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

[xnewyorka]

I spotted a 1960's Ampeg B15-N in a local shop yesterday. I am pretty happy with my Eden Time Traveler combo amp, and was not in the market for another, but since I have never even seen one of these beasts before, I had to check it out. I have to say, the tone was pretty amazing, unlike anything I have experienced before. The sales guy said it was 30 watts. I would have guessed more like 300 or 600. With the internal cab plus my 1-12 Harry Kolbe cab, the low B on a Dingwall Z3 shook the entire (huge) building with the volume at just 9:00. It sounded killer with a plain P Bass, and I had a hard time peeling myself away from its sonic beauty. Needless to say, I am considering buying it, hence this post. I am wondering what to look for in determining (a) whether or not to buy it, and (b) what it's worth. Obviously, it is working great. I noticed it didn't work with only the external cab plugged in and the internal cab disconnected. I assume this meant they are in series, and I wonder if that is normal. Wondering what to look for in terms of caps, transformers, speaker frame or cone, tubes, etc.
They are asking what seems like a LOT of money for this thing. But having never shopped for one, I have no idea what they are worth.
I am currently not gigging, and could not see myself ever gigging this thing anyway. I would use it for noodling, practicing, rehearsing and recording in my home studio. I wonder whether the cool VST plugins in the high end DAWs make it unnecessary to have something like this. But then again, no virtual amp modeler is going to have that delicious tube smell, nor be able to help heat my basement studio!

 

[lowplaces]

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.

 

[ahc]

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

 

[lowplaces]

The grill cloth looks like Sano.



Which had some connection to Ampeg iirc.

 

[MR PC]

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.

 

[beans-on-toast]

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!

 

[xnewyorka]

Thank you all for the really helpful replies. I went back to the store today and spent an hour playing the amp with my jazz and precision bases and just could not believe how fantastic it sounded. I got to the point where I could not walk away and leave it sitting there risking someone else buying it, so I took the plunge and I am driving home with it now in my car. I opened it up, and to my novice eyes it appears to be all original except for the power transformer and filter cap. I did not grab a photo of the speaker but here is a photo of the guts. The date on the schematic on top is March 65. On the schematic under that it says 2-65.

Bottom line: the thing sounds A-MA-ZING. But it cost as much as a decent car. So if anyone in the NJ/NY/PA area wants to rent it for studio recording purposes, I would definitely consider doing that to help offset the cost. Just send me a PM and we can discuss it. I cannot wait to get home and see how it sounds in the home studio.

 

[Bassquest]

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!

 

[beans-on-toast]

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.

 

[bobyoung53]

The amp appears to be early 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 ruse is normal but it is often pitting, not chunks of chrome missing.

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 is 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!

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.

 

[beans-on-toast]

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.

 

[coreyfyfe]

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.

 

[JimmyM]

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

 

[beans-on-toast]

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.

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.

 

[40Hz]

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!

 

[Davbassdude]

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!

 

[40Hz]

I went back to the store today and spent an hour playing the amp with my jazz and precision bases

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.

 

[Farfetched]

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

 

[xnewyorka]

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.
<snip>
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
<snip>
The power transformer looks not original, this is not unusual.
<snip>
It would be helpful to see the speaker to determine if it is original and the make.
<snip>
These are amazing sounding amps!

Howdy Beans - To address a few of your points:

What looked like rust under the power switch was actually just a reflection of a nearby speaker cabinet (my Kolbe 112 which is unfinished particle board.) There is no rust there and no finish damage at all, I'm happy to report. (See new photo attached.)

Thanks for the suggestion on the grille cloth! I will look into getting some just to keep it on hand.

I'll also attach a photo of the speaker - hopefully it's good enough and at the proper angle so you can tell what the speaker is. Whatever it is, it does sound great. When I went back to play the amp, I didn't bring my 112 cabinet, I listened to the Ampeg all by itself. Playing my passive basses, it stayed clean until past 12 o'clock, maybe about 12:30 or almost 1:00 before the distortion started to kick in. But the distortion was almost certainly the tubes, not the speaker. The speaker itself seems to be in perfect condition.

I see the amp was also listed on ebay. There are some more professional looking photos on there:
Ampeg B15-N Bass Amplifier 1960's USED | eBay

I read on your wiki that cycling it on and off a lot will shorten the life of the tubes. So I am probably not going to be using it for daily practicing. I will probably just use it for recording and for 'special occasions', when I am in the mood to let my tone put an ear-to-ear grin on my face.

Thanks again for the helpful info and especially for your incredible wiki page on the amp. I can't even imagine how many hours you must have put into building that. Thank you!

John

 

[beans-on-toast]

Howdy Beans - To address a few of your points:

What looked like rust under the power switch was actually just a reflection of a nearby speaker cabinet (my Kolbe 112 which is unfinished particle board.) There is no rust there and no finish damage at all, I'm happy to report. (See new photo attached.)

Thanks for the suggestion on the grille cloth! I will look into getting some just to keep it on hand.

I'll also attach a photo of the speaker - hopefully it's good enough and at the proper angle so you can tell what the speaker is. Whatever it is, it does sound great. When I went back to play the amp, I didn't bring my 112 cabinet, I listened to the Ampeg all by itself. Playing my passive basses, it stayed clean until past 12 o'clock, maybe about 12:30 or almost 1:00 before the distortion started to kick in. But the distortion was almost certainly the tubes, not the speaker. The speaker itself seems to be in perfect condition.

I see the amp was also listed on ebay. There are some more professional looking photos on there:
Ampeg B15-N Bass Amplifier 1960's USED | eBay

I read on your wiki that cycling it on and off a lot will shorten the life of the tubes. So I am probably not going to be using it for daily practicing. I will probably just use it for recording and for 'special occasions', when I am in the mood to let my tone put an ear-to-ear grin on my face.

Thanks again for the helpful info and especially for your incredible wiki page on the amp. I can't even imagine how many hours you must have put into building that. Thank you!

John


View attachment 1179074 View attachment 1179075 View attachment 1179077

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