Official Ampeg Portaflex Club

[beans-on-toast]

Recently had to replace the original stock CTS in my '67 B15N. Man, did I have a tough time getting that bottom nut off the wood screw at the bottom of the speaker! The screw stuck out so much that I could'nt get a socket wrench deep enough to get at the nut. I finally had to use the socket by itself and hand turn it until the nut got loose enough to screw off by hand. I replaced the 15 with a JBL K140. Different sound, as the K140 is more of a full range sounding speaker, but can handle more power than the CTS. Getting a little more top end from the JBL also.

I've had to do the same thing to get the nut off. The nice thing about hand turning the socket is that there's less chance of over tightening the nut when reinstalling the speaker.

It's nice to try different speakers. Takes a while to get used to them. What happened to the CTS that you needed to change it? Are you going to recone it and keep it as a spare?


David

 

[davelowell2]

I did the same thing yesterday. The screws/ spikes were just hand tightened and that's how I put it back with the new speaker. I've now got it in the back of my head that I'll be chasing that screw rattle in a few months, we'll see.

 

[jnewmark]

I've had to do the same thing to get the nut off. The nice thing about hand turning the socket is that there's less chance of over tightening the nut when reinstalling the speaker.

It's nice to try different speakers. Takes a while to get used to them. What happened to the CTS that you needed to change it? Are you going to recone it and keep it as a spare?


David

I discovered that the CTS had a hole in it that I never knew was there until I turned it up to about half and all I got was fart city. Finally got it off and discovered the hole. Speaker paper looked kinda rough so I thought it was time for a change. Don't know what I'm gonna do with the original speaker yet. I did hacksaw that bottom screw thread just enough to get a socket wrench over it in case I switch out again. I'm kinda liking the JBL now, though. BTW, what's the harm in tightening the nut too hard?

 

[JimmyM]

Too hard and you can bend the frame. Also, you can patch up small speaker holes with a little rubber cement. I've even used duct tape and it works pretty good.

 

[beans-on-toast]

BTW, what's the harm in tightening the nut too hard?

What Jimmy said.

Warping the frame is not good. To prevent this, it's always a good idea to tighten all the nuts to the same torque. You can feel the force you are using as you are tighten each nut. Try to keep this about the same. Tighten the nuts a little bit at a time in pairs, always going to the opposite nut. Then repeat the pattern retightening the nuts that you have already done till they are all snug enough (finger tight plus a quarter turn). This keeps the pressure on the frame even while tightening.

David

 

[vintageampeg]

OK guys - I'm kicking off a project I'm pretty excited about. Mark at Vintage Blue has signed on to create a custom baffle that will convert my '67 B-18x into a 4x10!!! A 50 watt 4x10 fliptop -- how freaking cool is that going to be???

I'm all ears if you have any specific speaker recommendations! I suppose vintage SVT speakers would be something to aspire to...

 

[beans-on-toast]

OK guys - I'm kicking off a project I'm pretty excited about. Mark at Vintage Blue has signed on to create a custom baffle that will convert my '67 B-18x into a 4x10!!! A 50 watt 4x10 fliptop -- how freaking cool is that going to be???

I'm all ears if you have any specific speaker recommendations! I suppose vintage SVT speakers would be something to aspire to...

Since you mentioned vintage SVT, you could try the Weber Chicago Vintage Series ABA10 AlNiCo speaker at $65. It is based on the original SVT speaker.

Are you going to have a shelf installed in the cabinet to separate each pair of speakers like in the 8-10?

If Mark is building it for you, it's going to be top notch!

David

 

[kittyboy]

Hey Vint

Sounds cool. I'd be curious to know if there's room to turn a B-15 into a 2X12...would you mind asking him?

 

[vintageampeg]

good tip on the Webers - thanks! Nope, no shelf. I'll likely wire them in pairs though.

 

[JimmyM]

OK guys - I'm kicking off a project I'm pretty excited about. Mark at Vintage Blue has signed on to create a custom baffle that will convert my '67 B-18x into a 4x10!!! A 50 watt 4x10 fliptop -- how freaking cool is that going to be???

Should be pretty cool...that's what Will Lee uses on the Letterman show. That B-15R up there has a 410 inside. Or at least he used to...been a while since I saw it so I don't know what he uses now.

 

[vintageampeg]

Will Lee is a punk. I'm going to have the coolest fliptop EVER. That's right... EVER!!

Just kidding, of course. I am eying these speakers for the project...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330306633188

 

[JimmyM]

It's been a long time since I played a cab with those mid-70's Eminences in it. I think they're definitely worth a shot, though. BTW, the guy is wrong about the magnets meaning they can handle some serious wattage. They still aren't much higher handling than the CTS's they used previously, if at all. But it'll be plenty for your purposes.

 

[jnewmark]

What would cause farting in my B15N? I just changed the speaker to a JBL K140, turned it up a litle ways past half, and fart city, especially on the E string. Speaker is good as i have used it before. Thoughts?

 

[Loudthud]

Air leak in the cabinet or the speaker doesn't match well to the cabinet tuning.

 

[JimmyM]

Air leak in the cabinet or the speaker doesn't match well to the cabinet tuning.

More likely an air leak, I'd guess.

 

[jnewmark]

More likely an air leak, I'd guess.

There are no holes in the cab, as far as I can tell. Head fits snugly on top. No missing screws either. Tell you the truth, I've never had the amp up past halfway. Really have to back off the bass when I turn it up that loud. Otherwise, at lower volumes, I can dial in as much bass as I want.

 

[JimmyM]

Hmmm...well I didn't notice that you're turning it up past halfway. At that point, power tube distortion should be well present, and if you goose the bass knob too, you're probably bottoming the speaker out. Hard to tell without seeing it in person, but that's my guess.

 

[jnewmark]

Hmmm...well I didn't notice that you're turning it up past halfway. At that point, power tube distortion should be well present, and if you goose the bass knob too, you're probably bottoming the speaker out. Hard to tell without seeing it in person, but that's my guess.

How do you run your amp when gigging? I mean, are you close to halfway on the volume?

 

[JimmyM]

How do you run your amp when gigging? I mean, are you close to halfway on the volume?

The most I ever turn up is 11:00. Past that point and it's distorted. I also usually leave the controls flat, or I'll reduce bass depending on the room and the mix.

 

[beans-on-toast]

What would cause farting in my B15N? I just changed the speaker to a JBL K140, turned it up a litle ways past half, and fart city, especially on the E string. Speaker is good as i have used it before. Thoughts?

I find that this usually happens when you are overpowering the speaker or a resonant frequency is being generated in the cabinet which is causing the speaker to be overdriven.

It might be that your K140 has simply reached a limit in terms of what is can handle.

Do you have the insulation in the cabinet that should normally be there? If it is a resonance problem, you might be able to tame it by adding a little more and over a wider area. You could do a test by just stuffing something in the back.