Tube Amp Archive

I purchased an eminence cannabis rex for my low watt project. Seemed to be just what I was looking for based on the reviews that I read; a relatively flat response with a little emphasis in the low end, and less shrill highs.

The first thing I noticed was that the hemp cone seems very stiff. I've only ever owned vintage/used amps, and the speakers in these amps seem very loose, and have much better bass response.

Will the cannabis rex loosen up during break in? is there anything i can do to speed up the break in time?

Don't push the cone by hand, this can cause coil to rub.

The best way to break it in is to hook it to an amp and play a signal through it for a few days.

I've seen some break in with a fixed AC signal, but This only flexes one node of resonance.

Watch this video of wet corn starch on a cone, and you'll see some patterns.

http://youtu.be/cEEClj5nUdE

As a cone breaks in it flexes slightly along these nodes and this softens the fibers. Much like wearing in raw denim jeans.

John

Use a Variac.
60Hz makes the cone move a lot.

This is a guide that Jim from Scumback Speakers recommended.

Structo, I have modified that break in procedure three years ago after discovering the voltages were too too high.

Here's the actual SAFE voltages and break in method I've recommended since early 2011.

Speaker break in with variac voltage settings. Wire your speakers in parallel (or series/parallel) to do more than one at a time, but use these same settings as if there were only a single (Two/four 16 ohm speakers use the 16 ohm setting). If wiring in series (not recommended, since it's slower), double the break in time.

Variac break in times are cumulative, meaning total hours on the variac. You'll want to do them in two hour shifts (MAX), then two hours off to cool, then on again for two more hours. That means it will take two full days to do speaker break in with 8 2 hour cycles:

Speaker Ohm Imp Speaker Power Rating Break in Voltage How Long?
8 30/65/100 9 Light Break in= 2 to 3 hours
16 30/65/100 11 Medium Break in = 8-10 hours
Full Break in = 16 hours

Thanks for the clarification Jim.

I figured you would chime in with the correct info.

So is that 9 volts for the 8 ohm speaker and 11 volts for 16 ohm?

Structo wrote:Thanks for the clarification Jim.

I figured you would chime in with the correct info.

So is that 9 volts for the 8 ohm speaker and 11 volts for 16 ohm?

Correct. While my speakers can handle more, it seems that other speaker companies can't, so I've reduced it down to the "safe level" for any speaker so no one should get fried (literally).