Advice needed: Amps/Receivers/Formats

adrianip · Feb 17, 2004

Ok, am fairly getting into the whole home cinema thing now. Bought myself a couple of years ago what I consider to be a decent receiver (Harman Kardon AVR 5500). But the more I read about amps/receivers, the more confused I'm getting.

What is the difference between: preamp, power amp, high power amp, multi channel amp, receiver? I'm getting the impression that purists scoff at receivers, why? What are the alternatives? What's better about them than receivers?

Also, formats. I bought my HK thinking 5.1 sound was brilliant and about as good as it would get after my previous sony dpl receiver from years ago. Now I see all these 7.1 channel receivers coming out. What supports this? I don't know any dvd's (my main use of receiver) with 7.1 channel soundtracks. Will there be 8.1 channel sound next with a central rear speaker? Computers are easy relative to this, you just by the latest technology every couple of generations and are usually fine. When will the next generation of sound channels/formats be coming out if i don't upgrade to 7.1?

Also (sorry for going on). THX. I understand about Dolby Digital and DTS being sound formats, but THX appears to me to be more of a quality level than a format. Pros and cons anyone? Seems pretty expensive for a guarantee of quality!

Any answers appreciated!

RobDickinson · Feb 17, 2004

"What is the difference between: preamp, power amp, high power amp, multi channel amp, receiver? I'm getting the impression that purists scoff at receivers, why? What are the alternatives? What's better about them than receivers? "

Preamp just does the decoding and switching , no amplification.
poweramp Just amplifies signals. No switching or decoding. Can be 1 channel or 7+.
high power amp same as power amp. probably supply more current than lower powered amps. Current (from transformer/cap mains stage) is as important as wattage, you cant drive the speakers if the transistors have no power.
Multi channel amp Just power amp? or inegrated reciever? Multi channel amp just means it amplifies more than 1 channel of sound. A stereo amp is multi channel. If you mean multichannel av amplifier it probably has a preamp built in.
Integrated amplifiers You missed this one out. Either stereo or multichannel. They have the Pre amp (stereo = input switching/volume control etc, AV = Decoding+video also) and the power amp(s) in one box.
Recievers Just like the Integrated amp/av amp but with a radio built in.

As to why purists scoff :

The more you put into a box, be it technology components (pre amp/amp/ power transformer etc) generaly the less purist it will be. Its mostly down to costs. If you make an AV reciever for £1000 that does it all it wont do amplification as well as a £1000 power amp - and nor should it. Manufacturers ALWAYS make compromises with build costs and prices.

Generaly the more you pay, the more boxes you get for it, the better it will sound. Theres very few separate AV stuff for < £1k etc.

But all in 1 AV recievers are very convinient , and often far cheaper than total separates. There are some £3k all in one Av recievers from denon etc. How they compare to £3k's worth of separats is arguable. Any all in 1 box is hard to upgrade too. With separates its easier to keep the nice amp stage and change the decoder etc.

"Also, formats. I bought my HK thinking 5.1 sound was brilliant and about as good as it would get after my previous sony dpl receiver from years ago. Now I see all these 7.1 channel receivers coming out. What supports this? I don't know any dvd's (my main use of receiver) with 7.1 channel soundtracks. Will there be 8.1 channel sound next with a central rear speaker? Computers are easy relative to this, you just by the latest technology every couple of generations and are usually fine. When will the next generation of sound channels/formats be coming out if i don't upgrade to 7.1?"

For me I dont have space for more than 5.1 Its suppose to be ok but I have enough speakers already. Mebee if I move and have a dedicated cinema room or something.

Reiner · Feb 17, 2004

What is the difference between: preamp, power amp, high power amp, multi channel amp, receiver?

Pre-amp - either a dedicated unit or part of an (integrated) amp / receiver, allows input selection and volume control. In case of AV amps/receivers it also handels the decoding (DD, DTS etc.), DSP modes, bassmanagement and video switching. AV pre-amps are also known as AV processors.

Power amp - either a dedicated unit or part of an (integrated) amp / receiver, all it does is amplify the signal from the pre-amp and feed it to the speakers.
Dedicated power amps come in different flavours: monoblocks (single channel), stereo (2 channels) or x-channels (multichannel)

High power amp - a power amp with an extremely high power output (e.g. Mark Levinson No.33H), up to 2400 Watt into 1 Ohm - requires a special AC supply to deliver that current though.

Multi-channel amp - any amp with more than 2 power amp stages.

Receiver - an amplifier with a built-in radio (tuner), can be of the stereo or AV kind.

I'm getting the impression that purists scoff at receivers, why? What are the alternatives? What's better about them than receivers?

True, some would not settle for an integrated unit where pre-amp and power amp are cramped into little space, fearing lesser performance. Hence they choose eperated units (i.e. pre-amp plus power amp).
As well it gives more flexibility in matching and upgrading, but it's more costly than an integrated unit (i.e. receiver).

Also, formats. I bought my HK thinking 5.1 sound was brilliant and about as good as it would get after my previous sony dpl receiver from years ago. Now I see all these 7.1 channel receivers coming out. What supports this? I don't know any dvd's (my main use of receiver) with 7.1 channel soundtracks.

There is currently no 7.1 format available to consumers, the most it will go is DTS ES Discrete, which is a true 6.1 Format. However the 6th channel is often split for two speakers and amplified twice (though the signal remains mono) - resulting in a 7.1 loudspeaker setup.
7.1 can also be derived from DD Ex or DTS Es, the matrix flavoured 6.1/"7.1" formats.
Not many DVDs support 6.1 formats though and not everyone likes that many speakers. I see it as an optional thing, not a mandatory one.

Will there be 8.1 channel sound next with a central rear speaker? Computers are easy relative to this, you just by the latest technology every couple of generations and are usually fine. When will the next generation of sound channels/formats be coming out if i don't upgrade to 7.1?

6.1 does add a center rear already (in a 7.1 setup there are two speakers called surround back L&R).
Of course there is L7 (Logic7) which uses 2 additional side speakers compared to 5.1 and the new DPLIIx sticks with the surround backs. Both are however not discrete, they extract the information from the stereo or 5.1 source - that's why they aren't called 7.1 formats.

New formats might pop up in time, who knows. Speakers above, below and all around you - 12.4 here we come ...

Also (sorry for going on). THX. I understand about Dolby Digital and DTS being sound formats, but THX appears to me to be more of a quality level than a format. Pros and cons anyone? Seems pretty expensive for a guarantee of quality!

Just search for THX, many posts with different opinions about that around here.

adrianip · Feb 17, 2004

Guys,

Thanks for the explanations. So now let me explain my situation. I have an old set of 5 satellites + passive sub bought when I was living in the US (Cambridge Soundworks Ensemble IV). Not the best setup I know. They sound good, but am considering floorstanders.

So what would you guys recommend as a system for me? It doesn't need to have built in tuner but does need to do the following:

DD/DTS etc decoding as main use of this is DVD's/tv.
Video switching (negotiable if brilliant sound is an expense of this).
Excellent sound quality.
Low distortion at high volumes and plenty of grunt, like to hear things loud.
Excellent 2 channel music playback.

I'm pretty convinced by the pre amp/power amp argument, but looking into it, not too bothered by THX. What should i be thinking about in terms of speakers? Lots of reviews recommend the Kef Q7 AV package (pair Q7's, 2x pair Q2DS, Q9C, PSW2500). But reading the above not hugely convinced of the necessity for 7.1.

As with most people, I'm on a budget and would like the lot (speakers + pre amp and power amp) to come in at under £3500.

RobDickinson · Feb 17, 2004

£3500 gives you a lot of options.

Is this just for speakers + av reciever?

Do you want new or would consider 2nd hand?

As for what kit, it realy depends on what sounds good to you with the stuff you listen to / watch. Its all very personal realy.

Last time I went speaker shopping the Kef Q5's were near the top of my list, after hearing them they were in last place, I hated them. Mebee they'll sound great to your ear - who knows.