Whay Don't HPS Conversion Bulbs Need an Ignitor?

[Jimster]

It's a well known fact that you can run a MH bulb using a HPS ballast, but not vice versa, due to the HPS requiring a high voltage spike to start the arc. Once struck, both HPS and MH run in a similar fashion. Without the ignitor to provide the high voltage surge, the light will NOT light up.
Conversion bulbs are simply HPS bulbs that can be used with a regular MH ballast, eliminating the ignitor and making one ballast useful for both MH and HPS systems. I've looked these bulbs over, and I can't see ANY difference in construction between conversion and regular HPS bulbs. Do we have any engineers out there that could enlighten me on this tricky question? Thanks in advance to anyone for any and all help!

 

[MIMedGrower]

It's a well known fact that you can run a MH bulb using a HPS ballast, but not vice versa, due to the HPS requiring a high voltage spike to start the arc. Once struck, both HPS and MH run in a similar fashion. Without the ignitor to provide the high voltage surge, the light will NOT light up.
Conversion bulbs are simply HPS bulbs that can be used with a regular MH ballast, eliminating the ignitor and making one ballast useful for both MH and HPS systems. I've looked these bulbs over, and I can't see ANY difference in construction between conversion and regular HPS bulbs. Do we have any engineers out there that could enlighten me on this tricky question? Thanks in advance to anyone for any and all help!

Not sure if this is the answer but conversion hps puts out far less lumens (intensity) than a regular hps.

I have a 600w hortilux blue mh (hps conversion) and it is not powerful like the 600w super HPS. And gave 30% less yield in testing.