5 channel amp

[KRC]

I am moving from an AV receiver to a pro/amp combo and doing research I found some companies have 5 independant channels within the one chassis and others have the transformer/power supply divided into the five channels. I noted that the Classe 5100 does not have the independant channels.......does it matter? One method better than the other? As long as the design is done well? In my mind it makes perfect sense to have five independant channels, one for each speaker that the sound track is directed.

Kevin

[Glen B]

I'm not clear on what you're calling "independent." The power transformer of CA-5100 employs three separate secondary windings spread among the 5 channels which is a variation of method #2 in the list below. That's pretty good. There are about four basic ways that manufacturers implement power supplies, whether for 2-channel or multi-channel amplifiers:

1. Separate power transformers with individual rectifier and set of filter caps for each channel.

2. Single power transformer with multiple secondary windings - each feeding a separate rectifier and set of filter caps for each channel.

3. Two power transformers, each with multiple secondary windings split among the channels - each feeding a separate rectifier and set of filter caps.

4. Single power transformer, rectifier and set of filter caps shared by all channels.

Separate transformers offer the advantage of lowest crosstalk/interaction between channels and theoretically better channel separation and imaging but at greatest cost. One channel's current demand does not affect the other.

Multiple secondary windings offer some of the same benefits as separate transformers but at lower cost by essentially providing "separate" transformers on a single core. The downside is that crosstalk/channel interaction may be slightly greater than with individual transformers. Heavy current demands of one channel may have some effect on what is available to the other(s) but not as much as in the case of a single power supply feeding all channels.

A single power supply shared among all channels has the greatest crosstalk/channel interaction of all. This kind of power supply is the most cost-effective and is common in receivers and budget-priced amplifiers. Heavy current demands of one or two channels can affect the amount of current available to the remaining channel(s).

Classé is usually very good at implementing power supplies in their products and have a history of always meeting or exceeding published specs. I would not agonize over the power supply in the CA-5100.

[KRC]

When I mention independant I refer to the Bryston 7B with 5 channel modules and a Krell model has the same and there are others out there then there is a Rotel 5 channel model that has two transformers feeding the 5 channels and the Classe 5100 has a huge transformer with 3 windings feeding the five channels. So with these different technoligies out there is one better than the other? Comes down to cost (mulitple transformers/modules)? Makes for a nice reading sales brochure? Or the method does not meet the end result, it all comes down to the sound? Oh boy......

Kevin

[Glen B]

When I mention independant I refer to the Bryston 7B with 5 channel modules and a Krell model has the same and there are others out there then there is a Rotel 5 channel model that has two transformers feeding the 5 channels and the Classe 5100 has a huge transformer with 3 windings feeding the five channels. So with these different technoligies out there is one better than the other? Comes down to cost (mulitple transformers/modules)? Makes for a nice reading sales brochure? Or the method does not meet the end result, it all comes down to the sound? Oh boy......

Kevin

I'd like to thing my previous post spelled it all out. In theory, individual transformers feeding each channel would be the very best, with multiple secondaries in a single transformer being second best. In practice is one better than the other ? Individual transformers should be best but its not that simple. Things like transformer construction, core size, regulation, power supply capacitance, overall power supply size, etc. can all affect amplifier performance.

All of the current and older Classé 2-channel and multichannel amplifiers employ transformers with multiple secondaries feeding the two or more channels, yet look at the following the brand has here at HT Guide. Personally, I would be focusing on sound instead of worrying about transformers. IMO, its sort of a non-issue with the popular names (Bryston, Classé, Krell, Macintosh, Levinson, Halo et al).