B15R baffle mod

[micahturner]

First off, I'd like to give credit where it is due. I used the B15R cab that was ported by JKoelher as a template to port my B15E cab.

First, I disassembled the B15E cab by removing the phillips head screws from the back cover. Careful when you pull the cover off, the speaker wires coming off the crossover to the speakers are short and could damage the terminals if you pull them off.

Disconnect the speaker wires. Remove the tweeter(4 small phillips head screws) and the 15in speaker(phillips head screws). Remove the factory speaker baffle by removing 10 phillips head screws(might need a flashlight). To remove it from the cab you'll need to unscrew the side handles. Push the baffle from the front at the top to let it lean back. Then you can easily pull it out through the back.

I'm cheap, so I used a razor blade to cut the grill off the factory baffle. There's more than enough material to cover the baffle screen I'll be making.



The next thing I did was frame the inside of the cab with 3/4in plywood. This creates the space needed for the double baffle.

[micahturner]

Another pic of the framing.



While you are there, go ahead and trim the cab insulation around the sides. It's kind of tough to get the new baffle mounted in there nice and tight to the framing. It's thick stuff.

[rodl2005]

Interesting!

[micahturner]

Tonight I cut the baffle using a template I made. I understand that I'm lacking some explanation on the dimensions of the baffle. I'm not a woodworker, so........yeah. I'm working with someone to hopefully get a template put on the site. More to come on that.



Tomorrow I'm going to cut the grill and attach it to baffle. I'll have more pictures.

[vin*tone]

What's the mod do?

[Caca de Kick]

It's to improve the tone, give it more 'bloom'. The original B15 cabs were double baffled (ported), and the B15R is sealed. If I still had mine I would have done this mod too.

[JimmyM]

Good luck with it, Micah!

[micahturner]

Originally Posted by JimmyM

Good luck with it, Micah!

Thanks! After church I should be able to finish it up. I just need to cut a few more things and reassemble.

[micahturner]

Originally Posted by vin*tone

What's the mod do?

It would have been helpful to explain that in the beginning. Caca nailed it, and I was able to reconfirm it by A/Bing my modified B15 reissue cab against an unmodified reissue cab. The double baffle really adds a lot of depth to the cab, and motivated me to do the same mod to my other cab. The only other thing I'm doing to bring the reissue cab up to vintage spec is to remove the tweeter. I never use this. I'll be removing the entire crossover board on this one and just wire it straight into the new Eminence Delta 15 I picked up for it. It's also one more hole I don't have to cut.

Thanks

[JKoehler]

I wish I had taken more pictures, any for that matter, of when I modded the B15R. When I get working on a project I get tunnel vision and forget to take pictures. I agree with the comments on adding a double baffle, it seems to give the cab more character sonic-wise, much closer to the Ampegs from the 60`s. I would have kept this amp, but a 63 B18 fell into my lap and couldn`t justify, or have the room for both. Keep up the good work Micah.

[main_sale]

I have a B-15R/15E, so this is very interesting to me.

[micahturner]

It rained today, so I went a head and mounted the speaker and baffle into the cab. Hopefully I get to finish it tomorrow.

[micahturner]

Rain again today, going to the field tomorrow for ten days....
I guess I'll get back to this in a bit.

[ddbassGA]

Very cool Micah!

[dhsierra1]

what speaker is used in that model/era of Portaflex?

Wouldn't using a bass reflex porting scheme accomplish the same thing as the double baffle but more simply?

I'm all for doing it the way Ampeg did it back in the day as I have a soft spot for good vintage gear and keeping it that way, just asking.

Fun project, looking forward to the outcome

[JimmyM]

Some sort of custom Eminence, probably based on the Beta or Delta 15.

And yes, a regular port would do the same thing, but you'd still have to do some modding to the baffle to make it happen, so why not go double baffle style?

[dhsierra1]

Originally Posted by JimmyM

Some sort of custom Eminence, probably based on the Beta or Delta 15.

And yes, a regular port would do the same thing, but you'd still have to do some modding to the baffle to make it happen, so why not go double baffle style?

thanks, Jimmy

Th less damage to the original the better if that's the way to go

[billfitzmaurice]

Originally Posted by JimmyM

And yes, a regular port would do the same thing, but you'd still have to do some modding to the baffle to make it happen, so why not go double baffle style?

The advantage to a standard ducted port is the ease of tuning it, you just change the duct length. Jess probably would have done it that way if Theile/Small had come along five years sooner.

[JimmyM]

Originally Posted by billfitzmaurice

The advantage to a standard ducted port is the ease of tuning it, you just change the duct length. Jess probably would have done it that way if Theile/Small had come along five years sooner.

He did, indeed, use a shelf port in his Oliver Powerflex amps, his updated B-15 after he left Ampeg.