Bass Cab

swiggyswag · #1 03-22-2010, 10:42 AM

I got a Oscar Schmidt OA75B Bass Combo Amp. It has a 15 inch driver in it. Well I want to replace the driver but I can't figure out what Ohms the driver is and what I should put in it. The combo amp has two output in the back to go to a 4 ohm or 8 ohm extension cab (not sure if that helps) I just cannot find anywhere that says what kind of driver it is. Not even on the driver itself. It just has a cheap "oscar schmidt" sticker on it. Can anyone help me ? Here's a post with my combo amp on it Has anyone ever seen one of these?

Thank You Tons

therh · #2 03-22-2010, 10:48 AM

Get a multi-meter and match the positive to positive and negative to negative.Do not forget to set the it to Ohms and on the 200 setting. This will tell you the Ohms of the speaker.

abarson · #3 03-22-2010, 10:51 AM

I'd say it's a safe bet that it's 8 ohms. This is typical for 115 combos. I'd guess that it's something like an Eminence Alpha 15-A, since it's so inexpensive.

therh · #4 03-22-2010, 11:07 AM

Well you never know, it could be 4 Ohms so you can get more power out of a smaller cab.

Rick Auricchio · #5 03-22-2010, 01:01 PM

1. A multimeter will not accurately show the speaker impedance. It will instead show DC resistance, which is perhaps half of the impedance.

Why are you replacing the driver?

Without detailed specs on the existing driver---which the manufacturer doesn't publish---there is no way to know what replacement will work well. You could take detailed internal measurements of the cab and its port, then use WinISD to "test" various drivers.

**iriegnome** · #6 03-22-2010, 01:08 PM

You are pretty much safe with the 8Ohm speaker. If you are really concerned, the back of the speaker should have some sort of markings on it. Also, you can call
Washburn, US Music Corp, Oscar Schmidt and talk to someone over there in Customer Service/Parts and ask. They (gulp) should know

Rick Auricchio · #7 03-22-2010, 01:37 PM

The OP said there are no markings on the driver.