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Is this a legit vintage Ampeg B-15???

#41
hey guys
so, i did what beans suggested, i tried different heads/cabs. seems like the hole is making that unwanted noise.


so, at this point, knowing that the cab is a later 60's paired with an early B-15N head, should i try look for an orphan double baffle cab instead of buying an new Eminence and installing to the single baffle cab?

i read here and there that JimmyM suggests the double baffle cabs paired with early 60's B-15 heads.
considering that a new eminence is about $100, will a doufle baffle hurt my wallet?

BTW... i paired the B-15 with my Aguilar GS112+GS210 (both 8 ohm) and sounded memorable... not sure if the head can handle 4 ohm load without damaging...
 
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#43
You're making good progress.

Why not try patching the hole next. The puncture is small which makes it easier. You have nothing to loose if you are considering replacing the speaker.


Fold any torn flaps into the hole to position the paper where it originally was. Carefully dab on some alcohol to clean any dirt with a Q-Tip. Let it dry. Apply a thin layer of rubber cement (elmer's glue, carpenter's glue, etc) onto the cone. Layer on a small piece of craft tissue paper (not toilet paper) that is just a little bigger than the hole (about ⅛-¼"), use the edge of a toothpick to apply more glue if it is dry, add another layer of paper and spread it down with a toothpick. Do this around three to five times till you think that it looks like it will be strong enough. Let it dry overnight. I use a cement called Speaker Service Cement made by MG Chemicals that is specific for the job. You want a rubber based product that will remain flexible. In the old days we used to use a dab of nail polish on small holes. But a hard glue can cut the cone over time.

Yes, the cab that went with your head was a double baffle. If you want the best double baffle cabinet available, check out Mark's site, http://www.vintage-blue.com. A little more in cost than fliptops but way better.
 
#45
beans-on-toast said:
You're making good progress.

Why not try patching the hole next. The puncture is small which makes it easier. You have nothing to loose if you are considering replacing the speaker.


Fold any torn flaps into the hole to position the paper where it originally was. Carefully dab on some alcohol to clean any dirt with a Q-Tip. Let it dry. Apply a thin layer of rubber cement (elmer's glue, carpenter's glue, etc) onto the cone. Layer on a small piece of craft tissue paper (not toilet paper) that is just a little bigger than the hole (about ⅛-¼"), use the edge of a toothpick to apply more glue if it is dry, add another layer of paper and spread it down with a toothpick. Do this around three to five times till you think that it looks like it will be strong enough. Let it dry overnight. I use a cement called Speaker Service Cement made by MG Chemicals that is specific for the job. You want a rubber based product that will remain flexible. In the old days we used to use a dab of nail polish on small holes. But a hard glue can cut the cone over time.

Yes, the cab that went with your head was a double baffle. If you want the best double baffle cabinet available, check out Mark's site, http://www.vintage-blue.com. A little more in cost than fliptops but way better.
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im going to try patching the hole. i will keep you posted on the progress.

yeah i saw the vintage blue cabs... some day i will get one. just keep in mind i paid 500 bucks for the b-15... its out of my budget.

for now i will keep my self entertained fixing up little by little. its getting way too interesting!!!!
 
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#46
I would just go with the new Eminence speaker for a hundred bucks. At that point you could save the money for the double baffle cab at your leisure. No need to rush it, not like that one doesn't work as it is. The repair as described above may do the trick as well and you may be able to hold off on the new speaker too.
 
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#50
bostero77 said:
congrats on your M-50 mate!
actually the previous owner was a nice lady that used to punk rock in the 80's. yeah, she told me there were a few interested in the amp. i was lucky she lived 15' from home
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Darn Craigslist anonymous relay e-mail system!

And thanks! I can't wait to get it back from my tech, new switches, pots, and tubes. Hello closest you're every gonna get to one of the holy grails of guitar amp tone without paying through the nose for a real deal. I should get a Lil' Bastard 30 next.
 
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#51
OK....... im not sure if I should open an another thread but here it goes

as far i read about this amp's inputs Channel 1(left ) is bass, Channel 1 (right) is guitar, and Channel 2 is Instruments.

The other night i was testing the inputs and i found out that the Channel 1 Right input is Channel 1 and 2 together. It also combines both
volumes (Channel 1 + 2). Btw Channel 1 and 2 have very different sounds.

i kinda find this modification useful, im just curious if this is modification is somehow desirable.

thanks
 
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#54
i guess this as a player's amp is a plus but as a collector's item is a minus. is this reversible?

the current speaker is not stock also has a very small hole on the cone. i was very tempted to change the speaker. now, with this find should i install a 4 ohm speaker? would this damage the amp?
 
#55
bostero77 said:
i guess this as a player's amp is a plus but as a collector's item is a minus. is this reversible?

the current speaker is not stock also has a very small hole on the cone. i was very tempted to change the speaker. now, with this find should i install a 4 ohm speaker? would this damage the amp?
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It won't damage the amp but I've never liked the sound of B-15's using a 4-ohm load. Sounds good but a little too tight and compressed to me. They're built to have an 8 ohm load in each speaker jack and that's what I'd stick with. Eminence Delta 15a...sounds just like the old CTS speakers they used back then.
 
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#56
JimmyM said:
It won't damage the amp but I've never liked the sound of B-15's using a 4-ohm load. Sounds good but a little too tight and compressed to me. They're built to have an 8 ohm load in each speaker jack and that's what I'd stick with. Eminence Delta 15a...sounds just like the old CTS speakers they used back then.
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i hear ya Jimmy. it makes complete sense what you're saying. most likely the amp will stay at the studio only for recording purposes and i don't need it to be loud. thanks for your input.
 
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#57
bostero77 said:
OK....... im not sure if I should open an another thread but here it goes

as far i read about this amp's inputs Channel 1(left ) is bass, Channel 1 (right) is guitar, and Channel 2 is Instruments.

The other night i was testing the inputs and i found out that the Channel 1 Right input is Channel 1 and 2 together. It also combines both
volumes (Channel 1 + 2). Btw Channel 1 and 2 have very different sounds.

i kinda find this modification useful, im just curious if this is modification is somehow desirable.

thanks
Click to expand...

I doubt that is a mod, it was the same way on my early B-15. In effect you have the feature of bridging the channels by using that input. Push both volumes up to the 1 o'clock range and check out the different eq curve and maybe even some overdrive/grind.
 
#58
i found these papers inside of the cab. they seem to be diagrams of modifications. im just a dumb bassist so even though is written in English i feel im reading Egyptian hieroglyphs...
any ideas of what these mean? i always appreciate your inputs
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#59
Well, whadya know! Mine worked the same way, so maybe this was common mod. I did purchase mine in '75 from Prune Music, where the Mesa Boogie amps were being developed in the back room by Randall Smith. That looks like it would be easily reversible. Do you like the way it sounds? I loved it. Or are you more worried about the resale?

"This allows a little more EQ flexibility" says it all.
 
#60
Looks like they changed it to a fixed bias instead of cathode biased circuit, set up the middle input as a bridged input, and added a protection circuit of some kind. There is some mention of the hum balance but that should be there already I think, maybe modified that? I'd have to look back at some schematics to be sure.
 

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