X-24k (another) but allready modded

[nando]

Mods for Nando's MF x-24k:
1 resolder sloppy solderings
2 replace the 4 x 1000uF / 35V Jamicon SK with 4 x 1500uF / 35V Panasonic FM capacitors
3 replace the Jamicon SK 16V / 2200uF with Panasonic NHG series 3300uF / 35V caps
4 ...?


After opening up my Nu-Vista today I decided to look inside my MF -x24k.

There are some mods being done. There are IC's replaced, see photo's 4 and 5. Doen anyone know what these are?
Because the mod IC's were put in, there was need for some room and some components were removed and put back in place. This was done with the components put at an angle and ugly soldering.

Some soldering is very badly done, I guess the soldering iron was not hot enough.

I see some good mod threads elsewhere on the forum and that is maybe a good way to go.

What do you think of it?

1.


2. Even I can see that this is quick and dirty work.


3. Is this as the x-24k left the factory?


4.


5. There are two of these instead of some IC's that were standard on the pcb. Does anyone know what these are and what they do?

[PinkFloyd]

I'm off out now but will reply in full later on........ the opamps are Analogue Devices AD825...... two single SOIC channel opamps on a single to dual convertor plus SOIC to DIP8..... nice opamps.

Mike.

[nando]

Oke, Mike I'm looking forward to a full report.

If this mod is a good one, why didn't they replace other cheap components? But maybe the amateuristic soldering gives a clue.

[PinkFloyd]

Hi Nando,

The soldering is pretty shoddy but not the end of the world...... get yourself a hot iron (420C) and a desolder pump....... do each solder joint one at a time........

Desolder pump in left hand, solder iron in right hand...... melt solder and suck up molten solder with the desolder pump (suck it up while the iron tip is still on the joint) and then simply resolder each joint with just enough solder to do the job. Whoever soldered the opamps has used a bit too much solder..... you don't want great BLOBS of the stuff, just a little slightly domed mound of shiny solder.

Don't spend too long on the joints....... the 420C iron temperature allows you to go in fast and out fast....... quite literally takes under 2 seconds to desolder / suck up the solder and a second to flow the fresh solder fresh solder in. The thing is...... if it is working fine and you're not too comfortable with a soldering iron then then there is no problem with leaving it as it is.

You can tidy up the 825 opamp solder joins on the SOIC to DIP adaptor quite easily..... get some desolder wick, lay it over the 4 joints (per side) and run a hot iron over it..... it will suck up all the excess solder but will NOT remove the solder between the opamp legs and pads. Again, this is only necessary if the unsightly blobs of solder offend your eyes.... if it's all working fine then whack the lid on it and listen to the music

I always use the desolder wick technique when soldering SOIC opamps..... it makes for a neater looking job:




IIRC..... the ceramic cap at the input comes like that from the factory.  The wiring solder joints underneath the 47uF 16V non polar capacitor are very shoddy looking..... WAY too much solder!  It looks like whoever did that spent way too long on the connection with an iron that wasn't hot enough.  Desolder the wires (noting which one goes where) and suck up all that damned solder from the pads (FAR too much, it hasn't even melted properly)...... re tin the wires with fresh solder and tin the pads, that's all you need..... hot iron on the pad, fuse the wire onto the pad and withdraw iron whilst holding the wire in position..... piece of cake.

As is usually the case a poor solder joint is caused by spending too long on it with a cool iron..... they key is HOT and FAST! As soon as the solder pools (turns liquid) get your iron out.... 2 seconds max for the wire...... sounds like a short time but when you count out "ONE.... TWO" it's actually quite a long time  FIVE would be the absolute longest I would keep the tip of the iron on the pad.  Another tip...... use low melting point lead rich solder, it turns to liquid in a second, the stuff I sent you with your X-CAN kit is the way to go Nando.  Lead free solder has a much higher melting point and is a bastard to work with.... it is also inferior to lead rich solder BUT "apparantly" green and eco friendly. 


BULLCRAP! most of today's "eco friendly" equipment ends up in a landfill site once the 12 month guarantee runs out and the rubbish explodes and is non repairable..... that's really "green" filling landfill sites full of lead free crap designed to last a year at best..... anyhoo, another time and another channel on that major con we are being force fed in the name of being "eco friendly".

Do you have any photos of the "top" of the X-24K Nando?  Would be nice to see what components are being used but I am 99.7% certain it will be the usual MF "Jamicon" livery


Hope this helps.

Best regards,

Mike. 

[nando]

Thanks Mike!

Stupid thing is that I photographed the solder joints and pcb from the bottom... but not the top in full view.
You know your MF equipment well. The x-24k is no exception. There are the usual Jamicon elco's.

Can you tell me more about these opamps that are in my x-24k? I read the datasheet AD825 but I lost concentration after a few sentences. Why would these be used in the x-24k?

I will be working on my x-pre and try to tidy the x-24k. That said I could try and put in some better components. Some elco's have more space to place some larger ones.

[nando]

I have made a photo to show that there is some room to work with.

[PinkFloyd]

Hi Nando,

I have been away all day today.... took my friend down to Inverness and back for a Hospital appointment (300 mile round trip) and arrived back home at 9.30pm so pretty much heading for bed soon but will reply tomorrow some time. All I can say, at this time, is the AD825 opamps are NOT the opamps that MF fit into the X-24K: rockgrotto.proboards.com/thread/2172/24k-music-fidelity-dac BUT they are very good opamps for audio / AD825 are highly regarded.

I have ZERO experience of the X-24K so am pretty much blind with regards to its topology BUT (from what I can see) the AD825 seems like a decent choice.

Best regards

Mike.

[nando]

No worries, Mike. I'm not an impatient man, do what you got to do.

As far as I can see there are a lot of similar components that I replaced in my x-cans with your mod. Same goes for the nu vista by the way.

[PinkFloyd]

Jun 27, 2017 17:38:25 GMT nando said:

I have made a photo to show that there is some room to work with.

Height to work with but not much width Nando.

Those are Jamicon SK series general purpose 85C caps and well due a "removal and recap" with something more sonically appropriate.

The 16V / 2200uF will be approx 21mm H x 12mm W and the 35V / 1000uF will also be approx 21mm H x 12mm W.

I would recommend you replace the 4 x 1000uF / 35V Jamicon SK with 4 x 1500uF / 35V Panasonic FM capacitors..... the Panasonic FM caps are 36mm H x 12mm W so they will slot in seamlessly / room to spare....... more capacitance in this section is what we want.... Panasonic FM 105C rated caps are quality and good for many tens of years in your X-24K.

Plenty of wiggle room with the Jamicon SK 16V / 2200uF so I'd be inclined to fit Panasonic NHG series 3300uF / 35V caps here........ 33mm H x 16mm W.........

You'll notice a marked improvement (and then some) in every part of the sonic spectrum.

Best regards,

Mike.

[nando]

Aren't there good elco's that are higher but not wider?

[PinkFloyd]

uk.rs-online.com/web/p/aluminium-capacitors/7396831/

[nando]

Jul 1, 2017 12:08:11 GMT PinkFloyd said:

uk.rs-online.com/web/p/aluminium-capacitors/7396831/

wow... that is kind of a daunting website. I wouldn't have a clue where to start and know what is good.

I'll post some more detailed photo's of the pcb of the x-24k with components and the text on them. Maybe we can work out what to change.
By the way my goal is to improve my system but also make the x series survive another 20 years. I like the system so much that I don't want to go back to large black box audio.

[PinkFloyd]

Jul 1, 2017 19:17:38 GMT nando said:

Jul 1, 2017 12:08:11 GMT PinkFloyd said:

uk.rs-online.com/web/p/aluminium-capacitors/7396831/

wow... that is kind of a daunting website. I wouldn't have a clue where to start and know what is good.

I'll post some more detailed photo's of the pcb of the x-24k with components and the text on them. Maybe we can work out what to change.
By the way my goal is to improve my system but also make the x series survive another 20 years. I like the system so much that I don't want to go back to large black box audio.

I know RS inside out Nando..... not that daunting..... you just need to know what you're looking for With the right caps / values you will not only help your system to survive a LOT MORE than the next 20 years, it will also sound a helluva lot better too!!.

The PSU section of the X-24K...... I would deffo replace the 2 x 2200uF and 4 x 1000uF Jamicon 85C caps with 6 x 2200uF / 35V Panasonic FR caps. They will last for tens of years and the extra capacitance will reap sonic rewards too. The FR are rated at 10,000 hours @ 105C..... that means they will stay in spec for 10,000 hours in an ambient temperature of 105C..... that is their MAX rating!

The X-24K won't get anywhere close to 40C so that means the 105C rated caps will remain in-spec for MANY MANY thousand hours....... 30 years at least!!

The Panasonic FR also sound good, they have the classic Panasonic liquid / flowing house sound (similar to FM and FC) and with a 10,000hr rating @ 105C they will outlast you, for sure.

The warmest part of the X-24K circuit will be around the regulators (REG1 / REG2) so 105C rated caps are your friend in these positions..... the 85C general purpose Jamicon caps are not ideal BUT, all credit to them, they have lasted a couple of decades in most of the X-Series amps so we must respect them for that.

Best regards,

Mike.

[nando]

Great, learned something... again.

Do you order these parts in small quantities or have stock of most used components?

[PinkFloyd]

Jul 1, 2017 22:12:57 GMT nando said:

Great, learned something... again.

Do you order these parts in small quantities or have stock of most used components?

I have loads in stock Nando

[nando]

So here are some addional photo's of my x-24k. Sorry, I got carried away with my camera. I have more than these so I don't have to open up the thing for some details.


Here is a connection between two soldering islands. To me this looks like a soldering mistake. Is that true?


The little pcb for the optic fible connector.


optic fibre connector pcb











































What are these three pin components? Resistors?

[PinkFloyd]

This one?



Doesn't look right does it? What component is on the other side of the board?

Mike.

[nando]

Jul 4, 2017 12:07:40 GMT PinkFloyd said:

This one?



Doesn't look right does it? What component is on the other side of the board?

Mike.

On the other side is the connector with three wires.



Which lead to the top board, the opical wire connector. See right top of photo.

[PinkFloyd]

Does the optical output (or input) work? I don't think it will and that link (or whatever it is) needs to be broken mate.

Mike.

[nando]

Jul 4, 2017 12:45:14 GMT PinkFloyd said:

Does the optical output (or input) work? I don't think it will and that link (or whatever it is) needs to be broken mate.

Mike.

Well. Strange about it is that, as far as I know the x-24k is working fine. The optical link works perfectly. I only use optical wires from my tv, apple tv and playstations. So with the strange link on the pcb it works.
Don't fix what isn't broken?

[PinkFloyd]

Why ask a silly question? If it works why ask if it's broken?

[PinkFloyd]

I would STILL remove that link though Nando...... you may find it works a LOT better

[nando]

Jul 4, 2017 20:59:13 GMT PinkFloyd said:

I would STILL remove that link though Nando...... you may find it works a LOT better

exactly!

[nando]

Trying to learn about different capasitors to choose for my x-24k. Mike you reconmend the panasonic FM serie, but why? Sonnically, size, durability or other?

You use other brands elsewhere. How good are Teapo capacitors? Or should it be spelled C(t)heapo? Sorry, cheap shot...

[PinkFloyd]

Jul 11, 2017 18:07:22 GMT nando said:

Trying to learn about different capasitors to choose for my x-24k. Mike you reconmend the panasonic FM serie, but why? Sonnically, size, durability or other?

You use other brands elsewhere. How good are Teapo capacitors? Or should it be spelled C(t)heapo? Sorry, cheap shot...

Panasonic FR = small footprint for capacitance, good sound quality, long life, 105C rated and low ESR..... what is there not to like? Same applies to Panasonic FM as well.

Teapo = Cheap....... they don't offer ANY of the benefits of the Panasonic caps but are very cheap (especially when purchased in bulk) as are the Jamicon SK capcitors which MF use in most of their amps.

The difference is not subtle it is profound...... remove the Jamicon / Teapo caps and replace with Panasonic and you will hear a most definite improvement.

The values are also important, especially in the PSU section of the board..... get as much capacitance in there as you can. A 1000uF replaced by a 2200uF (for example) will always bring about sonic rewards.

Don't knock the Teapo / Jamicon caps though...... quite a lot of MF amps have been going strong for MANY years with them on board but could have sounded a lot better from day one if MF hadn't pared the parts bill right down to the bone but they have to make a profit and there always has to be a compromise. I would rather they produced the equipment as specced by the designer but they never do..... they always get the bean counters involved and cut as many corners as they can in order to keep costs down and profit margins high.

Teapo are very good value for money and really should have been called "Cheapo".... they don't profess to be anything special and are general purpose 85C rated caps..... perfectly good for general purpose usage but not ideal for use in a warm / hot environment. Quite funny because the first capacitors to fail inside an X-CANS (V1) amp are the two 100uF Jamicon SK 85C caps that are parked up hard, right next to the regulators Built in obsolescence? Maybe. The correct cap for the job? Certainly not! I always replace these with 130C rated caps...... 85C rated caps will be fine for a while (until they go high ESR) but you can be sure they most definitely WILL go bad eventually parked right up next to a regulator..... the 130C caps will be fine for MANY years parked up next to regulators because they are designed for high temp. duty.

The Panasonic caps are not the be all and end all BUT they are ones I use the most because they are UBER reliable, and sound great..... they are proven to be very good in service and I have (touch wood) experienced ZERO failures. They are consistently good from batch to batch, VERY well made (I have sawn quite a few into bits over the years) and if you asked me what capacitor manufacturer I would trust when designing a critical part in an aircraft OR piece of life critical medical equipment I would say Panasonic or Vishay all day long.

In certain parts of a circuit I like using ELNA Silmicll caps, in others I like the Nichicon MUSE ES (non polar) caps but the majority of the caps I utilise in my upgrade kits are Panasonic FM / FC / FR or NHG types..... all depends on whereabouts in the circuit they are being used. It's taken me many years to decide what sounds best where Nando and I'm glad to report that 99% of the people who have fitted one of my upgrade kits find it a HUGE improvement over stock. It's not simply a case of slamming a handful of Black Gate caps into a circuit and sitting back to enjoy Audio Nirvana...... nowhere near as easy as that! If anything, throwing a handful of Black Gate caps into a circuit will totally destroy the SQ..... I was never a fan of them BUT, in certain parts of a circuit, they could work wonders.

The thing with them was most novice audio guys would think "ooooh! Black Gate" as if they were some type of capacitor Gods and they would pepper their boards full of Black Gate caps..... big mistake! They would then go on forums and ask the question "how long for Black Gate caps to burn in?" and the answer would be "a long time!".

That's one thing I HAVE learnt...... if an upgrade doesn't sound like a major sonic leap forward from the first 60 seconds of listening then it isn't an upgrade! If it sounds worse it isn't an upgrade! I had one guy a few years ago who was still waiting for his Black Gate caps to "burn in" some 6 months after fitting them..... utter nonsense..... wrong cap for the job = crap sound no amount of burn in will turn a turd into a gold nugget.

Same goes with gold..... a mate of mine bought a Krugerand at a local auction a couple of years ago he was really chuffed because he bought it in a box of trinkets and the entire box of trinkets (including the Krugerand) ONLY cost him £90. He let me have a look at it....... It looked like a Krugerand right enough BUT when I got my magnet out and the "Krugerand" was attracted to said magnet it turned out to be a fake Krugerand and the £90 he had paid for the box of trinkets was probably £89 too much

This was his exact words "oh well, I'll stick it in a drawer for a few years and see what happens" I replied with "You can shove it in a drawer for a thousand years and it still won't be gold!"

Off to water my potatoes..... no rain for two days, they will be missing the constant downpour

Mike.