Yamaha G100-212-III

Picked it up for $20.00 at a yard sale not working. It had been broken and sitting for many years. Got it to my shop and found two fuses blown on the circuit board. Changed them and it powered up and worked great. Pots needed cleaning but everything else is perfect. I never heard of this amp before but I am very lucky to have found this at such a steal. Seems to be early 80's. Read all about this amps features below. No one has mentioned the foot switch. The foot switch on this model has two switches and controls channel A/B section and the parametric EQ on/off. This is great as you can set the eq for a nice clean mid boost switchable for solos. The foot switch does not control the reverb, but thats ok since I only use mild reverb. I purchased the schematics and modified a generic marshall replacement foot switch to work with the Yamamha. If it had tremolo I wouldnt need any other pedals. Other models of this amp had a third button on the foot switch for turning on/off the effects loop, would be nice if they had that feature on this amp. Contact me if you want to buy a foot switch for your G100 series III. The tone controls on both channels and the parametric eq have a huge effect on the sound. With a little patience you can dial in any sound you want. This a huge difference from teh Marshall solid state amps that the tone controls barely do anything.

Use a Mexican Strat and a 2002 Gibson Les Paul Special with humbuckers when I gig. Alsdo have a lot of cheap guitars that all sound fine through this amp. The clean channel circuitry is awesome and combined with the OE Yamaha speakers it makes a very sweet rich sound. My main rig uses a Peavey classic 50 head with a 4-10 celestion filled cab. This yamaha rivals the Peavey in the clean channel. I didnt think you could get such a sound without tubes, this amp does it. I am an amp technician and I bring many different amps to band practice to test them. My band mates all flipped out over this old Yamaha. I had offers immediately. It has more than enough power for gigs and it stays clean and loud if you know how to use it. I can get the clean channel to compress slightly but nicely with humbuckers,. The distortion channel is not easy to dial in. If you just crank the gain and use flat eq it sound very dull and sounds like a bad distortion pedal. However if you listen carefully and adjust the gain to where it just starts to break up when you pick lightly, then adjust the eq carefully to get a smooth blend of sound with different pick intensity, you will be very happy with the way the amp distorts. Its a very good blues, classic rock vibe. If you need more distortion just use a good effects pedal or processor, this amp will push the sound out. If it was the best sounding amp I ever heard it would be 10, so I would say this amp is a solid 8, but givin that it is solid state and sounds better than a lot of tube amps, I'll give it a 9. My Classic 50 would also be a 9.

I guess the blown fuses were either caused by someone trying to blow down the walls or possibly by a lighting strike, because this amp hasn't had the slightest issue since changing the fuses. I doubt that anything else is wrong. It is built very well and shows no signs of deteriting after all these years. Seeing its age and also the quality of the circuit boards and components, I think it will be very reliable for years to come.

I purchased the schematics online, didnt try Yamaha because I wanted an immediate download. I cannot comment in this area.

For the price I paid this is the best bang for the buck I will ever have. I doubt I could find another in good condition if this was gone. There are lots of nice amps out there so getting another wouldnt be a big issue. I've been playing on and off for over 30 years. Looking for a low cost quality amp with great sound, dont pass up one of these. (at the right price)

Early 80s amp, made in USA from Japanese parts. I traded a like-new Kustom Sienna 65 Acoustic amp for this, so it's like it cost me around $250. Ebay has one on right now, a Series II for $300 with $65 shipping, I believe I got a bargain. The trade satisfied a home-playing guy who uses pedals, and wanted lass weight and wattage. I lucked out. We are both happy. Ain't swapping great?

Dimensions:
width 27-9/16"
height - 21-13/16" with casters on,
depth - 11-11/16"
weight - 64.5lbs.
Black Tolex with black and pewter colored grill cloth. Plastic heavy-ribbed corner protectors.

It's versatile enough to handle jazz, metal, surf, rock, blues, you name it.
2 Channel, clean and overdrive, foot switchable. Headphone jack. An extension speaker jack that I think lets you keep the main speaker engaged as well. Footswitch single jack on front panel for reverb and channel changing.
It would be nice to have 2 50 watt stereo channels, with chorus, but no big deal. What it does, it does well. Besides, a mono 100 watt amp renders more headroom for loud clean sound.

So far used it only at home in my studio, but I'm gigging with it soon with my band.

These transistors really sound like the best of tube circuits, and the background noise is quieter than the Roland JZ120.

The stock speakers are perfect. No need to upgrade. Each channel has its own three band EQ, and the parametric Q boost affects both channels, as does the reverb.

I really like the Q filter, with level and frequency sweep. It makes this amp take on whole different tonal character. A similar amp I tried wile shopping around had one basic sound, and that was all you got. Not this one!

And forget what others say here, the distortion is creamy, pick-responsive and wonderful. Nothing wrong with it. Not glassy and shrill like a lot of built-in overdrives.

It sounds like a great twin 12" combo amp should.

I'm using it with a Strat, (single coil , & prone to noise)a Yamaha SBC-100 humbucker style, and a Rickenbacker 330-12 string, which makes it really shine. Even without compression, it renders the same treble-rich jangle of the Byrds. With real guts in the mids and lows.

I swear, it has the punch of my old mid-60s Bassman when I dropped in top-line Jensens and hit some chords. You get a punch in your diaphragm like a parade passing by with a big bass drum getting malleted!

No noise at all on the last two, and if I angle the Strat right and keep a hand on the bridge, the line noise is minimal. FAR QUIETER than a similar Laney amp (GC120C) I used to make up my mind which one to get. Yamaha's the winner.
The reverb has four springs, a nice long duration and great tone. There's a pull-switch on the OD channel's gain to enhance mid-range.

It's efficient and LOUD. I dare not go above 1 1.2 in the house before the neighbor's ears hurt. It's mighty darn powerful. I had it up to 50% power in the garage with no rattle nor clipping in the clean channel.

I can see using this for Bass, lap steel and keyboards if needed. It's clean and rich enough to handle anything. I heard that the amp circuitry's the same as Yamaha built for their most expensive home audio amps.

It suits my styles well. Anything else will come from a multi-effects pedal.

Oh, yes; if you find one BUY IT.

It's over 20 years old, and should last.

It came to me dusty and ragged, but with a little a little Fabric-Tac to glue down the loose tears, a lot of vacuuming, elbow grease with rags and Simple Green cleaner and then a lot of Armor-All, it cleaned up like a champ; I brought up the deep black color and flexibility of the Tolex.
THen a little paint from a Q-Tip on sume rubbed screws, and they faded into the overall blackness.

Electronically, all pots dialed cleanly, no scratchy at all. Now it looks and sounds like new!

not applicable

I've played most of my life, starting in bands and as a solo folkie guitarist/singer in the mid 1960s.
I own a dedicated keyboard amp, a Fender Frontman 25r practice amp and an UltraSound 50 acoustic guitar amp. Scads of guitars and bass and other acoustic and synth instruments.

If stolen, Id beat the bastard, then sell is brain-dead body for high-profit organs. Then search for another amp, same make.

It sounds like the great tube Twin Reverbs of yesteryear, the first amp I ever bought, then traded for a Bassman when I found more work playing that ax.

The previous owner took off and lost the wheels, so I installed some new. It really needs an anti-gravity device to prevent back strain, or a helium balloon to hoist it for you! I mean, 65 pounds is major weight. It's also pretty wide, high and deep.

Solid state, 2 channels, great reverb, more than enough power.
Heavy!!! I bought it for the rehearsal room and its never going to leave it.

It was not noisy at all in my house.
In the rehearsal room it hums a bit. No hiss, though.
Sound is ok at all volumes. I dont need a preamp (thats great news when you play violin!)

The roland JC-60 is my favourite amp. The Yamaha G100 III is less trebly, which could be a good thing for many people.
Your ears and wallet are going to like this one.
But remember, it s heavy.

I have had my G100 212 mkIII since the 80S. I bought it new, I play hard rock and metal with it, I really like channel A its so clean and quiet works well with all of my effects pedals and the foot switch is handy to use to even though channel B the distortion channel is very muddy I dont care for the distortion but then I dont use channel B only on a linited bascis it can be ok as long as you keep the gain turned down.It does have effects loop controls on the back of the amp but I prefer to play through the boards and plug into the front of the amp.I use my amp in my studio in the basement I used to carry it around to my practice sessions was a little heavy for that.And I can honstly say that its PLENTY loud enough I don't normaly play it above 2 or 3 if you do better wear some ear plugs. It is a solid state amp so if your looking for warm fuzzy distortion you wont find in this amp.you need a tube amp for that.

I use a lot of guitar effect pedals 30 of them made by boss and I am very happy with the way my guitars sound through this amp.the range of adjustments on the front of the amp is a lot better than the amp I used to have it was a roland cube 100. The frequency responce of the G100 is a lot better too.It can handle the octaver I use with out getting all distorted with the low frequencys.I currently play a couple of eppiphone guitars,and a couple of gibsons through it as well as my guitar synth, they all have hummbucker pickups.The amp is got good sound quality at the volume that I use.

Personally I have never hade any problems with my amp ever.I am a fanatic about keeping it clean and I keep the dust sprayed out with those cans of air you use to clean your computer.

I have never had to deal with the company so I can not say.

I have been playing through this amp for 20+ years. If it were stolen I would try to buy another one of these amps it is ashame that yahama does not make these amps any more because they would sell.They could have done a better job on the
distortion but all said and done it was a good value for me.
the specs are as followes off of the original ad


output power 100W RMS@10% THD into 4ohms
speakers JA 3111A 12"(30cm)X 2
input level impedance -20db (77.5mV)/1M ohm
return input -10db(245mV)/20k ohm
output level 100w (4 ohms)
send out /pre out(10K ohm) -10db(245mV)
direct out (10K ohm) -10db(245mV)
phones (8 ohm) -11db(218mV)
gain A ch (input-sp out) 70db
gain B ch (input-sp out) 88db
A ch (input - send out) 33db
(return input -output) 47db
noise
A ch (all volumes at min) -52db
B ch (all volumes at min) -52db
A ch volume,treb,mid,bass,at max -42db
B ch gain,m.vol,treb,mid,bass at max -24db
P.EQ level + or - 15db
Q 035-3.0
Frequency 100-5kHz
reverb 4EB3C1B
power req 120V AC 60 Hz
power consumption 180W
dimensions width 27-9/16" (700mm)
hight 21-13/16" (554mm) with casters
depth 11-11/16" (297mm)
weight 64.5lbs (29.3 kg)
standard accessory double footswitch

loud speaker specs
speaker JA3111A G100 212 mark III
cone diameter 12" (30cm)
voice coil diameter 52mm
magnet weight ferrite 2.6
frequency range (hz) 45-7k
sound pressure level 1m/w(db) 96
rated input (w) 60
nominal impedance (ohms) 8
fo (hz) 58

Mine is a 1985 model, given to me by a friend over 6 years ago. The amp has a huge range of musical uses, after lending it to many guitarists in varying styles, I have found it to produce a huge variety of sounds ranging from death metal to blues. It produces a fantastic clean sound, yet the distortion channel lacks any real 'meat' to it. There are two channels, clean and distortion, along with a parametric EQ, presence control, spring reverb and an effects loop. It has immense volume with excellent feedback control if EQ'd correctly. It sounds incredibly warm for a solid state amp, and does not get muddy when the bass is cranked up on the EQ.

The amp can make a huge array of tones for many different styles, the parametric EQ is extremeley useful for shaping and contouring the sound to your needs. The clean channel only begins to distort at 8 with a flat EQ. The distortion channel does lack any real punch, it is useful, but will not provide a satisfactory sound for anything heavier than blues. Yet an Ibanez tubescreamer through the clean channel will provide masses of distortion possibilies. I currently play a Fender Telecaster Custom using the bridge pickup mainly, along with the aforementioned Tubescreamer distortion pedal. The sound is phenominal, and perfectly fits in with the 'heavy indie' band I play in. The amp is exceptionally quiet, provided it is used with a good plug socket. It can get a little noisy if used with a cheap 4 gang power splitter. The only reason this amp does not make a 10 in this category is the shortcomings of the distorion channel.

This amp is, pardon my french, a brick shit house. Mine survived falling out the back of a van, twice, and tumbling down a flight of concrete steps and subsequently colliding with a wall. Worked straight from the off. The only problem I have ever had with this amp was with the wheels on the bottom, one has begun to pop out making the amp sit askew, not to mention making it difficult to roll in a straight line. But then, wheels don't change how the amp works.

Have never had a problem, so have never spoken to them.

I have been playing guitar for eleven years now. I currently play this amp with the gear mentioned in the 'Sound Quality' section of my review. I would definately strive to find a replacement model of this amp if mine were ever to be lost or stolen. It has become such a mainstay in my setup, I can no longer imagine life without it. It's looks are kitsch retro, and it always grabs peoples attention, down to its eighties styling. I previously owned a Marshall valvestate 2000, which was by comparison, terrible. If you ever see one for sale, buy it. They generally sell for peanuts, but are worth every penny twice over.

year-unknown

versatility-i have had this amp for about 2 years now and i love it it has good sound output and i love all the nobs i can twiddle. i play a range of metal to rock to anything i can think of that sounds good wheater it be heavilly distoted or clean and pretty.it sounds awsome with any effects pedal i have used to play metal or any mellow songs. im can get decent distortion through the built in but i would like to get the manual so i can figure out how to fine to it to perfection.

channels-
front- input, head phones (have to unplug the speaker 1 for this to work), foot switch

back- ac outlet, 2 speaker jacks,-10db direct out, -10db output send with level adjustment 1-10, -10db input with level adjustment 1-10, red (to) white (from) jacks for the reverb

features-
has everything i need so no complaints

use- i use this at home, id like to use it to play gigs when i get a band started. and i know that it can handle it because i have cranked it in a studio and my uncle who sold it to me used it when he toured.

equipment-i am using a ibanez G10 with an HSS pick up setup. i no longer have a zoom 707II effects proccessor but when i did it sounded oh so sweet.

style- works prestine with metal playing and any other style

noise- only noise you get is the kind you want, awsome.

clean-sounds pristene

distortion- still fiddling with this one havent gotten a perfect sound yet but i like it still

brutality- who needs a marshal stack with this kickin you in the nuts haha

gigs- hell yeah im going to use this when i start giging

breakdowns- never works like a charm

i cant answer this one jsut yet i need to call yamaha to see about getting a manual

been playing a goo7 years now i think, i only own this amp electric ibanez g10, and a crappy accoustic that i cant name off the top of my head and dont have it with me to tell you.

if this amp was stolen from me id cry then hunt donw the fucker who stole it. id buy anouther but there not easy to come by i got lucky with this one.

love it cant hate it.

what was to compare this was a steal.

It's a 100 watt solid state amp, most likely made in the 80's. The heat sink on the chassis must weigh at least 5 lbs by itself. By this I can tell this was designed to put out the power it is rated to produce. There are two channels, clean and distorted. Each has its own set of tone controls, all of which are very responsive. Additionally, shared between both channels is a parametric equalizer. This amp has a presence control, and reverb. Oddly enough, there's also a headphone jack. Adjustable input and output levels for the effects loop, two speaker jacks, and a footswitch jack round out the features.

I'll give it a 10 for features. Lots of versatility on this unit.

I don't play any particular style of music, I just grab the guitar, choose an amp, plug in and just play whatever comes to mind, even if it's just a random jam. The clean channel (A) is very clear and well defined, with very little background noise, even at high volume. The lead channel (B) has adequate distortion, which seems to be very shapeable with the tone and parametric equalizer controls. Channel B is also relatively quiet, though there is a bit more noise due to the additional gain.

I'll give it a 9. It sounds damn good for a solid state amp.

I thought it was interesting that the amp was built in the USA, just the parts were imported from Japan. The amp hasn't failed me, and it seems to be built like a tank. One odd problem that it had was that only one speaker was working when I got it. I'm thinking, Oh Man, it's blown, but someone had attempted to fix it in the past by pressing the wire to the coil into some kind of putty. I scraped the putty off of the wires and resoldered it together, and bingo!

Some of the pots are a bit scratchy and the footswitch jack is missing the nut that holds it on. I had some extras and tried to put one on, but the jack's threads are stripped. Eventually I'll pull the chassis and fix these problems.

I'd say it's dependable. I haven't gigged with it though. I'd probably use it as a backup for my Classic 50. Of course, if the band was loud enough, this one would take the stage.

I'll give it an 8 for reliability. It's old, so eventually something's going to give... whether it's tomorrow, or years down the road. As I mentioned before, it appears to be built like a tank. I'll know more once I pull the guts and examine the inside.

Haven't dealt with Yamaha's customer support. I've had, and have some other Yamaha products, and I've been happy with the equipment I have that they produced.

No rating for this category.

If this amp was stolen or lost, I'd certainly hunt down another one, and hope the thief broke his/her back trying to carry it. Honestly I don't find it to be *too* heavy, I'm guessing it weighs somewhere around 60-70 lbs. There's wheels on it for a reason!

I looked at many amps when I bought this one. I'm a bargain hunter by nature, and this one seems to be a lot of bang for the buck. Honestly, based on my playing experience, which isn't a lot, I really didn't need something that powerful, but the deal seemed too good to pass up.

I also read the reviews here on this amp and the other used amps I looked at in this price range, and this one had the best ratings over many of them.

Overall, I'll give it a 9. It's a real beast of an amp, quite versatile, though somewhat heavy. Unless you're a tube purist, you'll most likely be happy with this amp.

Let me just tell you! Whether its blues on the neck, twang with both, or rock with the Bucker's you are hooked up!! Great reverb, and clean channel will make you smack your mamma! Dirty channel picks up high's, mid's, lows's and some you didn't know was there! For an amp that was made in era sinonimous with "hair" this amp is something else! Direct in for foot, head, and loops. Talk about POWER!! If Tim "The Tool Man" Built an amp, this would be it!

What other kinds are there? I use THE 52', 60', and 72' Telescasters. As I said before, from Country, to blues, to 80's rock, to death metal! With the right processor, this amp can do it all! Not much much noise, except who is playing! You can crank it as loud as your drums can stand, and get no crackle or breakup. Good distortion on the second channel! Your can control it better than most amps! With the special "Presence" and and "EQ"'s you can customize your flavor!

Well, I have a history of wearing amps out! I have been through about six (been through as in BREAKIN') in the last four years. This amp has stood by me, through it all. Make me treat it a little better! Can't go wrong...

Never dealt with them.... Shouldn't have to with this one...

If you find one buy it! That is all I am saying! If you pass it up, You Will Hate Yourself, and whatever you bought in stead!

I have been playing for 14 years, and have found nothing as versitile, and plush chunky sounding as this amp! Rock, Twang, and OHH all in one!

i bot this amp at the local pawn (man, did i luck out). it looks like its been in every bar from here to the missisip !. But, i like the way it sounded at the pawn, so i bot it. this amp has a lot of options on it, the volume tone pull out, the parametric EQ, presence, nice reverb, two channels(clean/OD). I just play for hobby, since i don't have time for a band. But, i've been playen for 11 years or so, and have had more guitar equipment than u can imagine. i think it has a lot of features for its time..........thus i give it a 10

i'm a blues guy, but like some jazz stuff (SRV Jazz). i have a SRV warmoth, texas specials and the seymour duncan hot rail in the bridge. i also have a ernie ball axis sport (sweet). I must say, this is best sounding amp i have ever played. the one thing i noticed was that the amp had a somewhat compressed sound. i guess what i mean buy that is that you got very good bite from the amp. very well defined notes. to me, this is what a amp shood be ! and is something i could never find. I'm not kidding !! i have had so many amps, and currently have the fender hot rod 4-10. i play the yamaha more. i can't get the bite from the fender. when i hear hendrix or SRV play, you can hear the brite bite they have. this amp provides that. I hooked my Digitech Rp-14D to the amp and got some unbelievable sounds.
this is my set up, and i highly recommend u try it. i have a BOOMERANG, the Digitech 14D and the Yamaha G100. i can come up with a rythm (hey joe, eg.) with a nice clean sound, kick in the RP14D OD, and just rip !!. best F sound i've ever herd. I think this amp work well with effect units. Seem like tube amps have a tough time sounding good with effects. I give this amp a 10 for sound !!

this amp probably dates back to 1980 something
still runs great
the knobs make a little noise when turned, no big deal
i give this amp a 10 !!!!!!!!!!

well, i have had yamaha DG amps. i ask them to send me something, and they did. i also looked into a cabinet for the DG. it was tough trying to find the right people, but i did.

i've been playe nabout 11 yrs. i have owned a lot of shitt and sold a lot of shitt. i'm getting tired of buying and selling, but i'm a typical guitar nut. currently, this is my favorite amp, i love it.
its not as bassy as my fender hot rod 4-10, but thats why i like the yamaha, its got top notch bite and is so responsive to adjustment.
i give this amp an overall 10 !!! it deserves it !!!
hmmmmm, i have never given an amp this high of a rating !!
yes, i wood buy it if stolen
if i find another, i'll buy it for back up

Bought this amp used from a shop going out of business. Has alot of features including two channels, volume/gain, bass, treble and mids on both channls. Pull pots on both the volume (Ch1) and gain (Ch2) which increase brightness. Parametric EQ with three controls. Master presence and a very good reverb. Headset and footswitch front outs. On the back it has a courtesy grounded plug with ground switching. Extension speaker output. Effects loop with individual gain controls for both the send and return jacks. Also has a direct out. I think Yanaha was way ahead of the game on this one. I mean this amp was prouduced in the late 80's!! Two Yamaha 3111 12" 120 watt speakers with the amp rated at 100 solid state watts RMS.

Very versatile. I am playing a Gibson 135 with P-90's and a Godin SDxt configured with H/S/H. I am using this amp in stereo with a Traynor CV40 tube amp ran through a Digitech RP300 and am getting some really good sound. This baby can get really loud so I rarely run it past 3 with the Traynor at 4. Like alot of solid state amps the clean channel is really nice and since I don't distort very much I really can't comment on how it would behave really cranked up. I play mostly Jazz and standards and it fits my needs to a T. I do get some single coil hum when I run the guitars straight through it but I guess this is to be expected.

So far so good. I have had the amp about five months and play through it everyday. This amp was used as a rental by the shop I purchased it from so it has had a work our and seems in great shape. I had to tighten two of the imput jacks but other than that it seems solid. On that point, this amp is a real heavyweight. It weighs around 80 lbs so thank god its on casters! Any amp that has been around for over 15 years and still sounds this good with it's original speakers gets a 10 from me.

I have read some postings stating Yamaha customer service was almost non-existant. Well, I called them on this amp looking for a manual and some imformation on when the amp was made e.t.c. They were very helpful, gave me the year it was manufactured, which artists had and were currently using the G100 series amps and even gave me some history on the amp and its development. They are going to send me a manual when it is available in June. This sounds like good customer service to me. I think they went out of their way for an amp this old and out of production.

Been playing on and off for over thirty years. Own and have sold or traded too much gear to list. I was looking for a reasonably priced 2-12 combo to run in stereo with my Traynor combo. Looked at a few new combos but kept comming back to this guy for its overall sound and it's myriad of features. Only negitive is it's overall weight, this baby is heavy but puts out a really nice tight sound. If it were lost or stolen, I would buy another one in a minute. The only trouble would be finding one.

I bought this Yamaha amp (G100-212-III) from eBay for about 412$.
It has 2 channels ( clean, distortion), reverb, presence and parametric EQ. It is versatile for different Styles ( From Blues, Jazz to Rock, Punk, Grunge, Alternative and even Metal).
I used it often live and it works and sounds great. You get a lot of features for versatile styles with this amp.

I play a Fender USA with DiMarzio-Pickups. I get everything from nice clean tones to hard distorted Sounds. Works best for using effect-pedals ( like I do now: Boss MetalZone, some Reverb and a WahWah).
But the sound without is great too. Everything from Jazz, Blues over Rock to Grunge, Punk and Metal. The distortion can get very dirty, but is always defined. Very good!

Never had any probs so far! I can play without a backup on gigs. It's a ten...

Never dealt with them, that's a ten too...

Nice amp for a low price. The two speakers make a good sound. This thing is versatile enough for any kind of music... Good lady!
For this price it's a very good amp. Will lead you on the way to your Mesa Dual Recifter... ;)

I bought this Yamaha amp (G100-212-III) from a frend of my fathers for about 100 bucks. It doesn't say the year that it was built but i'm guessing it's not very new, probably mid to early 90's.
I play a mix of Rock and punk Rock, with the occasional light alternative music, and this amp is really good for each of those styles. It comes with 2 channels, reverb, presence and parametric EQ, which is enough to give you just about any sound you want (my opinion). the only problem i have is that it's a bit bulky and with all the crap i lug around to each gig it would be nice for something a little smaller, but i highly doubt i'll be getting rid of this amp any time soon.

As i said above this amp provides a lot of variety. each channal has it's own volume, treble, middle, and bass, but channal 2 has an extra knob for gain. and if that's not enough for you, you can also pull out the volume (on the first channel) and/or the gain (on the second channel) for a mid boost. that's nice for those songs that you just need the little boost on. In the Paramatic EQ, there are three knobs, Level, Q, and Frequency. It also has a Presence and Reverb, so i don't think you'll be getting to bored with this puppy for awhile. i'm not to sure of the sound quality though, because the guitar i use is a foreign peice of junk that was never grounded right, and for some reason no matter what i do i can't fix it, and neither can all the shops i've taken it to. So i get the hum that comes with an badly grounded guitar, and i'm sure it's not the amp. i do know that when you get the thing cranked up to full on the volume and gain it doesn't get very distorted, so that's a plus, and when you get distortion on this you're ready for any size theater. (but watch out, apparently neighbors find it to loud sometimes, i now have about 5 different cops that are tired of coming over, lol)

alright, i've had this amp for about a year, and the only problem i've had with it (and this is from day 1) is that some of the stereo fuses blow a lot, and about a week ago they've really started blowing out, and i can't figure out why. i've blown fuses right before i've started a couple of gigs, and so i could've used a back up sometimes. as for the fuses, i've had no other problems with it.

The fuse problem has sent me searching for any kind've wiring schematic for this amp. first place i went was yamaha's website, did it help,....... HECK NO, if i spent about an hour searching the site or a couple of days with it's tech support maybe i'd find something but i don't have that much time. so as i searched for a site that might help i ran into this one and thought i'd leave my oppinion's before continuing the search. (that's why these aren't to detailed.) so for right now customer support is kind've low.

I'd buy me another one if this was stolen, but i doubt i'd be able to find another one. it seems like it's not a really popular one and therefore i haven't seen this model around much. i have yet to compare it to other products but i don't think i need to, i'm confident in it's sound and plan on using it for a very long time.

This solid-state combo has two channels, switchable by optional footswitch, each with its own 3 level EQ. It also has a parametric EQ, an effects loop, a line out, a headphone jack, and reverb with presence control. My only wish would be for stereo input and output; someday I'll buy a Mosvalve power-amp to take care of that.

This amp sounds incredibly nice with my Yamaha 712 Pacifica, which has a Dimarzio humbucker in the bridge and hum-cancelling stacked single coils in the mid and neck positions. After some initial fiddling with the EQs, I was able to find settings which gave me a great selection of crunch, glassy sparkle, tubish mids, or hollow acousticity. VERY versatile.
Unfortunately, I've yet to find good settings on this amp for my Fender Strat. It sounds ok, but not nearly as nice as the Pacifica. This strikes me as odd since my Strat normally sounds much better on most amps than its Yamaha brother. I think this may be due in part to the Strat's maple neck instead of the rosewood neck of my Pacifica.
I'm in love with the clean channel. It sustains nicely at high volumes, without overdriving too much. The gain channel sounds poor on most settings but can be improved vastly by fooling with the Parametric EQ. Personally, I like taking a lot of the mid out of the gain EQ, but pulling on the mid boost on the gain knob at the same time. The concept sounds like a contradiction, but the result sounds nice to me. For killer distortion, I plug my Big Muff Pi, Ibanez Tubescreamer, and MXR Distortion + (EQed to boost mid) into the effects loop (mixing the Muff and the + with a Boss LS-2).
When I want to play really loud and get great sonic solos, I use my Tech 21 Sansamp GT before the input. It can sound just like a pricey Marshall stack. Though if you do this too much, you might not be able to hear the difference (or anything else) after a while. :)

It's never given me a problem, though the Yamaha plate broke off the front, and it looks quite cosmetically degenerate. Could be a plus, for some people. :)
A guitar tech I know and trust tells me that "Yamaha stuff" is well made, reliable, and solid. I've had a Yamaha effect pedal die on me once, but otherwise he's been absolutely right.

Yamaha never answers my questions. Luckily, the local music shop people have been very good at helping me. (They told me to disconnect the speaker in order to use headphones, for instance, when I thought my headphones simply didn't work.)

I like this amp a lot, sound-wise. It's rather heavy to lug around, and the power plug is only two-pronged (so be sure to use a surge-protector!) You'll need to fool around with the settings to get the sounds you like. If you play it in a store and think it's a piece of shit, it's probably just the settings that need some tweaking. Once you get your sweet-spots set, though, it's easy plug and play.
Generally, I'm not interested in big combo amps. I'd prefer to have a nice pre-amp, a good power-amp, and some FLITE cabinets. That option being financially impossible for me, I'm happy with the G100 and, for the price, would definitely buy it again.