[Russtafarian]

Ted:

Yes, the Oppo’s analog outputs sound great.  To summarize the basics of my Oppo mod:

I removed the 7805 5vdc regulator powering the DAC and in its place wired up a back panel power jack for a SB3 style 5vdc power supply.

I bypassed the L & R channel opamp by routing the DAC’s L & R analog outputs through 4.3uf coupling caps to upgraded RCA jacks on the back panel with 10kohm load resistors between + and ground.  All other analog outputs are left as is.

The final touch was using Lundahl LL1678 transformers set for 14dB of gain between the Oppo’s L & R output and my amp’s input.  The LL1678 might not even be the best choice for this as its distortion level rating is -8dBU (if I’m understanding the data sheet correctly).  The LL9206’s rating is higher at -2dBU.  Lundahl transformers available at www.kandkaudio.com .  Kevin @ K&K is very knowledgable and helpful.

Mark:

I’ve bypassed the opamp in my SB3 so it is also voltage output challenged and greatly benefits from being transformer-coupled directly to the power amp.

What I did for my dipole subs is take Linkwitz’ dual 12” dipole frame www.linkwitzlab.com/woofer.htm, and scale it for a single 15” driver.  I ended up a 24” x 20” x 12” dipole frame for each driver.  I cross them over at 40 hz with the ICBM and EQ the hell out of them with the Behringer.

Russ

[Gordy]

Thank you for the updates, Russ, most excellent!  Good to see you've sorted the sacd/dvd issue as I'm very interested in an inexpensive replacement for my long gone Denon player.

On another note, has anyone tried using the 980 usb connection as an external dac for a PC based system or know if it's even possible? 

Thanks! Gordy

[Ric Schultz]

Russ,
Just noticed this thread.  Good work!

The problem with running passive out is the output voltage is only one volt per phase so not so good for us passive chaps.  Of course, your transformer coupling solved that.  Usually, lower ratio transformers sound best.  So, a one to one transformer might give the best sound overall, but would not increase the voltage on the Oppo because it is a single ended DAC. 

Another problem with just running a cap out is that the signal is inverted in absolute sense.  If you are only using the Oppo as source then you can invert the speaker wires to get normal phase out.  Most CDs sound best when played using non inverting out.  The Oppo inverts phase in the DAC chip because Oppo is using a single opamp output stage in the inverting mode......ie: two inverts = non inverted.

Using a 4562 opamp and better coupling caps, etc. gives pretty darn good sound and still keeps the unit non-inverting and keeps the 2 volts out.  Of course, you could redo the filters/parts on the output stage and increase the output voltage to 4 or more volts, if you needed.

Yes, the Oppo will never be a great SACD player.....converting to 24/88 in their simple way is not really super.

Way to go!

[Russtafarian]

Ric,

Thanks for the feedback.  I’ve learned a lot from your website and postings over the years and appreciate your contributions to modification/DIY community. 

Usually, lower ratio transformers sound best.  So, a one to one transformer might give the best sound overall, but would not increase the voltage on the Oppo because it is a single ended DAC.

Maybe you’ve already traveled down this road, but I’m knocked out by how well these transformers work in this application.  They’re designed to impedance match and provide from 18 to 30dB of gain for 0.2mV moving coil carts.  That’s a pretty tough task.  Yet they can handle about 2vRMS of input at 20Hz according to Kevin @ K&K.  Used as a DAC gain stage they sound cleaner than any of the line stages I’ve owned both solid state (Meitner, ARC) and tube (Manley, CAT).  At $70 each, they represent a reasonably priced, high performance DAC output stage solution.  It would be interesting to hear out how they compare to your FET DAC output stage.

Another problem with just running a cap out is that the signal is inverted in absolute sense.

Wow, I didn’t pick up on this.  Thanks for bringing it to my attention.  Last night I switched the absolute phase on the output of the transformers and that made a positive difference.  The discombobulated bass issues I’d been fighting cleared right up.  Cool!

Russ

[Russtafarian]

After further experimentation, I’ve had to abandon the outboard 5vdc power supply approach to the Oppo 980.  This frustrates me because it sounded so good!  But I found that after I removed the 7805 regulator, the player started behaving erratically.  The transport would sometimes stop reading DVDs and SACDs and the LFE channel stopped working.  When I reinstalled the 7805, these issues went away.  Is that weird or what?!

So now I have a fully function player, but the magic is gone.  The sound quality dropped from “transcendental wow” to “it doesn’t suck”.  What a letdown.

I’ve ordered a 5v vreg from www.pilghamaudio.com to replace the 7805 based on mgalusha’s experience with it in his DCX mod. 

I’m also thinking of mounting the SMPS board in an outboard box for better isolation.  This would give me room to put a Felix on it, and bypass/upgrade some of the PS caps.  I plan on connecting the nine PS lines back to the player with a shielded CAT-5 umbilical and 9 pin RS232 type jack/plug.  Any opinions as to whether this would it cause more problems than it would solve?

Anyway, I’ll let you know how things turns out.  I want the magic back!

Russ

[mgalusha]

I’ve ordered a 5v vreg from www.pilghamaudio.com to replace the 7805 based on mgalusha’s experience with it in his DCX mod.

I really like the way these regs work, at least in the DCX. The only downside is they are limited to 280mA, so hopefully your Oppo doesn't draw more than that.

mike

[Russtafarian]

Hey Mike,

Thanks for bringing that vreg to my attention.  How many of the regulators are used in the DCX?

My hope is that the new regulator plus the felix will get me back to the sound I had with the outboard PS.

The only downside is they are limited to 280mA, so hopefully your Oppo doesn't draw more than that.

Maximum draw for the CS4361 DAC is 90mA, so I should be O.K.  Of course, that's what I thought about the other mods I tried. 

Russ

[randytsuch]

Hey Mike,

Thanks for bringing that vreg to my attention.  How many of the regulators are used in the DCX?

My hope is that the new regulator plus the felix will get me back to the sound I had with the outboard PS.

The only downside is they are limited to 280mA, so hopefully your Oppo doesn't draw more than that.

Maximum draw for the CS4361 DAC is 90mA, so I should be O.K.  Of course, that's what I thought about the other mods I tried. 

Russ

Is the DAC the only part the 5V reg powers?  But, if the 90mA is a max, the actual is probably much lower, maybe half that number.
The other thing is the 280mA is without heatsinking (per their website), so if things get too hot, you can add a heatsink, and it should be fine.

I wonder if the problems you were having with the external 5V is because the power sequencing.  That is, with the 5V reg, the oppo could control when 5V to the dac was turned on, but it lost that control with the external 5V.  Other question is does the Bolder supply put out exactly 5V?  A SB won't care if the 5V is high, it goes through other regulators anyway.  A DAC will care.

Randy

[mgalusha]

Thanks for bringing that vreg to my attention.  How many of the regulators are used in the DCX?

It has two 7805's on the main board.

Hope it rocks in the Oppo.

[Russtafarian]

Thanks Randy.

I wonder if the problems you were having with the external 5V is because the power sequencing.  That is, with the 5V reg, the oppo could control when 5V to the dac was turned on, but it lost that control with the external 5V. 

You're probably right about this.  Wish I could find a workaround, but that's beyond me.

Other question is does the Bolder supply put out exactly 5V?  A SB won't care if the 5V is high, it goes through other regulators anyway.  A DAC will care.

Yup, putting too much voltage on the DAC would not be good.  My DIY linear ps delivered 5.0 vdc to the DAC. 

It'll be a few weeks before I get the new parts into the player.  I'll keep y'all posted.

Russ

[jkeny]

I just got a 980H myself with the intention of modding it & running it into a Panasonic SA-XR57 which I already modded.

I'm thinking of changing the rectifier diodes to ultrafast soft recovery types & looking to upgrade or enhance the 400V 47uF cap on the SMPS board. Are there any other mods to the PS board recommended - OsCon caps where?

I'll be using the digital out (SPDIF & HDMI) so does the 5V upgrade apply here or just to analog outs? i.e. does the dig out come from the MediaTek chip directly?

Can't find a schematic of this 980H or a datasheet for Mediatek 1389 chip - anybody know any?

Will report back if there's interest!

[Russtafarian]

I'm still experimenting with the SMPS board and don't have anything to report yet.  Many modders have used the 385V Jensen 4 pole cap with good results but at around $60 it's expensive.

If the Panny has HDMI 1.1 or higher, the Oppo will deliver multichannel PCM over HDMI.  That might work pretty well.  Has anyone A/B'd PCM via HDMI vs. S/P-DIF.

[ted_b]

S/P-DIF won't support hirez multichannel bandwidth.  Only analog or HDMI.  So if you're talking 2 channel HDMi vs S/P-DIF, no, but at least it's "a/b'-able".

[Russtafarian]

So if you're talking 2 channel HDMi vs S/P-DIF, no, but at least it's "a/b'-able".

Yup, that's what I'm talking about. 

It's not a big issue for me because I don't have any outboard converters/processors.  Just curious if HDMI sidesteps some of the jitter/transmission issues that plague S/P-DIF for 2-channel PCM.

Russ

[jkeny]

I have tried HDMI (via PCM) Vs SPDIF & the differences are that HDMI has more micro-detail which gives it a more real/emotional presentation. I can A/B it with the remote so it's noticeable but not night & day. To be honest if I couldn't A/B I might not pick up the difference but that could be my lack of ear training

I don't know if this improvement is as a result of reduced jitter - I posted this question on DiyHifi.org "Had anybody levaluated the sound of hdmi" and being a bunch of engineers they nearly all gave me the technical reasons why it must be worse - but it is the opposite! So what do engineers know, eh!

I just changed the rectifier diodes to ultrafast soft recovery diodes & changed the existing 47uF/400V cap to 220uF/385V Philips/LCR cap. I had to lay the cap on it's side as I think would have to be done with the Jensens also!

I haven't had a chance to listen yet - it will be tomorrow.

[jkeny]

Oops, the diodes were 8A & blew the 1.5A fuse when I tested it - should have checked this before I installed them - I don't want to leave in these overspecced diodes as they might stress elements fiurther downstream so I'll have to put back the existing diodes & put snubbers across them

as well as change the fuse - this is a pain because it's not in a fuse holder but soldered onto the pcb - probably because Oppo put in a IEC after the board was developed so fuse holder would interfere with it.So I'll have to wire in a fuse!

What do people think of putting in OsCons on the PS board for the caps at the output? Would the Oscons be better used close to the ICs themselves?

Two other areas strike me as fruitful to investigate
- 7805 regulator could possibly be improved - this feeds 5V to 1389 chip
- changing 27MHz clock to VCXO clock circuit

[dragonknightTTTT]

After further experimentation, I’ve had to abandon the outboard 5vdc power supply approach to the Oppo 980.  This frustrates me because it sounded so good!  But I found that after I removed the 7805 regulator, the player started behaving erratically.  The transport would sometimes stop reading DVDs and SACDs and the LFE channel stopped working.  When I reinstalled the 7805, these issues went away.  Is that weird or what?!

Hi RUSS.
Thank you .
I am modding my oppo DV980 now.The same problem trouble me for a long time.I think the +5v of the 7805 maybe also a control signal of some circuit.Be －cuse  I find the power connect a audion.But I do not known the function of the circuit.Maybe the circuit can help you solve the problem.

[jkeny]

Just an update, I found some MUR160 diodes I had & I installed them - took off OsCon bypass cps from bottom of SMPS board, where I had installed them - it wasn't seating properly & I thought they were better used close to the digital ICs

When I powered up - no light - had a quick look at board & noticed a high power resistor R502 that had a mark on it - took it off the board & measured - it was open circuit.

According to the color code (Brown,Black,Gold,Gold) it is a 1ohm 5% but I don't know what wattage - I reckon about 2-3 watts. Don't have any handy - it will be tomorrow before I get any. This resistor is a Rsense resistor for the dip8 chip - a PWM current mode controller  that sets the voltage - I found this from the datasheet for the this chip - NP1200

I also noticed some missing parts:
- around the area of the blown resistorD506, C505 & R505 (an RC filter)
- in other areas too C503,
- ZD502, TC516 ( an electro cap from +5V to Gnd)
- L502 (jumper instead)

These are probably for another model - does anybody have values for these? My model, 980H is the European version ie. 230V input.

BTW, it would be good to figure out why we can't use an external supply:
- did you supply +5V, +-9V, & GND all in the external supply? ie. substituting the supplies on the 4 pin connector from the SMPS board to main board? This could be your problem: not giving the 5 + 9V supplies at the same time
- the problem could also be some match needed between the supplies going to the fron t panel & to the main board either in timing or in value! If that's the case we have a problem unless we can get a schematic

[jkeny]

Oops, the main input choke blew when I turned on the player (I tied 2 OR47 3W Rs together in series to get approx 1 Ohm)

I'm an idiot  now a dead player!

I can identify all the parts I need to replace apart from the inductor
L501 on my board (name on it is JLB2004) and
3 pin Mosfet? U505

I have drawn a yellow rectangle identifying the damaged parts on the picture uploaded to here http://www.4shared.com/dir/5422093/4db6362a/Digital_Amps_Service_Manuals.html

[jkeny]

Just got this PS board back working - had to replace all activecomponents + a coupleof passives.

But here's the real newsI wanted to post - about 10 days ago I emailed Oppo (in Sweden) about my stupidity & guess what their reply was? They got in a board from US & for €9 they are sending it to me.

Now is that excellent customer service or what? It's refreshingly unique to encounter this in today's business environment! Makes for great customer loyalty.