny Krueger wrote:

> Probably needs a visit from a vacuum cleaner.

Got that above the chassis, and a wipe-down with a strong ammonia-based
cleaner... much to do below yet.

> Those aluminum front panels like to oxidize, right?

Actually, the front panel and straight-from-the-front cosmetics are
excellent. It's the back-of-the-house that needs work. The end that got
the moist air from the dryer, I guess. Lots of pitting, no serious
rust. And a very fine coating of what might be oil-boiler soot...
slightly oily coating, but responds well to ammonia-based cleaners.

> I sold a jillion of these at that Lafayette Associate store I worked at as a
> kid. Those were Lafayette branded. I'm going to guess around 1965.

That makes sense. It has a 'betwixt & between" look to it. More modern
than the Scott & Fisher contemporaries, but not up to the 70s major
bells & whistles category. Any idea of the Lafayette part number?

> > It has dialable AFC,
>
> That would be diasableable.

On a "click" switch. Yep.

> > no mute function, tape-head, Tape, and Mag. Phono
> > inputs.
>
> Is the FM section stereo? I seem to recall that it was.

Stereo, most certainly. Good separation, high sensitivity.

> > Codicil: was it top/middle/bottom of the line in its day?
>
> Near the bottom. The EL 84 output tubes are the tip-off. I don't know if
> this was one of the Kenwood receivers with the *magic* output transformers
> that generated a lot of nonlinear distortion around 7 KHz to "brighten up"
> the AM.

Figured as much. And when I found out that the cover was both
'weighted' and 'expanded' (added a full inch in width, and about 4
pounds in weight), I knew what I had.

> Try listening to the FM with good (preferably SS) power amp attached to the
> tape outputs. If that cleans up the FM sound considerably, then you've won
> the booby prize. The FM section could sound good, but if you've got one of
> the ones with *special* output transformers, the amp side is pretty nasty.

Actually, I ran the tape-out directly to another system at first. No
discernable change when directly to the speakers. So, maybe not as you
suggest with this one.

> My recollection is that the FM section of this puppy is really pretty nice,
> with good tubes and alignment. Lots of IF stages, and a FM RF stage as
> well - Maybe 4 FM sections in the tuning capacitor?

Yep. Four sections visible inside the front-end box. And a full 10
tubes dedicated to the tuner section (Both AM and FM). It all comes
back to a 6AQ8, however. One of the quirkiest tubes out there.

> > b) There is a mysterious two-position slider switch
> > dead-center on the back of the unit, between the pairs of
> > output tubes, unlabeled. Any idea as to its function?
>
> Speaker phase switch?

Maybe, I will clean further this evening, under the chassis, and see
what-where-how it goes and is wired. Maybe even target a few caps at
strategic locations.

Peter Wieck
Wyncote, PA

[Sander deWaal]

"Peter Wieck" > said:


<Kenwood/Trio KW55>

>a) The approximate year of this unit? It has dialable AFC, no mute
>function, tape-head, Tape, and Mag. Phono inputs. Codicil: was it
>top/middle/bottom of the line in its day?


Based on model number and tube complement, I'd date this one somewhere
around 1963- 1965..
EL84-based units were middle-class AFAIK.
There's a manual available at:
http://www.radioera.com/k-manuals.htm
Scroll down a lot.

Google shows some results from Japanese websites, bud sadly, I don't
read Japanese.


>b) There is a mysterious two-position slider switch dead-center on the
>back of the unit, between the pairs of output tubes, unlabeled. Any
>idea as to its function?


Check the wiring to the output transformers, it might be an impedance
swith, or a speaker phase switch.
Most of these early stereo units were fitted with a phase switch, to
easily facilitate speaker connections.
It was common practice to use different speakers for each channel
then, so it may be omitted or bypassed if you're planning on restoring
and using it yourself.

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Arny Krueger]

"Peter Wieck" > wrote in message
ups.com
> Arny Krueger wrote:

>> I sold a jillion of these at that Lafayette Associate
>> store I worked at as a kid. Those were Lafayette
>> branded. I'm going to guess around 1965.

http://radioatticarchives.com/images/k/Kenwood_KW-55A_Potter.jpg

> That makes sense. It has a 'betwixt & between" look to
> it. More modern than the Scott & Fisher contemporaries,
> but not up to the 70s major bells & whistles category.
> Any idea of the Lafayette part number?

LR 440 keeps popping into my head.

It could be one of the later tubed models that avoided the strange output
transformers.

It was one of the nicer-looking ones.

[Peter Wieck]

Thank you all for your various answers. Here is the last I will bother
you with it...

Final tube count: 22. Including a strange little metal tube at one end
(6CW4). Near as I can figure from pulling tubes at strategic intervals,
there are 11 for the FM section, 3 for the AM section, 2 for the mag &
Tape-head pre-amp, and 6 for the amplifier section.

AM Band goes from 55 to 1600 (printed numbers) with some play to either
side.
FM Band goes from 80 to 108 (printed numbers) as above.

The little slider switch is a 110/220V switch.

With the controls fully cleaned, each tube & socket individually
cleaned, it runs quiet, cool, no hum, hiss or pops at any volume. Dead
silence on Mag. input at 3/4 volume, some hiss at full volume.

The Matsu****a-branded tubes all test well above minimum on the Hickok,
but a Royal PITA to go through all of them (Yes, the Hickok does test
the 6CW4).

This clearly does not have the "funny" output transformers. FM is quite
nice, no funny-business. But AM is good and clear as well.

I need dial lamps, one indicator lamp and a couple of spares. The dial
lamps are fuse-type, I am guessing 8V as that seems to be a favorite KW
voltage, but I will measure what is on the pins. The indicatiors are
colored 1/4" threaded-base lamps. I may look foolish purchasing nail
polish in the correct colors, but a with a cool enough lamp, this
should work OK. The fuse-type lamps I will have to find. I will also
have to take off the faceplate to get to them. A small price to pay.

Thanks again.

Peter Wieck
Wyncote, PA

[Jon Yaeger]

in article om, Peter Wieck
at wrote on 9/6/06 10:48 PM:

> Thank you all for your various answers. Here is the last I will bother
> you with it...
>
> Final tube count: 22. Including a strange little metal tube at one end
> (6CW4). Near as I can figure from pulling tubes at strategic intervals,
> there are 11 for the FM section, 3 for the AM section, 2 for the mag &
> Tape-head pre-amp, and 6 for the amplifier section.
>
> AM Band goes from 55 to 1600 (printed numbers) with some play to either
> side.
> FM Band goes from 80 to 108 (printed numbers) as above.
>
> The little slider switch is a 110/220V switch.
>
> With the controls fully cleaned, each tube & socket individually
> cleaned, it runs quiet, cool, no hum, hiss or pops at any volume. Dead
> silence on Mag. input at 3/4 volume, some hiss at full volume.
>
> The Matsu****a-branded tubes all test well above minimum on the Hickok,
> but a Royal PITA to go through all of them (Yes, the Hickok does test
> the 6CW4).
>
> This clearly does not have the "funny" output transformers. FM is quite
> nice, no funny-business. But AM is good and clear as well.
>
> I need dial lamps, one indicator lamp and a couple of spares. The dial
> lamps are fuse-type, I am guessing 8V as that seems to be a favorite KW
> voltage, but I will measure what is on the pins. The indicatiors are
> colored 1/4" threaded-base lamps. I may look foolish purchasing nail
> polish in the correct colors, but a with a cool enough lamp, this
> should work OK. The fuse-type lamps I will have to find. I will also
> have to take off the faceplate to get to them. A small price to pay.
>
> Thanks again.
>
> Peter Wieck
> Wyncote, PA
>



Peter,

Those are 8 volt bulbs which you can get pretty cheap from Atlanta Light
Bulbs www.atlantalightbulbs.com/

I'll send the manual in Word format via e-mail.

Not doubt a vet like you has already changed the output tube coupling caps.
If you didn't know already, ALL of the gray coupling caps are bad (leaky).
And test some of the Nippon tubes - a lot of the 9 pin ones are crappy too.

Jon

[Peter Wieck]

Jon Yaeger wrote:
> Peter,
>
> Those are 8 volt bulbs which you can get pretty cheap from Atlanta Light
> Bulbs www.atlantalightbulbs.com/
>
> I'll send the manual in Word format via e-mail.
>
> Not doubt a vet like you has already changed the output tube coupling caps.
> If you didn't know already, ALL of the gray coupling caps are bad (leaky).
> And test some of the Nippon tubes - a lot of the 9 pin ones are crappy too.

Jon:

Thanks for the link, the manual, and the advice. I have bulk-ordered 50
x 0.05uf@600V caps, there are a bunch of them in there. And I observed
that most of the 1uF @ 50V (electrolytic) caps are all swollen, so
before this beast is permitted out of quarantine, all such will be
attended-to. The remainder should be in my stock.

Thanks again,

Peter Wieck
Wyncote, PA

[Sander deWaal]

"Peter Wieck" > said:


>Final tube count: 22. Including a strange little metal tube at one end
>(6CW4).


A Nuvistor.
Hard to come by, they're also found in e.g. Fisher and McIntosh gear
from that era.

Since our little friend Michaelson decided to use them in his Musical
Fidelity "NuVista" range, they've become very scarce.

Maybe you van try a scope parts supplier , they were to be found in
certain oscilloscopes as well.


>I need dial lamps, one indicator lamp and a couple of spares. The dial
>lamps are fuse-type, I am guessing 8V as that seems to be a favorite KW
>voltage, but I will measure what is on the pins.


Indeed 8V, a voltage and shape the Japanese manufacturers used up
until well in the '80s.

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Peter Wieck]

François Yves Le Gal wrote:

> NOS 6CW4's can still be found for around USD 15.00 ea.

Just snagged two at US$3.00 each from my local supplier. He has a few
tubes in the back room, mostly TV types. Both are RCA, both NIB. As to
their actual performance, that remains to be seen, but I do not have
the need for now.

He is more-or-less on my travel path. When I asked, he gave me a
cross-eyed look, raised his hand in the air and went in back. Came back
with them in his hand, said "three bucks each, want 'em?".

Peter Wieck
Wyncote, PA

[Sander deWaal]

"Peter Wieck" > said:


>> NOS 6CW4's can still be found for around USD 15.00 ea.


>Just snagged two at US$3.00 each from my local supplier. He has a few
>tubes in the back room, mostly TV types. Both are RCA, both NIB. As to
>their actual performance, that remains to be seen, but I do not have
>the need for now.

>He is more-or-less on my travel path. When I asked, he gave me a
>cross-eyed look, raised his hand in the air and went in back. Came back
>with them in his hand, said "three bucks each, want 'em?".



Seems like I live in the wrong part of the world.
Any nice houses vacant there in PA, Peter? ;-)

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Peter Wieck]

Sander deWaal wrote:

> Seems like I live in the wrong part of the world.
> Any nice houses vacant there in PA, Peter? ;-)

A few....

http://livingchoices.com/home/homedetail.aspx?refer=homegain&hid=535568767&mid=6160


http://livingchoices.com/home/homedetail.aspx?refer=homegain&hid=535891517&mid=6160

http://livingchoices.com/home/homedetail.aspx?refer=homegain&hid=535701939&mid=6160


http://livingchoices.com/home/homedetail.aspx?refer=homegain&hid=535663966&mid=6160


http://www.weichert.com/search/realestate/SearchResults.aspx?q=19095&mlsnum=&minpr=&maxpr=&x=25&y=8


And so forth.

Keep in mind that the Philadelphia region was the home of Philco, RCA,
Sylvania, A****er-Kent, Cunningham and more than a few other suppliers
and supporters of the industry, and Westinghouse & GE had plants in the
five-county area. So, stuff is thick on the ground.

Peter Wieck
>From the Tobacco Road of Wyncote, PA