opinions on class H amps?

Class H has been around for a long time (eg Crest Pro series 7001, 8001, etc.) and are pretty standard for high power amps. I´d be more doubtful about the Class D...  




Edited by Earplug - 11 July 2012 at 2:34pm

Not using class D. And yes I know they have been around for a while. I've been using QSC for years. I just think the claim that they are that much more efficient is off base. Like I said in the opening post, I bounce the voltage with every pop of the kick. Is there really that much of an advantage to switch railing. The old heavy as a tank peaveys I had 20 years ago didn't seem to be any worse on power and quite frankly sounded better. Although I'm sure QSC has saved me a fortune in chiro bills.

Elliot,  as always a sensible answer :)

Tony

I'm very aware of the necessary current. I have always used independent 30 amp(120V) circuits on my bottom amps. It was in fact 2 cs800's bridged per circuit back in the day and they held a much more stable load (and never tripped) than a single QSC 2450 on the same circuit. This was exactly my point. It shouldn't do this. The QSCs should not be pulling this kind of a load. I would agree the DDT compression may have been helping the Peaveys with the gain reduction it creates but regardless the QSC amps should not be working this hard. To be fair some of my QSCs are pushing ten years old.
So is class H really running that much more efficiently when pulling low frequencies? 

B.M.F. wrote: I'm very aware of the necessary current. I have always used independent 30 amp(120V) circuits on my bottom amps. It was in fact 2 cs800's bridged per circuit back in the day and they held a much more stable load (and never tripped) than a single QSC 2450 on the same circuit. This was exactly my point. It shouldn't do this. The QSCs should not be pulling this kind of a load.

Once the amplifier is being driven at the given impedance load, at the desired output level, the amplifier is going to draw current. The only reason to use a higher ampere rating (30 amperes –vs- 20 amperes) is to lower the chances of tripping the breaker.

B.M.F. wrote: I would agree the DDT compression may have been helping the Peaveys with the gain reduction it creates but regardless the QSC amps should not be working this hard. To be fair some of my QSCs are pushing ten years old. So is class H really running that much more efficiently when pulling low frequencies?

I wasn’t referring to the DDT enabling the amplifier to draw less current. The DDT alters the sound once activated which, could be the reason you stated…

B.M.F. wrote: The old heavy as a tank peaveys I had 20 years ago didn't seem to be any worse on power and quite frankly sounded better.

Two Peavey CS 800’s, bridged mono, @ 4 ohms on a 120-volt line can/will draw 30 amperes continuous. The QSC RMX 2450 cannot exceed 20 amperes continuous @ 4 ohms bridged mono on a 120-volt line without current limiting taking place. Peavey CS 800 does not offer current limiting other than blowing its fuse or tripping its breaker (on the amplifier) pending on which model you own.

The QSC RMX 2450, 1850, 1450, in addition to 850 is QSC’s bottom of line series amplifier. The Peavey CS series was Peavey’s top of the line series. A brand new CS 800 cost $700. A brand new RMX 2450 was $700 before Behringer EX 2500 came about and QSC dropped the price to $600.00

QSC designs the most current efficient line of American amplifiers available on the US market. This is why QSC is so popular amongst small providers for they can plug them in a 20-A or even 15-A, 120-volt receptacle and have no worries about tripping a breaker.

Try to rent the old Crown Macro-Tech 2400 and, compare the power consumption to the QSC RMX 2450. The Crown Macro-Tech 2400 is class A/B and will show you how efficient Class H is compared to Class A/B is from a current draw perspective.

Best Regards,