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Anyone own a Pyp PB-1 battery amp?

Started by darwindeathcat, October 05, 2011, 02:13:44 PM

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darwindeathcat

Hi all! I just picked up a Pyp PB-1 (http://pyp-bomb.com/home.html) for cheap ($40) in a craigslist deal, but the only catch was that the guy had lost the wall wart adapter needed to charge the damn thing! So, I was hoping one of you lovely people might own one and could tell me the specs on the charger? I looked on the website and in the manual, and it seems they don't list the specs anywhere. I also sent an e-mail to the Pyp Bomb people, but haven't gotten a response. So, you guys are my only hope!

FWIW, I've got an adapter that charges my spotlight, which is also powered by a 12v sealed lead acid battery. The specs on that wall wart are 12v, 300 Ma, center negative. The barrel plug fits the power jack on the back of the PB-1, but I'd like to confirm that the specs match before giving it a try!

Thanks for any help you can give!
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J M Fahey

#1
The only "Pyp" I know is a certain Philip Pirrip from Dicken's "Great Expectations"  :P
I think if plug polarity matches , your charger should work ... although 300mA will take almost 24 H to charge.
Worst case, wire red and black crocodile clips to your charger and charge the battery directly, that should avoid connector hassles and doubts.
If the amp spent a long time discharged, consider the battery shot.
EDIT Ithink you will need a 20V DC 1A charger, proper plug polarity of course.
Or open it and go the crocodile way.

darwindeathcat

Thanks JM, that's really helpful! I'll probably try to the crocodile clip method for now, as I know the battery is getting near the "dangerously low" level and I don't want sulfation to occur!  The previous owner said that it had been "several months" since it had been charged. It wasn't totally drained, as I could still play it a bit, but there was some oscillation occuring, which the manual says occurs when the battery is really drained. The manual hints that the unit has a "smart charger". Does that make any difference in terms of the type of transformer I need to use? Is this why you added the edit to recommend a 20v DC 1A charger?

Cheers,

DDC
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J M Fahey

Yes, when I read the smart charger bit.
Download and study the Fender Amp Can schematic.
It also uses an SLA Battery and a smart charger, basically an LM 7815 with a series 1A diode.
Very clever: short proof, won't supply more than 1A to the battery, won't go over 15-0.7=14.3V (car regulators are set at 14.4V), CHEAP.
My only doubt would be whether it's built into the charger wall wart, or into the Pyp itself.
In any case you need about 20VDC unregulated before the 7815 to make it happy.
Hand draw and post the charge connector to battery terminals wiring to check which is the case.
In any case, you can use the crocodile direct method, even adding a couple external terminals to avoid opening it all the time.
Just make SURE they can never be`shorted, or it will turn into a real pipe bomb, no kidding.

darwindeathcat

Thanks! I'll have a look "under the hood" this evening, and let you know what i find!
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darwindeathcat

Okay, I had a look under the hood, and it looks like it has the regulator circuit on the board. I drew a little schematic of what I saw and am attaching it to this post. Looks like the regulator is an LM317. If need be I can track down a datasheet for this chip, but if you know off the top of your head what voltage I can apply to it, that would be awesome! The battery is labeled UB1213, which google tells me is a 12v, 1.2Ah SLA.

Cheers,

DDC

PS, I'm also attaching a "gut shot" of the whole board. I can't read the name of the amplifier IC, but judging by the size of the heatsink, it's probably a class D chip. Looks like the preamp is built around a TL082 opamp
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J M Fahey

Good.
Just what I expected.
They are using the LM317 as an adjustable version of my humble LM7815, I bet you have`between 14 and 15V anyway on pin 3, before the diode.
You still need a 20/22V DC power pac k, easily built with a 16 to 18V transformer, 1A`rated , and any diode bridge, 1.5A or more.
It should have its own 2200x25V capacitor, which will end being in parallel with the internal one.
Good luck.

darwindeathcat

Great! Thanks a lot for all the help! Looks I'm heading down to goodwill to sort through their pile of wall warts again! I should definitely be able to find one with those specs. Worst comes to worst, I have several raw transformers in the 16-18v range, as well as several diode bridges and even the correct value filter cap, so I could brew my own!

Cheers,

DDC
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joecool85

Keep us posted, sounds like a fun project.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

darwindeathcat

Well, I  just got back from the Goodwill, and the closest wall wart I found is 20v DC, but only rated for 500Ma. I bought it anyway (it was only 99 cents). Will I be able to use this adapter? If the only ramification is increased charging time, I can live with that (until I find a higher wattage adapter), but if there will be too much current draw for this transformer, I don't want to risk damage to the circuit.

And, yes, I know I'm being a bit lazy by not building one myself to spec, but the simple fact is that I AM lazy (;D), so I'd like to take the laziest route possible!  ;)

Thanks for all your help!!!!
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J M Fahey

Well, I'm lazy too, which usually means I have to work double because of not doing it right the first time.
Just wire the proper plug there (triple check) and plug it in, keeping a finger on it every 10 minutes for the first hour.
If no undue overheating, funny smells, etc. ... you're set.

darwindeathcat

Thanks again for the good common sense advice. I'll do just that and then keep you updated!

~DDC
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darwindeathcat

#12
Just a quick update: I've got the adapter hooked up to the input of the "smart charging" circuit using test leads (the plug wasn't exactly correct for the jack). Prior to connection, the battery was reading 12.2v (which is low, but not in the "danger zone" for SLA), and the adapter was reading 26v just hanging unconnected in mid-air. Connected to the circuit, the output of the adapter reads 18 volts, and the voltage at the battery terminals is 15v. All that seems pretty good to me. I can't get a DC current reading, however (but that may be a problem with my crappy multimeter). So far, I'm ten minutes in and don't have any heating or odd smells! Hopefully this works out!

EDIT: A couple hours have passed, and the wall wart is barely warm to the touch. No heating of the battery, and everything seems ok. Voltage at adapter output reads 24v now, and voltage at battery leads reads 14.2v. Seems to be going okay. I'll leave it for several more hours and then disconnect and then check the battery voltage.
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darwindeathcat

Well, I let it charge for about 8 hours. The battery voltage now reads 13.25, which is about 2.2v per cell, which I think is good. It seems that it all worked out! Thanks guys, for all your help!

If anyone is interested in hearing sound samples of this amp, let me know and I can make some...

~DDC
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J M Fahey

Looks good, I think you're set.
As of your music samples, feel free to post them.
We're curious about your PYP amp.