Multiple amps for line array?

[7V]

Has anyone experimented with using multiple small power amps for a line array? For example, an amplifier for each driver?

Regards
Steve

[norman bates]

Steve !!!!!!!!

7th veil !!!!!!!!!

Good to see you are still creaping around !!!!!!!!!!!


Norman

[MPM]

The 7th Veil speakers inspired me and some of my little projects. Inspire us some more.

I have no input unfortunately with your question.

[stratus46]

Originally Posted by 7V

Has anyone experimented with using multiple small power amps for a line array? For example, an amplifier for each driver?

Regards
Steve

Why? As long as the parallel load doesn't overtax the amplifier I don't see how multiple amps makes an improvement.

G²

[R-Carpenter]

Originally Posted by stratus46

Why? As long as the parallel load doesn't overtax the amplifier I don't see how multiple amps makes an improvement.

G²

my thoughts exactly.
May be for power tapering sort of like CBT? But then again, resistors are cheaper.

[7V]

Originally Posted by stratus46

Why? As long as the parallel load doesn't overtax the amplifier I don't see how multiple amps makes an improvement.

...Unless perhaps each amplifier is better...

Recently guys, I've come to love the sweet sound of Single Ended Triode amps. I'm in the midst of building a new speaker system (what can I say? my medication ran out) and I hope it will be my best yet. It uses 4 Bandor full-range drivers in a linear array - no surprise there for those that remember me - and of course no crossovers and a unique enclosure design.

Unfortunately, a single SET amp doesn't have the power that the speakers will need so I'm thinking of using a SET for each unit, giving me 4 x the power in total (in theory). I will attempt to build the SETs myself but am looking for people's views on the feasibility of this approach.

Regards
Steve

[Scottmoose]

I'm still scratching my head a bit though. Granted I can see some advantages to having a dedicated amplifier per drive unit, but I can't quite see why a single amplifier should find 4 unfiltered Bandors (presumably one of the 50mm models?) an unacceptable load if it's capable of powering a single example of those units in the first place.

Unless my calculations are out, which admittedly has been known, straightforward series-parallel wiring of two paralleled packs of two drivers in series should give efficiency gain of ~6dB over a single unit [10*log(number of parallel modules * Re]) & no impedance change, so the amplifier should in fact have an easier time than it would if it were powering just one driver. OK, so there wouldn't be any real sensitivity gain with this number of drivers & wiring configuration (10*log [Re / total array impedance]), but you wouldn't get any advantages by powering the drivers independently on that score either, so you're still back where you started, viz. no change.

[R-Carpenter]

you could build a larger line and bring sensitivity to a 100db 1w/1m or a bit over and even make it curved line array to deal with HF loss. I have heard a set up like this based on XJ92 (12 driver array) driven by a 5w SET and it was excellent.

[Scottmoose]

I would imagine Steve wishes to produce a compact system, like his old 7th Veil speakers.

[7V]

Originally Posted by Scottmoose

I'm still scratching my head a bit though. Granted I can see some advantages to having a dedicated amplifier per drive unit, but I can't quite see why a single amplifier should find 4 unfiltered Bandors (presumably one of the several 50mm models?) an unacceptable load if it's capable of powering an single example of those units in the first place.

Yes, it's 4 ohm, 50mm units. The efficiency is on the low side for a SET amp that puts out around 5 watts but gives its best for the first couple of watts.

Straightforward series-parallel wiring of two paralleled packs of two drivers in series should give efficiency gain of ~6dB over a single unit [10*log(number of parallel modules * Re]) & no impedance change, so the amplifier should in fact have an easier time than it would if if were powering just one driver.

In practice, I have found that I get a slight increase in efficiency by using 4 drivers, but not 6dB and mainly at the bass end.

OK, so sensitivity doesn't change, but you wouldn't get any advantages by powering the drivers independently on that score either, so you're still back where you started, viz. no change.

Except that instead of 5 watts of amplifier I would have 20 watts with four of them.

Cheers
Steve