[d-cee]

that's colossal

good work and keep it up!

we're all awaiting the results

 

[AudioCats]

Basically all straight forward direct parts replacements, expect the step where you add high voltage reservoir caps. This class requires the least skills.

----* Caution! Always make sure the batteries are out and AC is not plugged in whe you work on the PCB. You don't want to get zapped by the 550v charge from the little transformer on the board.
---- This to-do list is for info purpose only, you assume all risk associated with the modification. I can not be held accountable for anything happens to you (whether good or bad).

A)Opamp upgrade –
* Desolder the stock in-line-8 super slow opamps. If you don’t have a desolder station with air pump, the easiest way to do this is by bending the opamp back and forth until all the leads break off the chip, then desolder the leads off the board, one lead at a time. There is no need to save the stock opamps, you will never want to go back to it.
* Clean up excessive solder around the holes, then solder the SOIC AD8599’s onto the existing pads on the board….
* Parts Cost: about $15.

B)+/- supply caps:
-- replace C17 and C18. Absolute largest size you can use is 6.5mm (dia)x 13mm(high). My recommendation is United-Chemicon SMG 220uf/16v, (digi-key # 565-1038). The reason for using SMG is because it has the highest ripple rating in all the miniature 220uf/16v’s (rated at 260mA. The KMG is 180mA, Nichicon VR at 220mA).
Another viable option here is United-Chemicon NPCAP 100uf/16V, digi-key # 565-3053-ND, $0.75 each. Though the capacity is smaller than the SMG, it makes up in speed, the ripple current rating is 2820mA (not at the same frequency as the SMG rating, but I’d bet it is still much much faster than the SMG’s) .
* Parts cost: $1 to $1.5

--Replace C27 and C28. The absolute largest size for these spots are 6.5mm (dia) x 8mm (h). The battery compartment reinforcement feature and contact wiring is in the way, so 8mm is about as high as you can go. Recommendation is Panasonic KA series 100uf/16v, (digi-key # P833-ND).
Parts cost: $0.30

-- You can also add four more caps directly from the opamps’ VCC/Vdd pins to the ground. I will leave that to you, since it requires a bit of improvising. The caps to use will definitely be the United-Chemicon NPCAP 100uf/16v. As a matter of fact, if you decide to use the 100uf NPCAP in C17/18 location, you will really want to add these extra caps to make up the total capacitance. Adding a small film cap in parallel with the electrolytic for high frequency by-passing is also a good idea.
Parts cost: 0 to $5 depending on how many NPCAP you use.

C) Short out R33/34/35. These were originally for forming a “pie” filter to clean up the +/- 12v supply, but the new opamps require a lot more current and these resistors create too much a voltage drop. Just add a piece of thin wire across the resistor ends and short them out.

D) Replace the C3’s (two of them) with 1uf tantalum capacitor. First desolder the stock cap, then solder the surface mount tantalum chips onto the pad (on the under side). You can use low ESR tantalum chip like digi-key # 478-2412-1-ND, value is 1uf/35v. The reason for using SMD parts here is to clear up space so you have more possible space for more high voltage reservoir caps.
-- parts cost: $2.5

E) Desolder C1 and C2’s (four total); Install BC MKP 0.12uf/63v polyprop’s at C1 locations (digi-key # BC2056-ND, $0.68 each) and add two dip tantalums at C2 locations. I have no idea which tantalum dip will sound better, get a few different ones and try them out. The max size to use is 6mm(dia)x 13mm(h), here are two that might work: Panasonic 33uf/10v (PA2029-ND) and KMET 33uf/10v (399-3576-ND), both are less than $1.5 each. If you insist on not using tantalums as input but don’t have boutique caps to use either….. well, Digi-key does have Elna “audio capacitors” –-- “ ELNA developed new raw material for the separate paper which uses a silk fiber. Therefore, this series can give high grade sound for any audio design. This series can
be used to relieve the music’s vibration energy, to decrease the peak feeling sound at high compass, rough quality sound at middle compass and to increase massive sound at low compass." (this is what it says on the digikey catalog).
Part # is 604-1051-ND, price is a whopping…. 15 cents each

-- parts cost: about $4.5, or less if you use Elna audio caps

F) Desolder C7 and C8’s (four total); Install BC MKP 0.011uf/630v caps (BC2240-ND). You can also use the larger values such as 0.016uf/630v, the physical size is the same as 0.011 caps, it probably won’t make any sonic difference when driving the SR-001. (But larger value will give better bass if you do end up using an adaptor cable to drive the small pro-bias phones like Gama Pro or SRX pro).
-- parts cost: about $3

G) * Caution! Always make sure the batteries are out and AC is not plugged in whe you work on the PCB. Exercise extreme caution when wiring the high voltage caps since one mis-connection can fry the amp, the opamp stage will not survive a 550v hit.
--Desolder C6; Add two pieces of wires to a 0.1uf/630v X2 cap’s leads (digikey # 496-1881-ND, $0.48 each) then solder the cap into the board. The purpose of the wires is for paralleling more 0.1uf/630v X2 caps to it. You might also want to order some 496-2319-ND, it is also 0.1uf/630v ($0.32 each) but is thinner and longer; having two different size caps will help you utilize whatever room is available inside the case. This requires you to improvise though. I will recommend ordering 3~5 of each part # just in case.
You will want to pack in at least 0.3uf total (can easily be done), but there is no need to go higher than 0.8uf. Fix down the extra reservoir caps with hot glue (the good thing about hot glue is it hardens right a way, won’t smear, and if necessary, easier to get rid of later)
-- parts cost: anywhere from $3 to $5.

H) Add a good electrolytic cap between ground and DC input + (after the switch). There are no existing holes/spots for you to do this, so I will leave this up to you. A good cap aross the DC power input can make quite some improvements in bass texture presentation. Or you can build an external power conditioning box (actually a cap box), but that will be before the switch and will not be as effective. More on the cap box later.

By doing these mods you will increased the opamp’s speed by 50 time, high voltage reserve by 30 to 50 times, and +/- reserve by 10 to 30 times (which is required by the faster opamp, so you don’t really have a choice here

). All parts can be ordered from digi-key, total parts cost will be less than $40. Shipping/tax will likely be around $10, so < $50 all together.

-- Skill level required: if it wasn't for the Stax high temp (silver?) solder, I'd say it is a bit easier than building even the simplyest perf board Cmoy. At here you don't do wiring (except the paralleling more caps to X2 high voltage power reserve part), just replacing parts.

-- Total time to complete the FatCat class mods: anywhere from 45 minutes to 4 hours (from opening the case to closing the case), depending on your equipment and skill level. I can finish one within 45 minutes since I have access to an air pump desolder station, though I don’t see everybody using a station like that (the PACE 250 is more or less a $1200 machine). The mod is fully doable with just a pair of diagonal cutters, a pencil soldering iron, and a hot glue gun, less tool requirement than making a Altoids Cmoy.
If in doubt, go slow….. will be a fun little Sunday afternoon project.

 

[AudioCats]

Still mostly direct parts replacement, same skill level as the FatCat mods.
--Parts sources: SonicCraft BlackGates, SonicCaps; Partsconnexion film caps, BlackGates

----* Caution! Always make sure the batteries are out and AC is not plugged in whe you work on the PCB. You don't want to get zapped by the 550v charge from the little transformer on the board.
---- This to-do list is for info purpose only, you assume all risk associated with the modification. I can not be held accountable for anything happens to you (whether good or bad).


A)Opamp upgrade –
* Desolder the stock in-line-8 super slow opamps. If you don’t have a desolder station with air pump, the easiest way to do this is by bending the opamp back and forth until all the leads break off the chip, then desolder the leads off the board, one lead at a time. There is no need to save the stock opamps, you will never want to go back to it.
* Clean up excessive solder around the holes, then solder the SOIC AD8599’s onto the existing pads on the board….
* Parts Cost: about $15.

B)+/- supply caps:
-- replace C17 and C18. Absolute largest size you can use is 6.5mm (dia)x 13mm(high). My recommendation is United-Chemicon SMG 220uf/16v, (digi-key # 565-1038). The reason for using SMG is because it has the highest ripple rating in all the miniature 220uf/16v’s (rated at 260mA. The KMG is 180mA, Nichicon VR at 220mA).
Another viable option here is United-Chemicon NPCAP 100uf/16V, digi-key # 565-3053-ND. Though the capacity smaller than the SMG, it makes up in speed, the ripple current rating is 2820mA (not at the same frequency as the SMG rating, but I’d bet it is still much much faster than the SMG’s) .
* Parts cost: $1 to $1.5

--Replace C27 and C28. The absolute largest size for these spots are 6.5mm (dia) x 8mm (h). The battery compartment reinforcement feature and contact wiring is in the way, so 8mm is about as high as you can go. Recommendation is BlackGates PK series 47uf/16v.
All boutique caps can be ordered from SonicCraft (in Arkansas) or Partsconnecxion (in Canada). These two venders have basically the same price.
Parts cost: $2

-- add four fast electrolytics directly from the opamps’ VCC/Vdd pins to the ground. The caps to use will definitely be the United-Chemicon NPCAP 100uf/16v. Adding a small film cap in parallel with the electrolytic for high frequency by-passing is also a good idea.
Parts cost: 0 to $5 depending on how many NPCAP you use.

C) Short out R33/34/35. These were originally for forming a “pie” filter to clean up the +/- 12v supply, but the new opamps require a lot more current and these resistors create too much a voltage drop. Just add a piece of thin wire across the resistor ends and short them out.

D) Replace the C3’s (two of them) with BlackGates signal capacitors. Either the 1uf/50v N ($2.65 each) or 1uf/50v C ($1.45 each) will work, but the N is apparently a safer choice.
-- parts cost: $3~ $5.3

E) Desolder C1 and C2’s (four total); Install BC MKP 0.12uf/63v polyprop’s at C1 locations (digi-key # BC2056-ND, $0.68 each) and install two BlackGates signal caps to C2 locations. See the above cap test results for selection recommendations. If in doubt, use 47uf/6.3v NX, it might not be the best for your system but it is guaranteed to be at least good.
-- parts cost: about $6.5 ~ $15 depending on the BlackGates.

F) Desolder C7 and C8’s (four total); Install boutique output caps. Again see the cap test result above for some ideas on parts selection. If in doubt, use Sonic generatin I, you can choose from 0.01uf to 0.022uf, they will all fit on to the board. Again it might not be the best for your system but by picking this one you won’t mess up too badly.
If you use Partsconnexion as your source ( they don’t carry Sonicaps), the Multicap PPMFX 0.01uf~0.047uf/600v will be the only options due to the size limitation. You might want to pick a larger value just in case you might drive other pro headphones in the future). The price range is basically the same as the Sonics, I have no idea how they sound and what input cap to match them with though.
-- parts cost: about $18

G)** Caution! Always make sure the batteries are out and AC is not plugged in when you work on the PCB. Exercise extreme caution when wiring the high voltage caps since one mis-connection can fry the amp, the opamp stage will not survive a 550v hit.
-- Desolder C6; Add two pieces of wires to a 0.1uf/630v X2 cap’s leads (digikey # 496-1881-ND, $0.48 each) then solder the cap into the board. The purpose of the wires is for paralleling more 0.1uf/630v X2 caps to it. You might also want to order some 496-2319-ND, it is also 0.1uf/630v ($0.32 each) but is thinner and longer; having two different size caps will help you utilize whatever room is available inside the case. This requires you to improvise though. I will recommend ordering 3~5 of each part # just in case.
You will want to pack in at least 0.3uf total (can easily be done), but there is no need to go higher than 0.8uf. Fix down the extra reservoir caps with hot glue (the good thing about hot glue is it hardens right a way, won’t smear, and if necessary, easier to get rid of later)
-- parts cost: anywhere from $3 to $5.

H) Add a good electrolytic cap between ground and DC input + (after the switch). There are no existing holes/spots for you to do this, so I will leave this up to you. A good cap across the DC power input can make quite some improvements in bass texture presentation. Or you can build an external power conditioning box (actually a cap box), but that will be before the switch and will not be as effective. More on the cap box later.


----parts cost is less than $65, but you will have to get them from two different sources so there will be an extra $20 for shipping. $85 total.
---- You will want to use insulation sleeves on the output capacitor leads so there is no way they can zap the other parts by any kind of accident (plus it make them look "safer").



FatCatUltra mods
-- basically the same things to do as in the SuperFatCat mods, expect you will be trying to squeeze the Auri caps into meagerly available space in the 001 case, and you will have to make a quad SOIC --> SIP adaptor board so the 825’s can be used. You can see what I did in the opamp comparison post, I believe the pictures there showed enough info.
-- The best input electrolytic cap to use with the AD825 is most likely the BlackGates 220uf/6.3v NX.
-- the Ultra level is very depending on personal skill level and preference. If you find something works particularly well, please tell us

-- Parts cost will be about $30 more than than the Super (if you use Auri and 825's).

 

[AudioCats]

This one deserves a separate post. Important.

After the mods, the opamp stage will be drawing alot more power, the total current draw of the amp will be more than doubled (stock amp draws 220mA, while the FatCat and Super draws about 450, the Ultra draws 500mA). All these current goes into the step up inverter circuit on the PCB. The inverter is now working twice as hard, the Q15 (I suppose that is the swithing transistor --- update: not a switcher, but a linear voltage regulator) can get pretty hot, I will guesstimate the surface temperature reaching 80 degree C. And that is in the open air, it will only get hotter in the plastic case where air flow is restricted. Therefore, it will be a good idea to have a heatsink of some kind on Q15. I use a rubberized silicon thermo pad (patch)between the Q15 and the case wall so the heat will transfer to the case (using the plastic case as a heat sink). Will the Q15 get cooked if there is no thermo pad? probably not, just I don't want to take any chance.

I don't know who sells just the thermo pads, mine were from surplus/left over heat sinks. Here is a heatsink that comes with thermo patch. It is quite a bit larger (so better) than the little pad I am using.

I believe this will be all the info I have on the 001 mods. There might be a little update on the power conditioning cap box and the power source improvement later, but it might not be needed. After all, the battery DC is already proven to be the best there is……

Better find your soldering irons guys


Have fun


---- 2-8-08: for more about the Q15 heat issue, see the updated post #57 in the next page.

 

[AudioCats]

caps on the way, lets hope the cap box can make the adaptors sound more like batteries......

 

[HeadphoneAddict]

With a stock SR-001 I tested battery life. At about 3 hours 15 minutes with a pair of NiMH 2000Mah AA batteries, I started to hear a drop in sound quality.

I will keep listening till it becomes unbearable, but does this sound right?

Am I correct that the parallel battery mod will get the same battery life from a pair of 900Mah 3.7v lithium batteries after the SuperFatCat, which means over twice as much power drain and still a solid 3 hours, right?

 

[HeadphoneAddict]

Still running at 4 hours, without further degradation in sound since 3:15

 

[HeadphoneAddict]

5 hours and still running with no further sound degradation since 3h:15m when it had a slight but noticeable drop.

 

[AudioCats]

the stock 001 drains about 220mA, so a set of 2000mAH batteries (series), in theory, should last 8 hours or so. Now that is if you run the batteries all the way down which is actually impossible since the sound will get worse once the voltage get below 2.5v (fully charged is about 2.7V, and supposedly fully drained being 2.4v).
Also, since those are 2000mAH NiMH, I supposed they are at least three years old, the newer ones are already at 2600mAH. All common rechargable batteries have a service life of 3 years or less (even if you don't use them much, they will still age to death), it is possible the "used to be" 2000mAH capacity is now a lot less.

Two 900mAH 14500 Ultra fire in parallel should give at least 3 hours of good sound, in a SFC'ed 001. One good thing about lithiums is even when they get really close to depletion, the voltage is still high enough (at least 2.5v) to provide acceptable performence. Once the voltage gets below 2.4v the protection circuit will cut off the current so you don't have to worry about it

 

[HeadphoneAddict]

It went 6 hours 5 minutes before dying, and the green light switched to red about 45 minutes before it died. It sounded decent until it died quickly over a short period of time and faded out as the NiMH batteries died.

How long past the 3 hours will the parallel lithium batteries run before the superfatcat shuts off?

 

[sclee]

Is anyone use 4xNiMH battery box to SRM001 (4.8-5.6V ), will this damage for the amp.

 

[AudioCats]

4x will be too high, 2x too low, 3x NiMH should work great....

-- Update on Q15 (the one that requires heatsink): I partially traced power supply circuit tonight, and it turned out the Q15 is not a switching transistor at all, it is part of a linear voltage regulation circuit to make sure the switching transistor will see about 2.6-2.7v. That is why it gets really hot if 5v is plugged in -- there will be a 2.3v voltage across Q15, with a estimated 400~450mA current it will have to dissipate about 1W !!
Since the transformer will only see 2.7v the most, there is really no need to use DC input higher than 3v, to be safe lets say 4v should be more than adaquate..... After all, the whole amp was designed around a pair of AA. I think all the 4.5v transformers perform better than a pair of NiMH AA's because the adaptor voltage is higher than 2.7v while the 2x NiMH is usually less. Once the voltage is above a certain level then only the current capability counts. That kind of explains why the Sony 4.5v/500mA sounds so different from the Panasonic 4.5v/800mA....

So, to make sure Q15 doesn't over heat, it will be a good idea to keep the DC input between 3.5v~4v (the same voltage range as the lithium rechargables). That can be done by simply adding an extra diode in your 4.5v wallwart (not at the input jack, you don't want to lower the battery supply voltage) and use the 0.6v forward voltage drop to lower the Q15 voltage. That way the diode will get warm while the Q15 doesn't get too hot.

Have fun

 

[AudioCats]

Cap box "power conditioner", with 5 Panasonic FM 5600uf/10v caps (28,000uf total; using 10v caps because some 4.5v transformers' unloaded voltage can reach as high as 7v). There is a diode for polarity protection and provide a little forward voltage drop. I used a large power input jack because that is the only type left in my parts box

Does it work? yes and no. It does make the AC adaptors sound better, but I can still hear the wallwards "sound characteristics". With the cap box installed, the zip 5v still sound slightly hyper while the panasonic 4.5v/800mA still have a mid-range emphasis. (only able to compare these two since the power input jack doesn't allow the Sony to plug in. I have two Panasonic and two zip wallwarts so I converted one each to large plugs for testing).
I was kind of hoping the large capacity cap bank can erase AC adaptor's "personality" and make them all sound like the battery, apparently it didn't work out that way. On the other hand, it is still quite nice to have something that can run 24/7 and sound this good. The 5v zip + capbox combo, though still a little "hyper", provides the best overall sound in all my wallwards. (The lithium rechargables, in comparason, is calmmer and has slightly more weight to it.)

by the way, with the diode lowering the voltage down (3.8v output with Panasonic plugged in and 4.2v with Zip), the Q15 only gets slightly warm, no need to add the heatsink pad.

Larry, I have received the parts from digikey, you can send your 001 over whenever you are ready

Have fun

 

[HeadphoneAddict]

Quote:

Originally Posted by AudioCats /img/forum/go_quote.gif 4x will be too high, 2x too low, 3x NiMH should work great.... -- Update on Q15 (the one that requires heatsink): I partially traced power supply circuit tonight, and it turned out the Q15 is not a switching transistor at all, it is part of a linear voltage regulation circuit to make sure the switching transistor will see about 2.6-2.7v. That is why it gets really hot if 5v is plugged in -- there will be a 2.3v voltage across Q15, with a estimated 400~450mA current it will have to dissipate about 1W !! Since the transformer will only see 2.7v the most, there is really no need to use DC input higher than 3v, to be safe lets say 4v should be more than adaquate..... After all, the whole amp was designed around a pair of 1.5v AA (instead of the 1.2v NiMH), so all these make sense. I think all the 4.5v transformers perform better simply because of the higher current capability. That kind of explains why the Sony 4.5v/500mA sounds so different from the Panasonic 4.5v/800mA.... the voltage doesn't mean much, the current reserve does. So, to make sure Q15 doesn't over heat, it will be a good idea to keep the DC input between 3.5v~4v (the same voltage range as the lithium rechargables). That can be done by simply adding a extra diode in your 4.5v wallwart (not at the input jack, you don't want to lower the battery supply voltage) and use the 0.6v forward voltage drop to lower the Q15 voltage. That way the diode will get warm while the Q15 doesn't get too hot. If the DC input is at 4v then the Q15 will only have to dissipate 0.5w, that wouldn't be a problem even without the help of a heatsink pad. Have fun

So, if the RadioShack wall wart I am using now gives me a choice of 3v or 4.5v and has a 1000MA rating, can I just use the 3v setting? If the transformer isn't seeing any more than 2.7v, then 3v should be enough if it can supply up to 1000ma, right?

Right now at 4.5v the stock SR-001 does NOT get hot at all. I guess that at 220ma for a stock SR-001 that is why it isn't hot while I am using 4.5v, because the current draw is half that of the SuperFatCat, correct?

 

[HeadphoneAddict]

Quote:

Originally Posted by AudioCats /img/forum/go_quote.gif Larry, I have received the parts from digikey, you can send your 001 over whenever you are ready Have fun

I will be doing my stock SR-001 comparisons over the next day or two, and have 468 hours on the SR-001 already and it sounds nice. I have about 36 hours on the SR-003 that I am comparing to, but the SRM-1 Mk2 Pro is well burned in (thousands of hours I am guessing) and it sounds a little better already (even with less hours on the SR-003).

I am also comparing to Denon C700 and Livewires customs, with RSA Predator amp and Meier Headsix amp. All of these are well burned in (Predator has 905 hours, Headsix has about 400 hours, Denon about 600 hours as do the Livewires). I just need to get notes written about what I hear with everything, and will try to ship Tuesday or Wednesday if I am not ready to get it out Monday.

During that time I will keep burning-in the SR-003, until I am sure it is done changing.