EngineerNate's Sony TTS-4000 Build

the "1/4"" that I got from Michaels seems undersized significantly and is quite loose in the locating holes for glueup.


Tip make sure whatever you use is as straight as possible any distortion will cause binding
as the layers increase.

The use of a drill chuck makes removing the locating rods much more manageable and lessens distorting/gouging
the pins.

In an ideal world something like a section of "drill rod" either undersize or waxed, or by making the locating holes slightly
larger by a few thousands.
The use of a dissimilar material will make removal much easier.

These are key considerations, once you start the assembly/glue up procedure things can go sideways fast if
your pins bind, this from personal experience.
 
Tip make sure whatever you use is as straight as possible any distortion will cause binding
as the layers increase.

The use of a drill chuck makes removing the locating rods much more manageable and lessens distorting/gouging
the pins.

In an ideal world something like a section of "drill rod" either undersize or waxed, or by making the locating holes slightly
larger by a few thousands.
The use of a dissimilar material will make removal much easier.

These are key considerations, once you start the assembly/glue up procedure things can go sideways fast if
your pins bind, this from personal experience.

My original plan was to simply glue the dowels in place but I can see how binding on the pins could cause issues. I'll do a dry fit for sure before getting glue on anything. A block of wood and a hammer are useful tools to keep nearby when doing glue ups, wood glue likes to grab before you're ready for it to especially on large surface area projects.

I was also probably going to do it in stages, maybe 3 layers at a time in half hour increments to let the glue grab a bit before moving on to the next set.

Cheers!
Nathan
 
My original plan was to simply glue the dowels in place

Gluing as you go [with dowels] seems a reasonable alternative with the only caveat being as you stack and if for
some reason all the layers aren't perfectly lining up you have a problem.
Some wiggle room is always a plus.
 
Gluing as you go [with dowels] seems a reasonable alternative with the only caveat being as you stack and if for
some reason all the layers aren't perfectly lining up you have a problem.
Some wiggle room is always a plus.

True. During the dry fit I was planning to evaluate whether the tolerance on the outer profiles vs the dowels holes is going to pose any challenges. If everything lines up, building a little platform with a nice 90* corner to back each layer into for alignment could be a good backup to the dowels.
 
I'd use 1/4" all thread rod as dowels. It's slightly undersize and will allow a little manual tweaking of alignment. Add some nuts and fender washers and you've got effective clamps too.
 
I'd use 1/4" all thread rod as dowels. It's slightly undersize and will allow a little manual tweaking of alignment.

Now there's a good idea, I did have 1/4 and 5/16 all thread 8 foot lengths in the shop but they had a definite curve
to them.

The old saying "You can never have enough clamps" is so true especially when clamping up a multi layer plinth.
 
Nathan,
Progress!

Work completed:

Replaced parts:
-All electrolytics. I put the two tantalums called out in the SM back to tantalum (they were called out as tants but 'lytics on the board). I also went with the 10uF SM called out caps at C5/6. Thoughts on whether those are critical or if I should try lower values like what was installed before?
-Both trimmers with 47k Bourns cermet pots.
-The vref elements. D4, D5 with EGP20A and the zener with a 1N4737
-Diode D8 for good measure. Replaced with EGP20B. I need to measure the voltage drop across the EGP20A in circuit before I trust them for the snubbers, but my plan is to replace all of the diodes.

To my knowledge, mylars and solid aluminum caps are basically immortal, so I left those alone. I've ordered Vishay Dale 50ppm 1% metal film resistors to put in as well, but I want to do things in stages to avoid causing an issue with a change and then not knowing which thing did it.

Upgrades:
-Cleaned up some of the wiring to the board and added new heat shrink to prevent shorts.
-Replaced 12v zener shunt regulator with TI TL780-12 series linear regulator.

Building the regulator circuit:
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.22uF ceramic bypass on the output and .33uF on the input.

Heat shrunk and installed in board with heat sink. Thermal paste on sink as well.
MiczdTJ.jpg

UedgREr.jpg

SEBuC3a.jpg


Quick pic of the new pots + diode cascade:
PH7kGm0.jpg


After double checking things I brought it up on the DBT and I managed not to bork anything! :D The 12v rail comes up to 12.00v almost instantaneously and over the short amount of time I monitored it (I've been working on this for the last 6 hours and need to eat...) it was very stable.

I am still working on designs for the vref upgrade, and I'm not 100% happy with my zener setup. It's setting at 8.4v instead of 8.8 as the zener is at the low end of it's 5% tolerance and the new diodes drop a bit less per diode than the originals. I chose the diodes after comparing spec sheets and the EGP series seemed like the descendant of the 10D-05/10D-4 series that was in there originally but the EGP10 series is derated to 1.0A from 1.5 in the 10D series so I bumped up to the 2A capable versions. I'm not sure if that affects the forward voltage drop much.

Huge shoutout to @Pio1980 , @tnsilver , @restorer-john , @maxhifi , and @totem for their help and encouragement. :)

Cheers,
Nathan

Nathan, great work!
Do you have photos of the finished plinth?
A few years ago, I did the same thing. Changed resistors, capacitors and voltage regulators. Stock resistors and capacitors are not of good quality, their values vary even by heating with a finger, and some of them affect the speed stability.
You didn’t do one of the most important things, you didn’t change the C7-C9 (poor quality) mylar capacitors. I replaced them with C0G/NP0. One of them greatly affects the speed, but I do not remember which one exactly. If you want, I can open my turntable and clarify which one. It seems to be the C8. Heat it with your finger and you will see that the speed has changed.
I also replaced R11 and R13 trimmers with multi-turn potentiometers and carried them on wires outside the motor, multi-turn allows you to very accurately make the initial setting. I also reduced the resistance of R34, this helps to change the speed very smoothly, adjustment limits are reduced, but large limits are not needed.
Sorry my english is not very good.
Igor
 
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Good suggestions! I have always read that those old green mylar films are bulletproof, but maybe they aren't so great in timing applications where value accuracy and tempco are very important.

FWIW-It's been pretty darn steady since I did these mods. It's my main table at the moment.
 
"My TD-124 drifts a bit too, it never stays locked on speed like a modern unit, there's just too many variables at play and no speed reference."

"From what I have gleaned there was a known drift issue from the get go. As per an early review consequently lost to the ages."


My TD-124 drifted a bit, so did my TTS-4000. I didn't know if it was them, or me. I loved them both, even just looking at them — but sold both cheap, as I didn't want to stick someone with a problem. Now that I know they both drift, and everyone knows it, I'm rethinking that.

But no regrets, the 4000 went to a great home, and Nate — that plinth, even unfinished, is magnificent
 
"My TD-124 drifts a bit too, it never stays locked on speed like a modern unit, there's just too many variables at play and no speed reference."

"From what I have gleaned there was a known drift issue from the get go. As per an early review consequently lost to the ages."


My TD-124 drifted a bit, so did my TTS-4000. I didn't know if it was them, or me. I loved them both, even just looking at them — but sold both cheap, as I didn't want to stick someone with a problem. Now that I know they both drift, and everyone knows it, I'm rethinking that.

But no regrets, the 4000 went to a great home, and Nate — that plinth, even unfinished, is magnificent
Of course, two entirely different mechanisms, each with their own characteristic properties.
 
Bimasta-glad you like the plinth. I'll take care of her for you. ;)

Considering the mylars are about the only passive part left in the electrical side, I might replace them one of these days just to see if I can measure a difference and follow up with you guys. Almost everything here can be applied to the more common 2250/2251 units as well.

The plinth should get some love soon. I'll be tearing it down to move to our new house so, given its going to come apart *and* I'll finally have an actual workshop, I should be able to knock out the finish work. Then it's on to the JVC TT-101 I picked up. :rockon:

Cheers,
Nathan
 
Bimasta-glad you like the plinth. I'll take care of her for you. ;)

Considering the mylars are about the only passive part left in the electrical side, I might replace them one of these days just to see if I can measure a difference and follow up with you guys. Almost everything here can be applied to the more common 2250/2251 units as well.

The plinth should get some love soon. I'll be tearing it down to move to our new house so, given its going to come apart *and* I'll finally have an actual workshop, I should be able to knock out the finish work. Then it's on to the JVC TT-101 I picked up. :rockon:

Cheers,
Nathan

If you want to add a central heavy weight or periphery ring, I made a small cheap modification, I installed two ring magnets in the motor that repel each other and this relieves the load on the main bearing.
I bought in Japan a brand new! (NOS) 1976 Denon DP-7000 in the original packaging. It was sold as possibly non-working due to age, but it is fully operational. It was Denon's top of the line turntable except for purely professional tables like DP-100. It has an unusual and incredibly beautiful strobe.If to turn off the quartz lock, there is also a small speed drift with heating.
My TTS-8000 and Denon DP-80 with quartz lock off also have minor heating speed drift.
 
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Doesn't have a proper W&F track, but we can try with the 1kHz reference tone on it. Best to record on a few 'tables if you can as test records are far from perfect - help identified if issues are with the 'table or the record.

That said, your voltage reference drift is likely happening so slowly it won't manifest as wow or flutter.

EDIT - there's a thread about the polar plots on diyAudio - it's Python script Scott Wurcer wrote. Not to hard to set up if you want to do them on your own.
Please give the link how to make a polar graph yourself.
 
If that is a safe method I believe the value of R10 can be tuned with the replacement regulation scheme to get the right current through the regulator. It's tuned to ~17mA with the current value, pretty close to standard for old school shunt regulators and zeners, but if we drove it down to ~5mA we could use an incredibly accurate (in the range of 0.01-0.1% voltage accuracy is possible) voltage reference.

Correct me if I'm wrong, but there doesn't seem to be a need to supply Amy significant current through this reference voltage. In fact, I believe that would ve counter to the purpose since that could introduce instability in the voltage. If we can safely set the reference voltage with the lower current capability reference ICs we open up a lot of potential for high accuracy devices.

I'm really curious what this voltage would have measured from the factory. 8.84 is significantly off from the 9v called out in the 2250 service manual. Is the service manual simply rounding up or is the shunt regulator out of spec?

Cheers
Nathan

Nathan,
Any Zener diode for voltage regulation needs a minimum current that passes through it. Take the fictional numbers for an example.
Suppose that the Sony chip consumes 5 milliamperes. R10 allows current to flow 17 milliamps.
17-5 = 12 milliamps for Zener operation.
Now your proposal to increase resistance.
Now R10 allows only 5 milliamps to flow.
5-5 = 0. That is, there is no current through the Zener diode, respectively, it will not regulate the voltage at all.
Thus, the current through R10 should be -
The current consumed by the microcrochip + the minimum current for the operation of the Zener diode.

Maybe it makes sense to try such Zener instead of D3, D4, D5?
Temperature Compensated reference diode, temperature coefficient 0.001%/C.

https://mouser.com/datasheet/2/523/LDS-0155-1369764.pdf

9 volts is not a problem at all, the main thing is the stability of the voltage, my TTS-4000 works with this voltage, TTS-2250(1) also. Service manual note - "All voltages should hold within +-10%".

Of course, I could be wrong, I'm not an expert in electronics.
 
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That's why I recommended grafting monolithic regulators into them to help solve speed stability problems.
 
That's why I recommended grafting monolithic regulators into them to help solve speed stability problems.
The most stable monolithic regulator that I found and install has a temperature coefficient of about five times worse but at the same five-ten times cheaper than this Zener. Of course, it is necessary to test it, in fact it may not be so beautiful, today I bought several russian Zeners with the same TempCo, but in an aluminum case.
Monolithic regulator is a best choice for 12V line. IMHO
 
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