[Peter Wieck]

I have been offered one of these for US$150, clean, no top, missing
some tube shields (which I have, the fancy type) but otherwise intact
and fully operational (by ear, not instrument anyway).

Given my penchant for vintage stuff, how does this one stack up against
similar-vintage tube tuners? I am guessing from its faceplate and
general cosmetics that it is not TOL for McIntosh, but it does bear the
name.

Thanks in advance.

Peter Wieck
Wyncote, PA

[graham]

"Peter Wieck" wrote in message
ups.com...
I have been offered one of these for US$150, clean, no top, missing
some tube shields (which I have, the fancy type) but otherwise intact
and fully operational (by ear, not instrument anyway).

Given my penchant for vintage stuff, how does this one stack up against
similar-vintage tube tuners? I am guessing from its faceplate and
general cosmetics that it is not TOL for McIntosh, but it does bear the
name.

.... is this a stereo unit, they made two versions, 65 in mono, 65B is
stereo ... I had a MR-67 once and loved it ... sold it, but wish I didn't ..

[Peter Wieck]

graham wrote:

... is this a stereo unit, they made two versions, 65 in mono, 65B is
stereo ... I had a MR-67 once and loved it ... sold it, but wish I didn't ..

Definitely Stereo.

Peter Wieck
Wyncote, PA

[John Byrns]

In article . com,
"Peter Wieck" wrote:

graham wrote:

... is this a stereo unit, they made two versions, 65 in mono, 65B is
stereo ... I had a MR-67 once and loved it ... sold it, but wish I
didn't ..

Definitely Stereo.

Doesn't that make it a MR-65B? Or does it have the MA5 adapter
installed?


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Peter Wieck]

John Byrns wrote:
In article . com,

Doesn't that make it a MR-65B? Or does it have the MA5 adapter
installed?

Yes. The MA5 adapter is installed. It is now sitting on the check-our
bench, before I actually let it into a system, for testing.

Peter Wieck
Wyncote, PA

[Peter Wieck]

Follow-up:

A little whistley in Stereo using headphones, but good separation. The
variable AFC seems to be pretty much invariable. Given that this is an
early 60s unit and has been sitting for _a while_, I suspect the
electrolytics for a start. There are a bunch of them in the
multiplexer. But before that I will replace both tubes on that board
anyway as both of them test about 30% below "acceptable" on the Hickok.
(12AU7 & 6U8). Most of the other tubes in the unit are fine and
reception is excellent. The controls also really need a serious
clean-out as they are very stiff and intermittent.

After that, if it does not quit whistling, it will get sent to a friend
for an alignment. I might try microscopically tweaking the cans (the
are fine, Bret) but no more than that without instruments.

Peter Wieck
Wyncote, PA

[Peter Wieck]

Bret Ludwig wrote:

It's dumb to touch FM tuners without the basic test gear. But I would,
if I were serious about listening to it, change all the lytics.

Basic test gear I have. Many vintage FM tuners (Scott, Dynaco and Eico,
for instance) were within the reach of the end-user to align reasonably
well as they were initially kit-based designs. The McIntosh
emphatically is not.

I do know enough of the sequence-of-process to know what to tweak and
especially when to stop tweaking. In any case, I doubt I will change
any given slug more than 2-3 degrees unless I hear audible and
immediate results. And back to pre-tweak condition of course.

Yeah, there are at least a dozen caps that are going to get shotgunned,
including five (5) on the multiplex adaptor. And they will be carefully
screened. Most all of them I have in stock anyway.

Peter Wieck
Wyncote, PA

[robert casey]

Yeah, there are at least a dozen caps that are going to get shotgunned,
including five (5) on the multiplex adaptor. And they will be carefully
screened. Most all of them I have in stock anyway.


Just like in an AA5, recapping the electrolytic caps should have no
effect on the alignment. So I wouldn't mess with the alignment. Unless
it looks to be grossly out.

[Peter Wieck]

robert casey wrote:

Just like in an AA5, recapping the electrolytic caps should have no
effect on the alignment. So I wouldn't mess with the alignment. Unless
it looks to be grossly out.

I am hoping to quieten the whistle. This could be due to the two
marginal tubes and/or the caps. If it is still whistling (only in
"stereo") after all that, I will try tweaking those couple of degrees
at the carrier slug. No more. After which it will go out into expert
hands anyway if still not right.

Peter Wieck
Wyncote, PA

[Sander deWaal]

"Peter Wieck" said:


I am hoping to quieten the whistle. This could be due to the two
marginal tubes and/or the caps. If it is still whistling (only in
"stereo") after all that, I will try tweaking those couple of degrees
at the carrier slug. No more. After which it will go out into expert
hands anyway if still not right.


Stereo whistles or fizzling is usually caused by a misaligned IF, when
the bandwidth of the IF section is too narrow, or the S-curve is not
exactly in phase with the top of the bell curve of the IF section.

You'll need a IF sweep generator to align the IF coils, starting from
end to front, damping each IF coil with a resistor while aligning the
other.

It can be done, even without a manual.
But it takes skill, patience, and some good measuring equipment.

Replacing tubes in the IF section may lead to slight differences in
tuning of the anode resonant circuit, which may need to be addressed
by re-aligning.

As an experiment, you could try to broaden the IF bandwidth by
temporarily lowering the Q of each IF section with a damping resistor
over each coil, to seen if the problem stems from there.

If not, the problem is in the stereo decoder section, which, if I
recall correctly, is a separate little box, attached with a 4-prong
plug and a cinch cable to the tuner.
Not much to align there, except for correct phase of the 38 kHz, again
IIRC. Too long ago that I had one on my bench.
I remember I got it up and running again in 3 nights or so, just
taking the time it needed. No hurry.


Never try to stagger-tune the IF sections, though.
That will result in a mess and you'll probably never going to get it
back to normal again.

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

[Peter Wieck]

Sander deWaal wrote:

Never try to stagger-tune the IF sections, though.
That will result in a mess and you'll probably never going to get it
back to normal again.

You bet on that!

Anyway, caps replaced, whistle gone, back to a well-behaved unit. I am
even leaving the marginal tubes in place given that things are
apparently OK for now.

I even restuffed the little 50uF@ 150 Can on the MPX unit...

Peter Wieck
Wyncote, PA

[scott and barb]

How much you guys think a MR-67 is worth, professionally aligned 5 years ago
plays beautifully but chassis has lost some luster,Maybe a 5.5 on a 1-10
scale?
"graham" wrote in message
...

"Peter Wieck" wrote in message
ups.com...
I have been offered one of these for US$150, clean, no top, missing
some tube shields (which I have, the fancy type) but otherwise intact
and fully operational (by ear, not instrument anyway).

Given my penchant for vintage stuff, how does this one stack up against
similar-vintage tube tuners? I am guessing from its faceplate and
general cosmetics that it is not TOL for McIntosh, but it does bear the
name.

... is this a stereo unit, they made two versions, 65 in mono, 65B is
stereo ... I had a MR-67 once and loved it ... sold it, but wish I
didn't ..

[Patrick Turner]

Peter Wieck wrote:

I have been offered one of these for US$150, clean, no top, missing
some tube shields (which I have, the fancy type) but otherwise intact
and fully operational (by ear, not instrument anyway).

Given my penchant for vintage stuff, how does this one stack up against
similar-vintage tube tuners? I am guessing from its faceplate and
general cosmetics that it is not TOL for McIntosh, but it does bear the
name.

Thanks in advance.

Peter Wieck
Wyncote, PA

Tubed tuners can be truly exceptional sounding if all well set up and
adjusted
and aligned properly.

There can be noise problems if the signal input level is low
or else caused by spurious frequencies outside the FM band entering the
set,
so that typically you may get a whispering or fry-up sound at low
level in stereo mode.
I found that my own tuner suffered like others I have tried to
repair and upgrade due to noise in stereo.
The final answer was to have a 100MHz parallel LC bandpass filter across
the input terminals of the
300ohm antenna connection; this was a few turns of 1.4mm Cu wire
plus a small 0-27pF trim cap. Noise vanished, ie, went from audibilty,
probably 0nly -55dB SNR
to non audible, maybe -75dB, and this made a heck of a difference.

The stereo multiplex decoder is what determines the sound clarity in
fully
tubed tuners, and switching from mono to stereo on many tuners is a
dissapointing
experience but the MPX section really does have to butcher the signals
around a lot before giving us something beautiful to listen to.

Many sets I have worked on such as the Scott 350B had a litany of
problems
although they did kinda work a bit; poor F response isn't unusual,
poor separation, noise, balance, you name it...

I have often thought of making an MPX decoder based upon the the ideas
used
in Si chips with a set of differential amps instead of diodes
tp do all the mpx work.
The dynamic range of 1/2 a dozen 6DJ8 used as the bjt's are in a typical
chip decoder would be awesome.....

Patrick Turner.

[Peter Wieck]

Bret Ludwig wrote:

But if you call up and ask to buy a working but rough
looking one they will tell you "We never get those!" I busted a big
dealer in upstate NYC red-****ing-handed telling me this and they just
hang up on me now.

I think they hang up on you for other reasons. How do you think I found
the MR65? I asked the dealer if he had any junk lying around, he led me
straight to the tuner. How he set the price was quite interesting as
well. It was a straight back-down from an expected "retail" for that
unit of ~$700, and what he would have to do (to guarantee it) to
command that price. He wound up at $150, I agreed. End of story.


Peter Wieck
Wyncote, PA