Modding the Toshiba SD4960 DVD/DVD-A/CD/SACD player

Ektalog · « **Reply #60 on:** 16 Dec 2004, 08:52 am »

As I mentioned to BobM in a PM, I just got the HD841...but it is going to be replaced with a 941 unit. I have begun to gather all the mods info that I can to see what (and if) I can apply them to the 941 (if need be). The current assumption is that other than HDMI and the Faroudja chip, the rest of the unit is the same or similar enough.

Among the things I may need is the Swenson mod but John's web page is not working. Is this mod limited to caps and wiring or does it include replacing the output opamps with Burr-Brown plus other stuff?

BobM · « **Reply #61 on:** 16 Dec 2004, 01:56 pm »

deleted - duped post

BobM · « **Reply #62 on:** 16 Dec 2004, 01:56 pm »

There is quite possibly a slightly different board layout and/or component numbering scheme to the new unit, but you'll never really know unless you get the correct schematic for the 941. So be careful and look the new board over before you order up the parts. Prepare a complete inventory first.

As for the Swenson mod, it totally bypasses the op-amps and the switching circuit around them (that switching circuit eliminated any thumps on turn-on and turn-off. It doesn't bother me since my preamp mutes for the first minute when I turn it on, and I always turn it to another selection setting before I turn off the Toshiba. The few times I didn't the turn-off noise was very minor anyway and not alarming in any way.

What does the Faroudja chip replace (I hope not the Zoran)? The Zoran DAC chip is quite nice and possibly accounts for most of the great sound out of the 841/4960.

Enjoy,
Bob

CornellAlum · « **Reply #63 on:** 16 Dec 2004, 02:34 pm »

Bob et al.

I found another tweak for this unit on the asylum which I am going to do. Finding the part was a pita though. I will post it here once I have a free minute to cruise over there and look for it.

Daryan

Ektalog · « **Reply #64 on:** 17 Dec 2004, 01:11 am »

Quote from: BobM

...
What does the Faroudja chip replace (I hope not the Zoran)? The Zoran DAC chip is quite nice and possibly accounts for most of the great sound out of the 841/4960.
...

Yes, the Zoran is the one replaced. But I doubt that this would affect SACD sound because DAC would be handled by the Burr-Brown DSD1608, which I hope they didn't mess with. Still, they may have ruined something in the audio by virtue of other actions...I pray they didn't or I'll be a very sad puppy.

net-david · « **Reply #65 on:** 19 Dec 2004, 04:54 am »

I just ran out to Circuit City and purchased the Samsung DVD-HD841 for $169.95. I already have the popular to mod Pioneer 563 universal player, but I was taken by the asthetics of the 841; if the front panel was 1/4" or thicker aluminum and from a "high-end" company, it would probably win an indutrial design award.

Does anyone know if this unit converts DSD to PCM for bass management like some other inexpensive players do? I suppose the Philips SAA7893 handles the SACD audio functions.

Which set of outputs is the best to use, front multichannel or stereo mixed? I will be using a Perpetual Technologies P-3A DAC for redbook CDs.

Would someone with access to the schematics mind sharing the circuit around the 4560 output op-amps?

Thanks,
David

Ektalog · « **Reply #66 on:** 29 Dec 2004, 10:27 pm »

It seems I was wrong about the HD941, Bob. The Zoran chip is still in there according to this:

http://www.hometheaterhifi.com/cgi-bin/shootout.cgi?function=search&articles=121#SamsungDVD-HD941 (HDMI)

The link doesn't take you precisely to it but you can click on the list or scroll down to it.

Not a great review, I am afraid, but only if video is the driving factor. They don't care about the audio portion the way we do. Even video is really not that bad under the right conditions.

For net-david: Do you still have the HD841?

net-david · « **Reply #67 on:** 29 Dec 2004, 10:47 pm »

I still have it, but I am about to return it, I got a deal on the Sony SCD-C2000ES, $250 tax included!

I have some pics of the inside and can take more if anyone is interested.

Ektalog · « **Reply #68 on:** 30 Dec 2004, 02:05 am »

Yup, that's a great deal, alright!

Sadly, you'll miss all the fun to be had mod'ng the 841.

It would be much appreciated if you can do the pictures. I'll have to figure out how to "transpose" 4960/HD841 mods to the HD941. A variety of additional pictures of the 841 internals may reveal helpful details. Thanks for the offer.

net-david · « **Reply #69 on:** 31 Dec 2004, 12:12 am »

Pic of the 841 board:

Here is a link for the 2.5Mb big version
http://s88847504.onlinehome.us/841/big.jpg

Let me know what other poses you would like.

David

STeveL · « **Reply #70 on:** 4 Jan 2005, 06:03 pm »

Hi All,

I've done all of the Panasonic capacitor upgrades to the power supply as per Bob's instructions. Changed out the X caps for 600V AuriCaps. I have not yet done the Swenson O/P mod, as I'm waiting on some backordered AuriCap's, and Black Gate's for the voltage rails on the DAC and SACD processor chip.

While waiting I thought I'd change the Rectifier Diodes as Bob suggested to a faster, soft recovery type, suitable for a switching power supply. Not able to find any Skottky's of sufficent voltage here in Canada. I went with some FRED's made by IXYS. These are a 600V 8A 35ns diode in a TO-220 case. They are available from DigiKey in quantities as low as 1 for about $1. I bought 10 to get the price cut and have some spares. (PN DSEI8-06A-ND). I was able to get all 4 of them on the top of the board (heat shrinked 2 to avoid shorts)

I was not expecting much from this mod, perhaps a minor improvemnt. But....Wow! This made a huge difference. The bass really tightened up, the speed of the music seems to have increased (I believe it's called PRAT and Bob mentioned this earlier). It just seems much more musical, with perhaps a deeper soundstage. The vocals just seem more alive.... toe tapin' kinda sound, much more fun to listen to. This made much more of a difference than changing to caps on my setup. Two thumbs up from this reviewer.

Next up, Swensonizing. And for Christmas I bought myself a big $20 BG cap for at the front end of the PS. (Just had to try it, I'll report back).

STeve

BobM · « **Reply #71 on:** 4 Jan 2005, 08:58 pm »

I know there's a lot of disbelief about the effects of swapping out the rectifier diodes for faster and cleaner one's. However, I have heard definite benefits doing this in both amp's and digital front ends. Less so with tubed equipment though.

The overall improvement is usually exactly as we both have experienced - a faster power supply leads to faster overall response - or better PRAT.

And yes, finding these diodes was a royal PITA, but sometimes good things come to those who search harder.

Enjoy,
Bob

omedon · « **Reply #72 on:** 5 Jan 2005, 08:10 am »

I am considering buying either a Toshiba 4960 or Samsung HD841 and performing the mod on them. However, I have heard a lot of bad things about the HD841. Most of them in this thread:

http://forum.ecoustics.com/bbs/messages/2/103901.html

Has anyone here had these problems with the Samsung? Has anyone had them with the Toshiba? They are supposedly the same machine aside from the DVI.

I don't care much about the DVI problems (which seemed mostly to be with the operator not the hardware). But the losing of system settings may be troublesome and the skipping and excessive heating problems definitely concern me. I plan to use it soley for CD and SACD playback and will leave it unconnected from the tv most of the time.

I would prefer the Samusung, excuse my vanity, because of it's nicer case aesthetics. In order to close the price gap between it in the Toshiba I would have to purchase online and hopefully not have to return it.

Any help is appreciated.

Thank you for your time.

BobM · « **Reply #73 on:** 5 Jan 2005, 01:33 pm »

It sounds like most of those complaints are around the DVI settings. I'm puzzled about the automatic return to default settings, but again, it seems to happen to people who are using the DVI for their video.

I'm only using my Toshiba for music, so I really can't help there. I've had no problems with either CD or SACD. I really don't have any DVD-A's in my collection, but I can report that DVD-A playback may not be as easy as it should be.

I've tried some, and they work fine - although you really need a TV screen to navigate their menu. Other DVD-A's don't seem to work at all, and still others seem to load fine but then won't play. I haven't bothered with dual disk's and I probably never will, given their inherent inferior musical quality. These DVD-A problems were also experienced on an unmodded Samsung 841 unit by another friend when we were comparing the units - but not necessarily the same problem on the same disk. Go figure.

It's always a good idea to look at the newest models, especially if the company says that the new ones fixed old reported problems. I don't know anything about the 941, but that's where I would start first, especially if you are interested in the video parts too.

Enjoy,
Bob

STeveL · « **Reply #74 on:** 6 Jan 2005, 05:12 pm »

I have not had any problems with my HD841. Although I am not using the DVI output either. Bought this mostly for the SACD and liked the looks of the Samsung better than the Toshiba. Mine has played every SACD and Redbook disk thrown at it without any skipping. I don't have any DVD-A disks. The settings have not changed back to defaults as of yet.

The power supply does run hot, I don't know if this will be a problem down the road, I'm not going to worry about it too much. Maybe add some additional heat sinking. My Bryston preamp also runs hot and it's well designed with a 20 year warrenty... so I doh know about the Samsung.

STeve

BobM · « **Reply #75 on:** 7 Jan 2005, 02:29 pm »

The small transformer that is on the right front of the board (not the one by the power cord) is the hot culprit. I cut a piece of aluminum taps and fashioned heat sink fins out of it - then stuck it to the top (this tape is self adhesive). It should help dissipate it a little bit, though the top and bottom plates of the case still get warm. In fact, the little MiRoller that sits under that corner, for isolation, gets warm too (thermal conductivity).

There was a thread on Audio Asylum on the original Toshiba 3950/3960 that stated the unit sounded better after it warmed up significantly, and didn't sound quite as good after heatsinking the transformer. Apparently it warms up something on the board and makes it more efficient. I doubt that this was a planned design issue, but I also doubt that the designer would dramatically underspec the transformer to the point where it will melt anything or fail in an unreasonably short period of time. We'll wait and see about that, but mine is still running fine with no screw-ups after about 6 months now.

Enjoy,
Bob

BRN · « **Reply #76 on:** 8 Jan 2005, 12:31 pm »

Bob,

First, thanks for making this mod available. I plan on doing it in the next couple of weeks. I have already purchased the player (Tosh SD-4960).
I do have a couple of questions before I start. I have the a couple of .47uF sonicaps that I was planning on using for the Sweenson mod, but I see that you recommend something between 1uF and 2uF. Do you think the value I have with the 300pF mica will work or should I up the value? I could use them to replace the X caps at PCF01 and PCF02 and get different caps for the signal output. Also, I'm not sure what you mean by bypass? You state that you used the 300pF mice as a bypass for PER10 and as a bypass for the sonicap for the signal output. The way I understand it is that the cap are in parallel with the other caps in those slots.

Thanks,
Brad

BobM · « **Reply #77 on:** 8 Jan 2005, 02:40 pm »

You could probably use the Sonicaps for the Swenson mod. The reason I upped the value on mine is that the input impediance on my preamp is very high (20K). Most preamps have an imput impediance of about 5K-10K, and a 47uF coupling cap is sufficient. But with a high input impediance you could POSSIBLY lose some bass response if the coupling cap is not of sufficient value. I probably overdid it going to 3uF.

You could get 1uF caps instead and use the .47 Sonicaps for the AC / X-cap replacement if they are 600V rated. Don't use the typical 200V rated Sonicaps for that location though - not safe.

As for the bypass, because I went to 3uF with my coupling cap I thought it prudent to also have a small value (.1uF) bypass cap in PARALLEL with my coupling cap. It made a difference for me and is generally a good practice anyway. The silver mica cap that Swenson recommends is not in parallel with the coupling cap. It goes ACROSS the + and - connecting points on each RCA jack.

Good luck and let us know your results,
Bob

BRN · « **Reply #78 on:** 8 Jan 2005, 07:53 pm »

Thanks for the input. I purchased the .47uF caps based on what I read on sweensons webpage. He suggested that a .47uF cap be used if the input impedance is 50K and a higher valuse such as 4uF if the impedance is 10K. The input impedance on my amp is 100K. What would you suggest?

The sonic caps I have are rated for 630VDC, so using them in place of the X-cap is not a problem.

The 300pF mica you are using on PER10 as a bypass (parallel) is that correct?

I will post my results once I have completed my S.E.X. amp.

Thanks for all the help,
Brad

net-david · « **Reply #79 on:** 9 Jan 2005, 03:50 pm »

When I returned my 841 to Circuit City, I noticed 2 open box on the closout table for $129. This is the Circuit City on Venture Blvd. near Gwinnett Place mall in Duluth, GA.