R&C on Lightweight Amps - Power ratings

Youngblood asked me to start this thread, as it seems everyone on SP is afraid to comment on this for some reason.

At last R&C Amp shootout in Southall, ALL the lightweights tested, with possible exception of the Powersoft K10, were well into clipping,
driving 4 ohm stereo load, with the 2x PD1850s per channel still playing with ease.

Is a little strange, as the Lightweights specs were rated @ 4 ohms from approx 3kwpc upto approx 5kwpc stereo?

The Inf8Mk2 was different story, clearly having the force and grunt to smoke the both 1850s & Turbomaxes, well before clipping,
especially when it was drawing upto 20A from the mains at one point.

So the amp with lowest spec'd ratings, spanked all the lightweights bar one..

Seems fairly obvious, most lightweight amp manufacturers are telling porkies, and as always said on SP, an R&C test session/comparison
with decent transformer amp would expose this.

Comments?

Could it be the amps in question can deliver their stated outputs at 1khz but on very low frequencies fail to impress. Especially when playing Roots/Dub music where the bass notes require the amp to be able take sustained punishment all night without breaking a sweat.

NITZ V1505 wrote: Could it be the amps in question can deliver their stated outputs at 1khz but on very low frequencies fail to impress. Especially when playing Roots/Dub music where the bass notes require the amp to be able take sustained punishment all night without breaking a sweat.

Don't get me wrong, some of them did sound nice, but started clipping when driving low freqs & turned up..

Some even shut down... :lol:

Perhaps it's time for re-appraisal. This time I'd like to see what goes on. I'd certainly bring my amp in for comparison, baring in mind, none of this is competition. I'd like to know where we stand with various types of amp. I'm always tempted to go for the best.

Yes Lev, that's why i brought the inf8 down for reference, alot of people thought that was a bad idea days before the event. smiley1

it baffles me how manufacturers get their ratings? dont get me wrong they sound good but do not understand the power ratings? to me a ca18 with almost half the power rating would give most of them a run for their money on power. luckily for us we had the test to see what was really going on, Leon almost bought a pkn aswell for sub a while back....thinking he was getting 3k a side @ 4r.... heard stories of roots man using them and the amps early into a session start reducing power to cool down because they cant take it, yet the amp should have heaps of headroom and be running comfortable according to the specs?

luton_soundman wrote: Yes Lev, that's why i brought the inf8 down for reference, alot of people thought that was a bad idea days before the event. smiley1

it baffles me how manufacturers get their ratings? dont get me wrong they sound good but do not understand the power ratings? to me a ca18 with almost half the power rating would give most of them a run for their money on power. luckily for us we had the test to see what was really going on, Leon almost bought a pkn aswell for sub a while back....thinking he was getting 3k a side @ 4r.... heard stories of roots man using them and the amps early into a session start reducing power to cool down because they cant take it, yet the amp should have heaps of headroom and be running comfortable according to the specs?

+1

Plain and simple, 99% of the specs for lightweight amps are pure lies..

We saw that in Southall on that Sunday.

Shame some one didn't bring 2x Proline 2700 to bridge per 2x scoops, to embarass the lightweights some more... :lol:

Was also nice no one could complain about power in the building was lacking, as Tweeter ""mad max" Box, got Inf8Mk2 to draw almost 20A... lol

4 letters?

Daz wrote: I also wonder how mutch the instantainious current driving ability of SMPS units is effected by the size of the resovior capacitors used. :idea:

Conventional power supplies use massive caps usualy 10000uF+ for each cap. Wheras SMPS units tend to use smaller caps that are in theory maintained by recharging far more often (100Hz for conventional and usualy several thousand Hz for SMPS) The smaller caps are less capable of supplying high peak/surge currents. This would seem to suggest that the peak current driving ability of a SMPS unit is far more dependent on the supply as opposed to the resovior. Perhaps this could be why the SMPS units tend to hit a brick wall where there just isnt anything left in reserve.

I am assuming that you cant realy use the larger caps because the frequencey that the SMPS is operating at would not allow enough charging time between cycles (Or would require excesive Mark-space-duty cycle time to do so with PWM) and would result in the caps running undrcharged most of the time?

Daz

levyte357 wrote: Plain and simple, 99% of the specs for lightweight amps are pure lies..

no, just not tested on roots music program smiley36

Tony.A.S.S. wrote: Perhaps it's time for re-appraisal. This time I'd like to see what goes on. I'd certainly bring my amp in for comparison, baring in mind, none of this is competition. I'd like to know where we stand with various types of amp. I'm always tempted to go for the best.

Tony, I wouldn't really class the next outing as a " re-appraisal", or even a test.. Just another jolly...

Ren is a premier Soundman, who has mixed it with some of the best sounds in the UK, and has had Tony Andrews praises for the way he can engineer his sound.

It was his testing of the amps, that really demonstrated how the lie-weights ran out of steam powering 2x1850s per channel, while the transformer amp threatened to eat them.

Only the LabG, MC2 and FFA were missing really..

For years roots dudes on SP have been ridiculed for saying transformer amps are better on sub if you have the current.
Most of them on that Sunday would only have been suprised at how badly they compared with the Inf8v2.

saul wrote:

levyte357 wrote: Plain and simple, 99% of the specs for lightweight amps are pure lies..

no, just not tested on roots music program smiley36

Think in the next test, we should have a distro with Ammeter, just to show the current draw from the lie-weights, when they start clipping...