Mystery Sunn Items...

[Sunnshine Slave]

Hi - I have a Coliseum Bass amplifier and a 412L enclosure. Can anyone tell me when these items were manufactured? Might the amp have been made around 1973? (The serial number on the back is "50925".) I'm guessing that the enclosure dates from around 1980? Guidance please!!!

[Sunnshine Slave]

I've just realised that the 412L enclosure is rated at 8 Ohms while the Coliseum Bass is, I think, 4 Ohms?!?!  Am I going to damage the amplifier?!?!?!

[MusicFox]

I've just realised that the 412L enclosure is rated at 8 Ohms while the Coliseum Bass is, I think, 4 Ohms?!?!  Am I going to damage the amplifier?!?!?!

Solid state amps are less/not easily damaged by impedance mismatch. A reduction an power and a little more heated up components is all you'll experience with a 8 ohm load on a 4 ohm amp rating (Better than reverse.. or a 4 ohm load on 8 ohm output.)

Question for you is what is the speaker impedances individually and can it (cabinet) be rewired for 4 ohms total. That would be better.

Go Nuclear. Get another 8 ohm cab and run together (Parallel) for 4 ohm total (in out jacks on speaker cabs make it easy) 

[Sunnshine Slave]

Thank you very much - I hope neither my father nor Mr Booth (my old physics teacher) get to read this thread. I used to know my stuff, electronics-wise; as you can see, I'm pretty clueless these days!

So, yeah...giving myself and my memory headache here...if two 8 Ohm speakers are wired in parallel, then the total impedance becomes about 4 Ohms, doesn't it? Alternatively, er, if they're wired in series, then the total impedance would theoretically double to about 16 Ohms, wouldn't it? So, since the 412L enclosure contains four speakers and it's rated at 8 Ohms, er...hmm...what's the rating of each speaker? How is each speaker wired in the existing cabinet? Oh, Mr Booth - can you come and take the back off my cab, please?

I'd love to go nuclear and use two enclosures, but I think I'll have to wait a while before another 412L comes up for sale. Anyone in the U.K. wanting to sell one?

If I did run two 412L enclosures from that single Coliseum Bass, would I plug one enclosure into the amp and then use the other jack socket on the back of that enclosure to plug-in the jack leading to the second 412L? I notice that the Coliseum Bass has two outputs on the back, so I wasn't sure if I should run two cables out the back to seperate enclosures...erm, are we back to series and parallel again?!?

How would I go about re-wiring the 412L enclosure to 4 Ohms? Would that single enclosure subsequently be able to handle the power the Coliseum would chuck out if the speaker wiring was re-configured like that?   

Suggestions or calculations anyone?!?!? Any help very gratefully received        

[Sunnshine Slave]

Hi...yeah, I've experimented with 8 x 10s and, well, all sorts of enclosures in my time; this 4 x 12 does sound fantastic (...and I'd love another one!)

So, do you reckon the amp is from around 1973 or possibly even earlier? When I contacted Fender they told me that they haven't got a database for Sunn products 

So, if I'd been alive in 1973 (or whenever) and had the inclination to buy a Coliseum Bass, what enclosure(s) might the salespeople and designers at Sunn have assumed I'd use from their range? Did they actually sell speakers that were rated at 2 Ohms? I'm wondering if it was expected for more than one cab to be run from a single Coliseum? (The impedance being lowered to a match at 4 Ohms that way?)     

[Isaac]

Check the catalogs. My guess would have been 1974 for the Coliseum.

[MusicFox]

If I did run two 412L enclosures from that single Coliseum Bass, would I plug one enclosure into the amp and then use the other jack socket on the back of that enclosure to plug-in the jack leading to the second 412L? I notice that the Coliseum Bass has two outputs on the back, so I wasn't sure if I should run two cables out the back to seperate enclosures...erm, are we back to series and parallel again?!?

How would I go about re-wiring the 412L enclosure to 4 Ohms? Would that single enclosure subsequently be able to handle the power the Coliseum would chuck out if the speaker wiring was re-configured like that?   

Suggestions or calculations anyone?!?!? Any help very gratefully received        

2 outputs on amp makes 2 speaker cabs in PARALLEL so 2 -8 ohm cabs in both outputs from amp makes 4 ohm load. Yes you can go from cab to cab too. For Parallel again. Your right also about 2 x 8 in parallel makes 4 ohms and 2 x 8 in series makes 16 ohms. Your cabinet is probably a series parallel combination 2 x 8ohm in parallel twice (4ohms each pair) and the series those pairs together to get 8 again.

A specially made cable would have to be soldered up for a series connection with cabs it can be done but 2 x 8ohm you'd have 16 ohms that way.

The 2 ohm rating was a company trick to show higher wattage output on the sales flyer. (Solid state amps wattage rating CHANGES with impedance load) (Ohms). Goes up as ohms go down UNLIKE tube amps that are constant as long as right transformer tap is used. 8 ohm tap 8 ohm load etc. Nobody (Maybe) makes 2 ohm cabs but the amp would allow 2 x 4ohm cabs to be used for this highest wattage lowest ohms rating.
Cheers