Tell me about the 215-SH I just purchased...

[twistworthy]

I just purchased a Sunn 215-SH bass amp that looks just like this one:



I found this photo online, but it's the same amp.  I paid $100 bucks.
Here's what it says on the back:
Sunn 215-SH
Impedence 4 Ohms
Rating 160 RMS
Transducer 158B

Can anyone give me any info about it?  Age?  Is $100 a fair price?
Anything else..?  What Sunn head would be a nice fit for this amp?

Any info is appreciated... Thanks.

[Isaac]

It's not an amp, it's a speaker.

It's from the mid to late seventies. Two 15" drivers in a folded horn, it's very loud. Not a lot of high end, of course. I think it would be ideal with the Concert Bass.

A guy back in my home town had two of them. He arranged them so that the horns complemented each other, and powered them with a Coliseum Bass. He could kill at thirty paces.

[twistworthy]

Yeah... Speaker.

That's what I meant.

Thanks for the info.  Does anyone else have one of these?  I'm finding very little info about the 215-SH online...

[Isaac]

I don't think they were ever very popular. Most people who wanted a floded horn wanted an 18" driver, so the 118SH and 118VH, with the Cerwin Vega driver, were much more common.

As to the price, I'd gladly pay $100 for one, if I could ever find one. It would have to be local, though, as shipping would be a real deal-killer.

[destroy_all_monsters]

Eminence squarebacks, JBLs?

[Isaac]

Mostly comes down to the Q of the driver, I think. Really low-Q drivers work well in enclosures like that. JBLs, Altecs, some Eminence drivers. Maybe EVs, I'm not as familiar with them. Look for a Qt value around 0.20.

[destroy_all_monsters]

Forgive my ignorance but what's Q/Qt?  <br><br>I've got one of these and it looks like an Eminence squareback was probably the stock speaker (though I've no information on it. Emailed Eminence already - no reply yet.).  Just trying to figure out the best replacement for something with a tube head (Ampeg  now - still looking for Sunn gear). <br><br>As I understand it the squarebacks are ceramic as opposed to Alnico.

[Isaac]

Yes, the squarebacks are ceramic. I don't think that has any necessary effect. Magnetism is magnetism.

Q is one (several, actually) of the Thiele-Small driver parameters. Q is the quality of the resonance of a circuit. Highly resonant circuits have a narrow bandpass. In drivers, there is a mechanical resonance (Qm) and an electrical one (Qe) which are combined to yield the total resonance (Qt). Qt is easily seen in an impedance plot of a driver. Drivers with high Q factors tend to have response peaks at the resonance. This is more pronounced with tube amps, due to their higher output impedance. For reference, Q=0.707 yields a maximally flat response. Anything higher than that has a response peak, often referred to as a hump. Lower than that, the low end response starts rolling off at a higher frequency, but rolls off very smoothly. Such systems often have more deep bass than flatter systems.

I don't know if any of that helps. Understanding what Q is isn't nearly as important as understanding how it affects the system.

[claytoy]

I love the 215SH and I have been searching for another one.  I play in a little threepiece and have had my sunn215SH since high school (1977). I drive it with an old pevey standard also since high school.  I have recently picked up another pevey standard amp and desperately want another 215SH. I will place one on eitherside of the stage and the building and all that is in it will be mine -- ha ha 
please contact me if you don't like it or think it's too heavy.  since 77 when i bought it used i have only had to rebuild the speakersonce this was mosd recent.
in any case i am most jelous. 

[djc]

thanks again Isaac for the lesson.  that's great!  does anyone have a schematic of this cabinet?  I have 2 18" peavey black widows (not my choice but they're free) to play with.  I love my punchy 410 but I'd like to try something different with these 18's, all I need is a schematic.  any suggestions?

[Isaac]

The Peavey Black Widow has a relatively high Qts of 0.61 for the 8 ohm version and 0.47 for the 4 ohm version. Neither seems particularly well suited for a horn cabinet. If I had some to use, I'd put them into the largest sealed cabinet I could, then use EQ to get the response I wanted.

[djc]

thanks.  largest sealed cabinet?  or cabinet size suited to the speaker?
currently they are in cabinets twice the size they should be and sound ick...  did I mention I like my 410? 

I just assumed the cabinet made these things sound poor.  some guy took what was supposed to be, assumed bigger is better and made these cavernous cabinets.   

[Isaac]

Depends on what you like, I suppose. The largest sealed cabinet will give the flattest response. If you don't like flat response, then the response peak of a smaller cabinet might appeal to you. The 4 ohm version wants a cabinet over 9 ft^3 for flattest response. That's what I consider a cabinet size suited to the speaker. For the 8 ohm version, it's more like 33 ft^3. Reducing the cabinet colume moves the resonance up in both frequency and magnitude, causing a peak in the response and a more rapid rolloff below that. Lots of players like that, and you might, too. In an 8 ft^3 cab, the 1801-8 has a 1 dB hump and an F3 of about 50 Hz. That's not all that extreme, and 50Hz is better than a lot of commercial cabinets. Also, sealed cabinets are rather EQ-friendly, and I wouldn't hesitiate to add some boost below that if I thought it would help.

If you are interested in something more exotic, consider a 4th order bandpass. The 1801-8 models out with an F1 of 29Hz and an F2 of 74.5Hz. That'll give you some rumble! Of course, that takes a really, really big cabinet!

[Ryanx]

i like the look of these, i'd like to play on one and maybe add one into what i have going.