External amplification: I'm convinced (1 Viewer)

[Bill Kane]

OK, let's say I was ready to add an outboard amp(s). There are lots of 2-channel units out there (and my local hi-fi shop where I bought my speakers, for example, handles Rotel); then there are the Marantz MA700 @ $500 each; while the biggest step seems to be 5-chl, say Outlaw 750 @ $1050.
As Cees notes, opening the L/R audio is the first step; but we are DVD people, too, so we also want to baby our Center.
If we didn't upgrade incrementally, wud the 5-chl approach be where it's at? And what if we just used 3 of the 5 for the front soundstage and left the rears on the AVR -- any point to that?
I"m not necessarily asking for brand recommendations, but rather looking at the approach to going separates...
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[Henry W]

Until yesterday I was using a Denon AVR-5800 exclusively to drive my speakers. I picked up a couple of showroom sample Bryston 4B SB amps at a dealer close out with the express intent of reselling them. I hooked one up to my front speakers and bridged the other for my center speaker to make sure the amps were working properly. Now I'm not sure I'll ever part with them. It is that much better.
Best regards-Henry
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[Ryan Peddle]

Bill, it really all depends on you Movies/Music situation.
Myself am a big music listener. My stereo is always going. I am a 23 year old college student. Music is a major part of my life. Whether I am blasting drinking beers (MOOSEHEAD RULES) or studying for classes my music is always going. So my logical step is to buy a good 2 channel amp for my mains to improve my music listening. After that I will look a 3 monoblocks anf move the 2 chan to the years. That is my amp upgrade path.
If your system is mainly or completely a movie system, a 5 channel amp seems lie the best idea.
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Oops, I dropped my eardrums.
Could you pick them up for me?

 

[MatthewJ S]

2 thoughts for caution:
I don't want to rain on anyone's parade but, the pre-amp outs on most receivers just doesn't even come close to what a decent pre/pro sounds like......I mean, the quality of components in the audio output stage is generally abysmal .
Some years ago a few reviewers got together and measured the THD, voltage costants, etc., and almost universally concluded "why bother". The stats on receivers don't show the performance of the pre-amp outs because mnfgs feel that having pre-outs on a receiver is worth extra money to you because they can tout this as a feature but that putting any kind of quality parts or engineering into this is a waste based on the %age of people who would use it,let alone understand the effort and expense.
Also , one of the cardinal sins in quality HT is not voice matching your speakers, so unless you are using IDENTICAL amplification on all 5/6/7 speakers you have an unbalanced system...Now I myself, often having shallower pockets than dreams, have done things like this before as I was slowly moving towards audio nirvana, just try not to through good money after bad in these moves , and have an understanding of what you want to end up with and how long your willing to put up with an unbalanced system...just my $2.02,

 

[Dennis Kindig]

Ryan,
The PCB layout, construction details, and parts lists are courtesy of William Marshall Leach, a professor at Georgia Tech.
Leach Low TIM Amplifier
Leach SuperAmp
His design has been compared favorably to an equivalent Krell monoblock in terms of its sound. The Low TIM Amplifier should deliver about 150W into 8 ohms, and the SuperAmp should deliver about 270W into 8 ohms.
I bought my transformers from Plitron. Surplus capacitors came from eBay. I found an article on re-forming capacitors that had been in storage and didn't have any bad caps. The heat sinks came from Newark Electronics (recommended supplier). I have a local radioshack.com store that will let me come in and pick through their bins to beta-match all my transistors before I buy them. radioshack.com seems to have all of the electronic components. I bought a rack and the 6 chassis from Markertek (Middle Atlantic is the manufacturer). Blue LED's for power-on indicators from eBay (has to be blue!). I will be building a power-sequencer using solid-state relays bought from eBay.
I guess I should point you toward my main URL:
My fledgling web site
As far as voice-matched speakers and a quality signal source:
I built a full set of Audax HT speakers as designed by Joe D'Appolito, except I used a Shiva subwoofer instead of Audax's. I have also upgraded to a Sony TA-E9000ES preamp and I am temporarily using my Sony receiver as an amplifier stage via the 5.1 inputs. I am expecting a Toshiba 57H81 just any day now (should be by Wednesday at the latest).
Send me your email address and I will let you know as I update my site.
Dennis
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[Steve_D]

Matthew
My Denon 3801 pre-out (analog bypass) has a S/N ratio of 103 db. This is better than many of the dedicated pre/pros (see B&K Ref 30 for instance). I think, since receivers and pre/pros are basically computers..computers have advanced quite a bit in the last few years. I'd love to see a comparison now.
Now, if you want to talk audiophile quality passive pre-amps for 2 channel, that's a whole new ballgame. Nice thing is I can add one of these with a unity gain input, and use it for 2 channel but still use the receiver processing for HT.
Bill,
If your amplifiers don't have identical TESTED gain, then bi-amping can change the freq response of the speaker. This can be bad, as it can emphasize the mid-woof or tweeter too much. In fact, many audiophiles argue that passive bi-amping, even when done 100% correctly, is mostly a waste of money. Of course, others will vehemently diasgree...but almost all agree active bi-amping is where the big gains are.
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[Joseph Anlacan]

Okay, I'm almost convinced.
Can anyone give me advice? My present receiver is an Onkyo DS838 that is rated at 90w/ch L,C,R and 50w/ch RL,RS. I already have a pseudo-EX set-up connected so my surrounds are, in a way, externally amplified. I'd like to buy a stereo amp for external amplification of my fronts. Any guidelines/advice I need to follow? (how many watts at least? recommended brands? brands to stay away from?) I'm concerned I might get a stereo amp that performs not as well as the Onkyo's. Thanks!

 

[Mike Knapp]

The problem with using receivers as pre-amps is that the amps are still in there, still attached to the chassis and still on.
One of the reason for using separates is to "separate" the amps from the processing. Using a receiver for the pre-amp does not accomplish this.
Mike

 

[Martice]

I think the poster should identify the most cost effective way of experimenting. You may or may not hear any difference with the addition of a seperate amplifier. If money is of importance I would buy a nice 200 x 2 second hand unit. The reason for the 200 per channel rating is because it is more likely that you will hear an OBVIOUS boost in performance ranging from control and power. Inner detail and clarity is more left up to the rest of your system and how it is able to perform. There are a lot of amps out there in the late 300's to 600 dollar range that will let you know if there is anything to this switch up or not. I would not buy a 5 -channel amp yet because if you can't hear a difference with the 2-channel on the mains then I'm sure you won't hear differnce on the rears. I'm sure that for the time being, your receiver can handle the center and surround duties effeciently. Take a look on Audiogon.com and you'll see quite of few amps in a variety of price ranges.
Good Luck
Martice
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What if it gets no better than this!?!
[Edited last by Martice on August 13, 2001 at 07:56 AM]

 

[Patrick Sun]

Dennis, did you go to Ga. Tech (I'm an alum)? I took Prof. Leach's audio engineering class way back when, and though I've been tempted to look into building his SuperAmps, I just don't have the necessary test gear to make sure I didn't electrocute myself when I powered the sucker on.
Look forward to your progress.
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PatCave; HT Pix; Gear; DIY Mains; DIY CC; Sunosub I + II + III; DVDs; Link Removed

 

[Steve_D]

Mike,
I for one am not arguing that receivers are equal to dedicated pre/pros. I might make something of an argument that some receivers are as good or better than some entry level pre/pros. I will definitely argue that buying amps first and using your receiver as a pre/pro is a cost effective stepping stone to full separates.
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[Kevin. W]

Oh that itch is back and from what I've read its time too find either a good 3 or 5 channel amp. Currently I have a Denon 1801 powering my Paradigm Mini Monitors. Would it be smarter to purchase a 3 channel amp now and add a 2 channel down the road for the rears since the 1801 only has connections for LCR? Or would it be better to have a 5 channel to keep everything the same when I finally move to a seperates. Thanks
Kevin

 

[Mike Knapp]

Steve,
Agreed. Once the proper amplification is in line the next upgrade will be a pre-pro for sure. I doubt anyone that already owns external amps would buy a receiver to use as a processor.
Mike
[Edited last by Mike Knapp on August 13, 2001 at 09:04 AM]

 

[Ricky T]

Steve and Mike,
I used to have the following prepros: Angstrom 200/205, Sherwood 9080, HK Signature 2.0...all had their pluses and minuses relative to each other.
I now use an Onkyo 989 receiver as my prepro (and to drive my 3 rear speakers). Through out these prepro/receiver changes, the front amplification has stayed the same..two Citation 5.1 amps driving my front NHT 3.3s and AC2. The Onkyo has mains-in preouts for the front 3 speakers...so the internal amps are "not on" as they are disconnected and the preouts are, by definition of mains-in/preouts, designed to pass the signals to an amp channel via an rca interconnect. I seriously doubt there is a prepro under $1200 street, now and in the next 6 months) that is a better overall performer (sound and features) than the Onkyo 989.

 

[Shane Martin]

I doubt anyone that already owns external amps would buy a receiver to use as a processor.

Denon 5800 owners will have something to say about this for sure. I dare you to start up a topic on that. They will claim that they have a "software" upgradable unit and more features than 99% of the prepros out there. Same goes with the Onkyo 989 which now has a proven track record for upgrades software wise.

 

[Mike Knapp]

quote: The Onkyo has mains-in preouts for the front 3 speakers...so the internal amps are "not on" as they are disconnected...[/quote]
Can you extrapolate a bit on this? How is this done? The amps come "on" when the reciever is turned on, they may be bypassed but they are still on. Does the Onkyo have an amp disconnect feature? I have never heard of such a thing.
Mike
[Edited last by Mike Knapp on August 13, 2001 at 10:31 AM]

 

[Ricky T]

Mike,
What I mean is these 3 amp channels are not receiving an audio signal, so are "unactive." But I guess technically, then are "turned on" when the receiver powers up....it's like leaving 3 open channels in a 5 channel amp. Whereas most receivers without preout/mains-in and sending the signal to their speaker terminals at all times, even if you use external amps.

 

[Dennis Kindig]

Patrick,
I received my electronics training in the Navy, and worked in just about every possible function there is other than engineering (though I did do a lot of prototyping and worked in a design role for that). Chassis buildup, harness building, board stuffing, wave-soldering, ATE operation, final calibration/repair, quality control, field service, fixture building, prototyping subassemblies, etc.
I slid sideways into IT in 1987 and electronics has become more of a hobby now instead of a vocation.
eBay is an excellent resource if you need to build equipment. I found a three-gang 8A variac for $35 that I'm going to wire in parallel. This should handle up to 24A during my initial testing. This ends up being MUCH cheaper as it generally costs over $100 for a single 8A variac.
I see you live in Duluth. Drop me a line sometime if you'd like to hear the Audax HT speakers. I would like the opportunity to borrow a calibrated mic sometime if you have one so I can gauge the performance of my modified RS meter.
Dennis
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[Kevin C Brown]

Kevin W-
Plan for the future! Think about two 3-channel amps for THX EX/DTS-ES (6.1).
Or even 1 four channel and a 3 channel. (4 channels is hard to come by though.)
I have 2 Acurus 200x3's, and am quite enjoying life!
(Although that B&K Ref 7260 looks nice! Probably just a lateral step though.)
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[DaleB]

It may be difficult to prove that having the amp still ON effects the quality of sound when using a receiver as pre-amp, Mike.
Other than using a little more juice idling, I am not so sure how relevant it really is. The signal isolation should be sufficient to preclude any problems, even when it's used as a fully integrated receiver and amp.
One could argue the short path from pre-amp to amp in a receiver is of some advantage to running cables to an external amplifier where there is a greater potential for noise susceptibility.
I think in either case, unless we are talking about a receiver of marginal quality, we would be splitting hairs.
Barring the real world quality differences in a high-end pre-pro with premium components and a price to go with it, most quality receivers have very good to excellent preamps and the same manufactures of those receivers offer some pre-pros with very similar specs (should be no surprise) but have more optional features like variable sub crossovers, and more elaborate digital processing, etc. etc.