Happy Jack Posted August 1, 2020 Share Posted August 1, 2020 I've been rehearsing with both my bands out in the woods. It's been a lot of fun and a great opportunity to get back up to speed on DB, but some of the stuff we play simply won't work on DB and I need to play electric bass - with the covers band a good example would be Won't Get Fooled Again, with the rockabilly outfit an equally good example would be Summertime Blues. So here's the solution: Battery Pack --> DC-powered micro-head --> small bass cab. And it works, Well, it works but with wrinkles and I don't understand what's going on. Informed advice would be most welcome. First, the building blocks. Battery pack = https://www.woodbrass.com/accessoires-amplis-et-effets-pedalboards-boxking-rechargeable-pedal-power-supply-12800mah-p303438.html Micro-head = https://www.thomann.de/gb/hotone_nano_legacy_thunder_bass.htm Small bass cab = EITHER http://www.gigmaster.biz/gigmaster_soundworks_v4_008.htm OR https://www.db-bass.com/product-page/embee-1210 and that's where the fun starts. I started by using a https://www.amazon.co.uk/Sanyo-eneloop-Pedal-Juice-battery/dp/B007BZAGW4 which I already had knocking about. Great device with little to criticise except that it only has 9V outlets and the Hotone Thunder Bass needs 18V. Luckily anough, another useful device that I had knocking about was a https://www.andertons.co.uk/truetone-voltage-doubler-24v-or-18v-tt-tvd?utm_source=google&utm_medium=organic&utm_campaign=surfaces&gclid=Cj0KCQjwpZT5BRCdARIsAGEX0znb8Zrf0UBw5NvtqH0LfHrsiBfeJ08HwI9rCH3nAbt0tfw828zl7WIaAkbjEALw_wcB The resultant rig was a little clunky to look at, but it certainly worked. The 9V doubled to 18V was enough to power up the micro-head but the sound from the Crazy 8 (which is an 8Ω cab) was distinctly 'farty' and lacking in 'oomph'. I do hope you're keeping up with all this technical jargon. So then we tried swopping out the Crazy 8 and using instead the EmBee 12/10 (which is a 4Ω cab). The sound was cleaner and louder, but still not quite there yet. The 'fartiness' was the sound I associate with too little power in the rig rather than too much, so the jury-rigged 18V DC supply was the obvious suspect. What the hell, in for a penny in for a pound and I ordered the Box King unit. [For the avoidance of doubt, I had of course also tried plugging the rig together but using the mains supply for the Hotone Thunder Bass. The rig sounded great with both the Crazy 8 and the EmBee 12/10. Not as similar to an SVT as the advertising would have you believe, but a really nice-sounding head which is easily enough to deal with rehearsals, perhaps even with winebar gigs.] The Box King is a more modern unit than the Eneloop, size-wise it is designed to fit underneath a Pedaltrain Nano so it doesn't take up valuable real estate on top, best of all it has a dedicated 18v/24v outlet running at 450mA plus a USB charging socket for your phone. It arrived this morning so I plugged it all together. The instant I plugged the Hotone into the Crazy 8 (1/4" jack to Speakon) the Box King died. It didn't melt or catch fire but all the lights went out and the power went away. Hmmmmm. Disconnect everything, switch on, all fine, plug back together. The instant I plugged the Hotone into the Crazy 8 the Box King died. Again I say, hmmmmmmm. Disconnect everything, switch on, all fine, plug back together, but this time I plug the Hotone into the EmBee 12/10. Everything works fine, the sound is much better, the fartiness pretty much gone. And thrice I say, hmmmmmm. Given my appallingly limited understanding of volts, watts and ohms I can just about convince myself that connecting the Hotone to a 4Ω cab will draw current much faster than connecting it to an 8Ω cab, and that the rapid drain could somehow trigger a thermal protection circuit of some sort ... but actually it's the other way around. My battery-operated micro-rig works better with the 4Ω cab than with the 8Ω cab. What am I missing? Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted August 1, 2020 Share Posted August 1, 2020 4 ohms requires less voltage swing for the same result as 8 ohms. 1 Quote Link to comment Share on other sites More sharing options...
obbm Posted August 1, 2020 Share Posted August 1, 2020 Just a few thoughts. Did you charge the Boxking first or use it straight out of the box? The 4-ohm cab will draw more current than the 8-ohm so if the battery is incapable of supplying it then it will drag the rail volts down and give distortion. I have recently been looking at getting a PJB Double 4 and PJ says many batteries have a short circuit protection to stop them blowing up or catching on fire so the current capacity is limited. Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted August 1, 2020 Author Share Posted August 1, 2020 37 minutes ago, obbm said: Did you charge the Boxking first or use it straight out of the box? Fully charged on arrival. After the first bust-up the display dropped abruptly from four LEDs to two with the third one flashing. I recharged it fully before trying again. No similar issue after the second bust-up. Electricity is weird. Quote Link to comment Share on other sites More sharing options...
obbm Posted August 1, 2020 Share Posted August 1, 2020 What is the specification of the Hotone AC Power supply? i.e. How many amps can it deliver at 18-volts? Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted August 1, 2020 Author Share Posted August 1, 2020 (edited) The literature talks about 5W rather than specifying anything in amps or volts. The mains power supply produces 2A, if that helps at all? I could possibly have made a better job of reading your question ... Edited August 1, 2020 by Happy Jack Quote Link to comment Share on other sites More sharing options...
obbm Posted August 1, 2020 Share Posted August 1, 2020 It looks to me as if the Hotone wants more current than the 500mA that BoXking say it can supply at 18-volts, probably closer to 1-Amp which is why the AC supply is rated at 2-Amps. Although the Boxking is rated at 12800mAh that is spread across all of its outputs 11 outputs. Unffortunately there doesn't seem to be any detailed published specification. If you want to continue down this route then you'll need something like a 18-volt Laptop Battery which can provide the necessary current rather then a pedal psu, however they are considerably more expensive. Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted August 1, 2020 Author Share Posted August 1, 2020 And then there's the connectivity issue ... Quote Link to comment Share on other sites More sharing options...
obbm Posted August 1, 2020 Share Posted August 1, 2020 Not really. https://www.amazon.co.uk/Krisdonia-25000mAh-Portable-Charger-Projector/dp/B078XRBQKB/ref=asc_df_B078XRBQKB/?tag=googshopuk-21&linkCode=df0&hvadid=309981988222&hvpos=1o2&hvnetw=g&hvrand=6200007401106781183&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9045489&hvtargid=pla-423306057529&psc=1 Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted August 1, 2020 Author Share Posted August 1, 2020 Damn! I rather wish I'd seen that sooner ... Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted August 1, 2020 Share Posted August 1, 2020 2 hours ago, Happy Jack said: The literature talks about 5W rather than specifying anything in amps or volts. Assuming that 5 watts is into 4 ohms, which it probably is, that's 4.4 volts at 1.1 amperes. An 18v power supply at 500ma is 9 watts, so you're probably OK where the AC supply is concerned. The battery charger amp hour rating is moot, all that says is how long it takes to fully charge the battery. By the same token what the amp hour rating of a battery tells you is how much power it can provide for how long. 1 Quote Link to comment Share on other sites More sharing options...
MacDaddy Posted August 3, 2020 Share Posted August 3, 2020 Have you tried turning it off, then turning it on again? 😜 Quote Link to comment Share on other sites More sharing options...
andy67 Posted August 4, 2020 Share Posted August 4, 2020 (edited) The Hotone thunder bass runs on an 18v power supply. I've found when using my TC BC208, the most clean headroom I can squeeze out of the Hotone is by setting master vol at 3pm and gain around 12 without dirt, any tinkering either side of this produced farting. Edited August 4, 2020 by andy67 1 Quote Link to comment Share on other sites More sharing options...
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