Chevin A6000 @ 2ohm sub - VZ5 killer or not?

levyte357 wrote: RENSAAB wrote: Looks like a robust amp. Shame about the heat issue. If the heatsinks are undersized as i suspect, variable fans make no sense.   Like Chris-I said maybe hard wiring the fans would help.   Ren, If the Heatsinks are undersized, what do you think it would take to make the amp happy under 2ohms stereo all night? I'm thinking the variable fan speed was purposed for lower fan noise/power consumption. Trying to get a blown Q900 to you, that a mate has. But he wont let me have it without explaining fully whats going on, and what am I gonna do with it...

tweeter box wrote: levyte357 wrote: http://speakerplans.com/forum/forum_posts.asp?TID=7567&KW=a6000+heat&PN=2 jbl_man wrote: i Have a test report on the chevin amplifiers carried out by Ken Dibble.he states,and i quote"the Chevin is not a switchmode amp,in the accepted sense.it capitalises on the law of physics which says that transformer size is inversly proportional to frequency.thus a power supply working at 100khz will be orders of magitude smaller that one working at 50-60hz.......first the AC current is rectified,ramped up and smothed,and fed at 100khz at 340v to a special high frequency transformer using a Phillips ferite core,it is then converted using high speed rectifiers and caps to provide 85v+ - to feed the amplifier.  He goes on to say that its not happy in continious high power low frequency operation,and "the amplifier was getting very warm by the time we worked up to full power bandwidth test,and shut down just before a full test could be taken.following a cooling down period,it fired up ok,but shut down again immediatly after the full power test,with fans running at full speed and making a lot of noise. "clearly it is not happy at continious sine wave operation at full power,but the protection circuits do provide the level of protection claimed."  Is this any help? maybe its an excellent amp for mid-hi,but maybe not so ideal for prolong heavy bass?   from the back it looks like 2 amps joined together!!

the A6000 is two 3k mono amps in one unit tweeter, bridge mode is not possible.

RENSAAB wrote: levyte357 wrote: RENSAAB wrote: Looks like a robust amp. Shame about the heat issue. If the heatsinks are undersized as i suspect, variable fans make no sense.   Like Chris-I said maybe hard wiring the fans would help.   Ren, If the Heatsinks are undersized, what do you think it would take to make the amp happy under 2ohms stereo all night? I'm thinking the variable fan speed was purposed for lower fan noise/power consumption. Trying to get a blown Q900 to you, that a mate has. But he wont let me have it without explaining fully whats going on, and what am I gonna do with it...   I can only suggest upgrading the fans and shift as much air through the amp as possible (if you don't mind the noise).   I'm suprised that it's a mosfet design. Is each channel running in bridge mode? Any idea how many o/p devices per channel?   Ren

The amps run in class AB with a highish quiescent current.

The heatsinks are an assembly of aluminium plates in which the Mosfets mounted, if I remember correctly (was a few years ago since I looked inside).

The Mosfets are the Exicon double die T03 cans, eighteen complementary pairs in each channel.

The amp is literally dual mono, 2 units held together by the front and side panels. Each unit is in bridge mode. I suppose this is so that the devices can be relatively low voltage, 160V for the A5000 and 200V for the A6000.

At the time I bought them I was considering building an amp of similar ratings around the same o/p device but with conventional PSU. This was going to end up the size of a small fridge and weigh around 50 Kilos, JUST ONE CHANNEL!

I decided to go for the "lightweight" option!

They are power hungry, I used a pair of them for the FunBunch at the carnival in 2000 and 2001 and they were most impressive with a 63Amp mains supplying them, at one stage the meters were fully lit almost continously with the the clip/limit LED only faintly and briefly coming on. At other occasions with less juice, the Clip LED comes on more easily.

A 'stiff' mains supply is definitely required.

sKs01 wrote: thaught as much, so thats each channel runing down to 1r when running 2r sub... ouch

that definatley sounds logical, would explain why ive had clip lights so soon in one particular venue