Thursday, July 19, 2012

Ampeg V-4B Bass Amplifier Review


Until earlier this year I had used the same bass amplifier for a few years with no yearning for anything different, and I had become complacent about my tone. Then I got bitten by the tube bug, and I slid into a deal on an Ampeg SVT and an 810 cabinet. Things only got worse when a friend of mine offered up an early 1970s Ampeg V-4B bass amplifier head. I may be hooked.

The original run of Ampeg V-4B amplifiers was sold from 1971 to 1980, and were the sibling of the popular V-4 guitar amplifiers. There are a lot of similarities between the two, with the biggest differences being the lack of a reverb and master tone volume on the V-4B. These are popular amplifiers, but still can be found a bit cheaper than their contemporary SVTs.

The V-4B is a two-channel 100-watt all-tube amplifier, and was originally equipped with a passel of tubes, including: four 7027A power tubes, one 12AU7 driver tube, one 12DW7 preamp tube and two 12AX7 preamp tubes. Of course people replace tubes over the years, but these are the ones that should be in there. With all of this hardware and other related bits (transformer/power supply) they are pretty hefty, coming in around 65 pounds or so – a bit lighter than an SVT.

On the front of the head you will find two inputs (two channels), Volume 1 & Volume 2 knobs, Treble, Midrange & Bass knobs, and three switches for standby, polarity and power. There are also toggle switches about the equalizer knobs for Ultra Hi boost, three Midrange boost settings and Ultra Low boost.

On the back are speaker and external speaker outs, an impedance switch (2/4/8 ohm), two external amp outs, and AC outlet (really?) and a hum balance screw.

Any this all combines to make a neat amp. With all-tube power, 100 watts is plenty for most any venue. The V-4B will push my 810 loud enough that it makes me wince. Its tones are versatile: there is ample low end with a creamy tone that is sweeter than my newer SVT, but it still can get more than growly when I start to push it, making it a great rock amplifier. The only downside to this thing (if you can stand the weight), is that it is wider than any of the cabinets I own (even my Ampeg 810), so it looks kind of goofy sitting on top of the stack.

Mine shows plenty of wear, with torn tolex, a missing logo and most of the silk-screening worn off the control plate. But it still plays marvelously, and I consider it a keeper. Well, as much as anything that I own is a keeper, anyway.

There are not as many V-4Bs for sale as there are SVTs, but the prices are still reasonable: maybe $600 or $700 for a nice one. Of course, these amplifiers are old and have a ton of electricity coursing through them, so if you pick one up make sure to get it checked out by an amp technician to make sure it is not going to kill you. You might want to recap it and make sure the power supply is up to snuff.

Anyway, check an Ampeg V-4B out if you get a chance – you will find it to be a viable alternative to an SVT if you are not playing at the Coliseum. It is worth the weight!



  1. Great post - thanks!

  2. I have a 1970 Ampeg VT-22, which is virtually identical to the B4 - Circuit-wise. I used it for Guitar for a year, even did a session with it, it mikes up great, and I have 2 Celestions in it, I got it for 100 bucks, then I put four EL-34's in it, so it really pumps out the power, the only problem is, the power resistors in the output section are the wrong values, and I can't find the high-power ceramic resistors I need to fix it.

    It literally smokes, but I can play it for a 30 minute set, but I rarely fire it up until I can get the resistors replaced. If ya know where I can find them, shoot me a response on googol plus