On eBay; Ampeg B15N

capnjuan

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On eBay; one of Ampeg's best-regarded vintage amps; B15N - Portoflex (no ported cabinet in auction) here: B15N Auction Link Not even close to JP's similar model in cosmetics; style reminiscent of Marantz's 8b; late 60s audio amps of the highest quality.

ampegb15n.jpg

For the technically inclined: B15N Schematic
What others have to say: HC reviews B15N

Rated output unknown; 3X6SL7, 2X6L6, 5AR4 rectifier. Marketed as a bass amp, along with it's ported cabinet; mostly an enclosed back cabinet with a 2 - 3" 'pipe' of sorts sticking out the front to allow tuning and who said bass players didn't obsess over their tone too. Thought by many to be a top-notch guitar amp; two channels, big power / OT transformers, smallish - compared to most bass amps - output coupling caps to prevent damping the higher frequency interest, cathode cap only on the driver; not on the preamp tubes; that is, much in common with guitar amps. Jacked for pre-amp out and external speaker. Power supply set up for 3X40uf multi-section cap (available in aftermarket) and another loose 40uf.

With Ampeg cabinet:

b15.jpg


No idea of what it might go for. cj
 

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

FWI, I saw a cab for a portaflex on fleabay. Can't seem to locate it now.... :?
 

jp

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

These sound so amazingly good, and they're worth every penny.

Everything one needs for renovation can be gotten here -- http://www.fliptops.net/ -- including a cabinet. They also fabricate these interesting heads for those who want to just tote around the head.
B15R%20HEAD%20CAB.jpg

Kind of defeats the purpose of the fliptop, though.

My B-18X is missing the dolly, which I may eventually buy from here. I had also forgotten that the original Jensen High-Fidelity horn was replaced in mine some time ago. Wish I knew what model it was to restore to original specs.
 

capnjuan

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

jp said:
My B-18X is missing the dolly, which I may eventually buy from here.
Hi JP; thanks for the link; error ID'ing your amp model corrected. cj
 

jp

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

I think I posted this here once before, but here's a little history and interview with Jess Oliver, former Ampeg Vice President who invented the Portaflex. He still lives in NY and has an amp shop! He often restores old Ampegs and sells them on eBay. He's really accessible too and answers emails. What a living legacy from a great amp company. Click on his pic to read the article.

 

dklsplace

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

Anyone else remember the short lived Golden-Glo Ampeg series? Had one back in my high school rock band & wish I could find another. :(
 

capnjuan

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

jp said:
Click on his pic to read the article.
Did so; great article, terrific amps, thanks! cj
 

mad dog

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

How do these sound for guitar? I've never had the pleasure, always wanted to. Until I do, my favorite Ampeg is probably the M12, 2x6v6 pre-reverb. Great sound, little known alternative to the Fender deluxe, but every bit as good. Another Ampeg I'd love to try is the Gemini I or II - VI, only with 6L6s.
 

capnjuan

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

mad dog said:
How do these sound for guitar? I've never had the pleasure, always wanted to. Until I do, my favorite Ampeg is probably the M12, 2x6v6 pre-reverb. Great sound, little known alternative to the Fender deluxe, but every bit as good. Another Ampeg I'd love to try is the Gemini I or II - VI, only with 6L6s.
HI Michael; probably have to wait for JP on the how-does-it-sound question. On the electronics side, comparing the schematic of the B15N to both the Fender Bassman (5E6) and Guild Thunderbass (3/4-tube preamp 8417s or 6L6s), the Ampeg is more like a guitar amp in two respects; the B15N has no cathode bypass caps in the preamp; like a Silvertone 1482 and unlike the Bassman, Thunderbass, Princeton (6G2), and Gibson GA18 - all 25uf/25v or thereabouts.

Forgetting the physics for the moment, the cathode bypass cap of say 15/20uf or greater cuts highs boosting bass and bumping up gain. In this respect, the B15N has a front end like a guitar amp. In the Voicing Amps thread, there's a great graph one of our BBers made up showing the relationship between uf of cathode coupling cap and gain in db.

Output coupling caps: three makes/models:
Guild TBass - 3/4-tube preamp: .27uf
Fender Bassman: .1uf
Ampeg B15N: .02uf

The Ampeg as one-tenth the low pass filtering at the output grids of the TBass and and one-fifth of the filtering of the Bassman; the Ampeg outputs will see more sonic higher-frequency hash/trash/rasp than the two others. The Ampeg uses a 5U4 tube rectifier (the TBasses have diodes) and readily-available 2X40uf and 2X20uf can caps.

In short, the Ampeg has a lot of (more?) similarities to a guitar amp; has the saggy power supply owwaaooowwwaa thing, and is easy to find parts for its power supply. cj
 

Bumkneez

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

The B15N sounds great with P90's for Jazz. Haven't played Humbuckers or other styles thru it. Just Epi bass + Gibbie ES330.
 

jp

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Re: On eBay; Ampeg B15N; Best Ampeg Amp Ever?

capnjuan said:
mad dog said:
How do these sound for guitar? I've never had the pleasure, always wanted to. Until I do, my favorite Ampeg is probably the M12, 2x6v6 pre-reverb. Great sound, little known alternative to the Fender deluxe, but every bit as good. Another Ampeg I'd love to try is the Gemini I or II - VI, only with 6L6s.
HI Michael; probably have to wait for JP on the how-does-it-sound question. cj

Of course, everyone's taste in amps is different, but I think guitar sounds great through these. It's an expectedly clean full, bass-heavy sound that's powerful, rich, and tubey. My B-18X, like many 60s Ampegs, was originally for guitar and accordian and has reverb and tremelo--same circuitry as the B-12X. Sounds great for keyboards, guitar, and bass. I would love to have a Gemini I, which I think is rated at a lower wattage than the II-VI models.
 

capnjuan

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eBay Auction Link. One of the finest tube bass amps ever made; 3 X 6SL7s (like a 12AX7 but with a different arrangement for the heaters), twin 6L6s, and a 5AR4 rectifier. Seller says about 30 watts but most twin 6L6 amps running near 450V produce 50 watts B15N schematic. Seller also says mid-70s.

It's a flip-top; the amp chassis is bolted to the top panel of the cabinet; undo the hardware and the panel flips over providing safety for the chassis and making hauling the 100 lb rig little easier.

front-9.jpg



Very clean interior ... no scorching or discoloration on the cb. Note the small boards with the components of the tone stacks mounted on the back of the controls. Helps keep down the length of wire to/from the controls so the wiring doesn't act like an antennae picking up electrical noise and unclogging the primary circuit board.

cb.jpg



View of the tube deck:

tubedeck.jpg



Given the appearance of the chassis, I couldn't help but think of other premier electronics of the era: Marantz 8B left and a McIntosh MC275 right:

mac.jpg



Interesting article on the amp in Premier Guitar

And, finally my fellow BBers ... to any of you who post demo vids on YouTube or are going to ..... I give you the quintessential How Not To Do A Demo Vid For YouTube:

Lighting: it's so dark, you can't really see the amp.
Demeanor: the gent acts like the medical examiner: "the tolex appears to be scuffed .... " Appears to be scuffed? :shock: :shock: He's the one looking at it ... can't he tell? Is there some question whether it is or isn't? Did he look the thing over before he started?
Learn to edit: the viewer sits with bated breath while Houdini struggles to figure out how to put the camera back on the tripod. In order to appreciate the amp, is it really necessary for us to sit through 30-45 seconds of his fumblerooski?
Signal: Instead of a bass or a guitar ... which pretty much makes sense, he takes an iPod with a recording of somebody doing Dave Mason's 'Feeling Alright' and plugs it in ... it's a stereo signal but since the amp is mono ... all that comes out is one channel with the cheesy-sounding vocals and drums.

I had to stop the vid and wipe the coffee off the keyboard and make myself watch it all. If anybody was looking for something to help them make up their mind .... this vid will stop people from considering a B15N. It's just awful ... :p :lol:
 
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