Internal PSU - so space isn't the issue...

[The Elf]

I'm unconvinced it adds much cost. How much of a KT76's 150 quid is the PSU? A tenner?

To every manufacturer reading this: Add 50 quid for an internal PSU and I'll pay it every time.

[The Elf]

Behringer managed to put an internal power supply on their economy DeepMind synth. Did they get enough credit for this?

They did from me! Good on 'em! Even on the budget and diminutive DeepMind 12D and the new lightweight VC340. Great design choice, Behringer!

[Hugh Robjohns]

I'm unconvinced it adds much cost. How much of a KT76's 150 quid is the PSU? A tenner?

It's not just the physical cost of the power supply unit or components, it's also the design time and the testing time -- and all the associated resources. Those have real cost implications and lengthen the time it takes to bring a product to market -- something which is often critical in the more competitive parts of the market.

I'm not trying to defend the use of external PSUs -- I hate them as much as everyone else -- just explain some aspects of the other side of the coin.

To every manufacturer reading this: Add 50 quid for an internal PSU and I'll pay it every time.

Yes, sure, I might too... But how many other potential purchasers would? The vast majority of people seem to prefer to buy from internet box-shifters rather than support their local high-street retail stores just to save significantly less than £50!

H

[Folderol]

That cost is actually a significant over estimate, and I speak from direct personal experience.

I was responsible for the design of an industrial counter system which had to be fully isolated and capable of being powered by mains or 24V AC or DC. I spent very little time on the PSU. I simply allocated a large area on the PCB with a network of pads and trackwork. All that was then necessary was to solder in the appropriate off-the-shelf PCB mountable unit and wire to a standard IEC chassis plug, or required DC connector. This system also future proofed against obsolescence.

The whole area then had a plastic ventilated cover with the usual lightning strike warning. This lot was then inside the overall either plastic or stainless steel case, along with display, switches and connectors for sensors/controllers etc. The PSU modules we used retail for between £15 and £30 for an output drive current range of 1A to 5A at 24VDC. The firm was selling the counter for between £850 and £1200 depending on features.

Finally, dozens of these have been accepted by some of the most critical of all industries, i.e. medical leaflet printers. Their insurers are extremely fussy about both cleanliness and safety.

[James Perrett]

Folderol - did you have to have those units tested by a third party testing house for safety or did you just follow the rules and certify them yourselves? Or does the power supply's certification cover the whole unit? I'm just trying to get some idea of how much bureaucracy is involved.

[Folderol]

All the modules we bought in had multi-region certification (although we were only selling within Europe) and for the mains ones we self certified the wiring between the module and the and the mains chassis plug. The mains cable itself carries it's own certification.

We kept copies of the certification documents of all the modules we used and dated records of which were used in which counters. We CE marked alongside the socket, earthed the steel cased ones and marked the plastic cased ones as double insulated.

One of the pharmaceutical companies did their own checks on the first one we sold to them, and never said a word. We only found out because one of our guys was friends with one of theirs

They were more rigorous over the missing print detector we also made but not regarding safety - blank instruction documents result in serious trouble for everyone concerned.

By the time I retired, much of this was becoming moot, as the machine makers were starting to fit their own camera based systems to almost everything by default, rather than as paid options.

[James Perrett]

All the modules we bought in had multi-region certification (although we were only selling within Europe) and for the mains ones we self certified the wiring between the module and the and the mains chassis plug. The mains cable itself carries it's own certification.

So it would appear that partnering the approved power supply module I linked to above with an approved fused inlet with a suitable PCB layout in between would be sufficient.

[Folderol]

As a qualified employee of an established electronics company, yes.
As a private individual (if intending to sell the complete product) I would suggest getting advice, and at the very least provide a detailed statement as to why you consider the interconnections to be safe, and what protection you have included.
e.g. Do the tags on the socket have insulating boots? How much damage can the outer case sustain without exposing high voltages?
These days you are expected to provide some protection for people servicing the equipment, as well as for ordinary users.

[The Elf]

I'm unconvinced it adds much cost. How much of a KT76's 150 quid is the PSU? A tenner?

It's not just the physical cost of the power supply unit or components, it's also the design time and the testing time -- and all the associated resources...

All included in that tenner - I'm not just assuming the hardware (which is probably 2 quid's-worth!).

I'm not trying to defend the use of external PSUs -- I hate them as much as everyone else -- just explain some aspects of the other side of the coin.

I'm aware, mate. And rightly so - I think you know we're both playing devil's advocate!

The vast majority of people seem to prefer to buy from internet box-shifters rather than support their local high-street retail stores just to save significantly less than £50!

And they will reap what they sow.

Edmund Burke — 'Nobody made a greater mistake than he who did nothing because he could do only a little.'

[ef37a]

Will knows that I hold him and his technical expertise in the highest regard but, his example is rather "industrial".

The murky, cut throat world of domestic/prosumer audio electronics is rather different.
Once you put mains power inside a device that will be built and tested in its tens of thousands on an assembly line by largely non-technical personnel the costs and logistics get sticky.

I do understand the objections of the professionals and working musicians but of course, they only form a tiny part of the buying population and as been said, Peeps want CHEEP!

Just to throw another branch on the fire? I guess nobody wants to go back to captive mains cables? Well, you have to remember to bring the IEC for the amp or clover leaf for the lappy!

Oh! Just come to me. No pro gigs without as much backup as possible ("The Show must..." an all that swaddlin') ? Buy a spare PSU!

Dave.

[BigRedX]

It's all very well telling us to carry spare external PSUs, but the reality of the matter is that if you require something other than the standard 9V DC or USB style PSU, they are expensive and difficult to get hold of even if you go directly to the manufacturer of the equipment in question.

I've just had a look at the various musical devices I have that require external PSUs and there are at least 3 different voltage requirements other than the standard 9V DC and USB.

[ef37a]

It's all very well telling us to carry spare external PSUs, but the reality of the matter is that if you require something other than the standard 9V DC or USB style PSU, they are expensive and difficult to get hold of even if you go directly to the manufacturer of the equipment in question.

I've just had a look at the various musical devices I have that require external PSUs and there are at least 3 different voltage requirements other than the standard 9V DC and USB.

Well yes but, if you check the actual supply voltage and current needed you can usually find a much cheaper replacement online. My F'rite 8i6 is perfectly happy running from a 50 watt 12V monitor supply I had handy!

To me, spares and backup are just part of the job. NOT that I do it anymore!

To respond to the point that "even if Behringer can do it...." ? I have a BCA2000 in the loft. Great concept, good performance, rubbish reliablity and drivers! However it did sport an internal supply.The fact is though, huge companies like Behr' can afford to make their own bespoke SMPS ferrites say) and even if not themselves have SUCH clout that they will not be left in the lurch if a separate supplier wanted to stop production.

"They" do this to "us" you know? A lot of a production manager's time is spent chasing the buggers because they supply a different LED and you cannot know if it will work the same as the original. When you get "global" it becomes a full time freaking nightmare!

Mid sized and smaller concerns go for off the shelf watts because they can get them anywhere and plug 'em in!

Dave.

[The Elf]

I've just had a look at the various musical devices I have that require external PSUs and there are at least 3 different voltage requirements other than the standard 9V DC and USB.

If it were only the Voltage!

I've also taken a quick look around here. I have adaptors here that are...
AC or DC.
Anything from 24V down to 4.5V, I think... Some of them are impossible to read without a microscope.
Anything from 300ma to 2A, even when the Voltage is the same.
Centre-positive and outer positive.
Multipin and simpler 'barrel' connectors, and something that looks like an XLR on steroids. Another would be mistaken for a MIDI plug.
Something that looks like a telephone connector.
At least four different sizes/depths of barrel connectors with/without 'knuckles' - one of them is pin-thin.
USB of various types.

Most of the cables are variously far too short (Zoom LiveTrak by far the worst in this respect)/insanely long (stand up, Digitech RP1000 and RME MADIFace XT). Four of the wall-warts won't permit use of a socket above/left/right of them (I bought a couple of 'wart-friendly' power strips last year for the Christmas tree lights!)...

I should point out that this is after a cull of 'non-critical' gear that uses external PSUs!

I'd defy anyone without a degree in electronics to find many of these 'off the shelf!'

What an utter mess.

[Hugh Robjohns]

In the face of all that, Rane's concept of a universal power supply unit wasn't such a bad idea after all!

[The Elf]

In the face of all that, Rane's concept of a universal power supply unit wasn't such a bad idea after all!

Well I wouldn't say I'd be averse to it, but we already have a universal power supply. It's called a mains plug and an IEC socket! Same connectors, same Voltage/ampage, same polarity, comes in any length and takes only one plug space... Works like a charm!

But this is where we came in, and I haven't seen the horse moving for a while!

[johnny h]

In the face of all that, Rane's concept of a universal power supply unit wasn't such a bad idea after all!

Well I wouldn't say I'd be averse to it, but we already have a universal power supply. It's called a mains plug and an IEC socket! Same connectors, same Voltage/ampage, same polarity, comes in any length and takes only one plug space... Works like a charm!

But this is where we came in, and I haven't seen the horse moving for a while!

To be fair, multi-voltage PSUs with reversible polarities are very common and cheap, and they work well. I always keep a few spare when I'm on the road.

[The Elf]

In the face of all that, Rane's concept of a universal power supply unit wasn't such a bad idea after all!

Well I wouldn't say I'd be averse to it, but we already have a universal power supply. It's called a mains plug and an IEC socket! Same connectors, same Voltage/ampage, same polarity, comes in any length and takes only one plug space... Works like a charm!

But this is where we came in, and I haven't seen the horse moving for a while!

To be fair, multi-voltage PSUs with reversible polarities are very common and cheap, and they work well. I always keep a few spare when I'm on the road.

I have universal supplies too, but they don't always physically fit, and they don't always have enough ampage. They are also often bulky and the cable length is invariably inappropriate.

[ef37a]

I've just had a look at the various musical devices I have that require external PSUs and there are at least 3 different voltage requirements other than the standard 9V DC and USB.

If it were only the Voltage!

I've also taken a quick look around here. I have adaptors here that are...
AC or DC.
Anything from 24V down to 4.5V, I think... Some of them are impossible to read without a microscope.
Anything from 300ma to 2A, even when the Voltage is the same.
Centre-positive and outer positive.
Multipin and simpler 'barrel' connectors, and something that looks like an XLR on steroids. Another would be mistaken for a MIDI plug.
Something that looks like a telephone connector.
At least four different sizes/depths of barrel connectors with/without 'knuckles' - one of them is pin-thin.
USB of various types.

Most of the cables are variously far too short (Zoom LiveTrak by far the worst in this respect)/insanely long (stand up, Digitech RP1000 and RME MADIFace XT). Four of the wall-warts won't permit use of a socket above/left/right of them (I bought a couple of 'wart-friendly' power strips last year for the Christmas tree lights!)...

I should point out that this is after a cull of 'non-critical' gear that uses external PSUs!

I'd defy anyone without a degree in electronics to find many of these 'off the shelf!'

What an utter mess.

Yes indeed and I would be the first one to say "there orta be a law!" The fact is of course YOU bought all that kit with that plethora of supply arrangements.

Perhaps if we all, when looking for a new synth/mixer whatever, TOLD the manufacturer of the one you quite like "I would buy that IF it had an internal mains supply AND I would pay you an extra £50 or so for the convenience". I know that pester power from the consumer does work but of course the vast majority won't pay the excess.

BTW I do not have a degree in electronics (or anything else!) City&Guilds lad me but V and I and watts hardly warrants a doctorate!

Dave.

[The Elf]

Yes indeed and I would be the first one to say "there orta be a law!" The fact is of course YOU bought all that kit with that plethora of supply arrangements.

When you want a Kawai K1r, you just have to put up and shut up!

Perhaps if we all, when looking for a new synth/mixer whatever, TOLD the manufacturer of the one you quite like "I would buy that IF it had an internal mains supply AND I would pay you an extra £50 or so for the convenience".

Tried that. I was on the list for a certain 8000 quid synth. When I discovered it came lumbered with an external PSU (and a bloomin' special one at that!), I offered to pay extra to have a custom version with it mounted internally.
"No way", said they.
"No sale", said I.

They actually thought I was joking...

[Brian M Rose]

"Well I wouldn't say I'd be averse to it, but we already have a universal power supply. It's called a mains plug and an IEC socket! Same connectors, same Voltage/ampage, same polarity, comes in any length and takes only one plug space... Works like a charm!"

Just out of curiosity... When I worked in Broadcast Television, almost all 'glue' equipment had redundant power supplies, typically 2x IEC sockets, so that if power went down, the 2nd power supply would kick in.
OK, very, very expensive, but obliviously a television station or for that matter an OB simply HAS to stay on-air. Now I realise that live music and home studios may not have quite the same requirements; or do they?
At Radio Harrow our 10 year old B******r Headphone Amp went Awol. Just under £100 to replace which frankly was not bad (it was just an annoyance rather than a disaster). But for everyone - just how important is reliability?

[ef37a]

Yes indeed and I would be the first one to say "there orta be a law!" The fact is of course YOU bought all that kit with that plethora of supply arrangements.

When you want a Kawai K1r, you just have to put up and shut up!

Perhaps if we all, when looking for a new synth/mixer whatever, TOLD the manufacturer of the one you quite like "I would buy that IF it had an internal mains supply AND I would pay you an extra £50 or so for the convenience".

Tried that. I was on the list for a certain 8000 quid synth. When I discovered it came lumbered with an external PSU (and a bloomin' special one at that!), I offered to pay extra to have a custom version with it mounted internally.
"No way", said they.
"No sale", said I.

They actually thought I was joking...

Good for you Elf but of course, no manfctr is going to make a special for one customer, my point was that if enough people tell them what they want they might change the next design? Mind you, like taxes, what people SAY they will pay for services and what they actually vote for can be very different things!

The problem is the design of products, especially something as mind bogglingly complex as a £8k synth! is a very protracted process and lead times on components can be a total PITA. To have a DC powered, non-lethal prototype up and running to impress the boss is very attractive and if Marketing then put their oar in and say "we want it in the shops in six months", slapping an external supply on it is often the only way out.

And! I am sure it had happened that someone cocked up and a company is lumbered with 100,000 12V 2A line lumps. The design guys in the dungeon are then told "Most of what you think up next MUST run on one of these". !!

Dave.

[Folderol]

In the face of all that, Rane's concept of a universal power supply unit wasn't such a bad idea after all!

Well I wouldn't say I'd be averse to it, but we already have a universal power supply. It's called a mains plug and an IEC socket! Same connectors, same Voltage/ampage, same polarity, comes in any length and takes only one plug space... Works like a charm!

But this is where we came in, and I haven't seen the horse moving for a while!

To be fair, multi-voltage PSUs with reversible polarities are very common and cheap, and they work well. I always keep a few spare when I'm on the road.

I have universal supplies too, but they don't always physically fit, and they don't always have enough ampage. They are also often bulky and the cable length is invariably inappropriate.

They are also potential kit murders
Who can honestly say they have never plugged one in with the wrong voltage/polarity? It is especially easy to do in precisely the gig situation.

[ef37a]

In the face of all that, Rane's concept of a universal power supply unit wasn't such a bad idea after all!

Well I wouldn't say I'd be averse to it, but we already have a universal power supply. It's called a mains plug and an IEC socket! Same connectors, same Voltage/ampage, same polarity, comes in any length and takes only one plug space... Works like a charm!

But this is where we came in, and I haven't seen the horse moving for a while!

To be fair, multi-voltage PSUs with reversible polarities are very common and cheap, and they work well. I always keep a few spare when I'm on the road.

I have universal supplies too, but they don't always physically fit, and they don't always have enough ampage. They are also often bulky and the cable length is invariably inappropriate.

There are also potential kit murders
Who can honestly say they have never plugged one in with the wrong voltage/polarity? it is especially easy to do in precisely the gig situation.

Part of the legislation for standard supplies I would like to see would also include a requirement for equipment to be polarity protected or even not care! But once again it comes down to money. A simple series diode will suffice in many cases but degrades the supply's regulation and so a big cap is needed post diode (though many G pedal makers don't seem to bother!) A full bridge will need the supply to be a bit higher to cover the diode drops but then I see equipment using internal DC-DC converters and these have very good regulation.

Anything is possible if you can persuade the punter to pay. I know of valve equipment that is a bit "over-engineered" such that a valve flash over does not destroy other components and burn holes in the print but such hidden measures make the retail cost rather uncompetitive.

Dave.

[Hugh Robjohns]

...no manfctr is going to make a special for one customer...

Some will and do. Drawmer made a special custom version of the A2D2 A-D converter for me, for example (the LED meter colours are different to the standard model), and I know of a few other small manufacturers that will do custom mods where it is reasonably practical as a one off. And there are other companies where everything they make is semi-bespoke -- like Crookwood and others. But you're right in that it ain't gonna happen with a large mass-producing manufacturer.

H

[ef37a]

...no manfctr is going to make a special for one customer...

Some will and do. Drawmer made a special custom version of the A2D2 A-D converter for me, for example (the LED meter colours are different to the standard model), and I know of a few other small manufacturers that will do custom mods where it is reasonably practical as a one off. And there are other companies where everything they make is semi-bespoke -- like Crookwood and others. But you're right in that it ain't gonna happen with a large mass-producing manufacturer.

H

Ha! Bet they would not have done it for me! It can be a dangerous practice commercially. I was with a company and the MD had friends I think in the network industry and we often had odd jobs to build. Sometimes just wiring up a rack unit and testing* the result. Stock outlets and racks went out "empty" for the customer to wire. Sometimes he had bespoke metalwork made and coated, short runs of 20 or so boxes. All this stopped when the company changed hands. Word was these favours were in danger of sinking the company.

*That was an iterative process! Just one wire (of 96 pairs) in the wrong IDC slot and back to the bench, often more than once.

Dave.