Johnsonsdobro - Posted - 03/07/2009:  16:35:56

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I was wondering what amps you guys are using?
I have a gibson resonator with a fishman pick up, I have a Peavy 5150 tubed amp
I use for my electric guitars, If I plug in my dobro I get major feed back even on the clean channel, i also have a red dog cigar box guitar (awsome check them out at reddogguitars.com) and I get the same result. Do i need to go trough a pre amp or do I need another type of amp? any suggestions? Thanks again for your input.

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Edited by - Johnsonsdobro on 03/07/2009 16:43:37

RobA - Posted - 03/07/2009:  22:38:24

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Can I safely assume you have the older Fishman reso pick up? If so, I am pretty confident is telling you - YES - you need a pre-amp! The older style Fishman reso pickup can sound good but it needs a pre-amp/e.q. to dial out the considerable treble that those pick up's are known for. If its the new Fishman pickup then it may be a whole different story...one I can't comment on, since I don't have any experience with that pickup.

As far as amps go, there are plenty of good ones to choose from. Over the years I've owned an AER Compact 60, AER Acousticube, a Fishman Loudbox Performer and my latest amp, the L.R. Baggs Acoustic Reference Amplifier. All of the above amps are good quality, with pros and cons to each...The thing I like about the new Baggs amplifier is that it seems to add the least amount of coloration to my sound.

Hope this helps!

Regards,
Rob Anderlik

Bradskey - Posted - 03/08/2009:  09:52:07

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You don't really want to use an electric guitar amp for acoustic pickups. I have the passive Fishman pickup in my dobro, the kind they were selling a couple of years ago that installed on the bottom of the cone on the bridge screw, not the latest and greatest whatever it is. There was also an active variety with its own built in preamp, powered by a 9V battery, usually accessible under one of the sound holes. I run mine through a short high-quality gold cable into a Fishman Pro EQ Platinum outboard preamp. There are cheaper models of the Fishman and there is also the LR Baggs Paracoustic DI and some others. These can be used as direct boxes, the way I use them now, and run directly into the PA. I've never had trouble with feedback with the dobro (banjo totally different story).

Crate makes some decent acoustic amps that are relatively inexpensive and made in the USA. I have a 60W Crate acoustic (the Gunnison) that's pretty good. Technically you could run your passive pickup directly into the Crate or almost any of these acoustic amps, but although they all claim to have built-in preamps the input impedance is far inferior to that supported on outboards preamps like the Fishman and LR Baggs. My Fishman preamp has an input impedance of 10M ohms, while my Crate acoustic amp has an impedance of only 3.3M ohms. This is a subject you can read about on the net. You want to use as short good cable as possible to the highest impedance input preamp you can get for the best possible sound with these type pickups. By short cable I don't mean 3 ft, but you don't want to use something crazy like 50' either.

Johnsonsdobro - Posted - 03/08/2009:  10:36:21

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Thanks for the input
My pick up is a passive fishman so I will check out the pre amps, Also I should get an acoustic amp, Ill check out the crate amps as well as the baggs, I just need something small for thehouse because i dont play in a band or with other insturments, thanks again for your input
Aaron

Preston Thompson - Posted - 03/09/2009:  03:52:32

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Just a question here. With the acoustic amps, is it feasible to just mike the instrument and run it through the amp. I need just a little amplification but don't have a pickup in the guitar. and in a Roland AC 60, is the pre-amp workable?

pt



Play it again, Sam. Over, and over, and over:

Bradskey - Posted - 03/09/2009:  07:33:57

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quote:

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Originally posted by Preston Thompson

Just a question here. With the acoustic amps, is it feasible to just mike the instrument and run it through the amp. I need just a little amplification but don't have a pickup in the guitar. and in a Roland AC 60, is the pre-amp workable?

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Hi, I'm sure that would work fine, although you often cannot get as much volume with a mic before feedback, you will get a somewhat more natural sound of your guitar though. A little (not-so) secret is that acoustic amps are really just sort of mini PA systems. You can also use acoustics through real PA's or things like keyboard amps/speakers, etc, the acoustic amps are just nice little all-in-one packages. I used an acoustic amp with a dynamic mic for years for my saxophone, and you'll notice that Roland AC60, like many acoustic amps, has a dual input that supports XLR so you can just plug a good dynamic mic into it and you're all set.

I'm sure the preamp is okay, would work fine for an active or magnetic pickup, serviceable for a piezo pickup. I've seen the input impedance on that size amp range anywhere from 1 to 3 M ohms. Higher impedance gives better bass response and highs for a passive pickup, although too high can theoretically pick up noise and hum but I've never seen that happen.

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Edited by - Bradskey on 03/09/2009 07:41:14

Philsweep - Posted - 03/09/2009:  19:13:21

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I can get a great sound through my Crate acousic amp where I don't have to use a pre amp. If I am going through a PA system I always use a Pre amp just to control my sound myself, it seems Just going through any Pa system I don't get the sound I am looking for. I switch between dobro and banjo also so the more control I have the better and when changing intruments I can totally turn one off with the pre amp. And since most sound guys don't know squat about bluegrass the more control you have the better. Stick with an acoustic amp.

Preston Thompson - Posted - 03/10/2009:  04:08:44

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What do you mean most sound men don't know squat about bluegrass? What's the difference?

Play it again, Sam. Over, and over, and over:

jmb3450 - Posted - 03/10/2009:  06:40:54

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I've played with bands in several situations where there were multiple groups performing and the other groups were not accoustic. In most of these situations the sound techs did a poor job, sometimes a horrible job, setting up and running the sound for my band. Running sound for an accoustic group is very different from doing the same for a group that plays electric instruments. My experience with this is that many sound techs don't understand how to set up and run sound for a bluegrass group - they'll set mic levels and EQ's incorrectly so things are way out of balance and feedback is terrible. By out of balance, other than EQ, I mean things like rythm guitar or bass louder than lead instruments, vocals not balanced, and some lead instruments too loud while another can barely be heard. Perhaps this is the type of thing Philsweep is referring to?

Jim

axeslingincowboy - Posted - 03/10/2009:  08:01:59

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I'll second that. My band, Grandpa's Cough Medicine has bluegrass instruments along with drums and an electric guitar. Sound guys have done a fabulous job at making us sound terrible. When we run our own sound it sounds great. I run my dobro thru a crate acoustic amp, but I'm about to get a fishman nashville installed in my W/S mahogany and I think that will sound much better than the piezo i have used in the past. And if it doesn't I'll just buy the aura pedal.

Dobro playin'' mofo.