Could I run an amp using this?

[MythSte]

[quote name='teej' post='886657' date='Jul 5 2010, 08:48 PM']Down here in the south - Hampshire/Dorset etc - there's an Irish/Bluegrass outfit called the Huckleberries who use electric bass. T[/quote]

Christ! Are they still going?! I have a CD of theris from what must have been '98. I was just 8 years old going through salisbury and remember being blown away!

[teej]

[quote name='MythSte' post='886965' date='Jul 6 2010, 03:35 AM']Christ! Are they still going?! I have a CD of theris from what must have been '98. I was just 8 years old going through salisbury and remember being blown away![/quote]
Yes, they're still going. '98? I reckon they must have only just gone amplified back then. They started off as a wholly acoustic trio: banjo, upright bass and guitar, with the banjo player tapping a tambourine with his foot and the bass player playing a little suitcase with a bass-drum pedal (also operating a remote control car with a collecting box on top - the controller cunningly hidden, taped to the side of the bass).

I was busking Salisbury around the same time with a blues/rockabilly outfit called Swamp Things.

[teej]

[quote name='bigjohn' post='886666' date='Jul 5 2010, 09:00 PM']Tea chest is the best idea so far![/quote]
Absolutely, it was a serious suggestion. You could knock something together for next to nothing (one of your requirements, I note), keeping the whole outfit at the same acoustic level. Visually it works - people will stop just to see it. You can paint the band's name on the side, stick posters to it advertising gigs or cds for sale. And, up to a point, you'll make more money just because it's unusual. Top tip: try playing it with a drumstick rather than your hand - it's louder and you don't get blisters!

There's at least one tea chest player here: I'm sure I've seen a very fancy-looking one on someone's avatar. Anyone remember who that is? If it's you please step up and comment...

[flyfisher]

[quote name='Phil Starr' post='886841' date='Jul 5 2010, 11:18 PM']I think people are being a bit pessimistic about the inverter. The guy who did the calculations is probably pretty close ( i can't fault his reasoning) but remember you are not playing full volume continuously, there are loud and quiet bits. My 20W Peavey practice amp almost matches a drumkit when we practice in an enclosed practice space and even, say, 5W will be louder than an acoustic bass and more than match an acoustic guitar. If you turn it down it should give you a lot more battery life and are you really going to play longer than a two hour set.

I'd try it and if it runs flat too quickly you can always connect it to a car battery for more life.[/quote]
I'd go along with all that. Indeed, that's why I chose the 10W amp to illustrate the issues rather than the larger 20W option. But my real point was to show how these sorts of things can be worked out rather than just guessed at.

Maplins sell plug-in power meters, which could be used to measure the actual power consumption of the proposed amplifier and this would then enable a more accurate calculation of the likely playing time.

But the bottom line is always going to be the basic battery capacity and, in general, the smaller, lighter and cheaper the device in question, the less power it will be able to dispense.

Personally, I'd favour a car battery on a small luggage trolly - preferably one of those fully sealed ones that don't spill battery acid.

[teej]

[quote name='flyfisher' post='887063' date='Jul 6 2010, 10:22 AM']Personally, I'd favour a car battery on a small luggage trolly - preferably one of those fully sealed ones that don't spill battery acid.[/quote]
There are lots of guys out there doing just that. I almost understood how you worked that out, but not really (I'm OK with maths, but the whole electricity thing is a bit of a closed book to me). We use a Yamaha Stagepas 500 (500W) for vocals and double bass, and a '70s Roland Cube (100W) for guitar. We perform for a good 3 hours, maybe 4. Some of the blues is pretty mellow and some of the rockabilly/jump jive is full-on.

So before we get into questions of efficiency, we need something capable of providing 600W x4 = 2.4kW ?

But we might actually need twice that if our equipment is 50% efficient? = 4.8kW ?

And if we're losing 20% to the inverter, then we'll need 6kW ?

When I'm looking to see what battery I need I'm multiplying the voltage by the Ah? And looking for an answer of 6000? (can you tell I'm struggling here?)
err, and as the voltage is going to be 12v I need 500 Ah ? A quick look at Leisure/Marine type batteries suggests the best I can get is about 135 Ah...

So have I understood the calculation method? I was going to ask how to check the efficiency of our gear, but I see you've answered that flyfisher, thanks.

[flyfisher]

Almost there. As you say, ignoring efficiencies, you're looking to draw 600W. From a 12v battery that will mean 600 / 12 = 50A. If you draw 50A for 4 hours that's 50 x 4 = 200 Ah.

That's quite a lot of power, even for a car battery. However, as previously pointed out, you're unlikely to be running everything a full whack, especially (I'd guess) a 500W PA.

We can guess about amplifier efficiencies but actual volume will likely be the biggest variable. If you're seriously considering a totally portable set-up then it would probably be worthwhile to get hold of a power consumption meter (I just checked and didn't realise they are so cheap these days: [url="http://www.maplin.co.uk/Module.aspx?ModuleNo=286534)"]http://www.maplin.co.uk/Module.aspx?ModuleNo=286534)[/url] and then measure your actual consumption at practical volume levels during your next rehearsal. Then plug the measured power figure into the above calcs.

I'm a bit out of touch with inverter efficiencies, but I reckon 80% would be a conservative figure.

If you still find you're short of power then a second battery might be an option and would double the capacity at a stroke, although you'd need a 24v inverter rather than the more commonly used 12v types plus, of course, another heavy battery to lug around.

You mentioned marine batteries; as I understand it, most of these are specifically designed for 'deep discharge' applications, i.e. where the battery is regularly discharged of almost all its capacity. This is an important consideration because most car batteries don't like being fully discharged and it can seriously shorten their useful life.

[janmaat]

Hi,

hands up I'm the tea chest player. Not so much tea chest - forget about that, it MUST be a bucket.

Have a look at the construction I'm using now here: [url="http://bucketbass.com/"]http://bucketbass.com/[/url] just get some bits of
wood and one of this "tuff tubs" from the b&q

Really loud - louder than double bass. add a finger board as i did and you get your 2 octaves on one string.
add a pedal like i have so you don't have to put your foot on the bucket all the time - plus it lifts the bucket off the ground making it louder.

difficult bit is the tunig peg - you need to make sure the string keeps proper tension. the first model i built used a hand winch,
like the thing you use to fasten belts when you tie loads to a car hanger etc. (not very precise in tuning, but hey your're fretless)
- slipping string is a bigger problem than a super-tight-fixed string.

You can knock a simple one together in 1/2 hour that will do the job, but you must plan for sand paper to avoid splinters!!!
washing line will do the job but an old wound db string will be better.

as for amplification, i'm still wondering why not build something off a car subwoofer with a car battery, that plus
a cheap shadow pickup, preamp, and 'nuf noise!' - plus you look super cool, people will just chock money at you

Good luck with that

oh and btw sorry i just had to change my avatar for a little while - i'm from hamburg (and actually IN hamburg now)

Edited July 6, 2010 by janmaat

[OldGit]

Tea chest / bucket bass sounds like a top idea for entertaining busking.
Cheap too..
I'd do that.

However if you still want to play electictric I have a [url="http://www.reddogmusic.co.uk/Guitars-Amps-and-Effects/Guitar-Amps/Acoustic-Amps/Crate-TX15-Taxi.html?origin=googlebase"]Crate Taxi 15 watt battery amp[/url] (I generally don't use it for bass though) and it's fine. Battries last a fair few hurs and it recharges fast so you coud nip into a cafe and recharge it over lunch.

£100 new, generaly around £50 used on Ebay. There's a big version too. 30 watts called the Limosin and a new one called the [url="http://www.guitarampkeyboard.com/en/10710"]Tx50DB with digital effects[/url].. . So for a tenner more than the battery inverter thing you get a proper busking amp and several less things to carry.
I strap mine to my bike's rear carrier and leave it on there (playing harmonica) to make it easier to move.




Thay also have the

Edited July 6, 2010 by OldGit

[teej]

[quote name='janmaat' post='887334' date='Jul 6 2010, 02:17 PM']Hi,

hands up I'm the tea chest player. Not so much tea chest - forget about that, it MUST be a bucket.

Have a look at the construction I'm using now here: [url="http://bucketbass.com/"]http://bucketbass.com/[/url] just get some bits of
wood and one of this "tuff tubs" from the b&q[/quote]
That's just the ticket!

Brilliant, I love it.

[MythSte]

[quote name='teej' post='886997' date='Jul 6 2010, 08:16 AM']Yes, they're still going. '98? I reckon they must have only just gone amplified back then. They started off as a wholly acoustic trio: banjo, upright bass and guitar, with the banjo player tapping a tambourine with his foot and the bass player playing a little suitcase with a bass-drum pedal (also operating a remote control car with a collecting box on top - the controller cunningly hidden, taped to the side of the bass).

I was busking Salisbury around the same time with a blues/rockabilly outfit called Swamp Things.[/quote]

Well, it was definately between 98 and 2000, and they definately had a drummer. I was far to young to notice any loud black boxes at the back

[d-basser]

truly intrigued by the bucket/tea chest bass idea, any advice on building one?

[teej]

[quote name='d-basser' post='887565' date='Jul 6 2010, 05:35 PM']truly intrigued by the bucket/tea chest bass idea, any advice on building one?[/quote]
Did you follow the link on Jan's post? There are some good pics and descriptions on there, but I must admit there are a couple of things I'm not entirely clear about.

I've only ever used the traditional design, which couldn't really be simpler, but does have its limitations. I used a zinc boiler like a tall saucepan.

There are bound to be some other sites out there with different approaches.

I feel a summer holiday project coming on...

[d-basser]

I had a look at Jan's link, just looking for a few pointers before I take a trip to B&Q

[flyfisher]

Just a quick update. I was curious about amplifier efficiencies as discussed above so I bought one of theose Maplin 'energy meter' thingies at the weekend and tried it out with my Ashdown Mag300 Evo II head.

I was only testing it at home and couldn't really run it at full volume without shaking stuff off the shelves. I was running it at about half volume, which would be easily loud enough for some outdoor busking, probably too lound actually.

Anyway, the meter indicated a maximum power consumption of 143 watts, which was lower than I expected.

Not sure if that helps the OP directly but, for anyone thinking of a 'mobile' solution, I'd certainly recommend one of those 'energy meters' as a quick way to get some real figures for their amplifier instead of just guessing.

[EssentialTension]

[quote name='bigjohn' post='886523' date='Jul 5 2010, 05:51 PM']I've never seen a band busking with electric bass. Have you?[/quote]
Yes, quite a few, both in Brighton and London.