Ampeg V4B or B15R

casterbro · #1 08-20-2011, 06:30 AM

Once again, need some help!

I've bought a 65' B15N here a couple of weeks ago and it's definitvly the best amp I've ever played with... THE sound I was looking since the last 20 years. Nice clean tones and the crunch is awesome (bought at least 20 drive pedals to get that sound and never get it!).

I'd like to get a more powerfull amp to put in my rehearsal room... B15N will not be loud enough (and thanks to you guys, I've decided to take my 65' B15 for giggin' with a good mic!).

What should I take?

I want an amp powerful enough to play with my 2 guitarist and the drummer. And I'd like to get clean tone if I want and a nice crunch tone too if I'm playin' louder!

I'm thinking of the B15R or the V4B, any opinions? I'm based in Europe, so not easy to try those... Guess I'll get enough power?

And if I wanted to get a V4B, which exact model (year) should I take?

THANKS!

beans-on-toast · #2 08-20-2011, 07:11 AM

You are proposing to switch from a 30W amp to a 100 watt amp.

With the same speaker cabinet, doubling your power will give you about +3db sound pressure increase. The accepted standard is +6dB is needed to double your volume level. Based on that, the other two amps are going to offer you a bit less than double the volume. Would this satisfy your needs?

Now at a fixed power output, if you increase the number of drivers you will get more volume. The B-15R came with a 15" driver and a horn. The late 70's V4B came with a four 12" drivers. Others use a 2 X15 cab. I don't know what the driver displacement specs of the Eminence based B15R vs the CTS V4B drivers are. This determines which will move more air. Based on my listening experience, the V4B is louder.

I would prefer the V4B over the B-15R. There is more tonal flexibility and much bigger transformers which is better. The V4B also puts out more power than it is rated for.

The V4B is a better amp no question. Go for an original 70's model if you can find one. It is better than the reissue V4BH in my opinion.

RickenBoogie · #3 08-20-2011, 07:22 AM

Yes, volume means speakers, so whatever you do, it will entirely depend on what and how many speaker cabs you have connected.

coreyfyfe · #4 08-20-2011, 07:25 AM

Definitely V4. What speaker cab are you planning on using? Your location will definitely limit your options in terms of availability. A vintage V4/V4B is not the same kind of sound as the modern V4BH. Likewise, the modern B15R, while 100 watts, doesn't entirely retain the vintage B15N sound. In fact, the B15R and V4BH were very similar amps (100 watts, 4x 6L6, 12AX7 pre-amps, etc). I wouldn't expect the vintage V4/V4B amps to give you the same sound as your B15, but you can probably get pretty close.

nysbob · #5 08-20-2011, 07:29 AM

You won't find much argument against the old V4B around these parts. Guys that have 'em tend to love them...me being one.

casterbro · #6 08-20-2011, 07:34 AM

thanks!

My aim is not to get the same tone as my B15N but a good amp in the same spirit with more power!

I was interested by the V4B but want to be sure! So I'll try to find one. I'm planning to use ot with 2x15" (younger I really liked the 410 but gettin' older I like to 15" much more!).

I'm not in a hurry, so I'll take time to find a V4B!

Any advise on which exact model to take? (seems there's at least 3 differents versions of the V4B in the 70')

Mike in Chicago · #7 08-20-2011, 08:01 AM

My '74 is just getting out of the shop after a cleanup. I still have the 2x15 folded horn cabinet too.

I was thinking about selling this stuff, but I see you're in Europe.

coreyfyfe · #8 08-20-2011, 08:02 AM

I prefer the non-master models, but if you want to try to drive the pre or power sections having the option to adjust gain and master volume independently could be helpful. But don't limit your search to just the V4B, the regular V4 - while technically a guitar amp - works just as well for bass. It still has the same transformers so you can get a good bass response out of it unlike a modern guitar amp and the only real difference is the lack of the bass boost button, the mid eq frequency centers and a few associated caps in the preamp.

casterbro · #9 08-20-2011, 08:08 AM

Thanks, I was thinking of a non master too! I'll check the V4 too, as it's not easy to find, it will be easier to get one!

@ Mike: so bad you're in US... buyin' a 215 in the US would cost so much for shipping' (can't even imagine how much it could be... at least 500$) but I may buy a head in the US...

danclaro · #10 08-20-2011, 08:39 AM

When I still had my V4B, I often regretted not using the money I spent on the amp plus repairs on an SVT. Mine was a 1971... cost me a lot to have it fixed up with new tubes, caps, power cable, etc., after I bought it. The amp sounded great with a 4x10, and was plenty loud in most applications. It's definitely a loud 100 watts but it distorts a lot when you push it so if your guitarists like to crank the guitars and your drummer hits hard you might want more volume. It's also around 70 lbs with one small handle on the top. Oh, and also, it's wider than most cabinets are so that's something to keep in mind.

If you want volume, get an SVT and call it a day. You can use an SVT with a 1x15 cab, or an 8x10 cab. It weighs just a little bit more than a V4B, and will give you all the bass you will likely ever need.

casterbro · #11 08-20-2011, 08:49 AM

thanks! but I guess it's impossible to get a nice overdrive from anSVT?

coreyfyfe · #12 08-20-2011, 09:12 AM

I'd go with the V4 if you want distortion. The issue with an SVT, especially with a vintage SVT is that you're limited on cabinets, and you'll be deaf before you really hit the sweet spot if you're using a big cab. The V4/V4B have a 2/4/8 ohm switch which makes them extremely versatile in terms of picking/mixings cabs. With a vintage SVT, you can do one 4 ohm load or two 4 ohm loads, you can't just switch over to the right impedance. The newer SVTs are easier since they have a 2/4 ohm switch.

As far as V4 repairs/upkeep, I think I spent a few hundred on top of the buying price having my amp cleaned up, recapped, retubed (with 6550s), and having the 6550 conversion fully done (was apparently half-assed prior to getting the amp). If you're buying from the US you'll also need to have the transformer replaced for 220V operation or use a stepdown transformer. I ended up trading my V4 and cash for an SVT which also needed a few hundred worth of work when I got it. Such is the downside of buying vintage.

casterbro · #13 08-20-2011, 09:32 AM

you're right, I'll try a V4!

and I'm ready to spend whatever should be necessary to get it 100% workin'.

so you think the 6550 conversion is a good thing to do?

nysbob · #14 08-20-2011, 09:36 AM

Theough a pair of 15"s you probably won't need to mess with the tube conversion. I sure didn't.

nashvillebill · #15 08-20-2011, 10:45 AM

I would not do the 6550 swap. Many people did this years ago when 7027A tubes were not readily available. Now that they are being made (Sovtek and JJ) that's no longer an issue.

The 6550's don't add much (if any) power, despite some claims to the contrary--the amp is limited by its power supply and output transformer, that dictates the max power available. You've got 585 volts B+ (if my memory is correct) and a fixed primary impedance on the output transformer, that determines the max power that the amp can deliver. What the 6550's do however...is draw substantial more heater current. That is not good. While many people have used 6550's without difficulty, it's probably pushing the power transformer's heater current capacity to its limit. Note also that the power tubes are right next to the PT which is bad from two aspects--the physical size of the output tubes can be an issue if you get big coke-bottle tubes (they might not fit), and also the heat from the tubes is going to go into the PT (which would already be running hotter since the 6550's draw quite a bit more current).

**B-string** · #16 08-20-2011, 10:58 AM

Quote:

Originally Posted by nashvillebill

I would not do the 6550 swap. Many people did this years ago when 7027A tubes were not readily available. Now that they are being made (Sovtek and JJ) that's no longer an issue.

The 6550's don't add much (if any) power, despite some claims to the contrary--the amp is limited by its power supply and output transformer, that dictates the max power available. You've got 585 volts B+ (if my memory is correct) and a fixed primary impedance on the output transformer, that determines the max power that the amp can deliver. What the 6550's do however...is draw substantial more heater current. That is not good. While many people have used 6550's without difficulty, it's probably pushing the power transformer's heater current capacity to its limit. Note also that the power tubes are right next to the PT which is bad from two aspects--the physical size of the output tubes can be an issue if you get big coke-bottle tubes (they might not fit), and also the heat from the tubes is going to go into the PT (which would already be running hotter since the 6550's draw quite a bit more current).

The output tubes are next to the OT. I actually moved my OT forward to reduce the heat transfer and added a fan. But with that said some of the PT's could not handle the 6550's heater draw and a outboard filiment transformer was the answer. My Magnavox V4B with 6550's was running 128 watts with mains measured at 118 volts.

coreyfyfe · #17 08-20-2011, 11:28 AM

Quote:

Originally Posted by casterbro

so you think the 6550 conversion is a good thing to do?

Not necessarily. Mine came that way, sort of. They usually use 7027s which went out of production at one point, but given that sovtek and JJ are both making them now, I would just keep with the 7027s. 6550s use higher plate current and can be more taxing on the power transformer of the earlier V4s (later 70s V4s were sold with 6550s as a performance upgrade package, but I think the circuits were slightly different). I never had a problem with mine, and my tech said it was a common mod and shouldn't cause a problem but if it's not already done I wouldn't bother.

nashvillebill · #18 08-20-2011, 11:36 AM

Quote:

Originally Posted by B-string

The output tubes are next to the OT. I actually moved my OT forward to reduce the heat transfer and added a fan. But with that said some of the PT's could not handle the 6550's heater draw and a outboard filiment transformer was the answer. My Magnavox V4B with 6550's was running 128 watts with mains measured at 118 volts.

I stand corrected, thanks! My memory is not what it used to be, I recalled a space limitation with the transformer but again my recollection was that it was the PT...darn memory loss...

Mojo-Man · #19 08-20-2011, 11:38 AM

If your going to gig, then the V4B is better.
With a nice 2x15 cab it rocks.

For recording the B15R is great.

Both amps are around 100 watts.

It's about cab size and volume.

**B-string** · #20 08-20-2011, 11:51 AM

Quote:

Originally Posted by nashvillebill

I stand corrected, thanks! My memory is not what it used to be, I recalled a space limitation with the transformer but again my recollection was that it was the PT...darn memory loss...

I hear ya, ever have a vivid memory out of no where and wonder what brain cell just died?

Getting older just sucks