B-52 Pro Audio AT-100 Tri-mode Rectifier Head

The amp was purchased in 2007, I don't know when it was made. I bought it used after the original owner replaced the tubes. The Amp is one of the most versatile tube amps on the market, even not considering it's insanely low price, and can handle any style of music fairly well. It comes with two adjustable gain channels, and these channels are definitely the same assuming you have the same settings on them, though some people may imagine differences. It has a contour knob which is assignable to either or both of the gain channels and separate volume and gain knobs for each channel, though they share an EQ. The clean channel has an independent EQ, a "bright switch" which boosts the treble, and it's own channel volume. There is also a low-resonance control, which adds some serious power to your low end and is a feature that needs to be included on more amps! It makes your palm mutes sound really amazing and forceful without making your sound excessively muddy. Finally, it has a reverb control which applies itself to both channels. Whew! That's a boatload of features, now let's talk about their faults. Obviously first of all there's no eq for both gain channels which limits the amount of customization and differentiation between the two gains, not a huge deal really. Then there's no presence knob, which really hurts the overdrive channels. It's not so bad for the clean channels s ince there's the bright switch to boost the high end, but for overdrive channels I found the lack of a presence knob very inconvenient. Finally, the reverb is close to useless and very weak. You'll need reverb from another source. I use the reverb mostly on the clean channel, the cleans sound pretty "wet" without the reverb enabled, but when you do enable it the difference is much too small. While the b-52 is a very versatile amp with some unique features like the low res and the contour knob, you're going to need some pedals no matter what. I play a few styles of music, primarily death metal, doom metal, post-rock, ambient, and jazz. For this I needed extremely high gain capability as well as fenderish cleans, and not any need for medium gain crunch. b-52 delivered for the most part but wasn't without it's flaws. The b-52 at-100 also includes a 3 way rectifier switch, included mostly as a gimmick so that people will compare it to a mesa. There's definitely a slight difference though.

I'm using 2 different guitars, an Ibanez RG120 with stock pickups tuned to B standard and a cheap Squier 7 string tuned down to A standard, also with stock pickups. The amp has enough gain for extreme metal styles, technically, but you'll need to turn the gain up to 8 or dime it to get there, and that causes a great deal of fizz. I stuck my line 6 toneport, which is sort of like an expanded computer based POD, as a preamp and that fixed the gain problem right up. I could roll down the gain to 6 o clock at most and still have just the right amount of gain using some of the pedal emulation in the toneport as well as the noisegate. This amp is VERY VERY noisy in the overdrive channels, you will need a noisegate no matter what. It's not noisy at all in the clean channel. The distortion is very good overall, it doesn't sound like a Mesa or a Marshall as many people claim. I found it sounded very very similar to the peavey valveking actually. With the contour knob, it can be smooth and midrangey, scooped and brutal, or a slightly grainy but very warm midrange tone without the contour engaged. The 3- rectifier settings make a slight difference in the overdrive sound, tube A sounds really grainy to my ears but is very well suited toward medium gain type sounds, tube AB is perfect for monster gain balls out metal sounds, but it's still a little warm. Solid state has a treble with a little more attack and slightly tighter bass, but sounds a little more sterile. The sound is a little muddy, but that's likely a result of me tuning down so far while using cheap stock pickups.
The clean channel is where this thing really trumps almost the other high gain amps on the market. The B-52 at-100 is really special because while it has almost as much gain as the big boys, the mesas, the 5150s, the Marshalls, and the ENGLs, it doesn't sacrifice so much from it's clean channel. If you need fenderish cleans but also want brutal chunky distortion that isn't thin and fizzy like fenders, you can have it for much less money than you could one of the "boutique" tube amps. The clean channel has a lot of customizability, can sound really sparkley or really natural and acoustic. It doesn't break up at high volumes at all and stays crystal clear. You will need some outside reverb though unfortunately.

Haven't had any problems yet.

Haven't dealt with them.

I've only been playing about a year and a half, the only other gear I own is a cheap marshall practice amp and a line 6 toneport which I used stand alone as a modeler for a long time before making the leap into tubes. If it were lost or stolen, I'd have a tough decision between this and a 5150(the holy grail of extreme metal). If you're mostly a metalhead looking balls loads of gain and don't really care about the cleans, don't buy this amp, either save up for a single rectifier or go with a 5150. If, however, you plan to make extensive use of the clean channel and don't want to have to use the ****** clean channels supplied on most high gain amps, this is the amp for you. You can do anything from jazz, blues, classic rock, country, or heavier styles like extreme metal or hardcore. This amps main selling point is it's versatility and it's unique features. You will need some pedals in front of this thing though, but as it's around a 3rd of the price of more popular brand names which are barely better, that won't be such a problem. 8.5/10.

I use this mainly for metal/hardcore. It's got a nice clean channel and two brutal gain channels. I really like being able to change the tone of the two gains by using the little switch (contour, I think it's called.) The only thing I wish it had was seperate EQ's for each gain channel. For the price, I understand it can't have everything. Overall, quite a decent arsenal of features.

I'm a metal/hardcore geek ala Crowbar, Corrosion, Clutch... anything beginning with the letter 'C'. I currently run an LTD EC-500 with EMG 81 & 85 straight through into an Avatar 412 with G12T-75's and V30's in an X. The distortion is chunkier than a mofo as-is and I don't need to run any pedals. It can be very hissy at high volumes (which it always seems to be set on), but I'm used to it. I may get a noise gate or Hush pedal in the future.

I had this head for about 3 months and noticed an annoying "ringing" after I would palm mute anything. I bought some new Sovtek tubes for V1 and V2, but no change. So, since I bought the GC Performance Guarantee, I shipped it off to Akron for a two week vacation. The tech told me that the Sovtek tubes I was using were probably louder than the stock Chinese ones that it came with. He did a bunch of tube switching until he settled on Svetlanas. Seems to really have quieted down the ring. I'll probably replace all the Chinese tubes with Svetlanas soon.

Customer support was awesome. They will email their schematic and tube chart if you just call. I spoke with a guy named Todd and he was top notch. When my warranty runs out, I plan to use an authorized B-52 service center which I found much closer to home.

Features wise the amp is a little above average due to the rectifier select switch. That feature alone actually makes is pretty versatile. it also has an effects loop, channel switching (switching between clean and overdrive, then between the two overdrives). its 100 watts of tube power, so its a little bit too much for my uses right now. i pretty much use every feature with the exception of the effects loop.

first i use ibanez iceman guitars pretty much all around, one with the stock pickups and one with emg 81s and 85s. obviously the emgs scream a lil more than the passives. imho, it works very well for blues, classic rock and (dear i say it) metal. if you take some time with it u can pretty much get any style out it. the amp is noisy though, with the gain set to the highest (obviously) you can barely make it past 3 on the master volume. and even going down with the gain and up with the volume it is still quite noisy. and i agree with the user below, the effects loop is pretty much crap. the clean channel is clean at pretty much all volume levels, and it has that bloom you kinda expect from a tube amp. probably the best feature/channel on the amp. the distortion is pretty awesome as well, albeit a little noisy as i stated before.

ive only had the amp about two or three months and so far so good. its an electronic so anything is prone to happen, thats why i got the guitar center performance guarantee so im covered either way. the amp does run pretty hot in class A mode (you know THE MOST IN EFICIENT MODE EVER CREATED) which of course its going to especially at higher volumes. you'd have to be a fool to not realize that. i put a fan on it and im not too concerned about that anymore. oh, and the tolex scuffs easily, but im not putting it on my mantle for show, so i dont care about that anyways... it could completly fall off for all icare.

never used em'

ive been playing for about 6/7 years and before this amp i pretty much stuck with solid states because i like aconstant sound. i also have a valve jr head, with weeping demon wah, whammy, a various other nick nacks to keep me tinkerin. if it were lost or stolen, id be up for parole in about a few years, but depending on the loot i had at the time probably. i love the versatility of the amp, not so keen on the noisiness, other than that all pluses. i love the tone, as its pleasing to my ear (which every one seems to forget, tone is subjective). after comparing it to the spider valve, the windsor, valve king and various other favorites of people who fear taking chances... pound for pound sound for sound this guy won out. if it were less noisy id say itd be the best bang for buck amp. as far as the whole, this amp sux because its not built well, id had marshalls die out on me for no reason, so dont give me that crap. the honest truth i could say is go out and try one, i mean really try one out and form a decision for yourself, i can stand by that statement.

For features, this is an average head. Anymore, there are so many options on channel-switching heads that you can spend a few days just learning how your amp functions. The AT-100 is much less so. I liked the rectifier select, although the best-sounding setting (Class A) ran the amp a little too hot for comfort and the solid-state rectification sounded too inarticulate and lifeless. So there's really only one rectification setting that was worth using (A/B).

The switchable reverb is a plus, but it's so weak, it's not even worth having on the amp!

The two gain channels are identical. Those who think they sound different are imagining things. They're voiced exactly the same. Additionally, the contour function saves the preamp voicing on the gain side from being altogether too midrangey. The gain also does not clean up well when you back off your guitar volume. Medium and low gain sounds are about impossible to dial in, unless you overdrive the clean channel which sounds OK.

The effects loop distorts easily and sucks volume when engaged making it impossible to use modulation effects before the power amp in anything approaching a usable tone.

The master volume also sucks tone. If you run it at anything less than 10, it removes some of the high end from your signal. Hence, I tended to run it maxed out and used individual channel volumes for adjusting loudness...which means that the master volume was a complete waste of a knob.

I'm using mid-output passive humbuckers (JB's, Tonezones) in all my guitars and I think this amp might be suited better to active pickups. The AT-100 is not an especially responsive amp. Considering it's price, it does sound pretty good, but it's failings in reliability and build quality ruin what should be a very good amplifier. (See above.)

In addition to what I've already mentioned, the gain channels are NOISY. I do understand that high gain comes with a certain amount of noise, but the noise level of the AT-100 is not acceptable. Your clue that B-52 understood this fact are the EH preamp tubes that come standard in the V-1 and V-2 positions. EH 12ax7's are known for eliminating unwanted hum and microphonics, and after testing EH pedals, I can see why this type of preamp tube was developed by EH (i.e., EH gear is F'ing NOISY). So, rather than tweak the preamp circuit (which takes time and money to engineer) they decided to cut noise by installing preamp tubes guaranteed to minimize preamp noise. The problem with that of course is that the preamp is STILL NOISY as hell! Add to that the fact that EH tubes are crap tonally. I replaced them with sino 12ax7's in all positions and was rewarded with much improved tone, but with the ever-present noise still intact.

Adding an EQ in the effects loop helps the gain channels a lot, but is a hassle because of the mind-numbingly bad loop (again, see above).

The clean channel is good, except that it suffers the same problem with the master volume as the gain channel (see above), although, it isn't so great that I can understand the hype about it. It's decent, that's all.

Why did I buy it in the first place? I liked the gain sounds with the resonance turned up, and for some reason I can't quite understand, all gear sounds better in the store than it does at home. I should start to compensate for this effect somehow and save myself the trouble of cycling through so much gear. But anyway, the gain channels when dialed in well have a very nice bloom to them, very much like a triple rec. Note however, that this is primarily due to the Sovtek 6L6WXT's that come standard. I changed them out with EH 6L6's and was flabbergasted at how much worse my sound got. So I put the Sovtek's back in and left them. I'm now a Sovtek fan and I can understand why Mesa and Fender tend to use them as stock power tubes.

All in all, the price is great, the sound is ok, but B-52's manufacturing problems and poor design erase what value this amp could have.

The reverb is practically useless. The master volume is a complete tone-sucker. The effects loop distorts easily. And the class-A rectifier setting is harmful to the amp. The tolex is extremely fragile. The amp always runs hotter than it should.

Add all that to the fact that this amp has a reputation for shoddy performance and reliability, and this amp is officially a dud.

It's just not worth the money no matter how cheap it is.

I traded this amp in before it developed any major problems. I count myself as lucky.

If B-52 ever decides to address the problems inherent in their materials and manufacturing of the AT-100, they could be producing a very, VERY respectable high-gain head. As it is, it's not worth anyone's time. I realize that this is a budget head, but an unreliable amp won't save anyone money no matter how good it sounds. And, since the B-52 leaves a few things to be desired sonically, I don't see the advantage of owning one. Save your money for equipment you can depend on!

I would be extremely hesitant to buy any B-52 product at this point.

ok, so like i got one of these B52 at-100s after reading the reviews on this site and elsewhere, and it pretty much lives up to what is said. i've had it for two months now and it's louder than hell, the clean channel (with the brightness switch) sparkles beautifully, and the distortion is pretty decent (tho being more of noise guy, i could use a bit more fuzz - but my metal friend was able to dial in a pretty mean and heavy black metal sound quite easily). however it sounds good with all of my pedals, so yeah, i think it's actually quite versatile for the price and what you get. definitely a good starter for a tube amp, which is how i've approached, as it is my first tube amp and i wasn't ready to drop 2-3 grand on an amplifier. it's definitely an upgrade from my $350 crate amp, haha! and i've definitely already damaged my ears with the damn thing. gotten wear them earplugs everytime, cuz this mofo is loud!!

ok, so i guess you gotta replace the tubes, that's pretty much a given, tho i reckon it sounded decent with what it had. the reverb tho, was crap as the reputation preceded it. mine barely worked at first, so i contacted the company, and they said if i shipped it to them that they would fix it and ship it back for free. but at 62+ pounds, that was a no go. anyway, it crapped out on me entirely after a month, cuz the springs are ***** and just popped completely out, so i just got a new tank put in. still not terribly wet, but i'm gonna get a holiest grail eventually anyway, so whatever.

well i blew out a preamp tube after a month and a half right as i was getting ready to do some recording, so that sucked, and the line out seems noisy as all hell, but maybe that was cuz the tube was about to blow out (but it seemed like it wasn't grounded properly).

took a couple days to hear back from tech support when i had issues with the busted *** reverb. the warrently is pretty worthless cuz it'll cost you as much to ship it to them for repair as it will to get it repaired in town.

i'd say this is a solid starter tube amp. i will probably upgrade in a couple years or continue to mod it out as needed. it has all of the fundamentals for a really affordable price and the sparkling clean channel really is bright and sunny. really the main issue is that it is heavy as hell and is not balanced in weight (the left side is way heavier than the right side). it's hard to move around becuz of the way it is weighted and i'm almost always afraid the top holder strap is gonna rip off and the thing will fall crashing to the floor.

I went through 4 of these pieces of ****....... they all seem to have the same problem with the OUTPUT TRANSFORMERS, the first I owned for about 6 months and then it died.... so I got a new one thinking it was something I did... (not owning a Furman and all)
The 2nd one I took it out of the box and it came dead.
the 3rd one same issue as the 2nd one.
finally I had some luck with them 4th one..... and then when I thought I had gotten rid of the bad stream of luck.... It died again. But the sound was ok for the time being

NOT RELIABLE..... you will spend more money buying new ones that it will just be worth buying a Laney, Mesa, or a Marshall from the get go.
I highly suggest to not get this amp..... you will regret it if you aren't the kind to switch your pwr tubes once every 3 months at most.

Customer support is terrible.... they have some ******* frech dude working there who doesn't know what the **** he is doing.

crap

Some features on this head are really cool...some not so much. I'm actually on my second one and I noticed that, along with a $200 price drop since I bought my first, some of the quality has gone out of these. Most notably, the preamp tubes on my first one were EH 12ax7's (and one 12at7) which are fairly decent for stock tubes. My new head came with these cheap-as-hell, no name Chinese tubes(the same kind they put in ART Tube MP mic preamps, which if you're smart you'll replace imediately). So it's pretty much a given that you'll be spending over $100 to replace them right off the bat. I went with GT's this time. I like JJ's too...lots of balls. Wasn't too happy that I had to spend the extra money though. I the rectifier tube in my head was also faulty so I replaced that with GT 5AR4. The only good thing is that if you can't replace the recto tube you can just use the solid state setting on the head and it will still work. The power tubes are sovtek's which are actually not bad at all, though I plan on eventually rebiasing my amp for KT88's.

As far as the amp's functions: I've been using the head for about 3 years so I'm pretty used to it. The only thing I wish it had was a separate EQ and a switchable (on/off) contour for each overdrive. Besides that the amp is darn good. Really loud when I need to be and sounds better the higher I crank the volume. A half stack is more than enough for pretty much any mid-size club.

I play metal and that is what this amp is good at. I don't think it would be right for softer rock styles.

With high output pickups and cranked gain it can get pretty noisy depending on your environment. I don't really get any radio signals through it but I do get a lot of noise from lights and other electronics. The best tip I can give if GET A VOLTAGE REGULATOR AND A POWER CONDITIONER. It's the best thing I've ever done for my tone. A good Furman will clean up all the excess distortion from dirty power and makes this amp sound like a million bucks.

As for the sound of the amp: the clean channel is ok and will sound good or bad mainly depending on what kind of guitar and pickups you use. Lower out-put pups will probably sound best if you want a really really clean tone. Going through the low input, higher output will push the clean channel when the volume is at 11 o'clock or higher. The high input jack can be really friggin loud on the clean channel and this may not be a good thing because it's harder the balance the two channel volumes. As far as tone, I'd say the clean on this amp resembles a marshall somewhat, depending on what rectifier setting you use.

The Overdrives on this amp are very good. Without the contour on, I'd say they resemble a high gain marshall as well. The mids are really pronounced and the lows have great crunch as long as you don't go nuts with the low res control. The red channel seems much drier than the green and a little darker sounding with emphasis on the lower mids. The green channel has much more gain and more emphasis on the higher mids with slightly rounded off highs. Great as a lead boost since it also seems to be a bit louder than the red channel and has more sustain and harmonics. I usually have the red channel gain at around 2 o'clock and the green's back at 11 o'clock so I have good crunch and clarity on both while emphasizing the differences between the two. I also set the red volume higher to even it out with the green (both volumes are at around 3 o'clock where they tend to sound best). Low res at about 9o'clock and everything through a BBE and this thing really rips.
I don't use the contour at all. I agree with one of the other reviewers who said that it makes the amp sound kind of weak. It seems to be an attempt to make the Mesa recto sound available on this head but I just don't think it works to well. I've used Mesa's to record and they sound much more powerful. The mid contour on this head tends to cut the presence from your sound too so I stay away from it. I think I'd just go with a pedal if I was really interested in that particular type of distortion tone.

My first one actually burned out on me a few weeks ago (almost exploded). It was an internal electrical problem most likely caused by bad power in the room I rehearse in. Never had any problems with it before that and I got a Furman conditioner and regulator with my new head to make sure it doesn't happen again. I would and have gigged without a backup.

Never dealt with customer service. The only repairs I had done was a rebiasing on my first head to replace the power tubes. I think it would probably cost too much to have my original head fixed up so I just bought a new one.

I've been playing long time and although I don't have my dream rig yet, I'm satisfied with this amp as a center piece to my set up. What i love about it is that it tends to surprise people in the other bands I play shows with. A lot of people don't expect this amp to sound as good as it does. You just have to figure out what it's good at doing.
What I hate about it is that it's heavy as hell and it doesn't feel like a quality piece of equipment compared to some other amps. My bandmate has a Framus Cobra and just from picking it up it feels like its worth the $2500 it costs.
But all in all its a great product. Probably the best of all the cheaper tube heads that are becoming available now. I compared it to a Peavy Valveking and I like the B52 much better. It has way more attack and raw power. Of course a VHT Deliverance 120 will blow this thing out of the water but what else could you expect? Until i win the lotto I'll just happily stick with this amp.

B52 AT100 yeah ok I bought this amp from my friend, and it seems he got gypped! for one thing, the circuit he got is not reliable! Why does it always seem to blow a voltage regulator when we go to a gig ???
why do they advertise a birchwood Plywood cabinet when it is particle board. and last but not least all tube means ALL TUBE not 4558s with tubes. MY advise is to stick with a Fender Bandmaster or AMPEG or Marshall or other alltube design and not a falsely advertised hybrid
Signed
Arthur Wayne Smith

NO

I can never seem to contact them
it a good thing I rebuild old fender amps and have a large collection of marshal schematics

Way Cool Triple Mesa Knock-off!
Three channels with footswitch for efx and reverb
Ohm selectrot on back
effects loop

Played a mex tele thru it at guitar center yesterday!

Clean channel- nice and spanky, eq. has lots of control
Couldn't get a believable surf tone with verb. I don't
think it was intended for surf though. With the neck pick-up I
got very cool clean chunky fat rythmn tone! SRV-ish.!! VERY GOOD!

Channel two- Great chunk, plenty of guts for hard rock, switched to
the bridge pick-up and ran thru some power chords very pleasing!

Channel three- Very heavy distortion, excellent crunch,with the contour knob you can flip between Mesa/Marshall fairly convincing
tones. I played this for about a 1/2 hour and it kicked out good tone for the money, $599.00 list, I bet I could get it for 5 if I tried. I'm giving it a 9, only because I own only tube amps and this amp would benifit greatly with a set of Grove Tubes or Sovtek. The price to retube this head would be pretty steep, This is one rweason they are selling it for so cheap.

As I was playing ch3 the amp volume died! Right in front of the GC Sales Guy, hehehe..Channel 1 & 2 were fine, most likely just a tube thing. We fiddled with it , powered off and on, and it did it again, only on ch3...hmmm....?
The amp is new at GC and it is not functioning proper after 1/2 hr of demo. It pains me to write this cause the tones are excellent and I like this amp and will be watching reviews closley to see how it works in the future. A big fat 5.

I've been playing since I was ten, I'm 41 now, not that I sound as good as I should! I went thru the 80's rack gear thing, playing in metal bands in so. ca. I'm into tube amps now. I have great collection of them, plexi, twin ,deluxe, champ etc. I like the B-52 for the fact that it pays attention to all types of styles, you can get alot of cool tones out of it for under 600.00 a fraction of cost compared to a JCM or a Boogie, So for those who can't afford the Benchmark there is now an option, Way Cool time to be a player. Go tube! Even a cheap tube amp set up right will out perform a solid state job hands down, furthermore when we say a tube amp we mean
Tube preamp and tube power stage! None of this hybrid stuff!

100w all tube power, 3 channels, global resonance and reverb, master volume, tri mode rectifier (class a, ab, and solid state modes.) assignable countour control for overdrive channels. Made in ~2004

This amp sounds great for the money with the stock tubes, but you won't believe how much better it will sound after you change the preamp tubes! The stock tubes which came in mine were crappy chinese tubes that were pretty harsh sounding, the power amp tubes however are very good in my opinion (sovtek 5881 wxt's). I replaced all the preamp tubes (except for the phase inverter) with sovtek 12ax7wxt+s, the reverb 12at7 with an electro-harmonix 12at7, and the rectifier with a groove tubes 5ar4 and wow! What a difference! So much more clarity and warmth and alot less noise as well! This amp has a very sweet clean channel that you wouldn't expect for a high gain amp, you can peg it pretty far and it won't break up much at all. The overdrive channels are definitely intense and depending on the settings, are reminiscent of marshall and mesa amps. Overdrive 1 is chunk city and is what I use for distorted guitar at all times except for solos, I never take the gain past 2 o'clock as it loses definition and gains noise past that mark. overdrive 2 is similarly voiced to #1 but has more of a smooth, silky quality to it and less "chunk". It has more gain than #1 so I usually set the gain lower than gain 1 to retain some defintion. The assignable contour knob is an essential element to getting the sound you want, it is basically a midrange filter that will scoop or boost your midrange. I keep mine pretty much up the middle @ 12 o'clock for my desired tone. the global resonance feature basically tunes in how much low end "oomph" you want from the amp and is very usefull for tuning the amp to the room and the other instruments you're playing with. The tri mode rectifier further tailors your low end sound. class a has that classic tube "sag" to it, very warm and vintage in tone, great for classic rock, blues and mellower tones. Class a/b ads a little more chunk and definition to the low end and is my personal favorite, it seems to keep just the right balance of warmth and definition to my tone. The solid state rectifier setting is very chunky but ads a sharp attack to the high end as well. This setting doesn't please my ears as well as the other two. It seems a little harsh to me, I think some death metal guys would like it though, just because it ads some brutality to the sound! The reverb is pretty good, not the greatest spring unit I've ever heard, but not bad at all. Overall I rate it an 9 for stock tones with stock tubes, however with replacement tubes I'd rate it a 10! (I don't know if a perfect "10" even exists!)

It has not given me any problems to speak of, alot of people get these amps with broken reverb units for some reason, I guess I am fortunate and received a pretty solid one. The vinyl that covers this amp is not the most durable material and will get scuffs from being gigged if you don't have a case for it.