Are these good amps for bass? There's one for sale and the seller claims the only difference in the guitar and bass versions is the reverb. Are the 70's V4B's in general good amps? Enough power? Thanks
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70's Ampeg V4
- Thread starter stickynotes
- Start date
Judging that Ampeg went through the trouble of reissuing them with some modern amenities, youd be wise to pick it up if the price is right. They are great sounding amps with the right cab.
-Jeff
-Jeff
Just echoing the others here but thought it might be nice to get yet another opinion...
It's a fantastic amp! If the price is decent (relative to its condition), you should jump on it. Even if the condition is not top notch, these amps are usually easily repairable and sound great. As I said, price has to be right as you might put a couple hundred dollars into it but it's totally worth it. If it's been serviced recently (re-cap'd, new tubes, 3 prong power cable, etc), take that into account on the pricing. Hard to compare prices on a newly serviced one versus one that has not seen much love. Because of that, they can range from $400 - $900+. Of course, sometimes you just stumble onto a great deal - if so, snatch it up!
It's a fantastic amp! If the price is decent (relative to its condition), you should jump on it. Even if the condition is not top notch, these amps are usually easily repairable and sound great. As I said, price has to be right as you might put a couple hundred dollars into it but it's totally worth it. If it's been serviced recently (re-cap'd, new tubes, 3 prong power cable, etc), take that into account on the pricing. Hard to compare prices on a newly serviced one versus one that has not seen much love. Because of that, they can range from $400 - $900+. Of course, sometimes you just stumble onto a great deal - if so, snatch it up!
This thread is fairly complete, but I believe there is a difference either in gain or sensitivity in the preamp, too.
Doubt it. They did switch over to separate master/gain in the later models, but turning the master all the way up and using gain to control volume makes them end up behaving very similar.
The difference between the two is very minimal: a slight bit of low-frequency rolloff--very slight--for the V4 versus the V4B. Also, there's a difference in the EQ switch selections but IMHO not enough to worry about.
Gain and sensitivity is identical however.
Bottom line: the V4 makes a GREAT bass amp!!
I think it's just a resistor in the input section, Jimmy. If I am remembering correctly what my tech said, the V4B has slightly more sensitivity than the V4 with the selector at in the most sensitive position.
The first gain stages of the two versions are identical other than the sensitivity switch.They both have a 5.6M grid leak resistor. The schematic shows an optional 1K grid-stopper resistor on the V4 but mine does not have it. (The 1K grid-stopper has absolutely no effect on gain even if it exists).
Plate resistors on the V4 and V4B are identical at 390K, same plate voltage of 195 volts.
The sensitivity switch affects the cathode bias. The V4B has a 3.3K cathode resistor and no cathode bypass cap. The V4 sensitivity switch set to one position will have a 6.8K cathode resistor and a 10uF cathode bypass cap. This will increase gain at frequencies higher than a few dozen Hz.
There are online calculators that can tell us what gain versus frequency would be for these values, but overall I'd call it pretty much even.
edit: Note, these notes reflect the very first versions, not the later master volume/distortion versions.
Plate resistors on the V4 and V4B are identical at 390K, same plate voltage of 195 volts.
The sensitivity switch affects the cathode bias. The V4B has a 3.3K cathode resistor and no cathode bypass cap. The V4 sensitivity switch set to one position will have a 6.8K cathode resistor and a 10uF cathode bypass cap. This will increase gain at frequencies higher than a few dozen Hz.
There are online calculators that can tell us what gain versus frequency would be for these values, but overall I'd call it pretty much even.
edit: Note, these notes reflect the very first versions, not the later master volume/distortion versions.
Clearly you know WAY more about it than I. Just going by what the guy who works on my stuff said. Maybe what I am remembering is that he eliminated the sensitivity switch on mine - originally a 1973 VT-22. My tech had some other interesting things to say. The designs changed slightly overtime. In fact, among the many schematics he did find, none were exactly correct for my amp. He also mentioned that from amp to amp often certain places on the boards are simply not populated.
But to answer the OP's question, I think they are fine bass amps. The only thing is that low end cap stuff as mentioned. My understanding is that whatever the V4 capacitor situation is, it rolls off some lows kicking in at 40 Hz whereas with the V4B is at lower frequency. This may be a concern for 5-string players and the V4. Not a complicated or expensive thing to fix.
I'll preface this by saying that I've never used any variation of a v4 before: I believe these amps are 100W, if you're playing in a very loud rock or metal band, you may find yourself lacking in clean headroom. Take this post with a grain of salt, i play downtuned doom metal at volumes most of TB would consider ridiculous, so 100 gloriously overdriven tube watts might be perfect for you..
I own a late 70's V4B and it's easily the best amp I've ever owned! (at least for what I'm playing)
I play in a very loud doom influenced band and it does very well volume wise.
I doubt you'd regret it if you get it!
I used a friend's V4 once before I got my V4B and I didn't notice a very big difference between the two.
I play in a very loud doom influenced band and it does very well volume wise.
I doubt you'd regret it if you get it!
I used a friend's V4 once before I got my V4B and I didn't notice a very big difference between the two.
I don't know about the new ones, but the 70s V4-B is a lusty wench for sure. I bought when they were kind of considered throw aways. (Paid a considered over market value of a $120 in 1989) Played many a show with that thing and you have to try really hard to make it sound bad. Throw it on a 610 or a 412 and you're going to blow the roof off!
Great advice from all. It sounds like it is enough power for me and for $650 I might just have to check it out. Anybody know if these are all point to point wiring?
No, they have printed circuit boards. However, they are well made boards with through-hole mounted components, not the tiny surface-mount devices of today.
Point to point is a "gimmick" IMHO. Great for an old Fender guitar amp with just a few parts, but for a complicated amp like the V4, PC boards are the way to go. Much easier to control noise and oscillations by maintaining a clean layout. Look at a quality piece of electronic equipment from the same era, like a HP piece of test gear, it'll have PC boards.
Point to point is a "gimmick" IMHO. Great for an old Fender guitar amp with just a few parts, but for a complicated amp like the V4, PC boards are the way to go. Much easier to control noise and oscillations by maintaining a clean layout. Look at a quality piece of electronic equipment from the same era, like a HP piece of test gear, it'll have PC boards.
+100 on the above. I owned a 75 v4, and it was a great sounding head. However, it is very important that you pair this head with the right cab. I found that when paired with a smaller cab, the v4 runs out of clean headroom fairly quickly. If you like a bit of over drive in your sound, the v4 is heavenly. If you need a good bit of clean headroom, be sure to pair it with a larger cab.
