last updated 03/23/2005 ---
This DVD player has been quite the rage out in the online audio forums, so much that one day I felt like
spending $39 on ebay and trying it for myself. Given I already had a great DAC, I didn't care about some
of the popular analog out mods, but rather to mod the unit as a custom transport for redbook audio CDs.
If you aren't familiar with this DVD player and it's potential as a "giant killer" audio component, search the Audioasylum or other DIY audio forums for 3950 and "Vinnie Mod" or "Swenson Mod" - you will find a large amount of information about what can be done to improve the performance of these components. If you're not into audio, but rather are looking for a high grade DVD player, the very same mods will result in a player that can compete with the best of them.
I picked the SD-3950 over the SD-3960 others have modified successfully because a) it comes in a metal enclosure, b) has a much better remote control, and c) has no known versions that don't lend themselves for modification (the 3960 is available with main processors that allegedly sound very poor, no matter how much you mod the rest of the unit). Also, I was able to pick up a second SD-3950 for just $20 for spare parts, making the base player quite affordable. The fact that the final player cost me about $200 in parts may sound insane to some, but once you compare the transport to units costing 10 times as much, you may not feel like it was such a bad investment after all. I've been considering to replace some of the capacitors with more expensive Blackgates and include more Auricaps for bypassing, but there's a certain level where the cost/benefit analysis slows down the modding plans. My idea to put the unit into a complete custom enclosure, either built from carbon fiber, or an aluminum/Lego block composite was axed when I saw how the panel switches were implemented. Basically, the time you'd spend to transfer the panel to another case would probably equal the total time I have spent on this project without necessarily benefitting the sound one bit. AT the same time the transport now retains its "sleeper looks" - who'd think that this $50 street price player can sound this good? :) This will probably be my last CD player anyway, since I have had very promising results when testing a USB to SPDIF interface on a computer transport. Meanwhile this Toshiba will serve me well.
The actual modification of the player didn't take more than a few evenings of soldering and damping. Things went much faster on this unit because of my experience modding the Cambridge Audio D500. In fact, the Toshiba was easier to mod, mostly because I didn't need to be afraid of damaging my one and only "expensive" player.
Tools needed: Soldering iron, desolder braid (don't even try this without it), screw driver, some tin snips, dremel. Don't do this stuff if you don't know what you're doing. There are lethal voltages inside the unit and I am not posting this page as an "instruction" to copy what I did. On the other hand, if you have done this kind of work and are looking for some ideas, this page may give you a few ideas that are applicable to other CD and DVD players as well.
There the Parts List for those who want to know every detail: XLS file - Zipped XLS
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Where do we start? Disassembly of the 3950 is quite easy - just be careful when you pull the flat ribbon cables from the boards to label them and keep them in a safe place. Once the unit is open, you'll be able to remove the boards and the drive mechanism pretty easily. I started the mods on the switching power supply board. I followed instructions from the popular mods, replacing caps with mostly high grade Panasonic FC series parts. There are a few Vishay film caps on the board, replacing some high-voltage ceramics. The diodes in the low voltage section were replaced with 100V rated schottky diodes, while the main rectifier posed a problem - the 1amp 600V schottky diodes I tried there kept blowing up, even though the stock parts were not rated any higher than that. For the time being I kept using the stock diodes and focused on other tweaks. The biggest change in the power supply section are the two 0.47uF 600V Auricaps across the AC (but behind the fuse). Search the Audioasylum Tweaks/DIY forum for "Auricap Tweak" for more info about this mod. Know what you're doing when you do this mod! |
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The bottom of the PSU board - I believe in bypassing! A handful of Wima MKP10 0.22uF caps I had in the parts bin were used up in this project. I think I bypassed very single electrolytic capacitor in the entire unit, not just on the power supply side. Why? Why not? |
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Another view of the power supply board early in the construction phase, still showing the stock diodes below the yellow Auricaps on the left. |
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Installed back in the chassis with rope caulk damping (more about that below). Here you can see the new IEC connector at the back of the unit, allowing me to use one of my Chris VH design power cords with this player. The stock cord is pretty much a joke. |
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Here a photo from the final mod. A friend tried some 4amp rated 600V Schottky diodes in the 3950 PSU and had good results, so I got a set of those. Installation required removal of the board, which is when this picture was taken. Note the black heat shrink around the diodes (TO220 package) below the yellow Auricaps: the back side of these diodes is conductive and you really don't want those to touch each other... Also installed here a 1.6am direct replacement ceramic fuse. Usually I solder these in place but apparently these fuses will easily malfunction after you heat them with the soldering iron. So instead it got cleaned with De-Oxit and sprayed with ProGold, just like any of the connector contacts on the back panel. |
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Here the whole PSU installed in the player with copper shielding towards the drive and signal board, plus with ERS paper covering the entire area. Note that Stillpoints ERS paper conducts electricity, which is why I kept it in the protective plastic bag it ships in. The copper plate is grounded, the flat ribbon power cable going to the signal board is completely wrapped in grounded tin foil. Everything is seriously damped with rope caulk. Don't be skimpy with this stuff - it's cheap and it works. |
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The first thing I did on the main board of the player was to replace the caps outlined in the Swenson and Vinnie mods, but after a little while I figured since they are so cheap, let's just do them all. I also added heat sinks to the main processor and later to all other ICs on the board. |
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An early photo, showing Panasonic FC caps in the foreground, plus 10V 47uF Nichicon Muse KZ caps in the center (gold black). The Nichicons are where the other mods were asking for Blackgates. I figured since I am not touching the opamps nor take the analog outs from the player, I could save a few dollars there. Still put in a few good caps, since I may want to use the player to watch movies from time to time, using analog out into a cheesy old receiver :) |
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This top view shows all the heat sinks really well |
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And since I believe in bypassing capacitors, I used up more of my Wima MK10 batch on the bottom of this board, bypassing every single capacitor on the top of the board. |
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When I got around to replacing the big fat capacitor in the back of the board, I realized I didn't have a 1000uF cap in the parts bin. So I put in a Nichicon Muse 10,000uF - no bad effects. I may replace that cap with a smaller one soon, since now I have a few 1000uF Blackgates in the parts bin |
 
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OK - now to the drive damping. These pictures show the mechanism removed from the chassis. Clearly, there's just thin plastic and really flimsy stamped steel holding everything together. Initially I was planning to convert the player into a top-loader, but looking at this structure I realized that cutting the top off would weaken an already weak mechanism far too much. So I decided to dampen what I had there, with special damping material where clearance was an issue (isodamp) and mostly with my proven rope weatherstripping material. |
    
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These five images show what I did to the case around the mechanism (watch below where the flat ribbon wires go - you don't want any sticky stuff down there. The shallow case also limited the amount of caulk I was able to apply on the top of the mechanism. All the hollow spaces in the plastic frame are filled solid with this stuff, while I used the isodamp sticky material on the smooth surfaces and near the laser where I didn't want to put any of the potentially messy caulk. The added weight of the caulk adds mass to the mechanism which will help with CDs that aren't perfectly balanced. I may even add some lead weights (left over at the tire shop, seen in $$$ modded DVD players from big name modders) to add more mass. I spent more time on the caulking of this drive than all the electronics parts replacement soldering... |
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In terms of connector upgrades, I only changed the power to an IEC inlet, allowing me to use my VenHaus design power cord, plus I added a BNC 75 ohm connector for the SPDIF out. The RCAs usually found in these units aren't anywhere close to 75ohm and I didn't feel like spending $45 on a Nextgen RCA that allegedly does 75ohm. I use BNC on the DAC input as well. |
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The BNC plug is wired internally with coax right to the board where I knew the signal was routed to go to the original rca connector. There may be a better place to connect it to, but I have no schematics nor do I understand this stuff too well. There's probably a perfect place right on the main processor to tie into the SPDIF signal. |
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Once the inside was all caulked, I turned my attention to the chassis base. Since I run my transports on roller bearings, I needed to add a solid polished aluminum base to the flimsy case the player came in. The best low resonant bonding I came up with so far is to simply connect the plate to the player with a big fat rope caulk sandwich. To do that, I had to build up the base with layers of caulk to get one even layer of caulk to make contact with the plate. |
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To make the surface as level as possible before bonding the plate to the player, I used food wrap and a rolling pin to level the caulk without having it peel off. Then before pressing the plate on the caulk, I heated the caulk with a 1000 watt shop light for 15 mins to get it really soft. Otherwise it won't stick too well. |
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Before assembly, I shielded all sorts of areas inside the player with Stillpoints ERS paper, or with grounded metal shields. The ERS paper needs to be handled with caution, since it is electrically conductive... |
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overview of the unit before closing the lid in September 2004. This picture was taken before the schottky diodes went into the player. It shows tin foil on the flat ribbon wire and a copper shield between power supply and mechanism. Both copper and tin foil are grounded. |
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This image shows the case just before closing the lid, with more ERS paper (inside plastic) and the damped lid, that features a mix of isodamp paper and cheap Home Depot floor tiles, plus has been spray painted black. I experimented with blue LEDs and an on/off toggle inside the unit, but I am either deaf or the blue LEDs don't do anything for this transport. So the LED is not inside the player now. |
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Here it sits on my old rack, bonded to the aluminum base plate and on the roller bearings.
There's also the old DDDAC (page on my new 16-chip DDDAC coming soon). Meanwhile I have added schottky diodes and
put a lot of hours on the transport. It compared favorably to a renowned modded DVD player based transport that costs over
$2000 and it clearly outperformed an even more expensive player that sells for $2000+ on the used market...
For the future, I plan to cryo-treat the internal flat ribbon wiring, especially the really thin wires connecting the mechanism to the main board. I may put a few blackgates into key locations and add some lead weights to the mechanism as well. If I should ever run out of other projects to do, I may revisit the transport and turn some of the voltages that feed the main board over to battery power and some super regulators. A better clock would probably be the peak but those mods are pretty expensive and I'm saving for a PC based setup to take over as my main source of music. This little DVD player will do fine for spinning CDs and since I have a second unit just for parts, it'll probably last me quite some time. |