Speaker question for first build

[Alley_Cat_Jack]

Working on designing my first tube amp. I was going to use as much salvaged parts as I can for the build as that is how I bild most of my projects. I have some tubes already but am concerned about speakers. I have learned that I should be using speakers specifically for guitar, however I wont likely have any from salvage any time soon. I do however have a pair of alnico speakers from an old radio/turntable cab. Will these speakers at least work for now until I get my hands on some proper guitar speakers? Multimeter sgows that they are 8 ohm.

[The Dude]

I see no reason why not providing they are able to handle the power.

[Alley_Cat_Jack]

I have been having trouble identifying them. Is there any way for me to test what they can handle?

[The Dude]

Are there any numbers on the speakers? Do you know the model of the unit they came out of? If you know what they came out of, how much power did that produce? How much power is the amp you're building going to produce?

[Alley_Cat_Jack]

The only identification mark I can find on them is E-9318. As for the unit they came from, I may be able to find out tomorrow. I just know it was made somewhere in Canada.

https://i.imgur.com/F8k8PdW.jpg

[The Dude]

I was able to find a little info on the identical speaker that came out of a Fleetwood console stereo. That stereo was 2 single ended EL84 amps. The speakers could be rated as low as 5W each, but are likely at least slightly overrated for the application. I guess now, it depends on what you're building.

Oh, and welcome to the place!

[Chuck H]

And, wattage capacity not withstanding, it's been my experience that many old "full range" or even woofer speakers from the 50's/early60's do have "that" sound and work just fine for guitar amps. They are very often low in efficiency though.

Other than warning about old hide glue used for assembly of older speakers turning brittle with age, etc. that's about all my experience on the matter.

[Justin Thomas]

Because, "back then," there was no such thing as a "guitar" or "bass" or "PA" speaker. There were just speakers, of various sizes, sensitivities, and power handlings (and all of those quite low by our modern standards). There were speakers, and cap values were tweaked for the desired frequency response. The difference between a Marshall Super Lead and Super Bass usually wasn't the speakers, it was a couple of five cent caps. If you DID decide to get the upgraded speaker cab, it as because it handled more POWER, not because it was a "bass" cab or whatever. No reason your speakers shouldn't work, as Dude said, if they'll handle the output and don't need a repair.

Remember - the same Jensens went in everything from organs to PAs to Bassmans. Will it make noise without blowing up? Yeah? We'll take it!

Justin

[olddawg]

I've seen old Magnavox stereos have the same 12" speakers as the guitar amps of the day and used them. They just added a tweeter and a high pass filter cap. I had a friend once that had no money and a lot of time put 4 used 6x9 car stereo speakers in a home made cab. He just cut the suspended tweeters out. Sounded ok and with grill cloth (a tie dyed sheet) it looked fine.

[J M Fahey]

Those are Marsland speakers.


Labels can be misleading, anybody can print anything and glue that label anwhere yhey want (same with rubber stamps ) but speaker *frames* are a made on a *very* expensive set of dies on *very very* expensive hydraulic presses so usually a large Manufacturer invests on a set of dies in different sizes , from 4" to 15 or 18" and use them to death, for decades.

Meaning frames are a very reliable way to identify speaker original manufacturers.

In USA you may find different "Fender" labelled speakers along the way, but by frame shape you can quickly identify them as Jensen/Oxford/Utah/Rola ; in Canada main suppliers were Marsland (this one) and RSC (Radio Speakers of Canada) which being built under license from Jensen ... not surprisingly *look* like Jensens

Power?: your question is certainly funny.
You donīt ell us what power is your build, not even the tubes you will use, nor what size these speakers are (they might be anything from 6" to 12")
So tell us speaker frame diameter and estimate voice coil size .
Carefully (donīt puncture anything) measure the diameter of the felt dustcap , actual voice coil will be 4 to 6 mm smaller and choose 1 of 3 possible sizes (voice coils usually are not any random size but follow a definite scale, so itīs easier to pick one or the other).
Then comparing them to standard same era Jensens we can estimate power quite accurately.
Popular Jensen voice coil sizes are:
* R: 1" or 25 mm ... stand 10/12W
* Q: 1.25" or 32 mm ... stand 12/15W
* N: 1.5" or 50mm ... stand 15/20W
"Fender twin speakers" which were N size, optimistically stated some 40W handling, but were regularly destroyed by dimed Twins (the early ones were about 80/85 W RMS).
Of course Leo designed them to be played *clean*.

And your speakers should be able to stand a couple EL84, be on the edge with two 6V6 and definitely not a couple 6L6 .

[Alley_Cat_Jack]

Thanks for all the info guys. I am still doing a lot of learning and planing my amp. I will measure up the speakers when I get home but I think they are 8". As for the power amp, I will be likely using EL84 since I have two or three of them. This build is basiclly with what I have around and lean on free salvaged stuff while I refine the pre-amp to learn how to make a really great amp.

[Chuck H]

I will be likely using EL84 since I have two or three of them.

Being as el84's are power tubes I take "two or three of them" as a little disconcerting. I wouldn't go to the trouble and peripheral expenses of even a salvage build without a decent pair of power tubes to count on. Decent, as it relates to power tubes, would mean, at least, same brand/age and similar performance/current draw at idle and conducting. I would never punch a board, a chassis, arrange a layout and build an amp,.. And then plug two random power tubes into it. If I made only one concession on a budget build it would be decent, reasonably similar, if not matched power tubes. The expensive stuff, like the output transformer, would be at risk with dissimilar "salvaged" power tubes. Don't risk more expensive hardware on behalf of cheap software.

JM2C

[Alley_Cat_Jack]

Two of the EL84's were salvaged from the same unit. Same unit that the speakers came from.