I suppose the hum issue doesn't exist when using the Stax wallwart?
The Stax SRM-002 mod thread
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gilency
Headphoneus Supremus
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Out of stock at staxusa.
you mean it is not a part of the system and you have to buy it separately?
Might as well just mod a battery pack to 5000mAH with power pigtail and call it good. The power pack can also work as desktop power supply ( run the amp while being charged via USB).
Might as well just mod a battery pack to 5000mAH with power pigtail and call it good. The power pack can also work as desktop power supply ( run the amp while being charged via USB).
gilency
Headphoneus Supremus
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No, it isn't.
Probably easy to just make one (using R-core transformer; wind your own secondary winding and get whatever voltage you want).
drp
500+ Head-Fier
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A-cats - thanks for posting about the USB battery pack mod; very cool and I plan to do this one. Even as is, the pack was a great buy; was able to charge my cell phone overnight while off the grid; was at 100% next morning. Certainly smaller than the wallwart I'm transporting, and USB charge while in use makes it a win-win.
From where did you order the protection circuit? Got a part number by chance? Oh, I did pop the top off my USB pack and it has a larger battery and no lead strip to add fake weight. Must be a few version floating around the web.
I do still plan to get around to the 002 mods you've described; at least the input and output cap portion. I actually took the 252A amp to the office so I could leave the 002 disassembled on the bench. Given my work schedule, that's as far as I've gotten.
From where did you order the protection circuit? Got a part number by chance? Oh, I did pop the top off my USB pack and it has a larger battery and no lead strip to add fake weight. Must be a few version floating around the web.
I do still plan to get around to the 002 mods you've described; at least the input and output cap portion. I actually took the 252A amp to the office so I could leave the 002 disassembled on the bench. Given my work schedule, that's as far as I've gotten.
has anybody done any mods to their 002 yet?
greenmountain
Head-Fier
I noticed that stax will bring out 2 improved amps: http://www.innerfidelity.com/content/ces-2014-stax-move
very interesting, those amps look like some super-sized SRM-001..... probably have all kinds of space inside for modding?
shipsupt
Headphoneus Supremus
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I'm not sure there will be much more space. I'm guessing a lot of space is dedicated to the new rechargeable batteries and of course the DAC components in the unit with a converter.
I'm looking forward to checking them out, and like the idea of some 002's set up for custom tips!
I'm looking forward to checking them out, and like the idea of some 002's set up for custom tips!
I wonder why they didn't use the more common 5 pin socket in the super-sized mini amps. Kind of a "portable" option for the existing 003's.
looks like I just bought a 002 system (base model) .....
Guess it will finally be the real "002 mod thread".
Thanks mods, for removing the "?" in the thread title.
Thanks mods, for removing the "?" in the thread title.
Got to play with the 002 a little today.
Observations:
1) exterior: the plastic used, in both the amp and the headband, looks cheap. Not exactly low quality plastic, but feels somewhat "ordinary".. This is a stax, we have high expectations!
2) the amp stack onto the battery pack (the one in post #11) nicely. The battery pack is only slightly wider.
3) internally: actually, does not look cheap at all. Components are very well arranged (meaning: suitable for modding....
. Lots of surface mount parts.
4) internal space available for upgrade parts: somehow it feels like there is tons of room available and it might even be possible to install premium components (which can not be fitted into a 001), such as Teflon output caps (!).
At a quick glance, my guestimate on the difficulty level of doing the mods: if one just want to do the mid level upgrade (like the SuperFatCat 001 I have done before), I'd say 001 and 002 are about the same. Above that level, 002 has advantage, it will likely require less fiddling around to fit premium parts, allowing a more straight forward operation. The srm-002 is probably the better base amp if one wants to go all-out and push the limit.
*phones comparison, SR-001 vs. SR-002 (it will actually be 003 vs. 003MK2 as I will be using 001 and 002 drivers with a 003 cable).
Experiment schedule:
1) basic circuit investigation (to see if it is too different from the 001 circuit)
update:
-- the output stage uses different devices. instead of two 2sk117 and two 2sc3405 per channel, it has a 5-lead device in the place of 2sk117's, and use two 2sc6127 for output. The 5-lead device is only marked "x y".
-- the opamp stage looks about the same as what is in 001 (see Kevin Gilmore's schematic in the 001 thread), except the input resistor (connecting to the DC-blocking input caps) is 1k instead of 2k.
-- power supply section is roughly the same.
2) Op-amp experiment
update: will not happen anytime soon. during the mod preparation I damaged one of the 2sc6127 and it seems that they are only available from China, price is about $1 a piece but shipping will be slow....
3) Fitting of actual mod parts
update: Soniccraft is helping me to find the right size caps that can fit into the case.... It turned out to be not as easy as I thought, the 16mm max diameter requirement on input cap is still too small for most boutique caps to fit.
Observations:
1) exterior: the plastic used, in both the amp and the headband, looks cheap. Not exactly low quality plastic, but feels somewhat "ordinary".. This is a stax, we have high expectations!
2) the amp stack onto the battery pack (the one in post #11) nicely. The battery pack is only slightly wider.
3) internally: actually, does not look cheap at all. Components are very well arranged (meaning: suitable for modding....
. Lots of surface mount parts.4) internal space available for upgrade parts: somehow it feels like there is tons of room available and it might even be possible to install premium components (which can not be fitted into a 001), such as Teflon output caps (!).
At a quick glance, my guestimate on the difficulty level of doing the mods: if one just want to do the mid level upgrade (like the SuperFatCat 001 I have done before), I'd say 001 and 002 are about the same. Above that level, 002 has advantage, it will likely require less fiddling around to fit premium parts, allowing a more straight forward operation. The srm-002 is probably the better base amp if one wants to go all-out and push the limit.
*phones comparison, SR-001 vs. SR-002 (it will actually be 003 vs. 003MK2 as I will be using 001 and 002 drivers with a 003 cable).
Experiment schedule:
1) basic circuit investigation (to see if it is too different from the 001 circuit)
update:
-- the output stage uses different devices. instead of two 2sk117 and two 2sc3405 per channel, it has a 5-lead device in the place of 2sk117's, and use two 2sc6127 for output. The 5-lead device is only marked "x y".
-- the opamp stage looks about the same as what is in 001 (see Kevin Gilmore's schematic in the 001 thread), except the input resistor (connecting to the DC-blocking input caps) is 1k instead of 2k.
-- power supply section is roughly the same.
2) Op-amp experiment
update: will not happen anytime soon. during the mod preparation I damaged one of the 2sc6127 and it seems that they are only available from China, price is about $1 a piece but shipping will be slow....
3) Fitting of actual mod parts
update: Soniccraft is helping me to find the right size caps that can fit into the case.... It turned out to be not as easy as I thought, the 16mm max diameter requirement on input cap is still too small for most boutique caps to fit.
some quick notes of available space:
*battery compartment area: by taking out the battery tray, has enough room to fit in a pair of (input) capacitors. Max cap size 16mm (dia) x 62mm (L).
*output daughter board:
-- resistors are 2mm height, if resistors stay on the top side, allows mod components with 8~10mm height (or dia).
-- if all resistors moved to the under side, the area closer to the battery compartment allows component height of 12mm or less; the area closer to the LED
allows 10mm. ( for output caps and high voltage reservoir caps).
*the space between daughter board and main board: after moving four 2.6M resistors to the underside of main board, there is 5mm space between boards ( which allows installing four 0.1uf/600v Epcos caps as high voltage rail reservoirs)
*underside of main board: max component height 3mm. Enough for extra surface mount tantalum caps as low voltage +/- rail reservoirs. Plenty of room to parallel them.
*battery compartment area: by taking out the battery tray, has enough room to fit in a pair of (input) capacitors. Max cap size 16mm (dia) x 62mm (L).
*output daughter board:
-- resistors are 2mm height, if resistors stay on the top side, allows mod components with 8~10mm height (or dia).
-- if all resistors moved to the under side, the area closer to the battery compartment allows component height of 12mm or less; the area closer to the LED
allows 10mm. ( for output caps and high voltage reservoir caps).
*the space between daughter board and main board: after moving four 2.6M resistors to the underside of main board, there is 5mm space between boards ( which allows installing four 0.1uf/600v Epcos caps as high voltage rail reservoirs)
*underside of main board: max component height 3mm. Enough for extra surface mount tantalum caps as low voltage +/- rail reservoirs. Plenty of room to parallel them.
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