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Orange Terror Bass v2 - Impedance Switch?

groovaholic

groovaholic

Protect your hearing. Protect your hands.
Supporting Member
Sep 19, 2004
5,360
9,933
Mount Prospect, IL
#1
Picked up a MINT Orange Terror Bass on Friday, based on the strong recommendation of @Wicked G. He owns (or has owned) several of my favorite amps, so I figure we have similar tastes in amps.

His suggestion of the Terror Bass was spot-on; this amp is exactly the modern/vintage tone I was looking for as a counterpart to my GK 700RB-II. Plugged into my LDS nEarful 15/6, the sound is like a very high-powered, high-def Ampeg B15.

Into my LDS 2x12, I liked it, but not nearly as much as into the 15/6 - which brings me to my question:

The 15/6 is an 8-ohm cabinet, and the Terror Bass V2 is advertised as a 500-watt (at 4 ohm) head.
So, pushing 8 ohms, I'd expect approximately 250 watts - which is how Orange rates it:
upload_2021-8-30_8-43-9.png


But then there's an impedance switch on the back of the amp:
upload_2021-8-30_8-39-9.png


upload_2021-8-30_8-40-11.png

I know that the impedance switch allowed the prior version of the Terror Bass to put out full power into 4 or 8 ohms, so that switch made a lot of sense on V1.

But since this newer version is de-rated at 8 ohms, I'm not sure what the switch is doing - is it just a carry-over from the prior version?
 
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#4
On many solid state amps, the impedance switch impacts the voltage in the power supply. Higher voltage is used at 8 ohms so the amp can make more power. Then at 4 ohms, a lower voltage is used to keep current in the output devices at a safe range. That does not appear to be what is going on with the original TB500.


Instead of being in the power supply, the switch is part of the input section of the class D poweramp module. I believe it may be part of an input limiter circuit. If I am correct, changing the switch modifiers the behavior of the limiter.

I don't have a schematic for the V2 amp.
 
#5
Wasnex said:
On many solid state amps, the impedance switch impacts the voltage in the power supply. Higher voltage is used at 8 ohms so the amp can make more power. Then at 4 ohms, a lower voltage is used to keep current in the output devices at a safe range. That does not appear to be what is going on with the original TB500.


Instead of being in the power supply, the switch is part of the input section of the class D poweramp module. I believe it may be part of an input limiter circuit. If I am correct, changing the switch modifiers the behavior of the limiter.

I don't have a schematic for the V2 amp.
Click to expand...
Great insight, thank you!
 
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#7
Thomas Martinez said:
So it doesn't matter, I can use 4 or 8 ohm on the head to my 8 ohm cab
Click to expand...

My guess is it matters. AFAIK, It changes the way the amp handles the signal and the manual seems pretty direct in inferring it's important to set the switch to the correct setting. It may be vital for the safety of the amp when pushing a 4 ohm load, or it may be intended to soften have the amp transitions into clipping.

When pushing an 8 ohm load, it may only change how much power the amp can make. If the switch is set to 8 ohms with an 8 ohm load, the amp produces it's full rated power before the limiter engages. If set to 4 ohms, the limiter make kick in at a lower power level.

This is an educated guess based on trying to analyze the limiter of the original Terror Bass...but it's still a guess as I am not an engineer.

Also, I have not seen the schematics for the Mk2 Bass Terror. The impedance switch in the current amp may not have anything to do with limiter. It may change the rail voltage in the power supply.

Your best bet is to contact Orange and get the official guidance from technical support.
 
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#8
Wasnex said:
My guess is it matters. AFAIK, It changes the way the amp handles the signal and the manual seems pretty direct in inferring it's important to set the switch to the correct setting. It may be vital for the safety of the amp when pushing a 4 ohm load, or it may be intended to soften have the amp transitions into clipping.

When pushing an 8 ohm load, it may only change how much power the amp can make. If the switch is set to 8 ohms with an 8 ohm load, the amp produces it's full rated power before the limiter engages. If set to 4 ohms, the limiter make kick in at a lower power level.

This is an educated guess based on trying to analyze the limiter of the original Terror Bass...but it's still a guess as I am not an engineer.

Also, I have not seen the schematics for the Mk2 Bass Terror. The impedance switch in the current amp may not have anything to do with limiter. It may change the rail voltage in the power supply.

Your best bet is to contact Orange and get the official guidance from technical support.
Click to expand...
Thanks
 
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#9
Question regarding the Orange Terror bass amp (500 w). I would really like feedback from those Orange Terror bass amp users (500w) regarding what types of music this amp is best for (I am a blues rock guy; early Led Zep, Humble Pie, Aerosmith, Grand Funk, Band of Gypsys) and very much interested in the reliability of these amps. For instance, any trouble with them? How hard is it to get them fixed or find someone who can fix them? Do they have plenty of power for gigging (indoor/outdoor)? I am looking to hook up a pair of OBC 115's to it and was wondering how close this amp comes to the AD200 sound/tone? Thanks! Bill
 

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