b15n - 68-73 era??

morehorn · #1 01-21-2013, 05:14 PM

just picked up a 70/71 Ampeg b15N and wanted to get some info from more experienced users of this period of the amp. I played one about 7 years ago in this dusty "rehearsal" studio in New York and have wanted one ever since - have messed around in stores on some others in the meantime but money's never been right until now. All I know is that the ones I have been playing were blue face (from what I know that puts it at 68-73?) so thats what i got.

First impressions are great so far but have questions...

mine came with a JBL D140 in it but also shipped with the original square-magnet. anyone have thoughts on what they like for what?

speaker rattle and slight distortion at about 10:30 on the volume -- is that normal? maybe a function of the changed speaker? tubes?

your recording "settings" -- eq, mic, mic placement. etc.

thanks.

christw · #2 01-21-2013, 05:20 PM

Check out the Portaflex megathread(s)! There's a wealth of information in there. There are many recurring discussions on recording, mics, speakers, tubes, repair, modification, rattles and more.

morehorn · #3 01-21-2013, 05:29 PM

that thread is 100 pages long and half of it is JimmyM going over Ampeg employee history of the 60s and 70s ("todd bailey '62-67, lets just say he wasn't so good with a time card but man did he know tubes"). I ran a search but i want this thread to be about me and my problems.

Ender_rpm · #4 01-21-2013, 06:16 PM

10:30 on the volume is getting pretty close to max clean headroom on that amp, especially if you have more modern (higher output) pickups. Ex- my G&L SB2 would drive the bejesus out of my '65 at ~11 o'clock. My Jazz got up to about noon before it started to really saturate. In neither case was the amp loud enough for me to play with a (rock) drummer and stay clean.

But oh, what glorious dirt

re: rattle- well, it IS a 40 year old amp

But double check your screws, maybe pull the speaker and check the gasket. The JBL will stay tighter at higher volumes, the CTS is mushier, but possibly in that good way. I'd probably stick with the JBL as the more versatile of the two.

nysbob · #5 01-21-2013, 07:29 PM

None of my ampeg tube amps stay clean past 11 o' clock...nature of the beast.

It's great that you also have the CTS driver, but concur that the JBL is superior in about every parameter. Swap them out on some rainy day and you'll hear exactly why.

christw · #6 01-21-2013, 08:18 PM

Maybe I'm crazy but I like the CTS 15 better than the D130f in my amp... My B-15 overdrives lightly on hard hits between 10-11 o'clock and really starts to snarl by 12 o'clock.

As for rattles, Make sure that all of the nuts on the baffle and speaker are lightly torqued down. The grill cloth can also create a rattle on these amps at higher volume. A lot of guys will put a felt lining on the baffle behind the cloth as a fix.

The reason I suggested that thread is that I can think of several instances where several members outlined their own problems and suggestions regarding chasing and fixing rattles and speakers. If I get around to it, I'll dredge some of it up for you.

JimmyM · #7 01-21-2013, 09:50 PM

Quote:

Originally Posted by morehorn

that thread is 100 pages long and half of it is JimmyM going over Ampeg employee history of the 60s and 70s ("todd bailey '62-67, lets just say he wasn't so good with a time card but man did he know tubes"). I ran a search but i want this thread to be about me and my problems.

Well aren't you Mama's special little angel?

So no employee nonsense...I used to have a 77 B-15N with a 71 CTS speaker in it similar to yours, and I thought it was a super dark speaker. I liked it a lot at first, but grew to prefer the brighter tone of my 64 B-15N with a 66 CTS in it. I would think the JBL would kick ass in it, but I've never tried it. Easy to swap them out, though. Just be careful not to poke a hole in the cone.

Depending on the output of your bass, distorting between 10:30-11:00 is about par for the course. It's possible a tube could be worn enough to cause earlier distortion, though...I had it happen with a preamp tube. Try swapping tubes around to see if you can find a culprit. Rattles...you're on your own there. Could be a number of different things causing it. Check the tightness of the speaker nuts, the hardware, check for leaks in the lid, etc. Rattle chasing is a PITA but you can clean them up.

Now go read the Portaflex Club thread and get an appreciation for Todd Bailey's efforts

morehorn · #8 02-06-2013, 10:23 AM

thanks guys -- good info -- kept me off the ledge.

i'm finding an extremely recordable sound at about 9:30, 12, 2 on the volume treble and bass. deep and bright off. pushing the volume a little more for some hair. using an Audio Technica 4047 primarily but even an sm57 sounds pretty good.

the rattling i was referring to was speaker rattle/flap. i'm finding that the JBL doesn't break up that nicely if pushed too hard. it kinda compresses and farts instead

Lo-E · #9 02-06-2013, 10:30 AM

If you have access to an EV RE-20, you might consider trying that.

coreyfyfe · #10 02-06-2013, 10:53 AM

I use pretty similar settings on mine, but I also have an earlier amp. As far as speakers, I've had a JBL K140, eminence beta 15, and now a reconed CTS in my 65 NC double baffle, and previously had a 67 NF single baffle with it's stock CTS. Of those, I preferred the CTS in the 65 the most, but I may be partial as my first experience with a B15 was with the stock speaker. I felt the JBL wasn't as smooth as the CTS, especially when running the amp at higher volumes.

jnewmark · #11 02-06-2013, 11:37 AM

I've owned a '67 and now own a '71. I liked the CTS in the '67, but not that crazy about the CTS in the '71. Don't know if it's because of the different porting scheme in the '71 or not, but the '67 was alot more creamier sounding. However, I did try a JBL K140 in the '67, and it gave me maybe a smidge more volume, so I could get a little past noon on the volume dial before all the dirt started. The '71 has the rocker switches, but I don't use them. I am going to try the K140 in the '71 as soon as I get the head back from my tech. There is a wealth of knowledge from B15N gurus on the Portaflex mega thread, especially Beans On Toast. PM him with specific questions, he loves talking about these amps.

morehorn · #12 02-06-2013, 11:38 AM

Quote:

Originally Posted by Lo-E

If you have access to an EV RE-20, you might consider trying that.

was thinking of getting one of those but I'm leaning towards pulling the trigger on an sm7. in addition to hearing great things about them for bass amps, engineers have used them for mellowing out my vocals.. i could use a little of that for my personal set-up

have a sennheiser 421, too... gotta say that I'm not loving it on the amp.

**jmac** · #13 02-06-2013, 12:14 PM

Quote:

Originally Posted by Lo-E

If you have access to an EV RE-20, you might consider trying that.

I don't know why akg discontinued the D12e, but ever since they did I became a big fan of the RE-20. If I were to mic my cab (live or studio) this is the mic I would use.

Lo-E · #14 02-06-2013, 01:45 PM

Quote:

Originally Posted by morehorn

was thinking of getting one of those but I'm leaning towards pulling the trigger on an sm7. in addition to hearing great things about them for bass amps, engineers have used them for mellowing out my vocals.. i could use a little of that for my personal set-up

have a sennheiser 421, too... gotta say that I'm not loving it on the amp.

SM7 is another great choice - similar to the RE-20 in a lot of ways. You might have better luck with the 421 if you roll off some mids in the 1-2K neighborhood.

I was never a big fan of the D12e. Okay on a kick drum, but never blew my hair back for bass.

Oh, yeah. My settings on the B15 are smilar to yours, but with the bass rolled up a bit higher. Sounds like there's nothing wrong with yours - it's right in the ballpark.
That is what this thread started out about, right?