(I’ve also included a few others brands you might encounter as aftermarket installations.) This should help you identify your speaker.You also mentioned that you’re looking for a speaker option that decreases the overall volume of your amp.You need a speaker with a lower audio output, so you should consider the spec known as SPL, or sound pressure level (sometimes called sensitivity).

dating fender bassman 100-79

That’s probably a moot point, though—experience tells me that most original speakers in amps of that age are substantially fatigued and generally sound very weak. It's a great-sounding speaker, but with a sensitivity rating of 100 d B, it’s relatively efficient and would probably be pretty loud in that amp.

Let’s take a look at a couple speakers from Warehouse Guitar Speakers (wgs4.com) so I can better explain this.

Their G12C/S speaker is listed as 99.79 d B, while their G12C is listed at 96.10 d B.

Whether it’s a vintage amp or a recent model such as this Fender Pro Reverb, hum can have several causes.

Possible culprits include the preamp tubes, the power tubes, the hum balance resistors, and the power supply caps.

Hi Jeff, I was just reading some of your responses about Jonny Lang’s Deluxe Reverb amps. I have a 1965 Deluxe Reverb and am trying to figure out if it has a Utah or some other kind of speaker. I also have one of the newer Fender Pro Reverb amps with an effects loop and a silverface Twin Reverb with a volume control. Steve Goldner San Diego Hi Steve, Thanks for your questions. Figuring out which manufacturer’s speaker is in your amp shouldn’t pose a problem unless it’s some aftermarket mystery speaker with no markings.

I was thinking of trying a Celestion Gold 50, but I usually only play in my bedroom, and I don't want to increase the amp’s volume. Both amps produce very loud hum whether or not a guitar is plugged in. Or is there some other possible cause you can point me to? Most factory speakers in Fender amplifiers have what is known as an EIA code that specifies their manufacturer.

You should be able to find a number stamped somewhere on the speaker’s frame.

The format may look like this: 220 637 Here the number 220 designates the speaker as a Jensen, and 637 indicates a production date of the 37th week of 1956 or 1966.

Fender has used only a handful of different speaker types over the years.

Here’s a list of brands along with their EIA codes.