BOD2

This is an example wiring diagram for that type of pickup

[url="http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=rickenbucker"]http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=rickenbucker[/url]

The wire colours don't match up, of course, but maybe you could try something based on that ?

Yes !

What you DON'T want to do is to rewire the actual cabinets. That would devalue them and also cause confusion over what is actually inside - especially at some later date.

It is possible to make a "box" that would connect two cabinets in series. You could then connect the two 2x10s cabs in series to make 16 ohms and then connect that box (16 ohms) to one speaker output on the amp and the 1x15 (16 ohms) to the other speaker output on the amp. The amp would then run at 8 ohms with all that connected.

What would it sound like ? That's anyone's guess ! It might sound good or it might sound no better than running with just two cabinets.

This diagram shows how the "box" would be wired using 1/4 inch jack sockets. The wiring would have to be good speaker quality wire and everything well soldered together.

[attachment=116375:SpeakerBox.jpg]

Were you mic'd up or using a DI ?

The sound guy would probably hear the hum when monitoring just your badd through his headphones.

If there's no hum at all when you're playing just with the bass and your amp then it could be the process of putting your bass through the PA is creating the hum.

This is quite a mystery !

Sorry to ask stupid, obvious questions but...

1. The patch cables are definitely MONO with mono and not stereo jacks on them ?
2. When you say you checked the patch leads, how did you check them ?

I've always been a bit puzzled by the myth of outrageously expensive cables.

Yes, you do need strong, robust cables with good connectors on them. Unfortunately you can't always tell from just looking at a cable so it's wise to go for reputable brand names already mentioned here (Neutrik, Switchcraft, Van Damme etc). Something reliable that won't let you down.

But beyond that some people talk of a slight attenuation or loss of brightness from some cables. Well isn't that why we have tone controls on the amplifiers ? If it sounds a little less bright then just turn up the treble a little ? Am I missing something ?

In my experience I've heard my sound change from one venue to another. Sometimes it's great, other times it seems a little muffled, or too bright whilst always using the same equipment. In which case you simply adjust the EQ on the amp to suit.

You can polish the fres with a very fine grade wire wool but you'll need to mask off the fretboard first. You can do this with masking tape between the frets. Line up the edge of the tape with one fret and stick it on, then line up a second bit (overlapping the first) with the next fret and so on. Once the frets get too close together to fit a singe piece of masking tape in between, stick the tape over the fret then use a craft knife to carefully remove the part over the fret. Run the craft knife at an angle into the bottom of the fret so thar you're not touching the board with the knife at all.

Once the fretboard is all masked off and protected you can polish the frets with wire wool. Make sure it's a fine grade wire wool - you just want to polish the fret and not change the profile at all ! Once you've done that finish off with "Brasso" (or "T-Cut" or any other mildly abrasive polish) to bring a shine up.

I've done this periodically with all my guitars and basses over the years and it works a treat.

The saddles have possibly been replaced at some point in the past. Perhaps the owner preferred that type and swapped them ?

As for the bridge position, it's possible that the owner has relocated the bridge at some point, moving it backwards. Perhaps there was an intonation issue with a particular guage or string type and this was his solution ?

You could easily check this by removing the bridge and checking to see if there is another row of screw holes underneath. If the bridge was moved backwards then any original holes would be covered by the new bridge position.

I had this same problem once with a Hartke 3500 head. I think the jack sockets are on their own little detachable PCB so you can take that whole assembly out of the head to work on it.

If I'm not mistaken, this is the type of jack socket that you need -

[url="http://www.ebay.co.uk/itm/1-4-6-35-Stereo-Jack-Socket-Panel-Mount-/120712212096"]http://www.ebay.co.uk/itm/1-4-6-35-Stereo-Jack-Socket-Panel-Mount-/120712212096[/url]

but have a good look at the photos to compare it first. It has a characteristic "bevel" on one corner of the plastic casing of the socket.

In my case I wrote to the UK Hartke distributor and was able to obtain a replacement socket from them.

When removing the old socket be careful not to apply too much heat to the solder pads on the PCB as it can sometimes damage the pads.

Since the old jack is being scrapped it will actually be easier if you "disassemble" it while still attached, so that just the legs remain on the PCB. That way you can then unsolder and remove one leg at a time rather than trying to do them all at once, which is tricky.

One of the main reasons for checking amplifier power specs is so that you can compare different amplifiers to see how they match up.

This is only possible when manufacturers provide the same specifications.

It's been generally accepted over the years that the most practical power specs to use are "RMS Power" ("Root Mean Square") ratings, as these are reasonably close to "real world" power use. Is RMS power listed in any of the specs for these amplifiers you are trying to compare ? If, so, then that's the best one to use.

"Maximum Output Power" is not very useful in a real world scenario (would you ever run your car at it's absolute maximum speed ?)

"Rated Output Power" is a more useful spec, probably a more practical "everyday" power spec but meaningless for comparison purposes unless other manufacturers use the same spec.

None of these power ratings give any indication of "volume" (or "loudness"). Volume is provided by the loudspeaker which converts the electrical power of the amplifier into sound. So the speaker cabinet used is very important as in indication of how loud a setup will be.

The best way to find out how loud an amp/cab setup will be is to ask on this forum about other user's experiences of that particular amp/cab combination. Use the experience of the players here to help you - and you can ask them specific questions about a particular setup.

Probably best not to use your amp at all if playing through headphones - half of the sound of your amp comes from the speakers anyway so if you turn it down to the point where there's no sound coming from the speakers then it's going to sound different anyway.

You plug your bass into your FX chain and then take a cable from the output of the FX chain and either -

1. Plug it into your PC, if that's a workable option. You'd probably need an adaptor cable or something to take your standard quarter inch jack cable down to the 3.5mm jack input on your PC, but that should work. The PC will have a sound mixer somewhere to set the levels.

2. If playing through your PC doesn't appeal then you could get a small mixer with a headphone output. Plug the output of the bass/FX into one channel, plug the PC into another channel, mix the levels to suit, then output from the headphone socket on the mixer. You could also attach other devices to the mixer (e.g. iPod, hifi etc.) if you wanted to.

A small mixer like this would do -

[url="http://www.thomann.de/gb/behringer_xenyx_802.htm"]http://www.thomann.de/gb/behringer_xenyx_802.htm[/url]


Downside is that the bass will sound a little different with no amplifier to "colour" the sound, but that might actually be ok for practice purposes anyway.


You can get software for a PC that will let you do lots of stuff but it depends on how comfortable you are on the PC as to how useful this would be to you.

Running 5.3 ohms and 8 ohms in parallel will create a load of around 3.2 ohms

[quote name='belgamrood' timestamp='1338464495' post='1674923']
btw, should this be speaker in instrument chord?
[/quote]

Instrument cord

[quote name='GregBass' timestamp='1338387450' post='1673703']
And isn't a flat voltage waveform actually a direct voltage?
[/quote]

No, a "flat waveform" is not a direct voltage - it's a square wave.

A direct voltage, if displayed on a scope, would be a continuous straight line above (or below - but NOT both) the zero line on the scope.

If you apply a direct voltage to a speaker (not generally a good idea) the cone will push out and stay out (or it will pull back and stay back). It won't make any noise as the cone needs to move backward AND forwards to create air pressure which creates the sound.

[quote name='bassickman' timestamp='1338387486' post='1673705']
I'm on tour with a London Community Gospel Choir. I have 5k to spend on gear. hense the questions so I can get it right.
[/quote]

Will the bass sound be put through the PA system ?

This is quite an important consideration. If the bass goes through the PA then you don't need a big powerful amplifier setup as it will only end up causing volume problems with the other players and you'll end up turning it way, way down so as not to deafen everybody (and then big powerful sound will come through the PA).

In that case you'd probably be looking at a mid-powered amplifier - say 300 to 500 Watts - with, as Chris_B suggests, a 4x10 or 2x10 cabinet of a smilar or greater power. Use your ears when playing - if you're pushing up the volume on the amp and it starts to sound unpleasanty distorted then simply back off a little.

Best advice is to have a look around to see what specific equipment you like and then ask for some opinions on here and people can tell you about it.

Are there any extension cables or 4-way mains blocks involved ? You need to check that all the earths are in place on all mains cables or extensions. If the 13 amp plugs are the type that can be opened up (i.e. they're not molded ones that don't open) then have a look inside each and ensure that they're wired correctly - paying particular attention to the earth wire (the green/yellow one) which should be connected to the largest pin in the plug.

Does the buzz happen in other rooms, or just the rehearsal space ?

Simplify your setup to test it - plus the amp directly into a mains socket (no extensions). Plug the bass directly into the amp with no effects. Does it buzz ? Try a different mains cable. Does it buzz ? Try the same in a different room.

You need to establish if there's a fault in the mains cable, the amp, or the room.

Avoid touching any other equipment while doing this.

Could the output of the pickups be too high for the tuner ? What happens if you select one pickup only, turn the volume down to zero and then just bring it up a little ?

Did you solder the braided shield on each pickup cable to the pot shells ? And are the pot shells themselves soldered back to the ground pin on the output jack ?

Sometimes all the ground wires are not shown in the circuit diagrams, but basically there is usually a ground wire between each pot shell and the last pot shell is connected to the ground of the jack.

The bridge ground goes from either a pot shell or the jack ground (whichever is more convenient) and should make a good contact with the bridge. It's not normally soldered to the bridge but make sure it has a good contact by cleaning up the metal on the bridge where the wire connects with a little sandpaper.

Pickup covers make only a slight difference to the sound. It became fashionable in the 70s and 80s to remove the pickup covers to show the bobbins and most people reckoned there was a very slight increase in brightness when this was done.

It can be tricky to obtain and fit pickup covers of the correct size. Traditionally they were soldered on to the metal base of the pickup with two or more big blobs of solder - but you'd need a seriously big and hot iron to able to do that as the metal base conducts all the heat away. Also, pickup covers often only have one set of pole piece holes in them (because humbucker pickups originally only had one set of adjustable poles). That might be a problem with the DiMarzio pickup since it has two sets of adjustable poles.

It's hard to be sure, but looking at your photo it looks as if you have two different pickups there - one with hexagonal "allen-key" pole pieces and the other with conventional pole pieces. DiMarzio did use allen-key adjustable pole pieces on it's "super distortion" range so there's a fair chance that pickup is a DiMarzio, which came with 4-conductor wiring as described previously.

The other pickup might just be a standard humbucker. That would have come with 2-conductor wiring, although the photo seems to show 3 wires ? If one of those 3 wires is the braided shield of the pickup cable then that doesn't count - the braided shield is always connected to ground.

On the "DiMarzio" pickup, bare and twist the black and white wires together then solder them to each other so the can't come apart. Put some tape over this join so that it can't touch anything else. You now effectively have a Dimarzio pickup with 2 free wires - red and green (plus the shield which always goes to ground). Solder the red (hot) wire to the appropriate lug on the volume control and the green (and shield) to the pot shell.

On the other pickup it's hard to tell which wire is which. I would probably solder the white wire to the lug on the other volume control and the black (and shield) to the pot shell. If it sounds "thin" when BOTH pickups are selected, then simply swap the black and white wires on this pickup (black to volume control, white to ground).

This is "standard" 2-pickup "Gibson-style" wiring

[url="http://www.guitarelectronics.com/product/WD2HH3T22_00/Guitar-Wiring-Diagam-w-2-Humbuckers3-Way-Toggle-Switch2-Volumes2-Tones.html"]http://www.guitarelectronics.com/product/WD2HH3T22_00/Guitar-Wiring-Diagam-w-2-Humbuckers3-Way-Toggle-Switch2-Volumes2-Tones.html[/url]

This diagram actually shows both pickups as 4-conductor pickups.

Yes, you do need a ground wire to the bridge somewhere.

Yep - sounds like interference from something. The usual suspects are light dimmers, fluorescent (or energy saving) bulbs or a noisy power supply (wall wart). Sometimes you can use the bass like a "aerial" and by moving it around you might hear the noise increase or decrease - that might help identify where it's coming from.

It sounds like using the headphone socket as the output is the main issue. The headphone socket is optimised to drive headphones which have a different impedance than the inputs on most other devices so there's a slight mismatch there.

How cheap ?

Behringer do the Xenyx 1002 for around £50

[url="http://www.behringer.com/EN/Products/1002.aspx"]http://www.behringer.com/EN/Products/1002.aspx[/url]

It has 2 x mono inputs, 2 x stereo (L/R) inputs and also has a separate "tape in" on RCA phonos.

Many people don't rate Behringer for reliability problems but if you make sure you have a warranty and treat it right then it should be ok.

There are similar and slightly larger format mixers available from other makers

[quote name='Jorn Overa' timestamp='1335529366' post='1632678']
BOD2:
I've had a look at your shimming tutorial. Would you say there's any risk to doing this, especially before my gig?

Thank you all for your help.
[/quote]

If you're comfortable removing the neck from a bass (and it's straightforward enough, as you can see) then there's no "risk" as such and whatever you do is completely reversible by removing any shim. In this case a shim at the body end of the neck pocket would tilt the neck a little and allow you to then raise the bridge saddles to compensate.

But some people, quite understanably, prefer to leave these things to an expert. The guide is intended for people who like to take things apart and are happy to do that sort of thing.

How are you connecting the iPad - from the headphone socket or the Apple dock connector ?

Experience with iPods (not iPads) has shown that the best way to connect one to another audio device (e.g. a mixer) is to use a cable with the Apple dock connector at one end and two RCA phono connectors at the other end. If you connect to the headphone jack then the output will often be very low.