What kind of amp?

[pmgnut]

Is there a special amp required for use with an electric acoustic guitar or can any amp be used?

[rafaelh]

Depends on what you want and need, but any amp will do.....it will sound better through some more than others.

 

My preferences would be;

 

1-PA

2- Acoustic amp or Keyboard amp...been thinking of trying one of those powered PA speakers.

3- Whatever else....it's all good IMO.

[TWANG]

I play my Taylor through my epiphone Valve Junior and it sounds pretty good.

Not pro good, but easily good enough to gig with at small joints.. and for practice, certainly.

 

I like a compressor with an acoustic because the attack is so hard and harsh from those piezos..

if you have a magnetic pickup no problem.

 

TWANG

[cGil]

I play my Taylor through my epiphone Valve Junior and it sounds pretty good.

Not pro good' date=' but easily good enough to gig with at small joints.. and for practice, certainly.

 

I like a compressor with an acoustic because the attack is so hard and harsh from those piezos..

if you have a magnetic pickup no problem.

 

TWANG[/quote']

 

For my acoustic electric, the best I've heard so far is from a VJr through a Jensen P10r or Celestion Alnico Blue, using the original v1 and v2 R2/R1 input resistor arrangement of 68k/68k, and NFB for the clean headroom and reduction of the bottom end boomies. I like it so much that I traded in my Ultrasound D50 cuz I suddenly couldn't find the tones I really wanted to hear from that old 3SB! Never did like the mic preamp on it anyway. :P

 

Gil...

[TWANG]

oh sure.. make me go back in.

 

*starts digging through the resistors and switches*

 

TWANG

[tonedeaf1281734100]

I usually play my Alvarez-Yairi through a "regular" electric guitar amp, but I have tried amps (at guitar center) specifically designed for box guitars and they do sound better. They are usually 2 way amps with a separate tweeter driver.

 

My guitar has both a piezo in the bridge saddle and a condenser microphone in the sound box.

 

Amps designed for acoustics usually have a compressor, which is useful for the reason TWANG mentions. They often also have a "notch filter" that allows you to selectively reduce output from a narrow "notch" of the frequency spectrum which you can adjust to reduce feedback, which is a real problem with electric acoustics, especially if they have condenser mics. If you have an on-board preamp on the guitar, it may already have a notch filter.

[Greg M]

pmgnut,

 

The main difference is that regular electric guitar amps don't usually have a speaker that can reproduce frequencies above about 6,000 Hz. Acoustic guitars can produce higher frequencies so acoustic guitar amps usually have a full range speaker or a piezo electric "speaker" to produce the higher frequencies.

 

When I play out, I usually run my acoustic guitar through my keyboard amp (full range output) and my electric guitars through regular electric guitar amps.

 

Hope this helps,

Greg

[cGil]

With the right electric guitar speaker cab, there should be more than enough top end sparkle. Perhaps too much, as I now prefer to keep my acoustic's treble control rolled off a bit. Greenbacks sound good with acoustics, too. Stronger mids than the Alnico Blue or Jensen P10r. Not enough sparkle with Vintage 30's, though. Too dull and flat sounding.

 

Here's a simple input impedance switch to set the amp up for both acoustic and electric. Or active or passive pickups. Whatever. Anyway, this switch provides either 1M to ground followed by 33k (summed) to the grid; or 68k to the grid followed by 68k to ground. It's the perfect combination of input impedance options. Leo knew it. So did Jim. That's why they've both used it so often on so many Fender and Marshall amps with dual input jacks per channel.

 

http://www.sewatt.com/files/sewatt/impedance%20switching%20-%20SPDT.GIF

 

Here's pretty much of a standard example of it using two jacks... pay no attention to the topboost preamp behind the curtain. http://www.sewatt.com/files/sewatt/sewatt/files/xov97u-topboost_preamp.pdf

 

Gil...

[m-theory]

I like this guy's tone. Too bad he's such a pathetic hack on guitar. ;-)

[Greg M]

cgil,

 

Adding a bunch more gain at 5-6 KHz (turning up the treble on a regular guitar amp) is not going to sound good, probably just irritating. Smaller amounts of higher frequencies will sound more natural and add "air" and sparkle.

 

Thanks,

Greg

[cGil]

It's the Negative Feedback that tames the gain and makes it sound brighter overall by reducing some of the bottom end response. Just try it. The amps I'm using for my acoustic with are basically extra- fat scratch build VJr's with no tone controls. Just straight up Volume (w/pull bright) on front, and an C3/NFB switch on the back.

 

Gil...

[Greg M]

cgil,

 

What I'm getting at is that if you look at the spectrum analysis of a properly recorded electric guitar and acoustic guitar what you will see is that frequencies drop off like a rock above 6 kHz for the electric guitar but for the acoustic guitar there is substantial sound being produced up to 12-15 kHz. This is because speakers designed for regular guitar amps just aren't designed to produce these frequencies - and generally that is a good thing for electric guitar.

 

Can you make a regular guitar amp work acceptably for an acoustic guitar? Yes. Will it ever sound as good as an amp and speaker designed to produce the higher frequencies of an acoustic guitar. Probably not.

 

I hadn't really thought about it much, but I wonder what a VJr would sound like for acoustic guitar if a true full range speaker was used instead of a guitar speaker.

 

Good discussion Gil.

 

Thanks,

Greg

[cGil]

Yep. Actually, even though guitar speakers generally start to roll off the high end around 5kHz, there are still frequencies above that range being reproduced, albeit at a significantly reduced level up to 20kHz. Personally, I find piezo guitar pickups kind of brittle up top anyway, to the point of being harsh when playing hard with the guitar's volume on 10. Yet with the right guitar speaker, the high end is pleasantly smooth. My Ultrasound amp did have a tweeter, but I traded it in anyway cuz my Juniors kicked it's butt! Even so, I may have to try hooking up a speaker from my stereo to a VJr just to see how it sounds. The Hammond OT's are rated for 100Hz to 15kHz. If you want more, try plugging your acoustic guitar into an 18watt with an NFB mod. The trem channel has the low impedance input and OT's they typically use are definitely more HiFi.

 

Gil...

[layboomo]

I'm gonna let you in on a little secret.........want to warm up the piezo(or any acoustic pickup for that matter)? Use one of these as a DI into your PA or whatever amp! They work GREAT and can be had used on Ebay for as little as $35!

[Greg M]

Gil,

 

I didn't mean to say that the recorded sound from an acoustic guitar was through an amp. Acoustic guitars are usually recorded with microphones in front of a guitar and never through a guitar amp. The rolloff through a speaker designed for an electric guitar amp is severe above 6 KHz. If you want to hear the frequencies of an acoustic guitar above 6 kHz (the tones that give it air, chime, and brilliance) you can't record (or play) it through a regular guitar amp and expect to get the same quality of sound.

 

Look, I'm only hanging in on this thread because there seem to be a lot of newbes on this forum searching for tone and they shouldn't be led to believe that a regular guitar amp will give the same results as an acoustic amp or PA with full range capabilities. You can get an acceptable tone playing an acoustic guitar through an electric guitar amp if you are playing out with a band. I've done this many times myself. But... you give up the high end.

 

Here's my advice. If you are playing out or with a band, plug your acoustic guitar into a PA or a full range amp like a keyboard amp or an acoustic guitar amp if you can. Short of that, plug it into an electric guitar amp. If you are recording, never go through any amp but use good properly placed mics and good mic preamps.

 

What is interesting to me is that pickups and on-board preamps for acoustic guitars are finally getting to the point where having this discussion makes sense. My LR Baggs M1 in my Taylor sounds much, much, better than the piezo pickup in my "83 Ovation Adamas (which was the top of the line acoustic with a pickup back in '83). Taylor's own on-board pickup systems sound phenominal. So having the right kind of amplification today makes a bigger difference than it did even 5 years ago.

 

Take care,

 

Greg

[cGil]

No sweat, Greg. I'll second that note on the new Taylor pickups being AMAZING with a capital G! Way better than the Fishman processor gizmos that twist the piezo tone into something a little more realistic. The Takamine cold tube critters are, well, okay I guess, but there are better sounding solutions such as what as Layboomo suggests. And I've used various Art tube mic preamps for years to go straight to the board for both piezo/acoustic guitars and my bass. I also totally agree that for recording a real acoustic, nothing beats a good pair of mics.

 

Didn't mean to come off all confrontational. I was merely suggesting folks give it a fair shake and try it out before writing it off. Please understand, I'm only looking at it from the plug 'n play perspective of my personal piezo plank, as well as the need to dump whatever gear I no longer need to drag around.

 

Gil...

[layboomo]

No sweat' date=' Greg. I'll second that note on the new Taylor pickups being AMAZING with a capital G! Way better than the Fishman processor gizmos that twist the piezo tone into something a little more realistic. The Takamine cold tube critters are, well, okay I guess, but there are better sounding solutions such as what as Layboomo suggests. And I've used various Art tube mic preamps for years to go straight to the board for both piezo/acoustic guitars and my bass. I also totally agree that for recording a real acoustic, nothing beats a good pair of mics.

 

Didn't mean to come off all confrontational. I was merely suggesting folks give it a fair shake and try it out before writing it off. Please understand, I'm only looking at it from the plug 'n play perspective of my personal piezo plank, as well as the need to dump whatever gear I no longer need to drag around.

 

Gil...

[/quote']

 

Actually I understand exactly the point Gil was trying to make .......nothing gets in your face faster than that thwacky piezo high end on some acoustic pickups and if the valve jr tames that down it can be a good thing! I also dig where Greg is coming from there is nothing like that sparkle on a well recorded good sounding acoustic......but in alot of live settings it's a compromise at best and I've really warmed up some so-so sounding acoustics with just a tube pre and a bit of eq.

[Greg M]

Gil,

 

I hear ya loud and clear about dragging around extra gear. I play in a classic rock band and we limit playing out to gigs that we really want to do in a large part because of hauling that gear around. In fact, we pay our kids as much as a band member to roadie for us. To get our band's sound we all use the vintage equipment we grew up with and its heavy. But, I no longer will take my '69 Twin out of the studio to play gigs because, even though it sounds great, it is just too heavy. I opt for my Traynor YBA-1 head and a 2X12 celestion cabinet (easier to carry 2 pieces than 1). Since I also play keyboards, I have to take a keyboard amp (a Roland KC 550, which I think is really just a glorified 4 channel powered mixer) to our gigs so I use it for acoustic guitar too.

 

layboomo,

 

I agree with Gil also about controlling that piezo qwack with the amp when playing out. Generally, you don't have a lot of control over room acoustics and it is more important to get rid of the piezo quack than getting the high end sparkle. It can be a good thing to get it with a Vjr.

 

You guys take care and have fun making music.

 

Greg

[mcrracer]

Hey Gil

Is NFB, negative Feedback resistor?

[layboomo]

Hey Gil

Is NFB' date=' negative Feedback resistor?[/quote']

 

Yup...he is talking about a low gain input with negative feedback and it sounds real nice with that application!

[cGil]

Yep. Without negative feedback in the VJr, it can be kinda boomy in the low mids and there's just not enough headroom to do anything clean AND loud. Also, my acoustic only has one "tone" knob and one volume, so there's not a whole lot of sculpting available to me at that level. NFB takes care of that perfectly, and makes it real easy to dial in other acoustics with the fancy eq's and notch filters. Oddly, I can't remember if I've tried it with a retrofit strap pin piezo job. Oughta sound great, cuz on the ones with eq's I've tried, I usually 'em dialed pretty flat for the VJr! Sadly, I had no choice but to send my good acoustics to my sister a few years back just to save 'em from the dreaded belly bulging, neck bowing humidity down here. My sister and bro-in-law both play, so they're in a good place. The crummy ones I gave away. The only acoustic to survive my place is a Fender carbon top Acoustasonic. Go figure.

 

Gil...