Quick recovery about lighter amps performance?

[djlivex]

Hi I was just curious as to Big Ronn's reply regarding quick recovery about heavy metal old Crest 9001 series amps? I can't find the post, can anyone enlighten us if the newest Crest E-Light amps with DSP and without have the umph or cough when you drive 2 ohm load at high power settings? Thanks for all the response! Have a good weekend everybody . . . ( thinking of the cheaper CPX by Crest for daisy chainning more than 12 T39's . . . whew!)

[DJPhatman]

Why would you subject your amps to 2 Ohm loads? Even the "old iron" has much higher distortion rates at 2 Ohm loads. Plus, working them that hard will end up making a lot more heat in the amp, which, in turn, more than likely shortens the amps usefull first life. IMVHO, it is not a very good business decision, nor is it a very smart one. Will it work? Sure, I've even done it in a pinch. Would I do it if I didn't have to? No way.

The upside is lightweight power is very cheap. 2 lightweight stereo amps, running 3 per side at a nominal 3.34 Ohm load, and still less weight than 1 "old iron". And, with recorded music, you will never hear the difference between the amps.

I run dual HL10C loaded T39's off each side of a Crown XTi1000. Never a wimper from the amp.

[Ron K]

What happens with whats known as "quick recovery" is the newer Class H-I designs use duty cycling to store power and release it during on peak demand time. This allows the amp to run higher peak levels because during the low peak times current is being stored.

What happens is if you run the amp at very high levels (not necessarily into full clip) but at a point where the peak or crest is no longer quite as high a ratio, the digital switching amps no longer are storing power and therefore there is nothing left to release. So when the signal subsides they need time to recover for the next high level passage and if that passage occurs before the amp had ample time to store more juice then the peak output suffers and it is audible. Again it only happens when you are near the limits.

In the real world most system operators try and get the most they can with their rigs without having to unload more stuff from the truck or probably and even closer reality is they've got 1 rig and use it (often beyond it's capabilities) for everything.

It's generally not a problem with the more expensive switchers like I-techs or PLs from QSC.PLXs I hear are decent as well on subs.

Conventional power supply's handle these tasks a bit better using transformers and large Caps when pushed close to their limits. With the less expensive switchers you just need to make sure you buy one with enough headroom to effectively run subs.

I dont believe it's an audible problem with the more expensive switching amps. There's a reason they cost more! With the cheaper models you simply try and use one with a bit more headroom.

In the recorded media world since the dynamic range is generally fairly consistent I dont think it's as much a problem since the crest factor just is nowhere near the demands placed by live audio. With live a way around the problem if you choose to not want as much headroom is to obviously compress heavily. It will work but I've found that heavily compressed live music clashes with the natural peaks being thrown from the stage and usually ends up in a rather funny sounding live event! Not to worry as the ears have a way of adjusting and adapting to these things but it's really not the recommended way!

Recorded you can hit the RMS limits faster because of lack of peak content but I dont believe there is any audible difference to be heard since recovery usually only affects peak content.

[Incognito]

Hi I was just curious as to Big Ronn's reply regarding quick recovery about heavy metal old Crest 9001 series amps? I can't find the post, can anyone enlighten us if the newest Crest E-Light amps with DSP and without have the umph or cough when you drive 2 ohm load at high power settings? Thanks for all the response! Have a good weekend everybody . . . ( thinking of the cheaper CPX by Crest for daisy chainning more than 12 T39's . . . whew!)

Crest E-Lite amps will have solid two ohm capability with lots of energy storage. They have been tested driving eight 18's totaling one ohm on a channel. They don't fold back and current limit, they don't overheat, they don't shut down, and they do punch. They will run with amps much higher priced. Sadly, little will hang like the 9001. It's not that a lightweight amp can't, it's more a matter of fewer folks willing to pay for it. The 9001 also has other circuitry that helps the sound, like the "Sliding I" circuit. That helps make it a sweet sounding amp that's difficult to match. E-Lites won't be available for months yet, so it's a bit of a moot point for now.

[Randall Dibble]

What do you think of the new Peavey IPR 1600 Power Amplifiers?

[Incognito]

What do you think of the new Peavey IPR 1600 Power Amplifiers?

According to the talkbass forum, bass players seem to like them. Peavey has been making class D amps for over 25 years going back to the old Decca series, so I expect the IPRs to work. The engineer that designed the old Crest amps from the mid 80's to mid 90's as well as the current 200 series designed the IPR. Expectations are high and early reports indicate these are very good sounding and are reliable. Having an empty rack weigh more than the amplifiers going into it is certainly a plus.

[chunkylover73]

I ordered an IPR 1600 but it kept cutting out during a gig. Turns out the fan wasn't working and it was overheating. I sent it back and ordered a Crown XLS 602 instead. I'll stick with heavy and reliable instead of light and cheap for a little while longer, at least until all the bugs are worked out.

[Incognito]

I ordered an IPR 1600 but it kept cutting out during a gig. Turns out the fan wasn't working and it was overheating. I sent it back and ordered a Crown XLS 602 instead. I'll stick with heavy and reliable instead of light and cheap for a little while longer, at least until all the bugs are worked out.

I would like to get more specifics about the failure mechanism. Would you mind PMing me with the retailer you returned it to? I'll also ask them what their failure rate is. That will be useful information for all.

[Incognito]

I ordered an IPR 1600 but it kept cutting out during a gig. Turns out the fan wasn't working and it was overheating. I sent it back and ordered a Crown XLS 602 instead. I'll stick with heavy and reliable instead of light and cheap for a little while longer, at least until all the bugs are worked out.

Peavey checked with both branches of the retailer you purchased the IPR from as well as with their online branch. They have no IPR1600 returns. As far as Axe Music knows, all of their customers are happy. I noted you made commentary on multiple forums and even left a negative review on the Musician's Friend site, although you didn't buy it there. I'd still like to find out what the cause was for the overheating. Can you help me?

Thanks

[chunkylover73]

PM sent.

[Ron K]

How do the IPRs handle Low voltage problems?

[Incognito]

How do the IPRs handle Low voltage problems?

Hi Ron. For the 1600, start up voltage is around 90. Drop out voltage is 77. Fluctuations don't bother it.

[Ron K]

How do the IPRs handle Low voltage problems?

Hi Ron. For the 1600, start up voltage is around 90. Drop out voltage is 77. Fluctuations don't bother it.

TY for that tidbit of info. Were gonna try and destroy one this coming weekend! Actually were just gonna test it good! LOL.Hopefully we dont destroy it!

The guy I'm working with likes to draw the mains power to a halt with his 29 year old dimmers and 20KW of lighting! So were gonna hook up an IRP on some horns and see how it goes. Not my rig though so I dont know when I'll be asked to stop before I ruin something! LOL. Weather or not I comply is another question probably better asked to my friend jack Daniels and my favorite inlaw Old Grand dad! I dont get many chances to blow up other peoples junk so it should be fun!

[AntonZ]

Please do report back, Ron. I probably need an amp later this year, looking at one of the cheapie new Behringers (most watts per €, lightweight and stupid small). But the Peavey looks good, too, and it might be available before the B's.

[Incognito]

I ordered an IPR 1600 but it kept cutting out during a gig. Turns out the fan wasn't working and it was overheating. I sent it back and ordered a Crown XLS 602 instead. I'll stick with heavy and reliable instead of light and cheap for a little while longer, at least until all the bugs are worked out.

In a semi-feeble effort to somewhat redeem Peavey:

http://srforums.prosoundweb.com/index.p ... msg_528905