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G-protection insanity

post #1 of 17
Thread Starter 
I may be getting insane but after extending listening I'm sure that my Sony D-EJ725 sounds BETTER with the G-protection on. There is an extra air and detail in the treble, which is good because the overall sound is too warm.
In comparison, the sound with the G-protection disabled (but still buffered) the sound is muffled. I tried several phones (EX70, 888, MX500, HP550) with the same result. This leaves me comfused. Could it be that the "G-off" mode is actually more compressed or the sound just gets brighter due to the the G shock protection, which compensates for the darker sound of this player. Or the G-protection is just more advanced, hence the reduction in sound quality is less.
Anyway, I could hear details with the G on that were completely missing with it off, i.e. the sound doesn't get just "metalically" brighter. The rest of the sound is nearly unchanged, perhaps some bass punch is lost, but it is not a problem since the 725 has enough low end.
In any case, I'd be interested to hear from other EJ721/725 owners here.
post #2 of 17
Hmmm... On my D-EJ721 player I couldn't tell any difference in sound with the G-Protection on or with the feature off. I could tell, however, that the sound is MUCH less compressed than the fudged Panasonic SL-CT470 (that model offers only the 40-second compressed Anti-Shock 4.0 - and even then it's less compressed than the earlier 40-second Anti-Shock II). However, the CT470 with anti-shock off edges out the EJ721 (but the CT470 skips too easily with anti-shock off).

Verdict: Though "buffered", the D-EJ7## series PCDPs have an uncompressed anti-skip circuitry.
post #3 of 17
Thread Starter 
Did some more listening, the same thing, G-protection sound a bit better to me more articulate and cleaner. However, I'm not ruling out the good old friend placebo. I'll try to convince my wife tomorrow to assit me with some blind tests.
In any case the G-protection doesn't hurt the sound at least. It is thus reasonable to leave it on since it prolongs battery life.
post #4 of 17
hmm, If G protection doesn't compress the sound, then it wouldn't degrade the sound in any way...

In fact by storing the data in a buffer, and then reading it off again with a cleaner clock, theoretically all of the jitter orignally on the disc could be removed... But I doubt jitter could cause such a big difference in sound, esp in a low quality portable DAC...

Another possibility is that the motors are shut off periodically when g-protection is off, so HF noise from the motor will not be radiated through the whole system, right to the DAC and headphone amp... This is a serious problem in my D-ej01...

wait, is there antiskip still when you switch off g-protection? if so, then it would probably indicate that the basic mode is compressed, while g-protection is not...
post #5 of 17
I think it's what Thomas suggests, the HF noise thing... there's a LOT of complaint about hearing "bubbly" noises (the kind you'd associate with the pickup reading) coming from Sony CDPs' headphone jacks. When I read the Japanese forums, at least... people were complaining about that. Virtually no such complaints with Panasonic and Aiwa PCDPs. One guy was also "urinated off" over Sony equipments easily picking up cell phone interference

The most extreme of people have, among other things, changed the output capacitor, and shielded the IC's with magnetic-insulating tape. And they do like the results *shrugs*
post #6 of 17
you can never go wrong with using ferrite clamps....
post #7 of 17
I run a D-EJ925
At present it is used as a transport feeding an out board dac.
Previous to that I used the analogue line out in the conventional
manner,there are two anti jog settings the lowest sounding
superior, the anti jog appears allways enabled in some form
and works still with the optical out enabled[I belive panasonic
players disable the jog protection in this mode]
I have no real complaints about the sound quality in the low

But regarding the motor noise I found the constant switch coast
switch, power saving action appeared to have audible effects.
This mode can be disabled by suppling power to the transformer
jack from a suitible bat pack, the analogue out sound seems
to have benifited from this sounding both cleaner and more open.

I do not know whether this applys to other players though.
post #8 of 17
Thread Starter 
Good points Thomas.
And yes, even when the G-protection is off there is still an anti skip enabled.
post #9 of 17
arent there two levels of g-protection 1 - 2.... 1 is small buffering and 2 is larger bufffering?
post #10 of 17
Originally posted by jamie
arent there two levels of g-protection 1 - 2.... 1 is small buffering and 2 is larger bufffering?
If you refer to the 925 then yes,
pherhaps some compression goes on in 2,
I have never needed it.
post #11 of 17
Blr, I am interested in your results of your blind test if you ever do it.

Here is my results about the G-Protection on/off with my HD570:

Sounds like there is some bass boosting during the reconstruction of the compressed buffer. The bass doesn't go as deep. The treble sounds clearer and more distinct, but unusually warm.

Sounds like a wider range of frequencies. I get deeper bass, but not boomy. The treble seems to go higher and "ssss" occurs much more often. Not as warm.

I have bright headphones, so the sibilance is very noticeable when the G-protection is turned off. With G-protection turned on, its less fatiguing to listen too because of the deemphasized bright spots, but the bass is kinda bloomy without depth.
post #12 of 17
The most extreme of people have, among other things, changed the output capacitor, and shielded the IC's with magnetic-insulating tape. And they do like the results *shrugs*
leon, can you please give me some more details about this mod? I'm not too confident about taking a soldering iron to tiny SMT parts on a $300 CDP, but as it stands the headphone jack is totally worthless...

BLR, The g-protection switch probably just switches between compressed (off) and linear (on) antiskip... Seems like a marketing ploy- according to sony G-protection mechanism uses faster motors/lens that can focus quickly, and if that's built into the CDP, why would anyone want to turn that feature "off" ?
post #13 of 17
To help sony claim the 100000 hour battery life maybe?
post #14 of 17

Are you using the headphone out or the line out?
post #15 of 17

Here's the link to pictures (click each pic to enlarge):


The guy forgot to take a picture of the "before", but the "after" is the last picture on the page. Because of space constraints, he did some wiring, cut the circuit board off a bit, and glued the new condensers in a corner. Refer to that picture to see what to remove.
He changed the "coupling condensers" (model used: Rubycon BlackGate-NX 47uF).

Check his other mod to get an idea of how to take the E990 apart:


Note the 2 screws on the inside near the hinge of the top lid, these are hard to access. There's wiring between the top lid and the circuit board, which you might want to temporarily remove using the solder. Once that's done, take the board and the pickup out together, and unplug the orange cable that connects the two.

This second mod is to increase the gain of the headphone amp. The E990 uses Toshiba's TA2120FN amp. Its 13th connector is a switch for an internal attenuator, and can thus change the gain (ON 8.5dB, OFF 16dB, Sony uses ON as default). What the guy did here is to detach the connector from the circuitry, which switches it to OFF state and increases the gain. The purpose of this was to increase volume, for use with the ER-4S; it is reported that with the gain increased there's less clipping at high volume.

Here's the English PDF datasheet for the headphone amp.


On G-protection: The very first G-protection uses linear data storage. However on later, switchable models you're switching between linear and non-linear. The capacity difference is roughly equal to 10sec/40sec, like the Panasonic 570's linear/non-linear.

I would take G-protection as implying that the pickup is more capable of resisting skipping, and recovering from skipping.

P.S. Is it just me, or does the E990 look like a messy engineering job?
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