Remote power for active basses

[dincz]

I'm thinking of modding my amp and bass to provide 9V for the onboard preamp and so avoid the problems that go along with batteries. It should be simple enough to do, so I wonder why manufacturers of amps and basses don't already offer this feature. Or do they?

[Bigwan]

EBS do this

[Musky]

I've got a bass that's been modded to receive remote power. It has an XLR instead of a regular output jack, although that connects up to a seperate power supply rather than an amp.

[lozbass]

I think that Alembic started this around the mid '70s. Most (if not all) Alembics will run on batteries but one of mine has six 9v cells (though four are for the lights)! Removing batteries and running on external power is preferable for me as it reduces weight.

[Steve A]

[url="http://www.zampower.com/"]http://www.zampower.com/[/url]

[Jean-Luc Pickguard]

[quote name='Steve Amadeo' post='1024309' date='Nov 15 2010, 09:28 AM'][url="http://www.zampower.com/"]http://www.zampower.com/[/url][/quote]
mmm interesting. Expensive though; I might have a go at building something similar.

[markstuk]

I'm trying to work out why they say it would improve the sound... I suspect they might say it provides a more stable power source than a bettery.. I remain to be convinced :-)

[ezbass]

[quote name='Bigwan' post='1024242' date='Nov 15 2010, 06:55 AM']EBS do this[/quote]
Beat me to it. I can't understand why more amp manufacturers don't offer phantom power, after all it's pretty standard on PAs.

[flyfisher]

[quote name='markstuk' post='1024407' date='Nov 15 2010, 11:06 AM']I'm trying to work out why they say it would improve the sound... I suspect they might say it provides a more stable power source than a bettery.. I remain to be convinced :-)[/quote]

There are few more stable and interference-free power sources than a local battery, so I'd be surprised if they use this as justification - although we are into snake-oil territory

Personally, I can't see anything wrong with remote power, if it's implemented correctly. As previously pointed out, mics have been remotely powered forever and it would cost peanuts for amp makers to implement. I suspect it's all down to the 'standard' jack socket used on most guitars. Just one of those things.

[markstuk]

Thus the "they might say" ..... :-) But I was struggling to think of a more stable and inteference free power supply than a battery :-)

[quote name='flyfisher' post='1024670' date='Nov 15 2010, 02:29 PM']There are few more stable and interference-free power sources than a local battery, so I'd be surprised if they use this as justification - although we are into snake-oil territory

Personally, I can't see anything wrong with remote power, if it's implemented correctly. As previously pointed out, mics have been remotely powered forever and it would cost peanuts for amp makers to implement. I suspect it's all down to the 'standard' jack socket used on most guitars. Just one of those things.[/quote]

[FlatEric]

Hi.

Peter Cook was doing this, Donkey's years ago.

See XLR in the dodgy pic with Peter and "some other bloke".

[attachment=63997:petercook_jae.jpg]

This powered the actives, from this power pack and had a feed
out to a Jack.
This is an actual Peter Cook unit and this one belongs to someone
who had a Axis Bass, many years ago and now uses it to power
another custom bass, made by Ray Cooper.

[attachment=64001:AxisPower.jpg]


Cheers.

[dincz]

The Zam unit kind of highlights the problem. Be careful of this and that and use a special cable from instrument to Zam (which uses a standard TRS jack plug). There seem to be lots of possibilities for accidentally connecting incompatible devices and/or cables. And it's yet another piece of kit (or two pieces including the power adapter) to carry around.

Even XLR (which I'll probably use) has problems in that it would have to be wired unbalanced with power on the spare pin. Unlike phantom power, which works differently, this would need to be used with care.

I think for this to work commercially, amp and instrument manufacturers would need to agree on a standard, using special connectors to prevent damage to standard instruments and equipment.

[Alec]

[quote name='ezbass' post='1024500' date='Nov 15 2010, 01:11 PM']I can't understand why more amp manufacturers don't offer phantom power, after all it's pretty standard on PAs.[/quote]

But that's the problem. Phantom power is *a standard* for PA kit with balanced inputs.

For instruments, there is too much kit that would not be compatible. Without a very clever solution, you'd need at least a 3 conductor cable/connector. OK, so stereo jacks & XLRs can do this. However, without ubiquity, your instrument wouldn't work with a non-compliant amp. Worse still, plug in a regular instrument and you may damage it and/or the amp.

It's an OK solution to add for your own kit, but you need to be well aware of the risks & limitations if you do.

And, even with PA kit, you're not immune to problems, as you'll always get the odd person who carelessly connects unbalance kit to a balanced input supplying phantom power. And I've come across units with balanced outputs that don't behave well if they get phantom power supplied.

And then there's the question of different voltage requirements - etc 9v vs 18v...

Thank goodness that the batteries in most instruments last almost forever!

[dincz]

My next thought was to use a 4 pin XLR to avoid accidents, but then doesn't DMX lighting gear use these? Any other suggestions for connectors?

[Bill Fitzmaurice]

[quote name='dincz' post='1024238' date='Nov 15 2010, 01:43 AM']I'm thinking of modding my amp and bass to provide 9V for the onboard preamp and so avoid the problems that go along with batteries. It should be simple enough to do, so I wonder why manufacturers of amps and basses don't already offer this feature. Or do they?[/quote]
It's simple, use an XLR at either end, tap into one of the pre-amp's positive rails. If the on-board will take more than 9v you can get additional headroom, but if not use a 9v voltage regulator. Be sure to filter the supply at the bass end. The advantage is never having a dead battery. Be sure to retain the 1/4" at both ends and back-up battery on board in case you ever need them.
Manufacturers don't offer this due to compatibility issues.

[Count Bassy]

Personally I would go for a rechargeable battery and charger circuit on board, with a seperate socket for a PSU.

Then aim to have your battery charged all the time, but plug the PSU in (or slip in a standard battery) if 'caught short'.

Best of both world as far as I can see: Normally no extra hardware required, and only a simple charger to keep in the case for when required. Rechargeable batteries are lighter than alkalines anyway, so the whole lot would probably weigh about the same as a standard battery.

If looking for a remote power supply then why not go for the existing phantom power supply standard , and use XLR sockets and balanced line outputs. New bass amps could then include this input option, and separate phantom power supply units with balanced to line level conversion are already available for use with existing amps.
I believe that the standard for phantom power is 50V 10mA, so 500 mW available - no idea if that's enough.


The Zam unit looks too complicated by far.

[dincz]

[quote name='Bill Fitzmaurice' post='1025904' date='Nov 16 2010, 03:25 PM']It's simple, use an XLR at either end, tap into one of the pre-amp's positive rails. If the on-board will take more than 9v you can get additional headroom, but if not use a 9v voltage regulator. Be sure to filter the supply at the bass end. The advantage is never having a dead battery. Be sure to retain the 1/4" at both ends and back-up battery on board in case you ever need them.
Manufacturers don't offer this due to compatibility issues.[/quote]

That's what I have in mind, but my only concern is the use of a standard connector which would allow accidental connection of standard gear/instruments that might be damaged or that might damage the power supply. I guess setting a sensible level of current limiting in the regulator would take care of the latter.

[Bill Fitzmaurice]

[quote name='dincz' post='1026042' date='Nov 16 2010, 11:41 AM']That's what I have in mind, but my only concern is the use of a standard connector which would allow accidental connection of standard gear/instruments that might be damaged or that might damage the power supply.[/quote]That would happen if somebody plugged a mic into your amp. A four conductor XLR would remove that possibility, as they're hardly used for anything anymore. So much so that they might be hard to find.

[Lfalex v1.1]

[quote name='Musky' post='1024247' date='Nov 15 2010, 07:34 AM']I've got a bass that's been modded to receive remote power. It has an XLR instead of a regular output jack, although that connects up to a seperate power supply rather than an amp.[/quote]

Variaxs get their power from a combined PSU/DI box via a Stereo 1/4jack lead. Similar sort of thing...
I like the way the East P-Retro gets its attached cells charged- by a dc adaptor that plugs into the bass when it's not being used.
Otherwise, the reason that I've heard bandied about is that it's more difficult/costly to supply the requisite quality power remotely (by whatever means) than to simply make the bass battery powered.

At the moment, I'm having a bizarre vision of someone playing live using a wireless unit but having their bass powered by a wired remote supply...

[TimR]

I thought about this a long time ago. The only 'problem' with batteries I can think of is it's difficult to change the battery. Why not get one of these:

[url="http://www.allparts.com/Battery-Compartment-p/ep-0929-023.htm"]http://www.allparts.com/Battery-Compartmen...ep-0929-023.htm[/url]

Edited November 16, 2010 by TimR

[thinman]

Just a thought but how about the following:

Make up a guitar lead with standard 1/4" jacks at each eand but using twin core and screen cable. Use one core and screen for the guitar signal. At both ends take the other core out of the back of the plug and terminate with something like a 3.5mm plug using just the tip and use this for +9v or whatever.

This leaves the guitar and amp standard with no risk of shoving 9v up the wrong hole. Might look a bit Heath Robinson though.

[dincz]

[quote name='Bill Fitzmaurice' post='1026239' date='Nov 16 2010, 08:17 PM']That would happen if somebody plugged a mic into your amp. A four conductor XLR would remove that possibility, as [b]they're hardly used for anything anymore[/b]. So much so that they might be hard to find.[/quote]

That looks like the best option then. The Neutrik version seems to be readily available in Europe. I thought they were used for DMX but apparently that's the 5 pin version.

[TimR]

I wouldn't mod the amp. I would build a box to sit on the amp that provided the 9v and had two 1/4" sockets. One a stereo (TRS) and one a mono. The mono to go to your amp and the TRS to go to your bass. Then you can simply modify your bass wiring so that the existing socket recieves the power instead of just switching it. Which is just linking out the battery on some basses. You can just use a normal stereo lead then.

But what is the problem with batteries?

Edited November 17, 2010 by TimR

[Bill Fitzmaurice]

[quote name='TimR' post='1026762' date='Nov 17 2010, 06:54 AM']I wouldn't mod the amp. I would build a box to sit on the amp that provided the 9v and had two 1/4" sockets.[/quote]The entire point of phantom is simplicity, which a separate box isn't. Someone with the chops to rightfully consider doing this isn't the least bit daunted at the prospect. I've run phantom for 30 years and never had a problem. Or a dead battery.

[TimR]

The problem is that you are then tied to always using that bass and amp combination. Any new amp will need to be modded and you can't take that bass to a jam or use another band's, venue's or practice studio's amps with your bass, unless you keep the 1/4" as well and your bass can run without the pre-amp.

If you're talking about proper phantom then just use a standard 3pin XLR, put in a DC/DC converter chip inside the bass to drop the voltage to 9v and the jobs done. But then you're still tied to using a mixer with a phantom supply. Although yopu can get stand alone phantom supplies that would work as I describe above.

It won't matter if someone plugs a mic in then.

DMX and XLR is always an issue anyway so just be careful like everyone else has to be.

I'll maintain the most simple solution is rechargeable batteries and an easily open-able battery compartment, rather than the 5 screws I have on my bass.

Edited November 17, 2010 by TimR