Date   

Re: Any experience/info re: Harman/Kardon Citation 18 tuner?

Mike Zuccaro
 

In a message dated 4/5/02 5:51:05 PM Pacific Standard Time,
blundry@mediaone.net writes:

<< al, as I'm a little
confused about a few of the controls. I'd also like to hear about any
firsthand experiences with this tuner, and how people think it
compares sonically to its competitors from Kenwood, Sansui, Marantz,
MacIntosh, Accuphase, etc. Look forward to hearing from you guys...
>>
Nameless guy:
If you like it, that's what counts. Nice tuner, I've worked on a few of
them. You will find it should fill you every need, and the money you spent on
the fix was well spent. It would cost far more than that to make that tuner
today. Always assume whatever you buy used, on ebay or garage sales or
swapmeets, or whatever, will need some (or a lot!) of repiar unless you've
checked it out first, or it's sold with a guarantee.

Got a name,or did you mother name you Blundry?
best,
Mike Zuccaro


Re: More on KT-8300 op amp upgrades

Mike Zuccaro
 

In a message dated 4/4/02 10:14:48 PM Pacific Standard Time, newaag@yahoo.com
writes:

<< 20kohm. You want to try soldering
a 10 to 100 pF cap directly across the leads of these 4 feedback
resistors listed above. For experimenting, use any cap available,
even ceramic. If this improves the sound, you have eliminated a high
frequency problem, most likely oscill >>
And very short leads- at 100mc even small caps can be resonant. Bad news.
Use the smallest micas you can find.
MZ


Re: Marantz 10B IF Filter Module Frequency Response?

Mike Zuccaro
 

In a message dated 4/4/02 3:27:19 PM Pacific Standard Time,
jbyrns@enteract.com writes:

<<
1.) Are all six filter modules identical, or are there several
different types used in the tuner?

2.) What are the frequency response characteristics of an individual
filter module as installed in the tuner?

Thanks, >>

John:
1- Yes, identical
2- Some time ago I swept one- about 350 kc wide, not perfectly flat. Dont
forget that there are 6 in series, the bandwith reduction factor gets it down
to about 225kc.

best
Mike Z.


Re: My sansui TU-9900

Mike Zuccaro
 

In a message dated 4/4/02 12:59:21 PM Pacific Standard Time,
charlesp@darwin.sfbr.org writes:

<< ded to remove the bottom metal cover and
> take a look inside. Well, looked like every part and soldering was
> original from the factory. The thing I did not understand was this
> sticky thin clear layer all over the PC boards. I put my fingers and
> touched it last night. Well, I washed my hands five times but this
> smell is still on my fingers. >>

No big deal- some Japanese products had a layer of clear anti-oxidant to keep
the exposed copper traces from corroding. Usually not on the front end,
though it's not impossible. It can be removed with pure 100% alcohol, but if
it works to your satisfaction, dont touch it!
Best,
Mike Z


Re: Sansui TU-717 problem....

Mike Zuccaro
 

In a message dated 4/3/02 6:42:15 PM Pacific Standard Time,
charlesp@darwin.sfbr.org writes:

<<
IMPORTANT, DO NOT USE ANY SORT OF CHEMICAL IN A TUNER (until receiving
further
instruction...)! YOU CAN EASILY DESTROY TUNER! ABSOLUTELY DO NOT USE "TUNER
CLEANER" which was intended >>
Very good advice. You may get lucky and be able to use a fine needle or fine
dropper. You've really got to be careful. If the wipers are green or
oxidized, it may re-occur if it's not used much.
best
Mike Z.


Re: Sansui TU-717 problem....

Mike Zuccaro
 

Matt:
Yes, it sounds like a front end problem. DO NOT even attempt to open up
and/or spray the front end or clean it. If you use the wrong cleaner, or get
it into any of the trimmers in the front end, you'll be very sorry.'

Should not be an expensive fix at all, if you can get it to me.

Best,
Mike Zuccaro


Re: My sansui TU-9900

Charles Peterson <charlesp@...>
 

Hi, thank you for your reply. My apologies if I was not clear about
this thin clear layer. This is not on the componets side. This
sticky
stuff is on the bottom (traces side). Boards F-2527( power supply)
and F-2539( AM IF Circuit )have more of this.
Sounds like some one has sprayed a coating on the bottom, that was
incorrect. It is typical that boards are "sealed" once built and
tested, to seal and preserve the copper/tin plated traces from
corrosion in tropical environments. Usually this is a thin coating of
clear or greenish clear colored hard substance. But I have also seen
cases, once on older tube gear, where this hard substance turns soft
and gooey over a long time. Sounds like the factory goofed, they or
There is nothing sticky or gooey on the bottom side of my TU-9900 either,
though the boards do look shinier than from the top. The bottom sides of the
boards are covered in a hard shiny green plastic which covers all the foil
traces, but not necessarily the soldering joints. I noticed no particular
smell (other than a trace of old capacitor, probably coming from the top side).

It does sound to me like someone applied some sort of "treatment" probably for
no good reason. Such treatments as might properly be applied (like microdrops
of Dexoit to the condenser grounds) should only be applied to tiny points very
carefully. If the treatment has only been applied to the bottom sides of the
circuit boards, it might not be particularly harmful to operation, except for
the smell.

I don't think the factory green plastic would have degraded into something
smelly and gooey, but if very harsh humidity and heat caused to factory coating
to come off, the raw phenolic surface underneath might become sticky and gooey
under those conditions. Before cleaning, you should see if the factory green
plastic is still there underneath the sticky surface. If not, cleaning might be
perilous.


Re: My sansui TU-9900

newaag
 

Hi, thank you for your reply. My apologies if I was not clear about
this thin clear layer. This is not on the componets side. This
sticky
stuff is on the bottom (traces side). Boards F-2527( power supply)
and F-2539( AM IF Circuit )have more of this.
Sounds like some one has sprayed a coating on the bottom, that was
incorrect. It is typical that boards are "sealed" once built and
tested, to seal and preserve the copper/tin plated traces from
corrosion in tropical environments. Usually this is a thin coating of
clear or greenish clear colored hard substance. But I have also seen
cases, once on older tube gear, where this hard substance turns soft
and gooey over a long time. Sounds like the factory goofed, they or
an ambitous owner (or dealer) used a bad lot of material. If you are
concerned, I would get a can of electronics flux cleaner from an
electronics store, and working with the tuner on the side, and a
small brush, try to remove the substance. I would test using very
small amount of spray to start. Make sure you keep all the run-off
contained in old rags held beneath the board, and that NO residue is
allowed to enter the RF cap area, or drain in other cavities. I
would not be concerned about resealing the board, you will most
likely not need to.

Bob


More on KT-8300 op amp upgrades

newaag
 

This is for Ryan, and others upgrading op amps in the KT-8300

If you are experiencing problems with new high speed op-amps, you may
want to try this. Problems could be ringing, whirring, high
frequesncy hardness, etc.
Locate the area around the the audio opamps. What you need to find
are the feedback resistors. On one they are Rg63,Rg64 - 47kohm, on
the other they are Rg133, Rg134 - 120kohm. You want to try soldering
a 10 to 100 pF cap directly across the leads of these 4 feedback
resistors listed above. For experimenting, use any cap available,
even ceramic. If this improves the sound, you have eliminated a high
frequency problem, most likely oscillation. I would use thre smallest
cap possible that fixes the problem. Of course, if you have a 100MHz
scope, your job is a lot easier, as you can see the oscillation, and
the cure when the caps are installed.

cheers,
Bob


Re: Marantz 10B IF Filter Module Frequency Response?

pabigelow <pbigelow@...>
 

Hello John,

All six modules are identical. Do not know the freq response
characteristics.

Best regards,

Paul Bigelow
--- In FMtuners@y..., "bta_50g" <jbyrns@e...> wrote:
Hi All,

Is there a Marantz 10B aficionado out there that could answer some
questions for me, about the 10.7 mHz IF filter modules used in the
Marantz 10B FM Stereo Tuner? My questions are:

1.) Are all six filter modules identical, or are there several
different types used in the tuner?

2.) What are the frequency response characteristics of an
individual
filter module as installed in the tuner?

Thanks,

John


Marantz 10B IF Filter Module Frequency Response?

bta_50g <jbyrns@...>
 

Hi All,

Is there a Marantz 10B aficionado out there that could answer some
questions for me, about the 10.7 mHz IF filter modules used in the
Marantz 10B FM Stereo Tuner? My questions are:

1.) Are all six filter modules identical, or are there several
different types used in the tuner?

2.) What are the frequency response characteristics of an individual
filter module as installed in the tuner?

Thanks,

John


Re: My sansui TU-9900

Charles Peterson <charlesp@...>
 

On re-reading your message, I see the "coating" was peculiar to the bottom.
I'll open the bottom cover on my Sansui tonight and report tomorrow.


I just got this FM tuner from ebay. This Sansui works great. I was
worried about its shipment but the seller had done a wonderful and
safe packing. Yesterday I decided to remove the bottom metal cover and
take a look inside. Well, looked like every part and soldering was
original from the factory. The thing I did not understand was this
sticky thin clear layer all over the PC boards. I put my fingers and
touched it last night. Well, I washed my hands five times but this
smell is still on my fingers.
This does not sound good!


Re: My sansui TU-9900

Charles Peterson <charlesp@...>
 

I just got this FM tuner from ebay. This Sansui works great. I was
worried about its shipment but the seller had done a wonderful and
safe packing. Yesterday I decided to remove the bottom metal cover and
take a look inside. Well, looked like every part and soldering was
original from the factory. The thing I did not understand was this
sticky thin clear layer all over the PC boards. I put my fingers and
touched it last night. Well, I washed my hands five times but this
smell is still on my fingers.
This does not sound good!

In all the cases I have seen, leaky caps create a small crusty deposit localized
to the area right around the capacitor, sometimes encroaching on a few nearby
parts. The deposit has a beige, brown, or gray color. (Sometimes there is also
nice circle of brown which is simply some kind of glue to keep the capacitor
upright during soldering.)

I opened the top cover of my 9900 last night, and there is definitely not any
clear layer over the boards. They have a very UN-shiny appearance like
flat paint or a matte photograph. I touched each board (in an unpopulated
area...) and there was nothing sticky at all. At most a tiny trace of dust
was on the boards. I did not open the bottom cover.

Now my Sansui can also fill up a room with a particular smell after a few hours
of operation, but I currently believe that is because of a few very obviously
leaky capacitors on the power supply board which I plan to fix before too long.
It is the classic "leaky electrolytic" smell which is common to very old
equipment and is something like the smell of the inside of an old car (where it
hasn't been masked by smoking or animals).

This coating sounds very suspicious, like something sprayed on by some foolish
person. I remember back when I was about 10 years old, a friend of mine took a
can of "Tuner Cleaner" spray and sprayed it all around the inside of some old
tuner, radio, or something like that. "It's tuner cleaner," he said. "It can't
hurt it..." I was suspicious at the time, and now I know that was wrong. Tuner
Cleaner has a very specific use for the contacts of old TV's, nothing else. It
can ruin an FM tuner, particularly if sprayed on the RF parts.

The mere fact that your 9900 still works may be a miracle...which may or may
not continue. It's possible that the fool who sprayed it did not open up the
box (on the 9900) in the center where the ganged condenser and RF parts are.
If that had been sprayed, it is likely the tuner would no longer work.

Any sort of "cleaning" might create additional problems. Search this group
for "cleaning" and/or contact an experienced and reputable technician.

I count my blessings that I haven't yet bought something with a problem
quite as intractable as this sounds. I would try to get some adjustment
from the person who sold this, and if not, adjust your feedback accordingly.


Re: Sansui TU-717 problem....

bta_50g <jbyrns@...>
 

--- In FMtuners@y..., "tromatic97201" <tromatic@e...> wrote:
I now have a 717 tuner that has a problem. When I tune across the
dial, there are very large woofer movements, even at low volume.
There is also a "scratchy" or "rushing" sound audible everywhere when
tuning. Once tuned, the noise disappears, altho I can make the
rushing sound by moving the tuning knob slightly. Any ideas? More
important, cost?
Matthew
The scratching sound is caused by dirty/corroded ground contacts on
the tuning capacitor, which Charles has already covered. The large
woofer movements are unusual, some movement is normal during tuning,
but I have never seen excessive woofer movement. Thoughts that come
to mind, has the tuner been modified, and the audio coupling
capacitors replaced with much larger values? That would extend the
low frequency response, which would cause exactly this sort of
problem. On the other side of the coin, if the capacitors are leaky,
and in need of replacement, this type of problem could occur with some
types of muting circuit, if muting is engaged. I'm sure there are
more possibilities that others will mention.

John


Re: Sansui TU-717 problem....

Charles Peterson <charlesp@...>
 

I now have a 717 tuner that has a problem. When I tune across the
dial, there are very large woofer movements, even at low volume.
There is also a "scratchy" or "rushing" sound audible everywhere when
tuning. Once tuned, the noise disappears, altho I can make the
rushing sound by moving the tuning knob slightly. Any ideas? More
important, cost?
Matthew
One more obvious thing...noise during tuning is normal. You are expected
to either turn down the volume (my preferred method) or use the "Muting"
control.


Re: Sansui TU-717 problem....

Charles Peterson <charlesp@...>
 

I now have a 717 tuner that has a problem. When I tune across the
dial, there are very large woofer movements, even at low volume.
There is also a "scratchy" or "rushing" sound audible everywhere when
tuning. Once tuned, the noise disappears, altho I can make the
rushing sound by moving the tuning knob slightly. Any ideas? More
important, cost?
Matthew
Could simply be dirty ground contacts on tuning condenser...one of the most
common problems with old analog tuners that haven't been used for awhile.

IMPORTANT, DO NOT USE ANY SORT OF CHEMICAL IN A TUNER (until receiving further
instruction...)! YOU CAN EASILY DESTROY TUNER! ABSOLUTELY DO NOT USE "TUNER
CLEANER" which was intended for old tv tuner contacts, not FM tuners!

You may be able to "fix" it simply by tuning up and down the dial a number of
times. Tuners which have not been tuned for awhile typically develop this
problem because of oxidation. The safest thing to do is just to use it for
awhile, in my experience the problem just goes away. If necessary, you can tune
up and down the dial (being careful not to go beyond the end points of the dial
and break the string...that is also terrible, but at least it can be fixed)
until the problem goes away.

If necessary, there is only one kind of cleaner to use. That is "Deoxit" in the
needle point dispenser, with tiny microdrops of cleaner put carefully only on
the ground contacts points at the center of the condenser (the thing with fins
technically called "plates"). If you get anything on the fins, or anything on
any of the coils or other parts in the RF stage you can easily ruin tuner, as
has happened many times before in this group (search for tuner cleaner, fins,
etc.). Deoxit is available from Audio Advisor (www.audioadvisor.com). I use
Deoxit on lots of things, but strangely I've never had to use it on a tuner
condenser myself. The ground contacts in all the tuners I've used just seem to
clean themselves. I suspect they were designed to work that way, unless the
oxidation gets very very bad.


Sansui TU-717 problem....

tromatic97201 <tromatic@...>
 

I now have a 717 tuner that has a problem. When I tune across the
dial, there are very large woofer movements, even at low volume.
There is also a "scratchy" or "rushing" sound audible everywhere when
tuning. Once tuned, the noise disappears, altho I can make the
rushing sound by moving the tuning knob slightly. Any ideas? More
important, cost?
Matthew


Re: To: Charles Peterson: Kenwood 600T vs. Marantz 10B sound quality and reception

Charles Peterson <charlesp@...>
 

David,

Sorry, but I'm no expert on 10B, no firsthand experience, I've just been asking
annoying questions about it, and I've observed how the selectivity specs didn't
seem possible, and others have agreed (now the tunerinfo site provides some
measured numbers of one sample: 70dB alternate channel selectivity and 10dB
adjacent channel selectivity, great by tube standards but exceeded by many of
the great solid state tuners, and far from the factory specs of 150 and 42). I
happened to notice in an Audio Magazine listing of tuner specs in 1964 that the
Marantz specs were not explicitly claimed to be measured by IEHF standards, as
some specs for other tuners explicitly were.

I've also read hundreds of 10B reviews, no other tuner seems to have generated
such polarized opinions (except, perhaps, for the Sumo Charlie). I'm curious
enough and fond enough of ancient technology that I wouldn't rule out buying
a 10B if I ever happen to have enough spare change after winning the lottery.
Likewise a Sequerra Reference, about the only one that looks cooler.

I think the 600T sounds good, but this is based on only a few hours usage,
and I have not owned many of the other greats for comparison. It is not
a particularly "euphonic" sound like you might get from a tube tuner
(such as my Fisher KM-61), however, so it might not be every audiophiles
favorite...

Accuphase tuners have a great reputation, and if you buy a brand new one you
will have a warranty, brand new parts (no leaky capacitors), and the pride of
knowing that you are supporting a quality manufacturer that cares about tuners
rather than an eBay speculator or ripoff artist. Once again, I have no
firsthand experience with these, however. I believe that all Accuphase
tuners have used a sophisticated "Pulse Count Detector," which may even
be better than the best by Kenwood because they "count" both positive and
negative zero crossings. The T-109 got rave reviews by both David Rich and
Richard Modaferri (of MR 78 fame) in the Audio Critic.

Some tuner fans might own just one (really good) tuner, but to qualify as
a "tuner nut" you probably do have to own more than one. Many people might
consider that nutty.

Good luck.


To: Charles Peterson: Kenwood 600T vs. Marantz 10B sound quality and reception

David B. Levinson <david52@...>
 

Dear Charles,
 
I am sending this message to you via the entire list, as I am sure everyone will be interested in your response.
 
I recall some excellent observations by you on your Marantz 10B.  You seem to be in an excellent position to give us all your opinion on the differences between the Marantz 10B and your Kenwood 600T Supertuner, and any other high performance solid state units you are familiar with.  Both on sound quality on strong stations, and on reception on weak and closely spaced stations.
 
I am now torn between buying an Accuphase T-109 or T-109v or a Marantz 10B, I can't afford both at this time.  I see Marantz 10B's are going for UNDER $2000 now on E-Bay.  I currently have a Magnum FT-101 upgraded by Don Scott, and I was wondering if I could improve the sound quality with either of these units.  Actually I think the Magnum sounds pretty good, but I figure no self-respecting tuner nut would own just one tuner.  So my long term goal may be:
 
     1. sensitive analogue:  Magnum FT-101      for DXing
     2. digital:                    Accuphase T-109    for scanning the dial,  32 presets and remote  Great sound?
     3. tube:                      Marantz 10B           Best Sound?  Recording LIVE radio performances of "Live at the Met" and the monthly New  
                                                                   York Philharmonic concert  www.newyorkphilharmonic.org.
 
Someone on this list suggested these three types as a good combination to own, and it sounds great to me.
 
Anyone else with firsthand experience of these comparisons, please chime in.  This has got to be a great topic, let the fun begin.
 
For anyone in the Los Angeles/Orange County area, on 105.1 KMZT "K-Mozart" at 12 noon this Sunday, is a great LIVE broadcast, get your tape recorders ready:
 
  On Sunday, April 7th 105.1 K-MOZART will present for the first time in Los Angeles classical radio, all five Beethoven piano concertos...performed and conducted live by Jeffrey Kahane and the Los Angeles Chamber Orchestra.
 
Hey, Mike Zucarro, point your Yagi towards Los Angeles and see if you can get 105.1 from San Diego !!

 
Thanks to all, and thanks for the great list.  I'm happy to be a member.
 
David Levinson
Newport Beach, CA.

-----Original Message-----
From: Charles Peterson [mailto:charlesp@...]
Sent: Wednesday, April 03, 2002 12:39 PM
To: FMtuners@...
Subject: Re: [FMtuners] Re: Kenwood 600T


> > They both have pulse count detectors.
>
> KT8300 has a 5MHz wideband detector with balanced output, but it is
> not a pulse count detector. But it is a very good one.

Thanks for the correction!  Indeed I must have been thinking of KT-815!

Useless because is too wide for use in strong alternate
> channel situations, which are quite frequent today.

Is it fair to say that if you don't obviously hear any interference,
than it is *not* too wide, or is there a point at which the interference
is very subtle so you might have to listen carefully to "wide" and "normal"
to determine which is best?


> > > Both use the same stereo circuit, based on the HA1156 IC. It uses
> the
> > > IC to run the PLL to extract the 38kHz fromn the 19kHz pilot, but
> > > that's about it.

I noticed the new audio comparison of 600T and KT-917 on the tunerinfo site (in
which they are found to be sonically identical).  I believe in some sense the
KT-917 is more "sophisticated" in having a 19Khz canceler.  But the effect on
frequency response in the specs is pretty small.  The 600T is spec'd up to 15Khz
and the KT-917 is spec'd to 16Khz, with a fraction of a dB improvement in the
tolerance.  I was also fascinated that the TU-X1 was found to sound "clearer"
than either.  I wonder if that wasn't some sort of euphonic coloration.  My
TU-9900 does seem to have slightly more "presence" than my 600T, which so far
I've been considering to be coloration, but I could be wrong...  So far I
consider the 600T to be better sounding than TU-9900.



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Re: Kenwood 600T

Charles Peterson <charlesp@...>
 

They both have pulse count detectors.
KT8300 has a 5MHz wideband detector with balanced output, but it is
not a pulse count detector. But it is a very good one.
Thanks for the correction! Indeed I must have been thinking of KT-815!

Useless because is too wide for use in strong alternate
channel situations, which are quite frequent today.
Is it fair to say that if you don't obviously hear any interference,
than it is *not* too wide, or is there a point at which the interference
is very subtle so you might have to listen carefully to "wide" and "normal"
to determine which is best?


Both use the same stereo circuit, based on the HA1156 IC. It uses
the
IC to run the PLL to extract the 38kHz fromn the 19kHz pilot, but
that's about it.
I noticed the new audio comparison of 600T and KT-917 on the tunerinfo site (in
which they are found to be sonically identical). I believe in some sense the
KT-917 is more "sophisticated" in having a 19Khz canceler. But the effect on
frequency response in the specs is pretty small. The 600T is spec'd up to 15Khz
and the KT-917 is spec'd to 16Khz, with a fraction of a dB improvement in the
tolerance. I was also fascinated that the TU-X1 was found to sound "clearer"
than either. I wonder if that wasn't some sort of euphonic coloration. My
TU-9900 does seem to have slightly more "presence" than my 600T, which so far
I've been considering to be coloration, but I could be wrong... So far I
consider the 600T to be better sounding than TU-9900.