60's Ampeg B15-N: Things to look for?

I'm guessing the internal speaker and external output are wired parallel. Someone will correct me if I'm wrong.

Hopefully you did not damage the output Transformer when you disconnected the internal speaker. You didn't hear anything because the amp was not seeing a load.

Someone more informed will be along shortly to help you out with it as far as value and so forth.

If you really are considering buying it I would call the shop and ask them if they would hold it for you until Monday.

 

Yes, they are only 25 or 30 watts depending on the year. The grill cloth in your pic doesn't look original, but that could be the lighting or camera angle. Otherwise it looks like a clean unit. For a ton of info on these amps, check out the excellent wiki put together by TBer @beans-on-toast.

The Ampeg Portaflex Wiki

 

The grill cloth looks like Sano.



Which had some connection to Ampeg iirc.

 

Looks like a good one. If it tickles your tone bone, grab it. It's not like you'll be able to audition another one in the flesh right away. Being able to try before you buy is always worth any extra $$ in the world of vintage amplifiers.

 

The amp appears to be early to mid 60's.

The rust under the power switch devalues an amp that is otherwise in very good condition. This could be used in bargaining. Some rust is normal but it is often pitting, not chunks of chrome missing, unless that is a reflection.

The grille cloth is not original, it is similar to one used in the late 50's. A close to original replacement is available from fliptops.net or tubesandmore.com

The power transformer looks not original, this is not unusual.

It would be helpful to see the speaker to determine if it is original and the make.

The amp can be dated from the pot codes, look for 137 followed by year and week numbers. There should also be a date based serial number inside the cab.

The amp is disabled when the plug is not connected to the main speaker cab. The ext speaker jack is intended to accept an eight ohm extension cab. With both cabs connected, they are hooked together in series and automatically switched to a 16 ohm tap on the output transformer. The speaker in the main cab should be 8 ohms.

I can't comment on value, to some extent, it depending on the year. Prices can be higher in NYC shops. Check out reverb.com for private asking prices.

These are amazing sounding amps!

 

Congratulations! I won't even ask what you paid as it's worth every penny. I'm curious what Ampeg has in their current lineup that may sound similar now that I'm feeling the gas coming on!

 

PF-20T or PF-50T or V4B reissue are all nice current tube amps.

 

How could you tell the power amp is not original Beans, looks identical to my layman's eyes. I'm also missing the rust, maybe it's time for a new monitor? I've seen that grille cloth on late 50's Ampeg Bassamps.

 

My eyesight is pretty bad, can't see much without my glasses.

The paint finish is more wrinkly on the power transformer can which means that it is newer. Once you know what to look for, it stands out like a sore thumb. The output transformer is much smoother by comparison.

Most vintage B-15's have had their power transformer changed. The one sold by fliptops is made by Heyboer, they are very good, specs are better.

 

I can't really tell much difference from the pictures, but I went and checked my amp given that this amp is made about a month after mine and is the same cathode biased but PCB layout. My PT has a grainy finish and the OT is smoother. I did replace my PT with a heyboer, but I had it repotted in the same can.

Here is an older pic before the PT change:



Along with the stock internal wiring:



And here is a shot I just took:



The wiring coming off OP's PT does look a bit fresher. Could still be a replacement transformer, but the can may be original.

 

Must be one of the last of the original double baffle B-15's.

 

Of course, I could be wrong about how rough it is. Cameras and lighting can play tricks and the resulting images can be deceiving. The early cans were smooth, just like you see on the output transformer. The ones with more crinkle came later, as are the new reissues and the ones that Loud uses. I find it better because the texture shows fingerprints less and it is a tougher finish. The current ones have an even more pronounced wrinkle in the coating.

I believe that Jess Oliver used a Harley Davidson motorcycle paint on the cans that he serviced. Not sure about the original coating. Mark may have more information. I can't recall the part number but have it on my other computer.

To my eye, your PT finish looks smoother, not as smooth as the one below.


Below is a 1964 with the smooth transformer cans.

 

Don't be shocked by the asking prices. These are legendary amps that are a mainstay for many recording studios. That alone is enough to keep their prices up.

In playable condition and good cosmetic shape, they start around a grand plus and can go significantly higher if they've been exceptionally well taken care of. I've seen a few in near mint to excellent condition fetch over $2K.

IMO they'd be worth it for their Baxandall tonestack design alone. Because although it looks like a simple two band FMV type EQ, the way the treble and bass controls work and interact with a Bax, you actually have far more control over your mids voicing than most amps with a dedicated midrange knob have.

Love the fliptop - and fear the Bax!

 

Every time I see one of those I think...Hello, old friend! I've never checked the year of my B-18N, but the checkerboard vinyl is the same (Yours is in slightly better condition). My brother's B-18 had the smoother black finish. I believe those old Ampegs were all very conservatively rated. Of all the amps I've had, it is still the one I love the most. May you enjoy your B-15 for many years to come!

 

There is that. A friend of mine said it best. A B-15 makes any bass you plug into it sound like you paid at least $200 more for it than you actually did.

 

I don't think you can call yourself a bass player without owning or at least playing one at least once.

 

John, a clean chassis, without rust, increases the asking price dramatically.

I wouldn't worry about cycling the amp on and off and tube life. Certainly don't let that concern get in the way of enjoying the amp. Put it on standby if you are taking a break for a half hour or so. Otherwise shut it down. I'll have to take a look at that section of the wiki and clarify what I meant to say.

Your amp is clean inside the cabinet. You have what is called a double baffle cabinet. Many find them to be the most desirable. Although there are others that are fans of the single baffle and the thiele cabs. When Ampeg released the HeritageB-15, the went with the original double baffle design.

Your speaker is made by CTS. This was the standard speaker used after 1963. A very good sounding speaker. I think that the grille cloth on your cab is very cool and personally wouldn't change it.

Looking under your chassis, the power supply caps and power cord were changed. The power cord is a safety issue and those electrolytic caps need to be changed with time to keep the amp in service. This is a plus when buying a vintage amp, you don't have to worry about putting more into it.

I get what you are saying about the sound of the B-15. It's truly amazing and inspires you to play better. One reason why it's used on so many records.


Feel free to drop by and join Jimmy's Official Portaflex Club: Official Ampeg Portaflex Club. Discussions there inspired the Wiki.


David