7 replies to this topic

[justw]

Im looking to repair my A-150's. The surrounds have gone away. I am deciding to try refoaming or trying to find a replacement woofer. Does anyone have the specs on the orig woofer?
Also how do I tell if mine is a series I II III?
Thanks

I refoamed my woofers about a year ago. As a backup I checked and BA still sold replacement woofers for $60.
The refoam job was easy and they sound like new.

[Mazeppa]

I'm jumping in as I also have a pair of A150 woofers that I'm even now cleaning up for surround replacement. This will be my first attempt at a refoam job. I'll be watching for the foam material recommendation.

Other questions: My A150s had been retrofitted w/some JBL woofers (sound very good) before I bought them and the original woofers were included. I want to ensure correct polarity for when I'm ready to reinstall the originals if my refoam job works out. The connection tabs themselves are unmarked, but there is a paper sticker with a date (Jan 1983) w/a red dot on the sticker adjacent to one side of the connection tabs.

1. Does the location of the red dot indicate positive connection point?
2. Can the Series of my speakers be determined by the date on the woofer sticker? If so, what have I got?

Really appreciate the info and encouragement available at Classic Speaker Pages.

[justw]

I'm jumping in as I also have a pair of A150 woofers that I'm even now cleaning up for surround replacement. This will be my first attempt at a refoam job. I'll be watching for the foam material recommendation.

Other questions: My A150s had been retrofitted w/some JBL woofers (sound very good) before I bought them and the original woofers were included. I want to ensure correct polarity for when I'm ready to reinstall the originals if my refoam job works out. The connection tabs themselves are unmarked, but there is a paper sticker with a date (Jan 1983) w/a red dot on the sticker adjacent to one side of the connection tabs.

1. Does the location of the red dot indicate positive connection point?

Generally, yes. Verify with a 1.5 volt D cell battery. The cone will move forward when + is on the +.

2. Can the Series of my speakers be determined by the date on the woofer sticker? If so, what have I got?

I'm no expert on the BA stuff.

Really appreciate the info and encouragement available at Classic Speaker Pages.

As for the foam I used, I PM'd both of you.

Good Luck with your project. (I really need to check this board more often...)

[Carlspeak]

I recently refoamed two Series III graphite woofers and tested them with the WT3.

Re=3.6 ohms
Fs = 23 hz
Qts = .50
Vas = 7 Cu. Ft.
Sens. = 88.2 dB @ 1W/1M
Qes = .560
Le = .61 mH

I'll be sketching the crossover as well and will post soon.

[Carlspeak]

Here is the A150 Series III schematic I promised. All of the caps are NPE's except the 3.3 uF tweeter series cap which appears to be a film type.
Resistors are all sand cast types.

Attached Files

•  Boston_Acoustics_A150_series_III_schematic.pdf   201.55K   413 downloads