Converting 9VAC to 9VDC

[Cortexturizer]

And D5 stays, right?
Can't believe I'm gonna have to order only one part and pay the shipping that could have bought 5 those parts...
Would it be particularly stupid if I was to put a 12 or 15V version (those I can get in my city) and then 7809 from there? Would 7809-ing after it limit the amount of current (I see from the datasheet that the available current is around 1A), or reintroduce ripple or something...I reckon not. It would call for another part in a low-parts-level plan, but hey...

[Thomas_H]

Yes, D5 stays.
But i dont understand what you are trying to tell me with using a 12/15v version and later replacing it with the 9v version?

You cannot use a version that is designed for higher voltages as it would not be able to work with an AC input too low.

[Cortexturizer]

No, I meant, after using all the benefits of the LDO (it is unfortunate that I can only get a 12 or 15V version of it) regulate to 9V using the 7809. My question was, would that work. Obviously, it's a workaround, but I'm not paying 20 euros for shipping a 1,3e part.

[Thomas_H]

But you have 9V AC, right ?

Can you get a 5V 2940 ?  You only would need 4x 1N4001 diodes to make it a 9V regulator. I can show you how.

[Cortexturizer]

Yes! I can get the 5V version. Just note that I'm gonna power a digital device (EHX Freeze) that draws around 170 mA. Would your design deliver clean enough power? I surely hope it would!

[Vallhagen]

P.S. Vallhagen my man did you ever receive that pcb and transistor I've sent you during the PIF rounds?

Man, my man, oh i'm SORRY that i didn't come back to you when it was on the carpet (or in the mirror;) ). It got lost between things i guess, but your worth a big thanx. I shall not miss such things. Yes i received that great package! Thanx a zillion! Somewhere along the line i will come up with some finnished builds!

Cheers! And thanx again!

(and to all others; sorry for OT)

[Cortexturizer]

Oh come on it wasn't a big thing, no need for all the thankyou's I was just wondering for the longest time whether you'd got it. Cheers!

[Thomas_H]

Yes! I can get the 5V version. Just note that I'm gonna power a digital device (EHX Freeze) that draws around 170 mA. Would your design deliver clean enough power? I surely hope it would!

It does:-)

To bring up the reg voltage you need to have additional 4V to between the regulator and ground. To do that you only need to put 4x1N4001 in series. They usually have a forward voltage of max. 1.1V, so this should be easy.
I would meassure the Vf of each diode to be close to 1V if possible. If you cannot get the 1V you now know the princliple and try other diodes you might have. (250mA min. in your case)

[RobA]

Don't the 2940 types typically only give 100mA?

Are you trying to avoid SMD? How small do you want the adapter to be? How fast do you need it?

I asked that last question because I'm just about to have to place an order to Mouser myself because I just discovered I don't have the voltage regulator for the Flintlock flanger (damn!). If we can figure out what to get you parts wise, I can put them in my order and then post them to you.

[RobA]

Yes! I can get the 5V version. Just note that I'm gonna power a digital device (EHX Freeze) that draws around 170 mA. Would your design deliver clean enough power? I surely hope it would!

It does:-)

To bring up the reg voltage you need to have additional 4V to between the regulator and ground. To do that you only need to put 4x1N4001 in series. They usually have a forward voltage of max. 1.1V, so this should be easy.
I would meassure the Vf of each diode to be close to 1V if possible. If you cannot get the 1V you now know the princliple and try other diodes you might have. (250mA min. in your case)

That's a good idea. You could do it with a Zener voltage regulator too since you know about the max power. They can be a bit dirty, but I saw a design a bit ago for getting clean power out of one and it was pretty simple.

Edit: Oh, and there are LM2940's I've seen that have higher current capability in the 5V types.

[Thomas_H]

RoB,  2940 is a TO220 device with 1A
I personally would not do a Zener regulation for this task.

[RobA]

RoB,  2940 is a TO220 device with 1A
I personally would not do a Zener regulation for this task.

Yeah, I was looking on Mouser here and had restricted my search to SMD because of the above mentioned thought of making it tiny. You are right though, in the TO-220, you can get them with higher output current.

Mouser here does have 1A 5V LDO's using SOT-223 as well.

Normally, I'd agree with you about Zener based regulators, but this idea looked cool and came with graphs of noise figures and such, so it looked fun. . I'll find a link if I can and put it up just for interest.

The other thing that was in my mind that might make the Zener regulator feasible is the I think from the gut shots I saw, the EHX Freeze may have a pretty good regulator setup on it's power input itself.

[RobA]

My "Electronics" bookmarks section in my browser is too big. It took me way too much time to find this link. I think I need to organize.

Anyway, here's the link to the Zener based guy I mentioned. (The page has various others too). I'm not saying that this is the way to go, but it is an interesting read.

http://www.tnt-audio.com/clinica/regulators_noise3_e.html

I played with it and it works well. But in the end, I went with using a TPS7A49xx regulator for the project I'm working on.

[Cortexturizer]

Guys...this is outstanding! Thanks a million Thomas! Great idea.
This hopefully solves all my problems. Man I'd buy you a beer right now. Gonna use your design asap, probably not today though, but as soon as, and report here. Awesome.

And RobA, thanks for wanting to include the 9V version into your order, what a nice move, thanks man. I appreciate it.

[RobA]

Guys...this is outstanding! Thanks a million Thomas! Great idea.
This hopefully solves all my problems. Man I'd buy you a beer right now. Gonna use your design asap, probably not today though, but as soon as, and report here. Awesome.

And RobA, thanks for wanting to include the 9V version into your order, what a nice move, thanks man. I appreciate it.

No big deal really and I'd still be glad to do it, but I think Thomas will have you up and running far faster than I could. Cheers and I'd like to hear what you think of the Freeze when you get to play with it. It's a tempting looking pedal.