Are there any cheap options for a Better Touch Power Supply?

[JohnSwenson]

Hello John, you think adding a ferrite core on the SB3 power supply cord like the Touch cord has, could help. I wrapped the cord a few times around a ferrite cylinder and found it to make a difference.

Pretty much anything will improve the SB3 supply so yes putting ferrite chokes will probably help, but its still a band-aid.

John S.

[woodnut]

I am still interested in trying a regulated linear power supply for myself and see that Farnell do this :


http://uk.farnell.com/power-one/hb5-...-3a/dp/1208815



* PSU, OPEN FRAME, 5V, 3A
* Power Supply Output Type:Fixed
* No. of Outputs:1
* Output Voltage:5V
* Output Current:3A
* Power Rating:15W
* Input Voltage Range:100V AC / 120V AC / 220V AC / 230V AC / 240V AC
* Length:53.34mm
* Width:101.6mm
* Height:123.7mm
* Approval Bodies:CE / CSA / TUV / UL
* External Depth:53.34mm
* External Length / Height:123.7mm
* External Width:101.6mm
* Max Operating Temperature:50°C
* Max Supply Frequency:63Hz
* Max Supply Voltage:240V
* Min Supply Frequency:47Hz
* Min Supply Voltage:100V
* Min Temperature Operating:0°C
* Mounting Type:Chassis
* Output Type:Fixed
* Power Supply Type:Linear
* Supply Voltage:230V





It looks to be the same as the one in post #24 of this thread by Amuata who is offering two of these units. I am thinking about giving it a whirl but I have a few simple questions if anyone can jump in.


- This is obviously meant to be mounted inside another chassis as it is an open frame design, would any Maplins metal enclosure do?


- What sort of cable should I use for the DC side? Should it be shielded? light gauge? I note the link earlier in the thread for the switchcraft connector, are these soldered?


- Should the AC side involve a power cable that plugs into the power supply and if so what connector would be recommended? Or should the power cable into the power supply be hardwired.




Many thanks!

[Phil Leigh]

I am still interested in trying a regulated linear power supply for myself and see that Farnell do this :


http://uk.farnell.com/power-one/hb5-...-3a/dp/1208815



* PSU, OPEN FRAME, 5V, 3A
* Power Supply Output Type:Fixed
* No. of Outputs:1
* Output Voltage:5V
* Output Current:3A
* Power Rating:15W
* Input Voltage Range:100V AC / 120V AC / 220V AC / 230V AC / 240V AC
* Length:53.34mm
* Width:101.6mm
* Height:123.7mm
* Approval Bodies:CE / CSA / TUV / UL
* External Depth:53.34mm
* External Length / Height:123.7mm
* External Width:101.6mm
* Max Operating Temperature:50°C
* Max Supply Frequency:63Hz
* Max Supply Voltage:240V
* Min Supply Frequency:47Hz
* Min Supply Voltage:100V
* Min Temperature Operating:0°C
* Mounting Type:Chassis
* Output Type:Fixed
* Power Supply Type:Linear
* Supply Voltage:230V





It looks to be the same as the one in post #24 of this thread by Amuata who is offering two of these units. I am thinking about giving it a whirl but I have a few simple questions if anyone can jump in.


- This is obviously meant to be mounted inside another chassis as it is an open frame design, would any Maplins metal enclosure do?


- What sort of cable should I use for the DC side? Should it be shielded? light gauge? I note the link earlier in the thread for the switchcraft connector, are these soldered?


- Should the AC side involve a power cable that plugs into the power supply and if so what connector would be recommended? Or should the power cable into the power supply be hardwired.




Many thanks!

The DC connector is soldered and you should not use shielded cable - ordinary unshield twin-core will suffice. Anything that can take 5 amps would be fine. The mains should be hardwired with 5 amp 3-core flexible mains cable also.
Alternatively you can use shielded mains cable (the shield of which is connected at the MAINS end ONLY.


Where cables enter the case you need rubber strain relief grommets.

As for the case itself, If you use metal you must connect the case to mains earth via a nut/bolt, fitted with a suitable solder tag and star washer.

Ventilation holes are required.


If I was building this, I would add a ferrite to the DC cable (@ the Touch end) and also fit a mains filter across the mains inside the case, before the PSU and an LED indicator (with dropper resistor - 2-300 ohms should suffice) for power on.

[woodnut]

As for the case itself, If you use metal you must connect the case to mains earth via a nut/bolt, fitted with a suitable solder tag and star washer.

Ventilation holes are required.


If I was building this, I would add a ferrite to the DC cable (@ the Touch end) and also fit a mains filter across the mains inside the case, before the PSU and an LED indicator (with dropper resistor - 2-300 ohms should suffice) for power on.

Many thanks for your reply!

Could I use a plastic enclosure? It may be a little easier to work with if I need to make ventilation holes.

I would be plugging the power supply into my Isotek Minisub GII mains filter so I guess I wouldn't need a mains filter inside the case?

Thanks again!

[Phil Leigh]

Many thanks for your reply!

Could I use a plastic enclosure? It may be a little easier to work with if I need to make ventilation holes.

I would be plugging the power supply into my Isotek Minisub GII mains filter so I guess I wouldn't need a mains filter inside the case?

Thanks again!

The isotek won't block RFI collected by the cable between it and the new PSU. However, IF you use shielded mains cable, you won't need the filter.

Yes you could use plastic (ABS). Probably need to consider siting the PSU well away from other stuff as the plastic won't block the magnetic field of the transformer...

[iPhone]

Many thanks for your reply!

Could I use a plastic enclosure? It may be a little easier to work with if I need to make ventilation holes.

I would be plugging the power supply into my Isotek Minisub GII mains filter so I guess I wouldn't need a mains filter inside the case?

Thanks again!

Question: Why spend $57 on a Power Supply when you already have one (plus the additional cost of end plug, cable, AC lead, enclosure and your time)? Sure it could be a fun hobby project but there is nothing to be gained.

The reason I ask is there is no improvement over the OEM supply because there are internal switchers inside the Touch AFTER the 5 VDC input. I have run the Touch directly off a 6 VDC alarm battery and compared the Audio output to the OEM PS using AudioDiffMaker, there was no difference. Listening tests did not reveal any differences IE all of us heard absolutely no difference much less some night and day difference.

[Mnyb]

Many thanks for your reply!

Could I use a plastic enclosure? It may be a little easier to work with if I need to make ventilation holes.

I would be plugging the power supply into my Isotek Minisub GII mains filter so I guess I wouldn't need a mains filter inside the case?

Thanks again!

I would still suggest a mains filter as you are conecting it in parallell with other stuff on your isotek and it also reduces rfi from the mains cable .
metal box shields even more .

If you got no ground in the outlet where your stereo is ?
Thats one of the cheapest and best upgrades you can ever do.

But it hink grounded outlets are mandatory in for example uk ?

[woodnut]

Thanks again for the replies.


Yes I have read several posts stating that there is nothing to gain but I have also read posts where people have reported gains so I want to see for myself. It is also a nice small project as I am trying to learn more about the basics of power supplies.

All my kit is grounded and there is an earth terminal on the Isotek unit.

I do intend to use a shielded mains cable for the power supply. I think that a metal case is probably best given your advise.

Is there any other components that I would need or any safety points that I should be aware of? I notice that some schematics inclde a slow blow fuse.

[iPhone]

Yes I have read several posts stating that there is nothing to gain but I have also read posts where people have reported gains so I want to see for myself.

Yes you have read those, but not one is backed up with any measurements or data. Just that "They" think its night and day now. If I just spent as much as the Touch costs just for a Power Supply, I might think I heard a Night and Day difference too. Why would you put any stock in statements based on nothing but somebody's impression that is foolish enough to pay hundreds of dollars for an external power supply for a component that only costs $300?

I do intend to use a shielded mains cable for the power supply. I think that a metal case is probably best given your advise.

On any DIY, I prefer a metal case that is grounded so as much interference as possible is taken to ground.

I notice that some schematics inclde a slow blow fuse.

Since its a DIY, you need a fuse for sure. But in my opinion you need a fast blow. At 3 amps on a small regulated supply, there shouldn't be any large inrush of current. Start with a fast blow.

[Phil Leigh]

I would use heatshrink tubing over all of your soldered connections inside the case as an additional safety measure - to make them mechnically secure.