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[John Halliburton]

While I'm not volunteering personally, if they can make PCBs that survive being launched into space, a PCB can be made that will survive inside a loudspeaker (or piggybacked just outside). To make a bad pun, this isn't rocket science.

Using SMD technology the mass of the components is lower so boards can be smaller and more rigid.

I understand that you are limited to OEM choices, and you don't need to spread yourselves thinner dealing with a different engineering discipline, but you might want to work with the vendor you had problems with, or find another source.

or not... 

JR
 

That's interesting, and probably true now, but back in the '80's at the original Intersonics, a lot of the circuits built for flight hardware/experiments(the ultrasonic levitation stuff that Tom Danley had a hand in designing) was built using point to point wiring on perf board.  The stuff actually flexed better without breaking.

Best regards,

John

[Ivan Beaver]

Is there a option for Lake/Lab-presets? Any closer releasing a official spec sheet?

Josh from Lab Gruppen was in the shop a few days ago and we collected data for the Lab preset.
We got most of what we needed-amid a series of computer issues and one very interesting "event".

My computer was the measurement system and Joshs was the control-both laptops.  We found that if you quickly short the outputs of the amp, it would blank out my computer and then cause it to restart.  I was just hooked up to the analog input of the amp and transformer isolated from the output of the amp and run through a USB preamp.  How does something on the analog side cause a restart?  Well it is my computer-that Josh saw one time tell me "UH-OH" and then die.

We started with the filters/eq etc that is in the Danley DSP and then adjusted as needed to match the response and phase curves.  Everything fell right into place, the only thing we had to adjust was the width of the filters.  The labs were a bit narrower than ours.  But it was pretty easy to do.

The one thing we don't have yet is the limiter settings.  Figuring out how the limiters worked to a bit longer than I expected.  There are basically 3 limiters on the Lab Gruppen PLM amps.  One on the output-to limit the max voltage swing.  That one is easy-and it is entered in RMS voltage reading.

The other limiters in the software are not where I expected them to be.  They are on the INPUT of the DSP section-ie before eq/crossover/amp gain and so forth.

So any changes to eq or amp gain etc will simply give more or less voltage to the output of the amp-and the limiter will not affect it.

SO we are going to have to look a bit deeper into that before the limiter section for the Lab Gruppen amps can be set for a true "preset".

Regarding the J2, we are working on changing the combining lense to get a bit more output in the 8-16K range.  It is being built right now.  For most applications the cabinet is fine and very usable now-but we want to get a bit more out physically-so it doesn't cost anything in power or heating with a small boost up there.

Push the envelope-so to speak.

When it is done, a proper spec sheet will be released.

[Ivan Beaver]

That's interesting, and probably true now, but back in the '80's at the original Intersonics, a lot of the circuits built for flight hardware/experiments(the ultrasonic levitation stuff that Tom Danley had a hand in designing) was built using point to point wiring on perf board.  The stuff actually flexed better without breaking.

Best regards,

John

That's great- now we have to build point to point switching amps-Now what's that gonna do to the price or size? HA-HA 

[John Roberts {JR}]

That's great- now we have to build point to point switching amps-Now what's that gonna do to the price or size? HA-HA

Being uncharacteristically serious for a moment, I'm not even convinced that was SOTA for the '80s. Circuitry for high vibration environments could be potted solid, but that would make it hard to make last minute changes in one-off experiment modules.

My personal experience is that SMD is more robust that through hole for general R & R applications. Putting circuitry inside high SPLl environments has been done before (think guitar amps), while there multiple considerations associated with frequency, mass of parts, geometry of PCB, etc.


JR

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