Kenwood KD-550 Refurb/Mods/Upgrades
ZLTFUL
Posts: 5,651
A couple of months ago, I finished up my office and began to put my 2 channel rig back together.
One of the nostalgia parts of my 2 channel rig is my Kenwood KD-550 turntable.
I enjoy listening to vinyl but this is more for the nostalgia and to fill my need for the occasional handling of the media.
Plus when my grandfather passed away, one of the only things I wanted from his estate besides his WWII memorabilia was the record collection he had that was from him, my grandmother, my dad and my 2 aunts. A lot of big band, classic jazz, classical, 60s and 70s rock and late 70s/early 80s country.
That along with the occasional record I pick up at one of the local stores or at a garage sale has me into about 200-250 records across a broad range of genres.
So any time I want to reminisce about hanging out in grandma and grandpa's basement, I can throw some wax on and kick back and drift on back.
But the problems begin with the fact that I bought this TT from a gentleman who bought it new back in the Army when he was stationed in Germany. So I had been using it with a Euro-->US plug adapter.
The table also had a very inexpensive Audio Technica cartridge on it and while the original tonearm cable was still good, it was...well the original tonearm cable.
I got the table set up in the new office and began to play a record and immediately noticed considerably more hum that I had ever had before at the old place with this TT.
I checked all grounds and they looked good.
I checked all connections and they were good.
I even ran a ground to tie the tonearm, pre and "chassis" grounds together with my integrated.
And still there was a miserable hum.
I had a friend over for a BBQ who is a huge Pink Floyd fan and I popped on my 2011 release of Wish You Were Here. 30 seconds in, he was no longer interested in listening and I didn't blame him in the least. It was annoying. Not only that, there was also some noticeable speed control issues that were making things even worse!
Throw in the hum getting 11ty billion times worse when I touched the headshell and I knew things had to be fixed!
Well all that did was motivate me to do what I had planned for a while to do and even had purchased a new cartridge for over 2.5 years ago.
So I decided I was going to install my shiny new ClearAudio Concept MM MKII cartridge on the table. Then I would set the tracking force and anti-skate and dig into getting the pitch dialed in and all would be great!
Wrong.
I began to gently pull the headshell wires off the old cart and was doing fine until the very last wire...I popped free with the headshell pin still attached. Crud.
Ok...forget this mess. I am going to do a thorough refurb of this whole d@mned table!
So I sit down and make a list...
Cartridge: ClearAudio Concept MM MkII (Already had)
Headshell: Ortofon Serato with new wires (Amazon)
Tonearm Cable: AudioQuest WildCat (Audio Video Logic...my buddy's shop)
DeOxit cleaner and lube for the pitch pots, switches and the motor (Amazon)
"Audio grade" IEC (Amazon)
12ga IEC to power supply board and chassis ground wire (on hand)
Service Manual (VinylEngine)
Tutorials and other misc information liquidaudio.com.au/kenwood-kd-500-kd-550-direct-drive-turntable/
1 can of black/white "Fleckstone" paint
Herbie's Matt (Already had)
Pangea AC14SE (Already had)
Cambridge Audio Azur 651P phono pre (Already had)
So the first step was to tear this beast down...
I was very intimidated as it seemed like voodoo magic and virgin blood was keeping this thing together and if any little thing was thrown out of balance, then a portal to the 7th circle of Hell would open up and devour my soul.
In all honesty though, I was shocked at how easy this was to disassemble.
Zip-tie tonearm to cue lifter.
Pull both pitch control knobs off.
Remove old headshell.
Lift off dust cover.
Lift off platter mat.
Lift off platter.
Remove 3 screws holding motor cover in place.
Lift off motor cover.
Remove 2 screws holding speed sensor to plinth.
Lift motor center-section off.
At this point, I could see some nearly 40 years worth of dried up spindle "lube" crusted to the motor shaft.
Otherwise, for a nearly 40 year old direct drive brushless motor, this thing looked like the day it got loaded up on a ship in Japan.
At this point, I removed the tonearm and tonearm base which was fairly straight forward...3 Allen head screws and a single Phillips wood screw holding the tonearm cable clamp in place and the whole thing lifted right off the plinth.
The next step was to separate the wooden base (or plinth) from the Corian chassis.
9 Phillips head machine screws and the wooden base is free.
I immediately took it into the wood shop (aka my theater in its current state) and sanded it smooth and filled the 40 years worth of travel dings. Once the filler was dry and sanded, I shot a coat of grey primer and then several coats of black and white Fleckstone paint on the bottoms and sides of the wooden base and a solid "misting" on the inside or top of the base.
I then ran a bead of foam weather strip around all of the points that the Corian chassis came in contact with the wood base.
No real reason for it other than for my own OCD peace of mind.
New I needed to remove the stock power cord and the "pinch" bracket holding it to the Corian chassis.
I then needed to mark out where I would be mounting the IEC...which mostly fit when the stock power cord opening was.
Some trimming with a utility knife and a hacksaw allowed me to open up the space to fit the IEC. Then I marked and drilled the holes (treat Corian like brittle plastic and you won't flub up anything) to mount the IEC.
Using a pair of stainless 6-32 screws and lock nuts I had on hand, I mounted up the IEC.
Somewhere in there, I swapped out the black "earth" I was going to use to a green 12ga length of wire that tied the motor ground, chassis ground and earth together.
Then I ran a black and white length to the power supply board.
At this point I realized that my Radio Shack soldering iron was finally ready for retirement.
So after saying a prayer to the electro-gods, I laid it to rest (on my workbench drawer because most likely, I will try to figure out what is wrong with it and fix it!).
I then ordered up a new Weller soldering station, a cleaning tin, some extra tips, and some solder wick since I was out. But I still have a huge surplus of solder laying around from Cardas Quad, Kester 44, Radio Shack Silver...so I didn't need any of that.
After some back and forth with @lightman1 and the service manual/wiring schematic to determine whether blue or black was the load on the power supply board, I de-soldered the old power cables and soldered on the new ones.
One of the nostalgia parts of my 2 channel rig is my Kenwood KD-550 turntable.
I enjoy listening to vinyl but this is more for the nostalgia and to fill my need for the occasional handling of the media.
Plus when my grandfather passed away, one of the only things I wanted from his estate besides his WWII memorabilia was the record collection he had that was from him, my grandmother, my dad and my 2 aunts. A lot of big band, classic jazz, classical, 60s and 70s rock and late 70s/early 80s country.
That along with the occasional record I pick up at one of the local stores or at a garage sale has me into about 200-250 records across a broad range of genres.
So any time I want to reminisce about hanging out in grandma and grandpa's basement, I can throw some wax on and kick back and drift on back.
But the problems begin with the fact that I bought this TT from a gentleman who bought it new back in the Army when he was stationed in Germany. So I had been using it with a Euro-->US plug adapter.
The table also had a very inexpensive Audio Technica cartridge on it and while the original tonearm cable was still good, it was...well the original tonearm cable.
I got the table set up in the new office and began to play a record and immediately noticed considerably more hum that I had ever had before at the old place with this TT.
I checked all grounds and they looked good.
I checked all connections and they were good.
I even ran a ground to tie the tonearm, pre and "chassis" grounds together with my integrated.
And still there was a miserable hum.
I had a friend over for a BBQ who is a huge Pink Floyd fan and I popped on my 2011 release of Wish You Were Here. 30 seconds in, he was no longer interested in listening and I didn't blame him in the least. It was annoying. Not only that, there was also some noticeable speed control issues that were making things even worse!
Throw in the hum getting 11ty billion times worse when I touched the headshell and I knew things had to be fixed!
Well all that did was motivate me to do what I had planned for a while to do and even had purchased a new cartridge for over 2.5 years ago.
So I decided I was going to install my shiny new ClearAudio Concept MM MKII cartridge on the table. Then I would set the tracking force and anti-skate and dig into getting the pitch dialed in and all would be great!
Wrong.
I began to gently pull the headshell wires off the old cart and was doing fine until the very last wire...I popped free with the headshell pin still attached. Crud.
Ok...forget this mess. I am going to do a thorough refurb of this whole d@mned table!
So I sit down and make a list...
Cartridge: ClearAudio Concept MM MkII (Already had)
Headshell: Ortofon Serato with new wires (Amazon)
Tonearm Cable: AudioQuest WildCat (Audio Video Logic...my buddy's shop)
DeOxit cleaner and lube for the pitch pots, switches and the motor (Amazon)
"Audio grade" IEC (Amazon)
12ga IEC to power supply board and chassis ground wire (on hand)
Service Manual (VinylEngine)
Tutorials and other misc information liquidaudio.com.au/kenwood-kd-500-kd-550-direct-drive-turntable/
1 can of black/white "Fleckstone" paint
Herbie's Matt (Already had)
Pangea AC14SE (Already had)
Cambridge Audio Azur 651P phono pre (Already had)
So the first step was to tear this beast down...
I was very intimidated as it seemed like voodoo magic and virgin blood was keeping this thing together and if any little thing was thrown out of balance, then a portal to the 7th circle of Hell would open up and devour my soul.
In all honesty though, I was shocked at how easy this was to disassemble.
Zip-tie tonearm to cue lifter.
Pull both pitch control knobs off.
Remove old headshell.
Lift off dust cover.
Lift off platter mat.
Lift off platter.
Remove 3 screws holding motor cover in place.
Lift off motor cover.
Remove 2 screws holding speed sensor to plinth.
Lift motor center-section off.
At this point, I could see some nearly 40 years worth of dried up spindle "lube" crusted to the motor shaft.
Otherwise, for a nearly 40 year old direct drive brushless motor, this thing looked like the day it got loaded up on a ship in Japan.
At this point, I removed the tonearm and tonearm base which was fairly straight forward...3 Allen head screws and a single Phillips wood screw holding the tonearm cable clamp in place and the whole thing lifted right off the plinth.
The next step was to separate the wooden base (or plinth) from the Corian chassis.
9 Phillips head machine screws and the wooden base is free.
I immediately took it into the wood shop (aka my theater in its current state) and sanded it smooth and filled the 40 years worth of travel dings. Once the filler was dry and sanded, I shot a coat of grey primer and then several coats of black and white Fleckstone paint on the bottoms and sides of the wooden base and a solid "misting" on the inside or top of the base.
I then ran a bead of foam weather strip around all of the points that the Corian chassis came in contact with the wood base.
No real reason for it other than for my own OCD peace of mind.
New I needed to remove the stock power cord and the "pinch" bracket holding it to the Corian chassis.
I then needed to mark out where I would be mounting the IEC...which mostly fit when the stock power cord opening was.
Some trimming with a utility knife and a hacksaw allowed me to open up the space to fit the IEC. Then I marked and drilled the holes (treat Corian like brittle plastic and you won't flub up anything) to mount the IEC.
Using a pair of stainless 6-32 screws and lock nuts I had on hand, I mounted up the IEC.
Somewhere in there, I swapped out the black "earth" I was going to use to a green 12ga length of wire that tied the motor ground, chassis ground and earth together.
Then I ran a black and white length to the power supply board.
At this point I realized that my Radio Shack soldering iron was finally ready for retirement.
So after saying a prayer to the electro-gods, I laid it to rest (on my workbench drawer because most likely, I will try to figure out what is wrong with it and fix it!).
I then ordered up a new Weller soldering station, a cleaning tin, some extra tips, and some solder wick since I was out. But I still have a huge surplus of solder laying around from Cardas Quad, Kester 44, Radio Shack Silver...so I didn't need any of that.
After some back and forth with @lightman1 and the service manual/wiring schematic to determine whether blue or black was the load on the power supply board, I de-soldered the old power cables and soldered on the new ones.
"Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
Comments
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I will move on to the cleaning and reassembling tomorrow as I am sleepy now.
But rest assured, the story has a wonderfully happy ending!"Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip -
So after finishing up the "internal" upgrades, I reassembled the plinth and chassis.
I did replace the felt on the feet but didn't feel a need to replace them as the stock vibration damping solution is pretty effective. Plus I have those isolation squares used for HVAC units and my rack has its own isolation built in. With the rack on a laminate floor over concrete, vibration doesn't even remotely get to the table.
Next up was the upgrades to the tonearm.
I assembled the ClearAudio Concept MM MkII cartridge to the Ortofon Serato headshell. Pretty straight forward. I used the plastic screws that came with the cartridge as a personal preference.
I then removed the stock mini-DIN to RCA tonearm cable and replaced it with an AudioQuest WildCat cable. This cable is a VAST improvement over the stock cable.
The Wildcat was a perfect, if a slight bit snug, fit into the connector but considering how easily the stock cable came out of the tonearm, I am OK with the replacement being firmly planted in there.
While I had the platter off, I went ahead and added some mass in the form of an off-brand version of Dynamat. It is actually a thicker product than Dynamat Extreme and it cuts easier with scissors or a utility knife and that it costs quite a bit less, I picked up a big box of sheets for stuff like this...
And finally, in my most anti-climatic manner, I reassembled everything and took some final pictures...
And just like that, my refurb was complete.
So my initial impressions...
HOLY SHIZZLE! Absolutely silent noise floor. No hum at all when powered on. No hum when touching the tonearm or headshell.
I set the tracking force and the alignment on the cartridge and threw on my old standby reference album, The Highwaymen, and played "Highwayman".
The overall quality was higher than it has ever been with a much more accurate soundstage, wonderful dynamics and virtually no more pops or crackles.
I continued to listen to the rest of the album and noticed that overall, the entire experience with the table was generally more enjoyable.
I am glad I dug into this classic tank of a turntable and look forward to getting many more years from it."Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip -
I'll be there tomorrow to practice my DJ Scratch-a-Lot skills on it.
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Dang it.... now I want to tear into my old Technics SL-B3 and get it working again to spin some with the kids lol......"....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
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I'll be there tomorrow to practice my DJ Scratch-a-Lot skills on it.
And you will get cut. I have also been cleaning all of my records so if you scratch a single one, I will feed your corpse to the cats."Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip -
He's gonna swing by that LP Store we hit up and throw on some Lil Jon, Dre, Snoog and Run DMC to scratch so your fine
You integrated those Dayton horns yet?"....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963) -
Classic table. Well worth a refurb. Looking fine.
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What do you have against your cats ??
Feed him to the pigs, pigs got to eat to !! -
What do you have against your cats ??
Feed him to the pigs, pigs got to eat to !!
I don't want to ruin the bacon."Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip -
Great job on the refurb/upgrade.
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So... one is curious. When you (or any of y'all who've done this) damp a platter thus... do you (did you) balance the platter afterwards (statically or dynamically)?
I really did try to read through this thread, which is beautiful and comprehensive, to see if this point was covered -- but there're just so many words. I apologize!
In total seriousness, were I gonna rehab one of these tts (which were/are pretty nice decks indeed), I would pore through it relentlessly.
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Doc, I wondered the same, so thanks for asking that question lol"....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
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EndersShadow wrote: »Doc, I wondered the same, so thanks for asking that question lol
DITTO!! -
Because we are only talking about a 1.5kg (~3.3lbs) platter, a marginal amount of extra mass and a maximum rpm of 45...coupled with a direct drive brushless motor and a rather stout shaft and shaft well, it probably isn't necessary.
If we were talking about some of the more massive platters and belt drive, I could see how it would be more of a consideration but really, the minimal amount of flywheel effect being added and that there is no visual shaft "play", I can't see the impact being enough to cause any premature wear (at least within my lifetime).
Good question though.
Now that you have brought it up, I started doing some reading and my thoughts are confirmed/validated by several TT dedicated forums which seem to share the consensus that low level of mass + low rpm speeds = not really a concern for the most part.
This quote from a Lenco forum (Lenco platters were balanced from the factory on some tables individually using holes drilled in the outer ring but then on tables with much heavier platters, they weren't...) sort of sums it up better than I did above...I wouldn't worry much about the dampening having the effect of unbalancing the platter. Try to add the dampening in a symmetrical fashion, and you'll be fine."Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip -
Thanks for checking into that!
FWIW, I always find it interesting to read what folk do and do not worry about.
Not to mention that dampening a platter probably isn't as good an idea as damping one
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mhardy6647 wrote: »Thanks for checking into that!
FWIW, I always find it interesting to read what folk do and do not worry about.
Not to mention that dampening a platter probably isn't as good an idea as damping one
Water + electricity = Bad Juju....
Ask me how I know.... -
Actually, "damping" and "dampening" could both be appropriate...
damping
[dam-ping]
SynonymsExamplesWord Origin
See more synonyms for damping on Thesaurus.com
noun Physics.
1. a decreasing of the amplitude of an electrical or mechanical wave.
2. an energy-absorbing mechanism or resistance circuit causing this decrease.
3. a reduction in the amplitude of an oscillation or vibration as a result of energy being dissipated as heat.
dampen
[dam-puh n]
ExamplesWord Origin
See more synonyms for dampen on Thesaurus.com
verb (used with object)
1. to make damp; moisten:
ex. to dampen a sponge.
2. to dull or deaden; depress:
ex. to dampen one's spirits.
3. damp(def 10).
In the case of the turntable platter, I added mass to damp (or dampen) the ringing of the untreated platter.
"Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip -
Unrelated, but how did you decide on that record clamp? I've been tentatively thinking about picking one up, but I've never used one before. I've always thought my vinyl sounds damn good, but I'm curious about playing a track without a clamp/weight, and then playing it again with one and seeing if I can detect any changes/improvements.
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mhardy6647 wrote: »Thanks for checking into that!
FWIW, I always find it interesting to read what folk do and do not worry about.
Not to mention that dampening a platter probably isn't as good an idea as damping one
Water + electricity = Bad Juju....
Ask me how I know....
add 10lbs of salt and it really gets real FAST...
De-Ionized/ RO water not so much.... -
Unrelated, but how did you decide on that record clamp? I've been tentatively thinking about picking one up, but I've never used one before. I've always thought my vinyl sounds damn good, but I'm curious about playing a track without a clamp/weight, and then playing it again with one and seeing if I can detect any changes/improvements.
it just locks or couples the record to the platter better. Only you can decide if it really makes a worth while difference. They come in all sizes and shapes. -
Mine isn't a clamp but just a simple weight. Honestly, cost was the biggest factor for me. I didn't want the plastic clamp because it just looked and felt cheap (although it does a fine job).
The AudioTechnica weight on the other hand feels substantial and looks decent to boot."Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip -
Are there any potential long term negative side effects, like increased wear on the direct drive motor from the additional mass?
I saw this one at CAS 8 and it was super heavy (and expensive): https://art-hifi.com/product/hi-fi/record-clamp/ -
High marks on your resto-mods!
This quote from a Lenco forum ......
Hanging around a Lenco forum usually leads to building one. I got in before even the beater tables started to become high priced.
Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 * -
Are there any potential long term negative side effects, like increased wear on the direct drive motor from the additional mass?
I saw this one at CAS 8 and it was super heavy (and expensive): https://art-hifi.com/product/hi-fi/record-clamp/
Direct drive motors that are brushless tend to be a bit more forgiving when adding mass as there is less stuff to irregularly wear out. Plus the weight is pretty much all resting on a single point (the shaft).
With a belt drive table, the extra mass could cause belt slippage but I wouldn't know anything about that.
"Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip -
mhardy6647 wrote: »Thanks for checking into that!
FWIW, I always find it interesting to read what folk do and do not worry about.
Not to mention that dampening a platter probably isn't as good an idea as damping one
Water + electricity = Bad Juju....
Ask me how I know....
Did I ever tell you about the boiling water incubator bath we had in the lab when I was in grad school? I learned empirically* that it worked the same way as those Hot Dogger hot dog cookers** -- twice.
___________________
* Hint. It didn't work too well if at all when filled with distilled water; tap water was required for it to quickly heat water.
** Or, more accurately, electrocutor.
