Problem with Steel stringed Guitar with Passive pickup

wayne

Hope someone can give me a little advice.

I have a Steel stringed acoustic guitar which came fitted with a passive pickup (Just volume and tone control). When I try to run it through the PA system it sounds terrible. It is very "tinny" and can't be corrected on the sound desk eq. the volume is also not very good...

Have tried using a DI box to boost the input signal to the desk and have also resorted to preamping through a ZOOM 505 effects pedal. Volume capabilities are better but it is still very "tinny". Why?? Someone said perhaps the nut is "hugging" the base strings. Could this be the cause and if so how do I fix it.

Thanks

AlanRatcliffe

Pretty much the textbook description of an impedance mismatch. Very percussive too?

If the guitar sounds much better acoustically it's not anything to do with the nut - that affects both acoustic and electric tone (and is unlikely to make things too bright anyway).

You tried a DI box (usually used for impedance matching), but which one? The problem is unpreamped piezos are extremely high impedance HiZ) and most inputs don't go that high - so unless the input of the DI had an impedance of about 2 megohm or better, you're still going to get a mismatch.

Cheaper piezos are also often made with ceramic piezo elements, which have a naturally brittle sound, even when preamplified, so chances are, while you can improve things with a decent preamp, the best route to go would be to replace the entire pickup system - but depending on the guitar, it may not be worth the expense.

Come to think of it, I think I have a Fishman Matrix Natural preamp with no pickup lurking in a box somewhere. PM me if you might be interested in it for a couple of hundred and I'll go digging.

Bob-Dubery

wayne wrote Hope someone can give me a little advice.

I have a Steel stringed acoustic guitar which came fitted with a passive pickup (Just volume and tone control). When I try to run it through the PA system it sounds terrible. It is very "tinny" and can't be corrected on the sound desk eq. the volume is also not very good...

If it's got volume or tone controls can it be passive? I'd expect it to have some kind of pre-amp and a battery within the body somewhere if it's got those controls.

So have you tried changing the battery?

Heath

ye it could be passive , i had a similar kind in a accoustic once ... didn't work very well . but yes it was passive

AlanRatcliffe

Yes - it can be passive. Very common to find this and in many cases the pots are the wrong values.

Bob-Dubery

Alan Ratcliffe wrote Yes - it can be passive. Very common to find this and in many cases the pots are the wrong values.

Ah.

I was thinking of a story that ex-Fairport Convention guitarist Maartin Allcock tells. He buys this Strat, and a bit later has somebody he know fit some pickups in it. It sounds great and becomes his main axe. Then a few years later he starts to find that the magic's not quite there anymore and the Strat doesn't sound as good. Things continue to deteriorate and so he "retires" it.

Years later he opens up a case, sees his old Strat and thinks that for old time's sake he'll give it a cleanup and new strings. He takes the scratch plate off and says "Oh... look a battery. What if I change that..."

A guy I know gets to a gig, plugs in for the sound check and thinks "that doesn't sound so good". So he scrounges a DI box and things get better, but not enough. Cue much swopping out of leads and general debugging of the PA. Then somebody says "doesn't your guitar have a battery inside somewhere?"

So I think it's often worth looking to see if there's a battery involved or not.

Heath

Sounds familar , we where playing a gig one night and the bassist guitar just sound flat , then it scratchie and the more he boosted it , the worse it sounded . so we had a short break while the bassist tried to borrow another bass from another band and when he put it down string facing the amp i notice a small cover closer to the jack , then it dawned on me the bass boost was active pickups . he didn't even know it was there . quick change of the battery and we were away again .

So yes Bob a good question to ask anyway. IMO i don't ever want active pickups in any of my guitars thank you very much.

Rudolf

IMO i don't ever want active pickups in any of my guitars thank you very much.

Ja nee gits from what I'm reading I have to side on that. But I think I'm stuffed already, does my Cort's Fishman electronic/acoustic pickup thing also use the battery or is the battery in that purely for the tuner?

AlanRatcliffe

IMO i don't ever want active pickups in any of my guitars thank you very much.

You do for an acoustic...

Bob-Dubery

Rudolf wrote
IMO i don't ever want active pickups in any of my guitars thank you very much.
Ja nee gits from what I'm reading I have to side on that. But I think I'm stuffed already, does my Cort's Fishman electronic/acoustic pickup thing also use the battery or is the battery in that purely for the tuner?

I'd assume that the pickup drives a pre-amp, and that battery provides the power to the pre-amp as well as the tuner. But the way to prove it empirically is to take the battery out and plug the guitar in ?

Bob-Dubery

Alan Ratcliffe wrote
IMO i don't ever want active pickups in any of my guitars thank you very much.
You do for an acoustic...

Something I've been pondering. If you have good quality pickup and pre-amp in your acoustic (say Baggs - all good quality, all made to work together) do you still need a DI box?

Heath

Sorry i did mean in my electrics , definetly active in accoustics. they just sound better

AlanRatcliffe

Bob Dubery wrote Something I've been pondering. If you have good quality pickup and pre-amp in your acoustic (say Baggs - all good quality, all made to work together) do you still need a DI box?

Not unless it gives you something that the preamp doesn't (such as anti feedback control). Sometimes the balanced line out is nice, just to give you the ability to run through a long cable to the board. A pro setup on an acoustic stage will usually have a few DI boxes in front of the snake just for that.

Bob-Dubery

Alan Ratcliffe wrote Sometimes the balanced line out is nice, just to give you the ability to run through a long cable to the board. A pro setup on an acoustic stage will usually have a few DI boxes in front of the snake just for that.

How long is "long"? I normally have a lead of about 3m between the guitar and the chorus pedal, and then there's another lead of about 10m to the desk. All leads just being co-ax with mono jack plugs.

Heath

wouldn't the chorus pedal act as DI

AlanRatcliffe

Bob Dubery wrote How long is "long"? I normally have a lead of about 3m between the guitar and the chorus pedal, and then there's another lead of about 10m to the desk. All leads just being co-ax with mono jack plugs.

You're fine. Because it's preamped your guitar is already low impedance, so you could probably run at least 20m cables with no problem. ? More than that and - while the signal level will not deteriorate - a balanced line will be preferable to keep interference out of the signal.

Bob-Dubery

Alan Ratcliffe wrote
Bob Dubery wrote How long is "long"? I normally have a lead of about 3m between the guitar and the chorus pedal, and then there's another lead of about 10m to the desk. All leads just being co-ax with mono jack plugs.
You're fine. Because it's preamped your guitar is already low impedance, so you could probably run at least 20m cables with no problem. ? More than that and - while the signal level will not deteriorate - a balanced line will be preferable to keep interference out of the signal.

Many thanks for that advice Alan. You have not only educated me but also saved me some money.