Mark's new Alpair 7

[markaudio]

Hi Guys,

Following on from user feedback, here's a pic of the latest modification to the Alpair 7. Its our CAD drawing for the addition of a moulded cushion that will be injected into the rear of the frame. This is effectively a "built-in" seal making it easier to fit the driver.

I had originally designed this cushion as additional mass-damping for the frame. I'm now modifying the design by adding 2 ridge rings (red circle lines on drawing) on to the cushion to further aid sealing the driver to box surfaces.

Cheers

Mark.

[markaudio]

Hi Guys,
Here's some sequential pics of the new extension connector components. The drawing is on post No-43 on this thread.

Follow this sequence of pics, you'll see how the extension connection works.

So far, I'm sample B. This connector block is the best. The design has an internal grip arrangement that holds the connectors in tight embrace. The total contact area for both the driver's and the extension connectors is 12-mm X 4.5-mm (54-mm2), more than enough for an excellent connection.

Recapping the reasons for this new addition:

1 - Allows for the remote off-driver soldering of cables.
2 - Allows for the use of large cables (up to 4-mm Dia cores)
3 - Allows for easier experimentation on cable types (solder remote extenders to as many cables as desired).
3 - Easier inter-changing of drivers (just pull out the extension to free the driver connection).

The new extension connector arrangement will be colour coded same as the driver's set. All connectors will be gold plated as per normal.

Cheers

Mark.

[markaudio]

Originally Posted by Andrewbee

Mark,

Will there be an 8 ohm version ?
Have you considered a similar speaker but 16 Ohms?
I prefer OTL amps hence my questions.
Thanks
Andrew

Sorry andrew, not yet (can't do everything all at once)
Cheers
Mark.

[Andrewbee]

Sorry andrew, not yet (can't do everything all at once)

Thanks Mark, thats encouraging since you did not say no


Andrew

[nielsenkb]

Hi Mark, excellent idea with the connectors, having built a number of Alpair 7 based speakers, I always worry about soldering so close to the driver and connectors generally available are often of inferior quality

[_henry_]

looks great

bravo mark

[markaudio]

Hi Chaps,
I'm now at the factory starting the final Alpair 7 main assembly process. All being well, we should complete by this weekend or early next week. I thought is might be interesting to make some posts during the glue drying times, or when ever there's a break while we bring on new parts.

Take a look at the 3 pics. This is the mass production (MP) connector extension set. You may have seen the prototypes earlier in the thread so these are the actual parts to be packed. They should make life easier when soldering cables.

A complete set will be packed with the screws.

Cheers

Mark.

[markaudio]

Hi Guys,
It's been a very long week making drivers. I'm nearly finished, hopefully 1 more day should wrap up the last of the driver making.

Here's 2 pics of the Alpair 7's being made. I'm not done that much pic taking this time due to lack of time and I've covered this driver production in previous threads. So this is more a taste of what goes on.

Worth noting is the large number of workers it takes to fix labels and clean in readiness for packing. I've got a couple of new ideas to improve this part of the production process. The first is to change the design of the rear cover. The second is a new location process for the rear sub assembly (motor) so it fixes to the front sub assembly (frame and power-train). I'll talk more on this in later posts, but the aim is to make the driver easier to make for improvement in its build performance. One of the golden rules for good production engineering is "keep it simple". Fewer assembly processes mean less errors. As you may know by now, I like to tight control the production.

Alpair 7's should be in the shipping warehouse by this time next week.

Cheers

Mark.

[h@kan]

I have a 5:1 TL design with the chr-70 tuned to ~40Hz. Since the specs on CHR-70 and Alpair7 is quite the same I upgraded to Alpair7.

If the CHR-70 is great the Alpair is absolutely fantastic!
Thank you Mark for offering this beauty to an affordable price.

Regards H@kan

[tresch]

It is really great and interesting to hear about your trial and error not just on speaker building as it relates to sound, but these simple manufacturing processes, too.

I love solving these little problems of efficiency... trying to make things simple or more elegant while maintaining or improving quality. It's one of the reason I love computer programming

I'm reminded of the motorcycle manufacturer Buell (RIP... the company not the guy) who did some really neat things with his motorcycles. When designing the XB series motorcycles he set out to remove any redundant parts, keeping it as simple as possible while maintaining or improving performance, reliability, and cutting weight. The result was a motorcycle that had literally HALF the parts count of your standard japanese sportbike, weighed considerably less, and handled like nothing else out there.

These are looking beautiful and I'm hoping I get the chance to hear some in the relatively near future!