Get 4.5V from 9V OneSpot?

[reTrEaD]

- both input and output caps are .1uF (i might have made a mistake ordering..)

=> is this a concern? is this creating more heat?

I would guess no, but if you have some extras you can parallel two or three capacitors on the input.

[strat80hm]

Oct 2, 2016 22:16:49 GMT -5 reTrEaD said:

- both input and output caps are .1uF (i might have made a mistake ordering..)

=> is this a concern? is this creating more heat?

I would guess no, but if you have some extras you can parallel two or three capacitors on the input.

That sounds like a plan - yes i ordered a couple of extra-everything so that d work.
Thank you for a good tip! I ll just do that

Currently trying to come up with a elegant way to solder all that together in a tight/smart way - i m thinking inside the angle of an aluminum profile corner (about 1 or 2 inch long, that d second as an additional heat sink as well)

[ashcatlt]

If you can touch it with your fingers, it's not going to burn the plastic. Stick it in the battery compartment and then you should be able to wire it directly to the battery terminals and be ready to go.

[strat80hm]

So you mean that the 220TO wont get any warmer than that?
Well in this case the inside-battery-compartment idea might be a real possibility..

[ashcatlt]

Well I don't have much practical experience with those things, but you said you ran it for hours, so...

I think the reasons they didn't put their own regulator in that box (and run off 9VDC like everybody else) were 1) To save a little space and B) To pick up a few extra dollars in accessory sales.

It might be interesting to stick a 10K pot in series with the 4.5V hot and just see how much resistance it takes to turn it off. Would help answer some of the questions from earlier in the thread.

[strat80hm]

Well I don't have much practical experience with those things, but you said you ran it for hours, so...

It s quite hot to the touch - not sure wether or not that d be enough to melt down plastic..

I think the reasons they didn't put their own regulator in that box (and run off 9VDC like everybody else) were 1) To save a little space and B) To pick up a few extra dollars in accessory sales.

I m with you, the Apple way... (http://guitarnuts2.proboards.com/thread/4526/folks-martin-lost-minds?page=1&scrollTo=78733)
Choosing 4.5V for a guitar device is really twisted i think.

It might be interesting to stick a 10K pot in series with the 4.5V hot and just see how much resistance it takes to turn it off. Would help answer some of the questions from earlier in the thread.

Let me rephrase this idea:
- connecting a 10K pot in serie at the 4.5V output
- turning the pot off till the PX4 shuts down
Did i get it right?

(note: all the pots i have are 250 or 500, 10K are the super small thing right?

[newey]

(note: all the pots i have are 250 or 500, 10K are the super small thing right?

For use in your guitars, I assume you mean you have 250K and 500K pots. 10K is a much smaller value, but is not necessarily a smaller unit physically. If you're thinking of the little trimpots that mount to PCBs, one of those can probably be had in 10K, but you can also find 10K pots of the same physical size as ordinary guitar pots.

[strat80hm]

For use in your guitars, I assume you mean you have 250K and 500K pots. 10K is a much smaller value, but is not necessarily a smaller unit physically. If you're thinking of the little trimpots that mount to PCBs, one of those can probably be had in 10K, but you can also find 10K pots of the same physical size as ordinary guitar pots.

Ok. Indeed i only have guitar pots 250/500K

It might be interesting to stick a 10K pot in series with the 4.5V hot and just see how much resistance it takes to turn it off. Would help answer some of the questions from earlier in the thread.

I tried with a 500K pot anyway - i could measure that at about 0.700K resistance, the PX4 would turn off: does this answer any question?


Then some smoke started to come from the pot so stopped it all - pot is probably fried (Resistance now ranges from 500K to 170K, doesnt go any lower anymore)

[strat80hm]

It might be interesting to stick a 10K pot in series with the 4.5V hot and just see how much resistance it takes to turn it off. Would help answer some of the questions from earlier in the thread.

I tried with a 500K pot anyway - i could measure that at about 0.700K resistance, the PX4 would turn off: does this answer any question? - then some smoke started to come from the pot so stopped it all - pot is probably fried (Resistance now ranges from 500K to 170K, doesnt go any lower anymore)

Is this possible that i fried more than the pot while doing that little experimentation above?

Ever since, the TO220 becomes crazy hot when fed with the 9V - and doesnt turn on the PX4 anymore (which still works with charger though) - Ok, gonna redo the entire thing with new components and see..

[ashcatlt]

TBH, I was a little afraid you might exceed the power rating of the pot, so I did some "napkin" calculations, but ended up deciding it probably wouldn't. Even if the full 4.5V is dropping across the pot (it's not) 4.5^2 / 700 isn't enough to worry about.

Now when I said "pot" I meant "variable resistor". You didn't set it up as a voltage divider? There is a way that you could wire that which could burn the pot, and I guess maybe the regulator also.

[strat80hm]

Apparently i just damaged the pot - all the rest is intact

I re-did the circuit - all is working fine! Used 2 inches of aluminum 90 degree-angled profile as a heat sink and the whole thing fits nicely inside the loop-switcher

=> I finally have a full system with one charger!

Thank you so much everyone for support, knowledge and expertise, much much appreciated!

[col]

Sept 21, 2016 18:09:19 GMT -5 cynical1 said:

Sept 21, 2016 16:09:25 GMT -5 col said:

You see...I was right!

Words David Cameron hopes to use in a sentence one day...

HTC1

A bit late, and I'm not sure of your point about Cameron (and it is probably best to avoid politics here). But, suffice to say, I did not like Cameron one little bit. The problem is, his successor is even worse. I am very worried for the future of ol' Blighty.

[cynical1]

Oct 21, 2016 22:23:22 GMT -5 col said:

...and I'm not sure of your point about Cameron...

Sarcasm. Nothing more. Voltaire said it better: "Those who can make you believe absurdities can make you commit atrocities."

HTC1

[col]

Oct 22, 2016 14:51:46 GMT -5 cynical1 said:

Oct 21, 2016 22:23:22 GMT -5 col said:

...and I'm not sure of your point about Cameron...

Sarcasm. Nothing more. Voltaire said it better: "Those who can make you believe absurdities can make you commit atrocities."

HTC1

Well, if you are referring to Brexit (seems that you must be), Cameron was never in favour of it, and only offered the referendum as an election ploy, never believing it would result in a 'yes' vote. He gambled the future of the UK against his reelection. He won - the UK lost.

It is possible to construct an argument for the UK not being in the EU, but it is leaving for the worst possible reasons, and at the worst possible time. I dread to think about the future of the UK (which might even end up as just England and Wales because of this). The question of what to do about Ireland is a huge unknown - and the majority of Scots will want out of the UK after this. But I am really taking about the United Kingdom's financial future. It looks bleak right now, and they haven't even pulled the trigger as yet (invocation of article 50).

Interesting times, C1.

[cynical1]

Yeah, I was referring to Brexit. The BBC has done a great job detailing all players along with all the ins and outs. I really didn't think the Yes coalition would be able to pull it off, but that's probably why I'm not a betting man.

It's somewhat ironic that Churchill was an very early proponent of a European Union and it's the UK that leaves first once it becomes a reality. Not casting aspersions, just saying... Hell, I still wonder if Greece wouldn't have been in a stronger position if they had actually left.

The EU has as much to worry about as the UK in this. I can't help but think the $14bn slap on the wrist the US gave to Deutsche Bank wasn't a shot over the bow to Merkel that Brexit needs to be less punitive than their rhetoric was implying. Take heart, if China's economic contraction continues Brexit will seem like a bad day at the track.

I wish you guys the best.

Happy Trails -

Cynical One