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

sjmikeb · « **Reply #200 on:** 24 Oct 2005, 10:52 pm »

I checked out the link you provided, but didn't really see anything about HexFreds (maybe I missed it).

Anyway FWIW, it just so happens there is a recent thread on AA:
http://www.audioasylum.com/audio/tweaks/messages/123567.html

Somebody there is recommending bypassing the Crees, another guy is saying he doesn't care for them. Although, following the thread, it seems to suggest there is less switching noise with the Crees. Probably should just look at the data sheets -- but that doesn't necessarily tell you how the devices sound (similar to what Paul was saying)

Who knows, almost seems like another one of those religious issues.

Regards,
Mike

rhale64 · « **Reply #201 on:** 25 Oct 2005, 08:40 pm »

Bob a quick question. I have the schematics sitting here in front of me. I was trying to find where to put two 10K rikens resistors that I had recieved for another mod. By the way looking at the Schematics where would they make the biggest impact? But while I was looking at the audio schematics I noticed that AE10 and AE20 where you bypassed for the Swenson, at least in my repair manual is for I believe the HDMI op amp. It comes in from the AIC1 from the vout1 pin to AE10. AE20 comes from vout 2 pin from same IC this feeds the AIC5 opamp. Is my schematics messed up or can we come out from AE4 for front left and AE5 for front right? Or am I just an idiot and really can't read a schematic? Or are you saveing the circuit intact on AIC3 and 4 for some other reason? Or is this AIC5 not beeing used in the Toshiba because it does'nt have HDMI, which it looks like that opamp may be for? Clue me in please. I am not trying to be an idiot. Just trying to learn thats all.

BobM · « **Reply #202 on:** 25 Oct 2005, 08:56 pm »

I'm picking up the signal right from the DAC chip. I agree that the schematic is confusing on the pickup points. I originally thought it was elsewhere, but by enlarging it quite a bit I found these points to be the correct ones for the L-R stereo output. The others are for the 5 channel L-R front RCA's.

No idea on the resistors.

Bob

rhale64 · « **Reply #203 on:** 26 Oct 2005, 03:06 pm »

Bob do you see any disadvantage to picking it up on AE4 and 5? I run mine into my preamp on 6 channel external in. This is clearly the best in my opinion. I just thought the purist signal always came out the multichannel analog outputs. Just what I was allways told. Or is this all just hype? I do not really see anything in the path that would degrade the signal the way you did it, however. I did notice the muting circuit that other modders have bypassed. How would you go about doing this? Just something else in the path that could be done away with.

BobM · « **Reply #204 on:** 26 Oct 2005, 03:15 pm »

If you come out the multichannel output you will be subject to the multichannel menuing for the front speakers - small / medium / large and bass management.

It will work either way. I just went with a 2 channel out, so I pulled the signal from the 2 channel taps.

Bob

rhale64 · « **Reply #205 on:** 26 Oct 2005, 03:21 pm »

OK thanx. How about this muting circuit? Did you ever consider disableing this?

BobM · « **Reply #206 on:** 26 Oct 2005, 03:37 pm »

I don't know anything about the muting circuit. Is it in the schematic before or after the DAC chip? If it's after, then it's a non-issue with a Swenson mod. If its before then I'm not sure what kind of rerouting you may need.

Good luck,
Bob

rhale64 · « **Reply #207 on:** 26 Oct 2005, 03:40 pm »

It is in the schematic at the bottom of the page. It is between the DAC and the AE 10-20. so it is before the bypassing of the opamp. So it would be signal degradeing probably. I do not exactly know what the muting circuit does though. Someone else mentioned they removed it.

BobM · « **Reply #208 on:** 26 Oct 2005, 03:52 pm »

YGIAGAM (Your Guess Is As Good As Mine)

You can pull it out if you want to, but you may actually want to use it at some point.. If you do, please report back on the change. I didn't see it in the path on the 2 channel circuit so I wasn't worried about it.

Bob

rhale64 · « **Reply #209 on:** 26 Oct 2005, 09:56 pm »

Bob by the way the Sonicap platinum in the 1uf 200v was 97.00 each. So you were about right on the money. I passed by the way.

But I may get six of them for my amp. Yeah right. I couldnt believe it when he told me.

sjmikeb · « **Reply #210 on:** 27 Oct 2005, 04:57 am »

I just read a letter in AudioXpress (Nov) about dampening ICs by bonding lead foil strips to them. Specifically the author of the letter had done this with opamps. I wonder if some improvement could be realized by doing the same to the DAC chip. Unfortunately, if you bond the lead foil to the top of the IC, it would likely be difficult to remove. I did dampen mine with Mortite

FWIW,
Mike

BobM · « **Reply #211 on:** 27 Oct 2005, 12:18 pm »

You would think that chips, which have no moving parts, wouldn't be so susceptible to vibrations. But we all know, everything makes a difference.

Lots have people have reported improvements by isolating and vibration-proofing op-amps, DAC and other chips in audio components. Some others say that this is over dampening and causes a lifelessness in the sound. Then again, others have said that they actually heard a difference using Peter Belt's foil!

I believe in controlled resonances. I don't think you want to deaden anything to the point of perfect isolation, but that you should control resonances so that you spread them out across a broad range - not isolate them to one specific range of frequencies (high or low).

I've found audio equipment definitely seem to improve with rational isolation of moving components, the chassis, clock crystal and also capacitors (but more for coupling them to the circuit board than smothering them with moretite). Everything else I generally leave alone.

Enjoy,
Bob

rhale64 · « **Reply #212 on:** 27 Oct 2005, 09:21 pm »

I need help. This will show my ignorance. I need to know to bypass the 1uf Sonicap would it go AE10----1uf-----.1uf----to rca+? or would it go little first then big? I have it the first way because that makes more sense. But this is electronics.

BobM · « **Reply #213 on:** 27 Oct 2005, 09:27 pm »

They ride on top of each other (parellel) not side by side as you have indicated (series). So the signal essentially splits itself into each capacitor(big and bypass) at the same time then joins back up and goes to the RCA jack.

Bob

rhale64 · « **Reply #214 on:** 27 Oct 2005, 09:56 pm »

Boy thanx a lot. That is wild though. The writing on the Sonicaps goes in the direction of flow, correct.

BobM · « **Reply #215 on:** 27 Oct 2005, 09:59 pm »

Doesn't matter, but as a general practice (being anal) I would make sure that the direction is in the same direction for both left and right channels.

Bob

rhale64 · « **Reply #216 on:** 27 Oct 2005, 10:04 pm »

One more question. Can they sit on top of each other like squeezed together? What I have done is put the 1uf in the hole then took the .1 uf and wrapped one leg around the lead that is going into the hole. Then the other leg of the .1uf is wrapped around the other leg of the 1uf. So this is what I would call stacked together. But they are right on each other. So should I stick something between the two to seperate them?

BobM · « **Reply #217 on:** 28 Oct 2005, 12:17 am »

You can throw a rubber band around them to keep them from moving about, or use some Moretite to hold them together. Either one will keep them from having any mechanical vibration.

Bob

rhale64 · « **Reply #218 on:** 28 Oct 2005, 12:32 am »

Is this Moretite like a putty. I have some black coax cable seal tape. It is like a putty but it is black. It is for sealing outside wires from the elements. I wonder if this would work? And for the crystal also.

BobM · « **Reply #219 on:** 28 Oct 2005, 12:17 pm »

Just make sure it will not melt in high temps (and possibly run) or freeze and crack under low temps. It should stay plyable and not solidify also.

Moretite is sold at Home Depot in the window and pipe insulation area. It's just a putty-like rope caulking compound. You can buy something like 1000' for about $4, then use extra to caulk your windows this winter to keep out the cold air too.

Bob