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Ampeg B-15 thread... first ever?

#121
Aaaaawwww, yeah! My new baby arrived Thursday safe and sound. It's in suprisingly good condition. I think it's actually one of my best amp finds yet. I had to clean about 35 years worth of dust off of the caster cart (which I was actually surprised to find was even included, as I thought the seller told me he didn't have it). I also opened it up to wipe a little dust off the tubes and around the tube compartment. Peeked inside the chassis to check the date codes on the pots, too--looks like mine's a '72.

The existing tubes sound fine. Power tubes have some rattle to them, but I have some new JJ 7027As I can replace them with. The current ones are old Magnavox and GE 6L6s. New Ruby rectifier tube, which the previous owner told me his tech just installed. Preamp tubes are all old Magnavox.

I was lucky enough to stumble upon a new Weber copper cap WZ34 s/s rectifer in town. Popped that and the 7027As in and gave the amp another listen. Didn't notice any difference in tone or output, which is what I expected from PBG's comments. I'll be taking the amp in to my tech on Tuesday to check bias and just give the amp a once-over. I'm hoping since there was nothing audibly wrong with the tube and rectifier change that I can get away with using them in the amp for my gig tonight? What do you think, PBG? Am I taking too big a risk playing it on a 45 minute set? I can always use the old tubes for now

Soundwise, the amp's everything I knew it would be. Someone mentioned favorite settings on these amps, and I'm finding the same thing I found with the B25B I used to own--it's difficult to get a bad sound out of this thing! I'm having a great time just fiddling with different settings, jumpered channels, bright inputs, normal inputs, etc. So incredibly versatile for such a simple layout.

I've got all kinds of pictures of the amp, inside and out, but I'm not sure what the best way is to post them. If anyone's interested let me know, and I'll try to figure it out.

Matt
 
#124
stringbass69 said:
Someone mentioned favorite settings on these amps, and I'm finding the same thing I found with the B25B I used to own--it's difficult to get a bad sound out of this thing! I'm having a great time just fiddling with different settings, jumpered channels, bright inputs, normal inputs, etc.
Click to expand...

yeah, i'm having that problem too. it just sounds good every which way. can't decide. generally I just put the treble and bass at 12 o'clock and turn off the hi and lo switches. but even bright input, all treble, no bass, hi on, lo off, sounds good. what the hell?
 
#125
madlee said:
yeah, i'm having that problem too. it just sounds good every which way. can't decide. generally I just put the treble and bass at 12 o'clock and turn off the hi and lo switches. but even bright input, all treble, no bass, hi on, lo off, sounds good. what the hell?
Click to expand...

Heh-heh. Well, I'm having a hard time seeing it as a "problem," but I know what you mean.

I'm off to my gig. We'll see how the new old amp works!

Matt
 
#128
Not sure about the front coming off the Theile cab. There are a lot of screws in mine, and I might replace the speaker down the road (and keep the original safe in storage) so I might have an answer to this at some point.

Nice looking cab on that Ebay link. Bet it'd sound cool with a V4B.

Matt
 
#130
My B15N sounded great at the gig last night, by the way. I was a little bummed the sound guy didn't have a decent mic to stick in front of it. Might have to invest in a good one myself, so there won't be any excuses. Sound onstage was good overall, untill our drummer went inexplicably Animal on us... That little amp would have been plenty loud for the setting if everyone in the band had a sense of dynamics and knew how to mix on stage. Oh, well. That issue will be addressed soon, one way or the other...

Matt
 
#132
madlee said:
I think soon, you will come to the realization that you don't want to waste that amp on your band mates and gigs, and it will simply become your practice/recording amp. Besides it's heavy as hell.
Click to expand...

Hmm... I understand what you mean, but I don't think that will be my experience. I love the tone, so that part's really just for me and not a waste in that regard at all. (Inexperienced drummers getting in the way of my tonal pleasure aside!)

And to me the weight isn't much of an issue. I mean, I've had a couple of those solid state B100Rs over the years, which are nice amps, but they're only 15 pounds lighter than this amp; and the tone, while good, certainly doesn't compare to the B15N.

Now that I think about it, I expected a lot worse, weight-wise, after reading so many complaints about that factor. When the amp showed up, I thought, "What's the big deal here?" Time will tell, of course, but I can't forsee it being an issue, unless I suddenly lose the ability to "lift with the legs, Hercules!"

Matt
 
#133
stringbass69 said:
I was lucky enough to stumble upon a new Weber copper cap WZ34 s/s rectifer in town. Popped that and the 7027As in and gave the amp another listen. Didn't notice any difference in tone or output, which is what I expected from PBG's comments. I'll be taking the amp in to my tech on Tuesday to check bias and just give the amp a once-over. I'm hoping since there was nothing audibly wrong with the tube and rectifier change that I can get away with using them in the amp for my gig tonight? What do you think, PBG? Am I taking too big a risk playing it on a 45 minute set? I can always use the old tubes for now
Click to expand...

As you later discovered, since the B15N is a fairly conservative circuit, the bias doesn't have to be exact or you'll have instant amp failure like in higher powered amps. As long as the plates in your new output tubes don't glow red or orange, you're fine. A tech bias job is needed for optimum performance, but your new tubes sound like they're happy at the same bias level the old tubes had. Congrats!!
 
#134
Psycho Bass Guy said:
As you later discovered, since the B15N is a fairly conservative circuit, the bias doesn't have to be exact or you'll have instant amp failure like in higher powered amps. As long as the plates in your new output tubes don't glow red or orange, you're fine. A tech bias job is needed for optimum performance, but your new tubes sound like they're happy at the same bias level the old tubes had. Congrats!!
Click to expand...

Thanks, PBG. Yeah, I kind of went by the old "let your ears be the judge" mantra. When I put the new tubes and rectifier in everything sounded virtually identical to the way the old ones sounded. And there definitely were no plates glowing on the tubes.

Quick question. I think I know the answer, but I thought I'd make sure. I'm planning on eventually trying some different preamp tubes as well and just saving the old ones for backups, or studio use if they sound noticably better than the new ones or something. I don't need to have my tech check anything on the new preamp tubes, do I? I don't need to have them in the amp before I have him give it the once-over, right? It was my understanding that preamp tubes are the one thing you can just "plug in and go" with no worries.

Just wanted to make sure. Thanks again.

Matt
 
#135
Okay, I think I've figured out the pictures upload function. Got a few to share, so I'll have to do it in multiple posts.

Matt
 

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#140
madlee said:
She looks just like my little lady. However, yours has a lot more printing on the back than mine.

Hey PBG, any idea if the front of the cab comes off?
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Hey, madlee, does your cab have some screws or bolts that are visible from the inside? Mine has some that appear to hold the baffle on, but I haven't had cause to try unscrewing them. I'm thinking they may hold the two baffles together or something. Or is the Theile cab a single baffle design? I don't recall what I've read on this. At any rate, it sure looks like you could disassmeble that part of the cab with those screws.

Matt
 

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