Someone just sent me a private message and asked a very good question.
One I have to admit did absolutely not occur to me: Is there a PCB included in the kit?
SO FAR, I HAD NOT INCLUDED THE PCB ! ! !
If anybody needs one, you can still order them through Ollie's groupbuy for the PCBs.
You can then ask him to just throw them into my shipment.
That way Ollie (and you) can save on the shipping costs.
Sorry if there was any misunderstanding about this!
I'll write everybody that has posted in this thread a message today about the matter.
Since the PCB's are going through one extra round of validation for the new design, we are not time-constrained.
One I have to admit did absolutely not occur to me: Is there a PCB included in the kit?
SO FAR, I HAD NOT INCLUDED THE PCB ! ! !
If anybody needs one, you can still order them through Ollie's groupbuy for the PCBs.
You can then ask him to just throw them into my shipment.
That way Ollie (and you) can save on the shipping costs.
Sorry if there was any misunderstanding about this!
I'll write everybody that has posted in this thread a message today about the matter.
Since the PCB's are going through one extra round of validation for the new design, we are not time-constrained.
Ive just found a transfo in my house :
EXTEL Transformateur 220V 12V K146 20VA 50/60Hz
will it work ? I guess i'm still in for the plug though.
EXTEL Transformateur 220V 12V K146 20VA 50/60Hz
will it work ? I guess i'm still in for the plug though.
Ayayay!
If this is really what you have at home... no.
Those on eBay are all 12V DC -> 220V AC!
You need 220V AC -> 12V AC!
AC/AC good - AC/DC bad...
edit: you need something like a halogen-transformer. just in an enclosure with some cables...
220V AC -> 12V AC
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@ Jokener: Great that you have found another transformer. But I guess it's still possible to order the cheap Mouser variant as an extra, right?
Does it make sense to switch my PCB's group order shippping adress to yours?
It's just that Ollie would have to change the spreadsheet again, and postage was already covered anyway, you know?
If it makes Ollies or your life easier, I'll gladly do it though.
Does it make sense to switch my PCB's group order shippping adress to yours?
It's just that Ollie would have to change the spreadsheet again, and postage was already covered anyway, you know?
If it makes Ollies or your life easier, I'll gladly do it though.
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The Mouser wall transformers, like the WAU12-200, are all 120 VAC input. They won't work in Europe without a 230 -> 120 VAC adapter transformer. You want something like this:
AC-1250EU
Farnell only shows 49 in stock. Are there more than 49 O2 builders in Europe?
This would also work but has the UK plug so you would need a UK -> Euro adapter:
AC-12100BS2.1
Also I will add a link to this thread in the O2 Resources section.
AC-1250EU
Farnell only shows 49 in stock. Are there more than 49 O2 builders in Europe?
This would also work but has the UK plug so you would need a UK -> Euro adapter:
AC-12100BS2.1
Also I will add a link to this thread in the O2 Resources section.
Of course I can ship you the Mouser part.
But the one you have selected is for 120V only.
Most countries have the superior (^^) 230 Volts.
So there should be quite a few potential buyers for the 230->12V transformer...
Edit: oops... RocketScientist was faster... What a surprise ^^
But the one you have selected is for 120V only.
Most countries have the superior (^^) 230 Volts.
So there should be quite a few potential buyers for the 230->12V transformer...
Edit: oops... RocketScientist was faster... What a surprise ^^
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Aah, thanks so much. Yes of course. I didn't have a look at the exact specifications of the transformer so that part just went unnoticed.
Living in Germany I'm gonna need a 230 V tranformer
So if you've already got the 120 V transformer in your spreadsheet for me, could you please cancel it?
Thanks guys
Living in Germany I'm gonna need a 230 V tranformer
So if you've already got the 120 V transformer in your spreadsheet for me, could you please cancel it?
Thanks guys
Ayayay!
If this is really what you have at home... no.
Those on eBay are all 12V DC -> 220V AC!
You need 220V AC -> 12V AC!
AC/AC good - AC/DC bad...
edit: you need something like a halogen-transformer. just in an enclosure with some cables...
220V AC -> 12V AC
I'm pretty sure it's an AC to AC that i have.
[image]http://www.maisonbleuet.com/565-626...nder-une-gache-ou-une-serrure-electrique-.jpg[/image]
Now i'm a bit worried about Jokener saying transfo should be used at least 50% load...
This is the right one. The one the picture has 15VA, the one you mentioned above 20VA (EXTEL Transformateur 220V 12V K146 20VA 50/60Hz), both of them are fine. You need just something > 8VA (i read somewhere the O2 need 4VA)...
In the "documentation package" there is a comment that states "min. 2.4VA" (or rather min. 200 mA, at 12V that equates to 2.4VA).
But I don't know what an O2 consumes during "typical" operation, in idle or when under maximum load...
And I am an engineer, but by no means of the electrical type but rather the mechanical/automotive kind.
So when a professor tells me "a trafo should be operated between 50 and 80% load" I can only restate that claim and add that I have no clue about its validity.
It might even be from an energy consumption standpoint, which I don't care about...
I'll shoot Rocket a message to clarify.
The AC/AC transformer I have available is of course in a housing (as mentioned, sealed for marine type of operations) and with the Euro-plug on the primary (230V) cable.
That makes it ideal for the majority of us and allows everybody else to buy a new plug (UK or whatever) for 2€ and you're golden again...
But I don't know what an O2 consumes during "typical" operation, in idle or when under maximum load...
And I am an engineer, but by no means of the electrical type but rather the mechanical/automotive kind.
So when a professor tells me "a trafo should be operated between 50 and 80% load" I can only restate that claim and add that I have no clue about its validity.
It might even be from an energy consumption standpoint, which I don't care about...
I'll shoot Rocket a message to clarify.
The AC/AC transformer I have available is of course in a housing (as mentioned, sealed for marine type of operations) and with the Euro-plug on the primary (230V) cable.
That makes it ideal for the majority of us and allows everybody else to buy a new plug (UK or whatever) for 2€ and you're golden again...
Thank you. Having a 50Hz transformer is cumbersome and heavy.
I'm thinking of just connecting a cheap Chinese switching adapter (>12V) by just removing the output rectifying diodes.
The 1N4002 in your circuit should be replaced with fast Schottky ones and maybe decoupling caps should paralleled to the existing ones.
Or, I could just make a -12V switching supply inside the circuit (on the areas reserved for the batteries), so that I could just feed it 12V DC from a cheap Chinese switching adaptor.
What do you think ?
Fireworks, please read about the power supply under Circuit Description
The O2 generates TWO power supplies from the AC input. If you want to use a DC adapter, you would need two of them--one for each rail. There is no way a single DC adapter will work unless you put a bipolar DC-DC converter in the O2.
It was a major design goal of the O2 to use the AC-input power supply as it keeps the price down and allows using a real ground and true bipolar DC power supply to power the audio circuits. The AC-AC adapters are small, cheap, light and readily available in the USA.
And Schottky diodes cannot handle the peak voltages involved if someone uses a 20 VAC adapter. That's why they're 1N4002 diodes. Bypassing them with caps does not change the already extremely good noise performance.
The O2 generates TWO power supplies from the AC input. If you want to use a DC adapter, you would need two of them--one for each rail. There is no way a single DC adapter will work unless you put a bipolar DC-DC converter in the O2.
It was a major design goal of the O2 to use the AC-input power supply as it keeps the price down and allows using a real ground and true bipolar DC power supply to power the audio circuits. The AC-AC adapters are small, cheap, light and readily available in the USA.
And Schottky diodes cannot handle the peak voltages involved if someone uses a 20 VAC adapter. That's why they're 1N4002 diodes. Bypassing them with caps does not change the already extremely good noise performance.
I looked at the schematics and everything is clear.
I know that. What I was suggesting was to MODIFY a switching DC adapter by REMOVING the rectifiers (and caps., etc.) thus transforming it into an AC suppply (a high frequency one).
Well, the Chinese AC-DC supplies (12V, 1A) on Ebay are $2-3 including shipping and probably much lighter than any 50Hz transformer of comparable power.
At the end of the day, you can play with your toys any way you please.
But I'd strongly recommend you start by following RocketScientists specs.
If you decide he has no clue what audio is about, you can still tinker with the O2...
But my point would be a different one: Do you really want to put your faith in something that comes out of china?
Seriously. If there is not a boatload of QC/QA involved, I keep my hands away from the stuff.
Because I definately do NOT want to put my O2, my 500$ headphones and my EARS behind a chinese psu.
Just my 2 cents.
But I'd strongly recommend you start by following RocketScientists specs.
If you decide he has no clue what audio is about, you can still tinker with the O2...
But my point would be a different one: Do you really want to put your faith in something that comes out of china?
Seriously. If there is not a boatload of QC/QA involved, I keep my hands away from the stuff.
Because I definately do NOT want to put my O2, my 500$ headphones and my EARS behind a chinese psu.
Just my 2 cents.
Ah! I thought you meant remove the rectifiers in the O2. I keep getting requests about how to use a DC adapter.
It's an interesting idea but proceed at your own risk. The RFI you would get from the cable would be huge as it's basically a square waveform loaded with harmonics. Plus the feedback (regulation) in the adapter depends on DC.
An ungregulated one might work, but hacking a 230 VAC adapter is not something I can endorse. If someone made an error they could end up with 230 VAC into their O2. There's enough to go wrong already without turning the power supply into a big unknown.
The ones with safety approval are also supposed to be sealed shut so you have to break the case to get inside.
I wouldn't fret too much about where my stuff comes from (for example China). But modifying a small plug-type SMPS is a bad idea for several reasons. First, these small thingies are often of the flyback type, which does not allow a symmetrical rectification. The idea simply won't work in this case. Secondly, these thingies use a feedback loop on secondary DC, which when removed allows the voltage to rise without control until something pops, unless the feedback loop is somehow restored. Thirdly, as RS already mentioned, the problem of transporting the 100 kHz to the O2 will give you quite an EMI challenge. Getting this to work at all is very tricky.
Besides this, these adapters are extremely dangerous when opened, as it is often unclear which parts of the board are harmless and which ones are live. Even when unplugged, they contain a dangerous voltage for a long time, because bleeder resistors are often omitted in order to save one or two cents. In this light, cumbersome and heavy doesn't seem like a just qualification for a conventional transformer at all.
Besides this, these adapters are extremely dangerous when opened, as it is often unclear which parts of the board are harmless and which ones are live. Even when unplugged, they contain a dangerous voltage for a long time, because bleeder resistors are often omitted in order to save one or two cents. In this light, cumbersome and heavy doesn't seem like a just qualification for a conventional transformer at all.
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