Jess Oliver Interview, Heritage B-15 Explained

[dadagoboi]

http://bassplayer.com/article/the-ampeg-b-15/March-2011/128073

This may be as close as you can get to the real thing.

[Dave W]

I won't make a judgment without hearing it. But I have to say, the article sounds like a promo for the new product -- typical for BP. Even with Jess Oliver helping design it, let's not forget that Ampeg is owned by the miserable LOUD Technogies.

[Aussie Mark]

I won't make a judgment without hearing it. But I have to say, the article sounds like a promo for the new product

A new product produced in a limited quantity of just 50.  I suspect there's no need to promote this "product" at all - I imagine the 50 units are spoken for already.

[Psycho Bass Guy]

The new amp, which I am sure is stellar, was handmade and will only be serviced by Metropolis Amps. Nothing came from Ampeg but the name. And no disrespect to Jess Oliver, but it seems that every time a new amp comes out bearing the name "B-15," it's nothing short of revolutionary. The basic idea of a circa 30 watt, 6L6 based power stage with a Baxandall preamp came straight out of the same RCA tube manuals that also informed Leo Fender. There have been more than few articles written over the years about Oliver's suggestions for "improving" the design which have been quietly re-shaped as a larger portion of the tube bass amp market becomes more familiar with the theory behind tube circuitry. Some of the original suggestions such as a cheap plug-in solid state rectifier and a four ohm speaker instead of eight can actually be dangerous to the amp!

The original B-15N has been through many iterations.  One I have right now is mid 70's model wth cathode bias, (and it came that way stock) which is not supposed to even exist! I still keep up my BP subscription and their "technical" reporting has become even more laughable and obviously ad driven. I suppose that it's inevitable that ad money and a soft economy will obviously lead to less objectivity in product reviews from mags like that, but it's still sad. I have that issue, and it is good, but then again, very few of their product profiles barely even scratch the surface enought to disclose if it wasn't now. Even in subtle ways, like describing artist rigs, when the player says he uses a vintage SVT onstage, BP puts a graphic of a currently produced SVT CL in the profile, implying they're the same.

[dadagoboi]

I gave up my BP subscription about 5 years ago for the reasons Psycho mentions but it's the same with almost all magazines in every field.  Gotta sell advertising or you're out of business.  Car mags are the worst IMO.

I was more interested in the JO interview than the connection to the new version of the amp.  Except of course what it does to the value of my '65 B15 NC.  The Ampeg and Fender designs come from the same origins but an original 4-10 Bassman and a Portaflex are very different beasts.

My technical knowledge is limited, I depend on my buddy Steve for explanations...

"I think one reason that the amp sounds so good for bass is that they put a _ton_ of iron in it, the transformers are really beefy for the output power of the amp, they are comparable to the ones in a Marshall 100, and it is only about a 30-40 watt amp, especially the 15n which is cathode biased (reduces the output power somewhat over "fixed bias")"

[Dave W]

A new product produced in a limited quantity of just 50.  I suspect there's no need to promote this "product" at all - I imagine the 50 units are spoken for already.

Probably so, but it still reads like a promo for the product instead of a critical look. And promoting the product is a freebie promotion for Ampeg, without discussing what the brand has really become.

Let's not forget that the current Ampeg isn't just a company that's changed ownership over the years, like Fender or Gibson. The original company went bankrupt in 1985. St. Louis Music just bought the assets out of bankruptcy court. The way this article is written obscures that.

[Chris P.]

A bit off topic: Me and Jess at this year's NAMM:) He signed his pic for me.

http://www.flickr.com/photos/chrispdekker/5535119746/

[Dave W]

A bit off topic: Me and Jess at this year's NAMM:) He signed his pic for me.

http://www.flickr.com/photos/chrispdekker/5535119746/

Nice pic.

He's looking pretty young -- oh wait, that's you on the left!

[Aussie Mark]

A bit off topic: Me and Jess at this year's NAMM:) He signed his pic for me.

http://www.flickr.com/photos/chrispdekker/5535119746/

I'm digging Jess's paisley tie.

[Rob]

I'm digging Jess's paisley tie.

He's going for the Mod look that the guys in the Dave Clark 5 turned him onto

[stiles72]

There have been more than few articles written over the years about Oliver's suggestions for "improving" the design which have been quietly re-shaped as a larger portion of the tube bass amp market becomes more familiar with the theory behind tube circuitry. Some of the original suggestions such as a cheap plug-in solid state rectifier and a four ohm speaker instead of eight can actually be dangerous to the amp!

Why would Jess's recommendations be dangerous for the amp? Just curious - I'm no tech.  I have a '63 B-15N that came with a factory solid state rectifier, and has been updated with a three prong cord. The original Jensen speaker was blown, and I let Jess re-cone  it to a 4 ohm load based on his recommendation. I've used the amp for a couple years now with an oldies project and have never had any issues with it. Works perfect, dead silent (no hum), and sounds great.

[Psycho Bass Guy]

The rectifier problem is with the cheapie plug-in rectifier distributed by New Sensor that was the only one available for years. It doesn't have the same voltage drop as a rectifier tube and on amps with old caps, they put out more DC voltage than the caps can handle and they explode.

A four ohm speaker demands more current from the output section. If any part of the amp can't handle the added strain it stresses the power supply and takes out either the rectifier tube or the power transformer or both. That's also the reason that blown power trannies on B15's are common.

You have the advantage of a stock s/s rectifier, which significantly lightens the strain on your PT. The rectifier tube draws a lot of current and with a lower load, much more so.

[bobyoung]

I needed a schematic for a 1959 Ampeg Bassamp 835 I bought on ebay 4 or 5 years ago, someone gave me Jess's email address and I emailed him asking if he had a copy of the schematic, he sent me one in the mail right away and refused any money.

[eb2]

I had the same thing happen.  I keep it in the envelope at my desk.

I still haven't finished my Bassamp yet.