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Implementation of ο1 on Marantz CD63 SE

omicron1: A low-jitter, low phase noise clock generator for upgrading digital audio devices

Implementation of ο1 on Marantz CD63 SE

Postby franjam » January 7th, 2018, 8:34 am

While awaiting for parts to arrive for the kDCX project and the o1 clock pcb :D I've decided to look at implementing the o1 on my Marantz CD63 SE.

I have already done a large part of the mods and rebuild detailed by Thorsten Loesch at TNT audio, plus the clock mod by Martin Clarke of http://www.acoustica.org.uk detailed below....

" The clock in the '63 is a simple Pierce-style oscillator implemented directly onboard the DAC chip using a dedicated logic gate. The relevant components are the NPC DAC (soldered to the underside of the board), CD02, CD03 and the 16.9MHz crystal, XD01. Having the clock built into the DAC is potentially ideal; but the clock in the 63 out of the box is known to be pretty jittery, obviously a product of mass-production in its execution, and those who've tried reclocking devices report tremendous gains, as you might expect after spending all that money.....

After much hacking about with an old 63SE we think we've found a good reason why. Go read the datasheet now and come back here afterward.

The crystal is connected across one end of the DAC chip, between pins 1 and 28. The 10pf caps CD02 & CD03 are tied to the ground plane via a PCB trace, basically forming a series resonant circuit with the crystal excited by the logic gate between pins 1 and 28 through RD02 (which you should not modify). The logic gate in the DAC even has separate digital supply and ground pins to decouple power supply noise; pin 2 is digital ground and pin 27 the +5v supply, fed through RD01 and decoupled by CD04 (electrolytic) and CD05 (tiny axial ceramic). So far, potentially outstanding butas laid out on the board:
The decoupling is less than ideal - CD04 & 05 are too far from the dac, adding trace inductance.
The logic gate ground interferes with the oscillator!

Pin 2 (logic ground) is connected to the ground plane from the _far_ side of CD02 & CD03, so every time the logic gate changes state, the voltage change across the trace inductance will directly modulate the series resonant circuit, because CD02 and CD03 are no longer at quite the same potential. ... no wonder there's so much chaos in there.....The cure is to add one new capacitor and cut one track.

Our new capacitor is fitted directly across pins 2 and 27, as tight to the chip as possible, since low inductance is critical; stacked foil poly types work for me, X7R ceramics are another good option. You can also mount it by mirroring CD05 (which BTW is too small in value for the job it's required to do) below the board; the critical thing is keeping the lead lengths under 2mm from body of the DAC for the cap to remain effective into the VHF range. Since the DAC is a surface mount device the best way to achieve this is to pre-bend the leads until the cap just fits across the DAC pins, and clip them until the new capacitor sits tight against the top of the chip - when the board is reinstalled, you'll only have about 1/8" clearance from the case for this cap to fit into! Pre-tin the cap leads with solder off board, then holding the cap in place, when you're sure you're in the right place, momentarily touch the cap leads with your soldering iron and the cap will be soldered in place.

To get rid of the ground bounce problem locate the ground trace from Pin 2 and follow back around to the ground plane under the DAC. Take out the scalpel and carefully cut the trace between pin 2 and CD02 solder pad, as close to CD02 as you dare, and again as close to Pin 2 as you can, isolating the trace so it doesn't become an aerial. Having cut the trace out, you're done since pin 2 is still connected to the ground plane by a minute trace below the dac.

While the boards out we also recommend swapping RD01 for a small axial choke and a couple of ferrite beads and increase CD04, as suggested in Thorsten's articles on the TNT-Audio site. That's all there is to it - once you've got the board out and can trace the circuit this really is a lot easier than it sounds - when inspiration struck it took just 20 minutes to do this tweak - but then it took two years for the inspiration to strike!.

Incidentally we think the 'ground bounce' issue is why 'superclock' upgrades work so well. If an external clock is used, the signal is fed into XTO (pin 28) and CD02, CD03 and XD01 are removed. Which means the internal logic gate is still used on the DAC, but it now has the ground trace to itself and so cannot interfere with the oscillator. Those with a clock upgrade should still try the additional cap.


a quote from another source says
Remove XD01 oscillator + RD02, CD02 & CD03 and replace with a quality low jitter clock 16.934Mhz. - Connect to XT1 of the dac.
so they add a resistor to the equation.

So after all that I'm telling myself using the o1 here might be a good idea and I'll get round to modding the DSP section in my DCX in a seperate project.... :)

The actual clock frequency is 19.9344mHz, the only one I have found is at Digi-Key : Abracon LLC ABMM-16.9344MHZ-B2-T part no.535-9156-1-ND , is this compatible with the o1?

Secondly I have Marantz service manual in .pdf, which I found at HiFI Engine, how do I determine which voltage to use? I'm kind of assuming it's 5v as that'a all Ive come across but obviously I shouldn't...

I also cannot find how to determine which voltage corresponds to this particular part..

Thanks for a little guidance ..

I'd just like to add that I did this complete re-build and modding to the Marantz for around 250 euros total, incuding the cost of the second hand player, just before christmas and the difference to this now more than 20 year old CD player was/is simply phenomenal, unfortunately I've nothing in a similar or higher price range to compare it to...
Last edited by franjam on January 11th, 2018, 1:21 pm, edited 2 times in total.
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Re: Implementation of ο1 on Marantz CD63 SE

Postby franjam » January 7th, 2018, 12:50 pm

here is schematic of DAC and clock for Marantz CD63
nope won't let me upload .jpg 498kb, help!...

I've read your info on disabling old clock which I can fairly easily identify on the pcb/schematic, however its exactly the best points to tap in for the various connections I need help with... how do I show an image on this post ?

I've also found this oscillator at Digikey OSC XO 16.9344MHZ CMOS SMD Part No. 300-8826-6-ND but it is clearly 3.3v max so it looks like finding one at 16.9344MHZ and 5V is going to be tricky :(

EDIT: just found this at http://www.tentlabsshop.com/DetailServlet?detailID=1671 it is a 16.934 custom XO clock running at both 5V/3.3v for about 30 euros but so far I have no information on dimensions or compatibility....
Last edited by franjam on January 11th, 2018, 2:17 pm, edited 1 time in total.
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Re: Implementation of ο1 on Marantz CD63 SE

Postby amb » January 8th, 2018, 4:43 pm

The ο1 is designed to replace a Pierce oscillator.
I don't understand why the original circuit used a 16.9MHz crystal but you're using a 19.9344MHz crystal to replace it?

The Abracon ABMM series are crystals, not oscillators. They are not compatible with the ο1. Look at the datasheet for its pin-out, and compare to the Crystek C33xx series.

The Citizen CSX-252F is also not compatible with the ο1 because it's a tiny 2.5mm x 2mm device. The sizes supported by ο1 are 15mm x 9mm or 7mm x 5mm.

Regarding the Tentlabs unit, if the picture is accurate, then it's a through hole device (not surface mount). It's probably a 13.2mm x 13.2mm "square" or "half size" metal can device, which is also not compatible with ο1.
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Re: Implementation of ο1 on Marantz CD63 SE

Postby franjam » January 9th, 2018, 1:37 am

I don't understand why the original circuit used a 16.9MHz crystal but you're using a 19.9344MHz crystal to replace it?


My mistake, it is indeed 16.9344mHz I got myself mixed up...

The Abracon ABMM series are crystals, not oscillators. They are not compatible with the ο1.


Yes It dawned on me after further reading...sorry

It looks like its going to be very difficult to find a compatible part in that frequency...any suggestions/sources?

You should check whether your device can work with a master clock with 3.3V logic level. Most 5V based systems will work fine with a 3.3V clock. If your device doesn't work this way, then you must use 5V oscillators for X1 and X2, and use the 5V output version of the U1 voltage regulator. The input supply voltage range should then be 6-15V.


Can you explain how I can determine this?

If not, can you reccommend a higher quality Quartz two pin clock I might replace the old one with? There are plenty of those around but I've no idea what criteria to lok for or how to make a choice..

Thanks for the help :)
Last edited by franjam on January 11th, 2018, 2:18 pm, edited 1 time in total.
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Re: Implementation of ο1 on Marantz CD63 SE

Postby amb » January 9th, 2018, 3:08 am

You might be able to use the Tent Labs metal can oscillator by bending its leads and soldering on the SMD pads. Trim the leads to make them as short as possible but still leave enough room for your soldering iron tip to fit under. There are also some 16.9344 oscillators on eBay that claims to have low jitter and phase noise. But in a cursory look, all I see are full size metal can through hole types, so pin-bending and soldering on the SMD pads wlll still be necessary.

The only sure way to know whether your circuit would work with a 3.3V oscillator is to try it. In most logic families 3.3V is high enough a voltage to be a "1".

Crystals are going to be inherently inferior to good oscillators.
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Re: Implementation of ο1 on Marantz CD63 SE

Postby franjam » January 9th, 2018, 3:21 am

Ok thanks Ti I 'll think about that one, I'm sill trying to upload the relevant schematic to make sure I'll be tapping into the right points....

is this the kind you are talking about..? https://www.ebay.fr/itm/1PCS-TCXO-0-3PP ... Sw-3FZGfY1

This is about the only one i could find without the word "crystal" in it somewhere :?
Last edited by franjam on January 11th, 2018, 2:18 pm, edited 1 time in total.
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Re: Implementation of ο1 on Marantz CD63 SE

Postby amb » January 9th, 2018, 3:53 am

Yes, that's like the ones I've seen. Maybe there are less of these on ebay.fr than ebay.com.

EDIT: If a device has 4 pins, with pin 1. Enable/disable, 2. Ground, 3.Output, 4. VCC, then it's an oscillator, not a crystal. The pin-out is important! On full size through hole metal can packages, the pin numbers are 1, 7, 8, 14. If pin 1 says "N/C" then it doesn't have an enable/disable function. For a single-frequency ο1 this does not matter.

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Re: Implementation of ο1 on Marantz CD63 SE

Postby franjam » January 9th, 2018, 4:16 am

Presumably low jitter is defined by the lowest ppm....?
Last edited by franjam on January 11th, 2018, 2:19 pm, edited 1 time in total.
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Re: Implementation of ο1 on Marantz CD63 SE

Postby amb » January 9th, 2018, 4:28 am

Not necessarily. Many of the oscillators with ultra low jitter have 20-50ppm frequency stability or more.
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Re: Implementation of ο1 on Marantz CD63 SE

Postby franjam » January 9th, 2018, 4:48 am

This is the spec file for one i'm looking at on ebay, the pins are at 7.62mm and 15.24 mm so bendable to fit the pads yes?
What do you think?
still can't upload schematics despite reduced size, check my other post :(

MDD 16.9334 oscillator specs.jpg


EDIT:

According to what you say above its the 4 pin config that counts and not wether the word "crystal' is in the description yes?, because I can see lots of examples such as this one with the 4 pin description :

One piece brand new Vanguard ultra precision Golden TCXO.

0.1ppm 16.9344MHz





Temperature compensated crystal oscillator.

It can be used for clock source and frequency source in communications equipment and test instrument.

Specifications:

Frequency: 16.9344MHz

Power voltage: +5 VDC / +3.3 VDC (+/-5%)

Power current: 25mA (MAX)

Waveform: TTL/CMOS

Duty cycle: 40/60%

Phase noise: -125dBc/1KHz

Package: 20.4 x 12.8 x 7.5 (mm)



Sorry if I'm going on a bit its just not 100% clear in my head :?

FURTHER EDIT:
another try with the scematics....
MDD 16.9334 oscillator specs.jpg


:D :D :D ok you just have to make REALLY : small :P
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Last edited by franjam on January 11th, 2018, 2:20 pm, edited 1 time in total.
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