7 channel DIY surround amplifier options

[sizzles]

Hi,

I'm new here, but the moment I saw the baking tray amplifier on the gallery I knew I was in the right place.

I'm putting together a home cinema system and fancy building the power amplifier myself. I've done plenty of electronics projects in the past and have been looking at my options.

The two basic ideas I have are:

1. Buy 7 replica Quad 405 boards for about $30 each which are about 100W RMS into 4 ohms.

or

2. Buy 7 class-D amps aiming for about 300W RMS each.

As a person who has studied power electronics I understand the technical differences. I also don't want to open up a long debate about how good different class D amps sound.

Given that the Quad circuit is well and truly tried and tested and can be had for less than $40, is there any real point in going down the class-D route?

FYI the surround system will be based on six ATCs SCM7s and one ATC C1CA, probably driven by an Arcam AVR of some sort.

Thanks in advance for your advice.

 

[russc]

The class D amplifiers will consume much less power and create much less heat. An important consideration especially with multiple channels. A no-brainer.

 

[454Casull]

300W each? Is this cinema for a home housing 40 people??

EDIT: 84 dB/1W@1m, 200 W gives you 107 dB @ 1 m *each*... I guess you like your reference levels high.

 

[sizzles]

Ha no, I don't anticipate more than 300W for the whole system. But the ATC SCM7s recommend 75W to 300W per speaker.

I read about the Hypex modules and see that the least powerful is 180W, I guess that class D is so efficient that low power ratings don't really save that much money for the manufacturer so everything is more powerful.

At the moment that Quad 405 modules look like the better value solution. I don't see anything in the class D world which has the same audio reputation for 40c per watt.

 

[Dominik H]

in Germany I would buy B&O Icepower 250A modules.
185€ for 8 pieces >>>> less than 23€/piece and less than 10cent/Watt
Special-Sale 2021| ICEPower A250 Verstarker-Modul | eBay

 

[454Casull]

At the moment that Quad 405 modules look like the better value solution. I don't see anything in the class D world which has the same audio reputation for 40c per watt.

Do ensure you consider the full cost, with power supply, enclosure, etc.

Do these kits come with trustworthy provenance, e.g. no knockoff ICs?

 

[sizzles]

You are quite right to point out the cost of the power supply, case, posts, etc.

As far as the knock off IC's go, the Quad amps are discrete devices only, it is possible they are of dubious provenance. I wonder if there are more or less fake IC's than transistors?

 

[454Casull]

Honestly, no clue. I could tell you that all sorts of devices are counterfeited but not how likely they would be for each type or family. But a kit not sourced from a reputable vendor is likely to be susceptible, especially if from Asia (though it can happen anywhere).

Also, speaking from a personal standpoint, I would not be very excited to assemble and solder 7 amp modules (exception: *maybe* the diyAudio Open Source LM3886). You can find mostly- or fully-assembled amp modules for quite a reasonable price (Dominik linked some above) that you can just drop into a chassis and wire up.

Alternatives to ICEPower include TPA3251/TPA3255, LM3886, etc.