Univox U1246 B Group Head

This is an update on my preveous review.
Well after having more time to try different things with this head & dialing it in, I've found that this amp is just a sleeper.
If you lust for plexi Marshall JTM45 tone but with lots of bottom end clarity, you need look no further, the trick is to boost the front end with about 15db of clean boost with a hair of treble. Without an attenuator, it's about as loud or maybe a touch louder than a cranked JTM45.
I use strat's mostly & this is how I set up the amp....
I just plug into channel 2's bright input & crank it full, the pull treble boost doesn't make much of a difference when the volume knob is full anyways, the bass is set at 11:00, the mid is full, the treble is at 2:00, & the presence is full.
I use a late 70's Big Muff that boosts the signal about 15db with a hair of treble, even when it's off, this is my not so secret weapon, but unfortunately, I havn't found another Muff that does this, I'm still looking though.

I have this head running a Marshall TV cab loaded with pre-rola G12H30's 75hz which may also have something to do with how well this amp does the plexi thing.

The amp sings with sweet overtones & gets nice & crunchy when the guitar's volume is full, when you turn down it gets cleaner but the ring & the sparkle is still in the tone, it translates dynamics wonderfully & changing to different pickups yeilds dramatic tonal variations, this is a killer amp for the price.

I tried to get a bit more gain by changing the 12AU7 out for a 12AT7, but it didn't yeild the results I was hoping, it just made the bottom end less tight & refined.

So far so good!
I check the trannies after I play for an 1&1/2 hour straight, the OT doesn't even more that luke warm, the PT get's pretty warm, but not hot to where is hard to hold for any length of time, this is normal.

NONE

I'm loving this amp!
If you get one of these, try it boosted, but not so much a mid boost, a treble boost is good as long as you can dial out the treble enough so that it doesn't get nasty, my turned off Big Muff does this perfectly.

I don't know when this amp was made, I'm not shure how to find out the age, but it looks like an early to mid 70's amp by the look of the graphics of the logo.
This amp is pretty bare bones, but it's all I need, as I don't use reverb, I don't like loops, I am into the less is more aproach when it comes to the amplifier itself because I use pedals, so the simpler the amp the better I find it with boosters & overdrivers & fuzz.
The amp is similar to an old 4 input Marshall in it's layout, 2 volumes, treble mid, bass, presence.
Volume 2 has a pull boost function but I don't think mine is working because I don't notice a difference.
60 clean watts & it's loud enough for rock-n-roll, it came original with 2 mullard 12AX7's, 1 mullard 12AU7, & 2 GE 6L6GC's

I play a strat with single coils mostly & I'm not into hot pickups, plugging straight into this amp, it gets loud & clean, it sounds very close to an old Hiwatt clean when dimed just not as much clang to the tone, this works good for me because I like to boost the front end of my amplifiers & if the amp it too clangy, my pedals don't sound as good.

This amp doesn't seem to have the input sensitivity as a Marshall, but there is no problem getting power amp saturation with this amp if you like to boost the preamp, you get lots of balls & drive without a hint of fizz or buzzy distortion, actually this amp sounds very much like an old Marshall when I use a boost, but it doesn't have that complex midrange that a good old Marshall has, but I get close with my EH Metal Muff.
This is why I like this amp so much, is because it can do all sorts of sounds by varying the ammount of drive you put into the front end.

My usual way I use my tube heads is to run them full with an Ultimate Attenuator, & just vary the drive with boost & fuzz pedals, & my volume & tone knobs on the guitar to get many tones from the amp this way, I use a EH Metal Muff for over the top sounds, but also get nice smooth overdrive with this pedal as well when I back off the volume & tone on the guitar.

This amp realy works well for me, actually it is better than some more gainy amps as my pedals sound killer in this amp, better than my Fender blackface bassman & my Traynor YBA's & Garnet's.

I could use a two amp set up with this head with pedals & my bassman head without pedals & there will be no stopping me!

I am rating this amp a 10 only because it works so freakin great for my application.
If you are a player who doesn't use pedals, & you go straight in, don't expect much unless you have hotter pickups & are willing to turn the beast up some.

When I bought this amp, it hadn't been used since '92, it still had the original tubes inside, & it looked dirty, but in very good condition for it's age.
I took it to my tech & he powered it up slow with a variac, tested the tubes, & checked the bias, he measured the plate voltage & told me that it was sitting at around 600volts, the screen voltage was around 300volts.
I'm not a tech, but that doesn't sound common to me, anyways, the original tubes were still strong, & the amp is dead quiet as far as any hum or hiss.
I think this amp has passed the test of time already!

Univox is history, but this amp is so simple to fix, any compitent tech with skills in vacume tube technology should have no problem with troubleshooting I fixing this amp.

I've been playing for close to 30 years now, I payed next to nothing for this head, I don't think I'll find one as cheap & as good a shape as this one but if I find one like it I will buy it as these amps are not going for big money even though they are vintage toneful amplifiers.
It's a simple reliable design that will work well the way I use it anyways.

Just want to update the review I gave in December 05. I had been using this amp through a 4X12 with V30s & G12H30s in an X pattern. I recently got an Earcandy Buzzbomb 2X12 and loaded it with the V30/G12H30 combo. I got the cab to use with my Vox AD60VTX Valvetronix but you know anything I had was going to go through this cabinet I put this amp through that cabinet and I'll be damned if it didn't sound like a classic late sixties plexi Marshall! I was really shocked. I knew that driving two speakers instead of four would increase the overdrive, but the sound changed dramatically. I went from sounding bland without the Carl Martin Plexitone to great all by itself. Like a real plexi, you've got to use a pedal for more distortion or to push solos into the nice metal singing stuff, but again--this amp for about $300 plus a Carl Martin for $200, or whatever vs. a real live plexi for two or three grand....or more. Hell, even the PA heads are going for over two grand now.

I used the Carl Martin and found that with a 2X12 you need to turn the presence all the way down on the amp and use the tone on the pedal as your presence otherwise you get this weird rumble, unless you're just using the pedal for solos or runs. I think it's safe to say, if you want this amp to sound like a plexi Marshall all on its own, use two speakers, not four, and make them QUALITY speakers.

I use this as a guitar amp as well. I've used a bass through it and it sounds cool but guitar is where it's at IMHO. I'm pretty sure this is a 1971 amp. It is set up just like a Marshall from the same era--4 inputs, volume I, volume II, presence, bass, middle, treble. Power and standby are the same switch: left standby, middle off, right on. Two channel amp that can be jumped just like a Marshall. Features are nil but this amp is about tone, or cloning tone as you'll read.

I don't wanna go nuts and 10 this amp, but here's the scoop: by itself, this amp will give you nice warm tones and nice crunch when maxed out. Rated at 60 watts, it's not Marshall loud, but it's loud enough. With the volumes lower and using nothing but a strat straight in, nothing special. Same with a Les Paul. Dimed it comes alive much better and can give you that "clean" distortion kinda like a bassman or something like the crunch on Led Zeppelin's Physical Graffitti album.

This amp is shape shifter though. I got Carl Martin Plexitone pedal and put it through this amp--OMG I have a plexi Marshall! I also got JCM800 tones with the Plexitone. I put it through a Crate Blue Voodoo 4x12 with Celestion Vintage 30s and G12H30s in an X pattern and had the channels jumped and the volumes dimed, using the level knob on the Plexitone as the master. This amplifier is gold now. I actually had it on ebay until I put the Plexitone through it. I pulled that auction in a heartbeat. This amp ain't going anywhere. Used a Marshall Supa Fuzz pedal and it was like Hendrix possesed my strat! By itself it was a cool amp but I have a Line 6 Vetta, a Vox AD60VTX, 59 Bassman clone with Mercury Magnetics transformers and SoZo caps and a slew of low wattage combos like the Univox U45-B and 65 Fender Champ. This amp alone was not as good sounding as any of these IMHO. With the Plexitone though it does Marshall better than my old Marshalls that I sold like the JTM-45 reissue, Plexi 50 watt reissue and bluesbreaker reissue. I'm not trying to say "hey look at me with all these amps", just trying to use them as comparisons. With a Plexitone, this amp is a 10, no kidding. I may sell off a few of the other amps now because when I start playing this one, I can't stop.

Who knows, lol. Been fine for over a year now.

hee hee

Incredible value. Just incredible. Had a 3 prong plug and tube, cap checkup and workover when I got her and she has been great. I figure it this way--Plexi Marshall, around $1700 avg. JCM800 around a grand...OR...One of these or a similar Univox (like the 1225 I guess) and a Plexitone pedal for about $200. I'm gonna check out some more of this series of Univox amps because the sound is jaw dropping.

I rate this a ten because of the value. I'm sure if you have a pedal that is supposed to model a Marshall, this amp will sound great with it.

This is a bass amp head which I am using as a guitar head made around 1971. The only difference from the Univox guitar heads is that this one has no Reverb or Tremolo. Not a big sacrifice. 4 inputs, 2 channels, 2 volume, bass, middle, treble, presence knobs. Has switch for 8 or 16 OHM loads. It's rated 60 Watts and has 5 tubes, 2-6l6's 2-ECC83's and 1-ECC82. No "overdrive" but even a ProCo Rat pedal set very low gain sounds incredible. I use a Tubeworks rack tube overdrive which sounds very natural and smooth. I am giving it an "8" for features since they more than enough for my needs. Some may wish for reverb etc...

Best amp I've ever played through. I am running it through 2 10" Jensen speakers circa 1959 with Alnico magnets. Very warm/sweet tone for any style of music. Plenty of low end and high end and middle ground in betwen. The middle is not honking or harsh as in many amps I've played with. For a 30 year old amp she is VERY quiet. I replaced the tubes with 2-RCA 6l6's and Telefunken preamp tubes which may account for the low noise and warm tone. Clean channel remains clean to ear piercing volumes with single coil pickups. With my Les paul it breaks up earlier but that's understandable. I try to avoid giving "glowing" reviews but I am in love with this amp.

Not a problem. Wish all amps were built this solid.

N/A

Don't pass up this if you are looking for a very warm sounding amp with versatility in tone range. I feel lke I stole it at $200 USD. Looks cool too with the blue tolex and two metal handles on top. very rugged.