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previous: Michael I have an Ampeg Gemini II with a si... -- 12/20/1999 9:41 PM

Re: How to tell if Speaker is blown?

12/20/1999 10:47 PM
Doc	Re: How to tell if Speaker is blown? The best way to determine if a speaker is giving you problems is to try the amp using a substitute speaker. If you can unplug the speaker from the Ampeg, or disconnect the wires at the speaker terminals, and connect a different speaker, you'll be able to try the amp to see if it responds the same way. Even if you don't have another 15" (or even a 12") guitar speaker to hook up to, you can use one of your home stereo speaker cabinets (if it's rated at 50 watts or higher). Temporary wiring can be made using lamp cord or other wire, such as the stuff your stereo is hooked up with. Get everything connected carefully before you turn the Gemeni on. It is very likely that an early Jensen has a problem. The voice coil forms tend to stick on large cone excursions because the alignment is not what it used to be. I own a Gemeni I amp, with a stock 12" Jensen. The speaker sounds sweet at lower volumes, but when cranked it becomes erratic and highly distorted, like the amp has a completely different sonic character. There are speaker rebuilders who specialize in reconing vintage Jensens, but I haven't gotten around to sending my speaker to one yet. If it turns out your 15" speaker needs attention, but it and the rest of the amp are in decent condition, it's probably wise to look into reconing the original speaker. Don't trust any old shop, find out who can do it correctly before you ship it. A new one of similar qualities will cost more.

12/20/1999 10:47 PM

Doc

Re: How to tell if Speaker is blown?

The best way to determine if a speaker is giving you problems is to try the amp using a substitute speaker. If you can unplug the speaker from the Ampeg, or disconnect the wires at the speaker terminals, and connect a different speaker, you'll be able to try the amp to see if it responds the same way. Even if you don't have another 15" (or even a 12") guitar speaker to hook up to, you can use one of your home stereo speaker cabinets (if it's rated at 50 watts or higher). Temporary wiring can be made using lamp cord or other wire, such as the stuff your stereo is hooked up with. Get everything connected carefully before you turn the Gemeni on.

It is very likely that an early Jensen has a problem. The voice coil forms tend to stick on large cone excursions because the alignment is not what it used to be. I own a Gemeni I amp, with a stock 12" Jensen. The speaker sounds sweet at lower volumes, but when cranked it becomes erratic and highly distorted, like the amp has a completely different sonic character. There are speaker rebuilders who specialize in reconing vintage Jensens, but I haven't gotten around to sending my speaker to one yet. If it turns out your 15" speaker needs attention, but it and the rest of the amp are in decent condition, it's probably wise to look into reconing the original speaker. Don't trust any old shop, find out who can do it correctly before you ship it. A new one of similar qualities will cost more.