[neobop]

That's what I didn't know about the JVC - the TOTL coreless motor and controllable damping in 2 planes.  On the other hand, mechanical auto functions means having cams or such attached to the arm - not a plus for performance.  The 770 also has a coreless motor and the arm is free of mechanical baggage.  The eff arm length is about the same. I suspect the arm on the 770 is a little better with the massive bearing housing, but I can't say for sure, and no damping means you should use a med compliance cart. I don't know which has the heavier platter.  The F6 prob has more torque.

I mentioned that after I heard the 770 I decided to keep it as-is.  It reminds me of the Goldmund Studietto/Zeta (DD-JVC motor) I used to have, really.  That cart pictured at left, is a Monster Genesis 1000, predecessor to ZYX and the same cart I used back then. It was $1K in late '80s, as was the arm.  The table was $2.2K. All that would be 3x that today. The 770 is not quite that level, but pretty damn good.       

Maritan,
If you want another table, the F6 looks like a steal if everything works. Just so you know, most of the chips used in the speed controls aren't made any more. Next post I'll give you some tweaks.  BTW, most ATs take around 50 hrs to break in. Yours has the PC OCC wire so it will probably take awhile.  Once broken in, a new stylus will only take a few hrs for the suspension to settle in. The generator is identical to the 150MLX and it will take that stylus or any 120/440 type. 
neo 

 

[JackD]

Neobop

Don't know the answers to the questions about which arm is better.  I only know what the F-6 is capable of as you know the Kenwood, but for a $100 if the F-6 is fully functioning and is in the condition the pictures in the ad says it is, I for one would find out and try them out to see.  Like I told Maritan I can't see what cartridge is on the F-6, but he could easily swap them and do a shoot out.  If he doesn't like the F-6 he could put it up for auction and make a few dollars.  The F-6 weighs over 25lbs and is has a substantial build and feel.  It would be an interesting test.  If he doesn't like the F-6, I would be willing to buy it from him if fully functional for what he paid plus shipping.

[Maritan]

Neobop - some tips on tweaking the 770D would be great.

JackD and others - I picked up the JVC F6. Everything works beautifully except the UP/ DOWN switch.  My lot in lofe with TTs, apparently. The auto function works, so it's just the switch not making good contact probably. The other issue was that the RCA cables outside the TT body had been cut off sometime in the past, but the seller soldered a new set on and covered it in heat shrink. I checked out both channels and they sounded fine.

The F6 came with a cartridge marked MA 2002. Too late now to check out what it is and too late to test out how it sounds in my system. Anybody have info on a "MA 2002" cartridge?

[JackD]

Here is info on the cartridge. It was a highly thought of in its day.  Replacement styli are in the $150 range when you can find them NOS.  There are no aftermarket replacements because of the design.

http://www.roger-russell.com/sonopg/micropg.htm

[neobop]

That's an exceptional cart, electret condenser with a beryllium cantilever and .2 x .7 elliptical. The downside is that replacement styli are unobtainium and Soundsmith charges $450 to retip such a cantilever with his best micro tip.  There's a guy in Wash state who might do it for less, his ad in US Audio Mart in cart category.  He's said to do nice work. 

Those cables on the JVC might not be good for most MM/MI carts.  I think the 2002 is immune to capacitance loading.  The AT certainly isn't.  It wants to see total shunt capacitance < 200pF.  That's arm wire + cables + preamp. I think 2002 compliance is high.  Max VTF is 1.4g. I think it would be best on a low mass arm or the JVC with some damping applied. 
neo

[S Clark]

Our revered moderator, TheChairGuy, has posted extensively on the F6 and has stated his preference for it over the Technics 1200 series.  Read up on the various simple tweeks he did to improve its performance.

[JackD]

Maritan

Like Neobop said you might to put a capacitance meter to those cables and see what the replacements measure.  If he just standard audio cables and not video or TT specific cables they could measure in the hundreds.  The original cables on that table measure at around 95pf with an empty headshell in place.

[Maritan]

Good info - JackD and Neo. Man, you guys are an absolute wealth of info. I really, really appreciate it. 

I quickly plugged in the JVC this morning as I was getting ready for work and listened to it in the background just to make sure it still played. With the same record, the JVC had more noise than the 770D. In my mind, the likely causes are

- Not completely getting the TT level
- Worn stylus
- Tonearm not setup completely correctly (damping, VTF etc.)
- MA 2002 is more sensitive to static and dust/ dirt on record?

Is there anything else I should check? Apart from the capacitance, of course.

So far, I love the simplicity of the 770D. Condition wise the F6 is hands down better. Absolutely pristine condition. Looks wise, I'm a little torn. I might just prefer the 770D. Sound wise, I don't think I have a "level" playing field. Ha. Get it? 

And, finally, here are terrible quality pictures of the 770D troubleshooting:

First, the table with the dust cover on:


Cover off and on its side:


Underside with its feet off:


The insides in terrible detail:


Last one. Using the scope probes to check signals:

[neobop]

You didn't describe the noise, but I would guess a worn stylus. The .2 x .7 has the smallest footprint of any stylus, except maybe a narrower elliptical, which I've never heard of.  .2 describes the width of the sides. It can track groove details that might elude fatter stylus sides, but longevity isn't the strong suit. You should try the other cart on there and see if the noise goes away.  Don't play your good records with a possibly worn stylus, it could damage the record. Most of us have some unloved or beater records for testing unknown entities.
neo

[JackD]

You can just swap the Kenwood headshell over to the JVC for a test run, just remember to set the overhang on the JVC to 48mm.  If you have access to a microscope at work I would look at that stylus on at least 200x to see what kind of condition it is in before using on good records.  One advantage though to moving the AT to the JVC headshell is that two part design locks the aligment in and lets  you easily slide the cartridge back and forth to change the overhang.  If you haven't gotten them yet, VE has both the owners and service manual for the F-6. Also while you are checking out the JVC it wouldn't hurt to spray Deoxit or some other electronics contact cleaner on the all the switchs and work them 25 times or so if the other guy never did.

[Maritan]

Looks like I've got more work to do. I'm going to focus first on troubleshooting the 770D. So, I'm going to remove the AT100E from the 770D and put it on the JVC and adjust everything and see how it sounds. That should be a slightly more apples to apples comparison.

I'll report back soon.

Thanks guys. I owe Neo and JackD at least a beer, no? 

[JackD]

Sounds like a plan.  If you've got contact cleaner and the little red spray tube you can slightly pull up on the cue lever while you spray and the cleaner should get down the shaft and maybe then you wouldn't have to take the bottom off.  Worth a try before surgery is required, plus letting it soak a little while you work on the other table should help.

[neobop]

The JVC has I assume, a standard SME type headshell used on S and J shaped arms.  The Kenwood has a straight arm and non-standard headshell like a Graham Robin or Jelco 250S.  All the offset is at the 770 headshell and standard is straight, having offset in the S or J shape.  Blame it on Murphy.
If you want to do any listening, you'll have to remove the cart and mount it in the JVC shell.  IMO you should take the 2002 out of service anyway until you can determine tip condition. 

I think there are a couple of threads on stylus examination.  Basically, you need 200 to 500X magnification and high intensity side lights, to see the reflection off the sides of the tip.  There's a sticky on Karma with some basics.
neo 

 

[JackD]

Oh I see it now that I looked at the picture again.  Just saw the collet collar and assumed, didn't even see the offset on the headshell on the first look so changing headshells it is.  At least that two part sled type headshell is easier to deal with.  Plus you will have music while you work.  I got an MA cartridge on my QL-Y7 and couldn't verify the condition of the stylus to my satisfaction so I just put the cartridge away.  Also didn't want to pay $150 for another one. One day I may send it to Marcmorin on AK and let him look at it.

[Maritan]

For everybody that was sitting on the edge of their seats and awaiting final results:

The 770D is now fully functional (I think)! The emitter of transistor Q9 was somehow disconnected from the post numbered 5. Got a wire soldered between the emitter and the post by a very skilled technician and the UP/ DOWN button now works.

Things to do this weekend, in order:

1. Put the AT100E on the F6 and listen to a record on it and make notes on how it sounds.
2. Put the cart back on the 770D and see how that sounds.
          2a. Check if the auto UP at the end of a record works.
3. Decide which TT to keep. I hope to base this purely on sound.

Neo, as an FYI: The resistance through the solenoid measured at 50 Ohms (49 point something). Also, I weighed the platters of the F6 (~4.5 lbs maybe a touch less) and 770D (~4.8 lbs).

[JackD]

#4 Deoxit the switchs on the F-6

In that JVC headshell you don't have to worry about any aligment issues as it will be locked in to square in the headshell.  Just set overhang at 48mm from back of washer to sylus tip and you are off. 

Advantage to me of JVC is damping and ability to use any SME type headshell and have mulitiple cartridges set up and ready to go.  But again my opinion unless you can find source for extra of those Kenwood headshells.

Good job with the troubleshooting and repair.

[neobop]

Maritan,
All right!  Good job, you're the perfect customer for one of these vintage tables.  Most people don't have a scope in their workshop and know their way around a circuit.  If I had that problem the table would go to my tech.  Luckily, we're friends and he gives me a big break on the fees. Repair shops are pricey these days. 

It sounds like you'll keep only one table.  Assuming the noise goes away on the F6, you could easily get $500 for either one.  They're worth at least that in my estimation, actually more.  I've seen the prices climb in recent years and I'm consistently shocked.  For lesser tables than either of these, people are asking more than that. Please don't feel obligated to any of us for sitting back and telling you where to look.

BTW, 770 headshells are hard to come by if you're into cart swapping. Either table would benefit from 5 or 6 lbs of clay inside. Even better is to brace it like a speaker cabinet and/or epoxy an aluminum plate on the underside of the deck in any large areas, especially in front of the arm. The feet on the 770 have 6 mm standard thread, bolts on top.  The JVC is prob the same. If you want to try spikes you can get bolts 1.5 or 2" long and nuts.  Grind the heads off the bolts to make the spike and thread it all the way up. Use the nuts as jam nuts. You can't use the spikes to level, they have to stay all the way up.

Finally, for the ultimate in listening pleasure,     I recommend a Boston Audio, or Delrin mat.  They start close to $200, but for the discriminating audiofool, a must have.  Little enough to pay for the hours ..... 
Have fun and get some records.
neo   

[S Clark]

For everybody that was sitting on the edge of their seats and awaiting final results:
...
3. Decide which TT to keep. I hope to base this purely on sound.

John TCG has highly recommended loading the JVC plinth with lots plasticene clay.  I'd load several pounds into it before making your final decision.
Check out John's gallery for several pics.

[JackD]

Maritan

I realized the JVC is more industrial looking than the Kenwood.  I say this while owning it plus two Rosewood JVC's and a gloss black one, so to some degree looks do figure in the equation whether we think they do or not.  In the end you will do what is best for you.  Like I told you when I encouraged you to buy the JVC, I will take it off your hands if it doesn't win your shoot out.  I won't however pay you $500 dollars for it as I already have one and because of it's industrial look it won't demand that on the open market like the rosewood tables do.  I would encourage you to keep both especially since you have only a song invested in the JVC.  With vintage TT's a backup is always a good thing especially if one is electronically based.  Again just my opinion and ymmv.  I have never done the pasticene thing with my F-6 like I did with my A7.  I was afraid to fool around the mechanisms of the F-6 and it already weighs 25lbs as it is.  I just put it on a 3" butcher block and let it play.

[TheChairGuy]

John TCG has highly recommended loading the JVC plinth with lots plasticene clay.  I'd load several pounds into it before making your final decision.
Check out John's gallery for several pics.

Yes - but make sure you have ginger ale handy in case your stomache gets queesy at some of the overzealous pictures of plasticlay in use.  Ha.

The mdf JVC tables are horribly prone to feedback issues....it's almost Herculean efforts to tame them of that.  The plastic body JVC's, like the F6, respond fantastically to the cheap and simple application of plasticlay inside.  It turns a good performer stock into something dramatically better afterwards.

My F6 is ugly with plasticlay inside and out but plays wonderfully.