orion xtr 2150 / 420 gt

First, I would like to get some different inputs on how low I can bridge an XTR 2150 (pop top). I have read no lower that 4 ohms bridged, and I've aslo read about people running at 2 ohms bridged. Is it a matter of how you set the crossovers? Are the people running them at 2 ohms bridged not being safe? I understand safe is a relative term. So if it's possible, that would put its 12v rms at 600x2, right? Fuse rating doesn't seem right for that kind of power though, unless I were to change them out to bigger ones. But I really don't know enough to start modding amps.

Lastly, I've seen the Orion 420 GT for sale online, but when I try to research it, I get nothing. I can't find one single piece of information on this amp. So if any Orion people out there can fill me in in these two things, I would greatly appreciate it.

Fine the employers.

Back when they made the 420, high power radios were in their infancy.  Older radios put out about 8 watts per channel.  I high power radio will put out around 17 watts per channel.  Yes even the ones that claimed 40 50 or 60 watts per channel.  That amp is a 4 channel amp rated at 20 watts per channel.  Most orion amplifiers would put put much more power than they claimed.  That is the one that would do it's rated power, but not much more.  In my opinion, that amp is a useless piece of equipment, unless you have a deck that has no speaker outputs.

You can not adjust a crossover to make an amp run into a lower than rated load.  I run all of my 4 ohm amps into 2 ohms.  It is not for everybody.  I understand that I can not play it balls to the wall continuously.  I would not do it if I were you.  If I break my amp I have the ability to repair it.  Repair shops are becoming a thing of the past.  With the number of 2 ohm and even 1 ohm amps available for purchase, I really hope you will not run yours into 2 ohms.

"Idiot", thanks for the info on the 420.

As far as the XTR 2150, it's not my first choice but I saw one with box, plugs, manual, and super minty for a sweet price. My plan is to switch out my amps for the vintage Orions. In doing that I'd like to keep everything red. Anyhow, I do not have the same repair experience you do. So I won't be running anything under what it's rated for. Especially something that costs alot and aren't made anymore. I could use it to power my mids. I don't know, I'm just thinking aloud. But since we're on the topic, do you know very much about the HCCA's? I want to know the difference between them, 225, 250, 425, 2100. Not sure what Digital Reference or "R" mean. I'm really only interested in the first 3 generations. Thank you!

Fine the employers.

A 425 is a 225 X 2.  They actually have 2 225s butted up end to end with a small RCA / DIN board mounted to the front of them.  As far as durability and being easier on your charging system, the 225 is much higher on the list of desired amps than any of the others you listed.  The older generations had bi-polar transistors in the power supply and in the output section.  They did go to a Mosfet power supply with bi-polar in the output stages. 

The 250 and the 2100 both are really demanding on your charging system.  With today's class D technology, there are many much more efficient amplifiers out there. 

I understand the whole thing about the charging system and there being more efficient amps out there. I'm running JL slash series right now (1k and such) I was looking to switch over to an older style install with these things on my wish list; class A/B unregulated brute strength. And It seems like every 225 I see is broken. Not a problem if I knew how to fix them!Fine the employers.