AVS Forum Archive 2 - Bryston or QSC?

Rich X

10-25-06, 02:20 PM

I've come to a dilema on which way to go to upgrade my amps. Maybe I'm nuts and maybe I'm comparing apples and oranges, but I have come down to this choice.

My speakers are Aerial Acoustics, they are tough to drive (86db, though a reliable source has measured them at 84). I have been using good 2ch and 5ch amps, but both are 200wpc into 8ohms and I think my system lacks punch and is too laid back. I'm also not happy with the blending between my center and front LR, which could be a result of using two different amps. My goals are to increase the power to get better dynamics and have a more even soundstage accross the front L/C/R.

With all of the postive results that people have been getting with pro-amps I decided to hook up my QSC PLX3402 that I have running my subs to my mains and see how I liked it. I did think it was an improvement, though I really couldn't do a full test with only one 2ch amp.

I have also heard Brytson with Aerials (though not in my home) and have been very impressed.

So I've come down to this choice:

QSC PLX2 3602 (LR)
QSC PLX2 3602 (Center, 1 ch unused)
QSC PLX2 2502 (Surr)
QSC PLX2 1802 (Rear)

OR

Bryston 6B SST-C (LCR)
Bryston 9B SST-C (Surr, Rear 4ch version)

I can probably get the QSC set-up for around $4000 whereas the Brystons will run me $7500 - $8000. Not a trivial difference in cost--I know I could do better on the used market.

thylantyr

10-25-06, 02:43 PM

I have alot of QSC PLX3402's, great amp for the money especially when you can snag alot
of them on the used market for a huge discount. Unless you need the new crossover
function of the PLX2, look into used PLX's.

Try this experiment. Bridge your PLX3402 and drive one tower. It should be amazing.
I drive all my PLX's in bridge mode for incredible headroom, probably more headroom
that what the Bryston offers. I'd have to look at Bryston schematics to know for sure.
I drive my PLX way below recommended impedance on my line array, 2 ohm on midwoofers
and under 1 ohm on tweeters. For woofers I would keep impedance in bridge mode at no
less than 4 ohms. The amps have great cooling and can hang pretty well. Fan noise is
the issue with any proamp.

Based on my personality, I would buy five PLX3402's or five PLX3002's.
Drive two PLX3402's {or two PLX3002} in bridge mode for LR speakers, the
rest in non-bridge mode.

Cost: $3750 - $4000 on the used market.

LR speakers; two PLX, each bridged.
Center; one PLX bridged.
Surr; one PLX
Rear; one PLX

That would be sweet.

To shave some costs. Get a PLX2402 for center, surr, rear.
[PLX2402 would be my minimum based on a little known secret that I can tell you in
private].

PLX 3402 for LR, PLX2402 for the rest would put in in the $3000 price range if you
buy used.

As far as I'm concerned this would rule over a single multichannel home amp.
Five QSC PLX = five dedicated switch mode power supplies and 100 pounds worth
of amp, easy to carry around. Also, there is an uprade path if you want more
clipping headroom. Get more PLX and bridge them for the remaining speakers,
that is if you want to get crazier in the future. Having that option is always nice
and knowing PLX is everyone makes it easy to snag later.

Rich X

10-25-06, 02:52 PM

Thanks for the input.

Looking over the QSC specs I had thought it was a no-no to run them bridged on a load that would drop below 4ohm (as my speakers do). But apparently you have found that this is not a problem?

It does appear that the 3402's are readily available used at good discounts--I've done some poking around on ebay looking for them. Bridged or no the PLX line is certainly a strong option.

thylantyr

10-25-06, 04:19 PM

There are two PLX3402 on that auction site, a good price used is $750 +/- $50.
They pop up often, so be patient. Earlier in the year, they had alot. Maybe the after
Christmas thing where people upgraded and sold off existing gear, lol....

You can run amplifiers below rated impedance depending on circumstances. Amplifier
build quality, how they over or under rated the amp, the load, tweeters/midranges are
an easier load than woofers. Depending on amplifier build quality [etc] and protection
circuit interaction, you can drive lower impedance if you reduce the power level to
compenstate for a lower impedance.

The PLX can easily drive ordinary HT speakers at very low impedance. Lets say
you wanted to drive 1/2 ohm per channel on surround/rear satellite speakers,
given the content of the sound playing [very low duty cycle] and easy load
[tweeters and midwoofers], that amp would have no issues 'cheating' with low
impedance. I wouldn't drive 1/2 ohm per channel trying to drive some HT subs as
you will place a bigger burden on the amp. This 1/2 ohm scenario is rare,
so even 2 ohm speakers that dip down to 1 ohm is a piece of cake in stereo
mode.

A few proamp gut pics [PLX, RMX2450, Crest are my pics, the rest are from
others who posted them previously].
http://home.pacbell.net/lordpk/proamps/

Rich X

10-25-06, 04:46 PM

Thanks for the pics--great build quality. Whenever I look inside these things I always find myslef searching for the missing big transformer, then remember it's Class H!

Still, I'm not sure how to reconcile the sound quality issue vs. the Bryston's. Without buying them both, a side by side comparison is not really possible.

sdv5

10-25-06, 04:58 PM

Why did you decide on PLX versus RMX? It appears that Bryston would be your first choice if cost were the same. You are looking into pro amps to save money and still be able to drive your inefficient speakers with good control. On the surface, RMX design resembles that of Bryston a lot more than PLX. Has anyone compared RMX to PLX for home audio application?

Rich X

10-25-06, 05:12 PM

thylantyr

10-25-06, 05:49 PM

[QUOTE=sdv5]Why did you decide on PLX versus RMX? It appears that Bryston would be your first choice if cost were the same. You are looking into pro amps to save money and still be able to drive your inefficient speakers with good control. On the surface, RMX design resembles that of Bryston a lot more than PLX. Has anyone compared RMX to PLX for home audio application?[/QUOTE]

I have both of them. RMX is the entry level amplifier. Great amp for the money.
Traditional power supply, good heatsink [better than Crown XLS], not
as beefy as PLX. PLX cost alot more but the heatsink
+ shroud make a mean wind tunnel for more abusive applications. The switch
mode power supply makes the amp lighter [no big toriod, yet packs alot of
power], and you don't need the high capacity power
supply capacitors that conventional power supply designs need as found in
expensive home amps and lack in pro amps not using SMPS. I've tortured my
PLX, blew it up, then repaired it, modded it with more caps and in the end,
there is nothing that I do to the amp that makes it sound bad. Even the cap
mod has measurable pros but I can't hear these measured improvements.
I concluded the stock PLX is a very good design and doesn't really need anything
else to be a big performer. The only thing it really likes is a nice stiff 120VAC input
for maxium power, otherwise voltage drops gain you less output power, this is
also true for the majority of the amplifiers on the market. If your budget is $4k for
amps, then buy PLX over RMX, you won't be sorry. But on the other hand,
I can make the RMX line work fine in that application also.

Rich X

10-25-06, 09:35 PM

I'm going to compare the QSC PLX3402 that I have to my existing 2ch amp (Classe CA-201) again this weekend--still not sure how that is going to help me choose.

I originally went with the Classe amp b/c when I originally auditioned these speakers they had them hooked up to Classe CAM-350 monoblocks, which sounded fantastic. I just don't think the CA-201 has enough power.

Soundood

10-26-06, 01:57 AM

I'm probably one of the few dealers who sell both the pro and consumer amps. The QSC is excellent, tons of bang for the buck and will give a HELL of a lot of highly respected amps a very serious run for the money. But, that being said, if cost isn't a factor, the Bryston would be my choice. It is more neutral, has a lower noise floor (not withstanding the fans) and is one of the few products out there I'd be comfortable telling my customers the amp would still work perfectly 30 years down the line. The Bryston was designed as a ultra serious studio amp with the highest levels of transparency and dead reliability in mind. The QSC is designed for a wider range of apps including theatrical and live use so it gives up the last bit of detail for portability. I wouldn't complain about having either in my rack, but if I had my druthers, I'd rather have the Bryston.

thylantyr

10-26-06, 11:40 AM

People make these claims all the time "A proamp isn't as good because it's designed
for PA use". These generic statements get old and silly. For best results it's better to
compare the two products in question and not compare the two industries trying to
judge SQ as it doesn't work.

If you learn amplifier design you will know that amplifier designers making product
for a reputable company don't design any amplifier to lack SQ in favor of portability.
Designers want to build a quality signal path, it's human nature. Home audio
amplifiers may be more crippled than pro audio amps if you think about it.

What compromises are found in proaudio amps? The first thing you see is they are limited
to a specific chassis specification so they need to cram alot of amplifier in a small package.
To do this, the big conventional cooled heatsinks need to be down sized and to offset
the lack of performance, they install fans to get performance back.

The average home audio amplifier may lack;

* gain controls - to optimize the gain structure of your system to reduce noise.
* balanced inputs - to reduce induced noise in cables.
* Clipping indicators - for visual feedback to allow system optimization.
* Clipping limiters - for loudspeaker protection.
* Subsonic filters - may help protect over excursion on your mains.
* May have crossovers built in for biamping.
* Best dollar per watt ratio - high powered amps are affordable.

Some of these features are selectable.

If you think sacrifices were made [detail] for portability, then feel free to download
the PLX schematics on their website, analyze the circuit design and report back
what SQ sacrifices were made and we can talk about it.

MKtheater

10-26-06, 11:54 AM

How would the crown k2 or K1 compare to thye plx series?

thylantyr

10-26-06, 01:30 PM

[QUOTE=MKtheater]How would the crown k2 or K1 compare to thye plx series?[/QUOTE]

I don't have K experience, but it's a different amplifier design methodology.
http://www.crownaudio.com/pdf/amps/bcapaper.pdf

Anytime you have something new in the amplifier world, you get mixed reviews in
the beginning and we've seen mixed reviews on various forums on K series full
range SQ ranging from it sound great to it's too edgy. These reviews are common
with 'switching' types of amps because it's new and people are skeptical.
K series seems unanimous that it's great for sub duty. PLX is old school AB
output stage w/ class H power supply, just called class H for short, nothing
different really from any audiophile home amp expect the two tier power supply
and extra 'stuff' as mentioned in the previous post. PLX isn't the only good
proamp on the market, I'm sure you can build a great sound system with other
brands.

Bob Lee (QSC)

10-26-06, 07:04 PM

[QUOTE=Soundood]The QSC is designed for a wider range of apps including theatrical and live use so it gives up the last bit of detail for portability.[/QUOTE]

What "last bit of detail" is it giving up, and what causes it to be given up?

Habs4life

10-26-06, 07:33 PM

[QUOTE=thylantyr]..

You can run amplifiers below rated impedance depending on circumstances. Amplifier
build quality, how they over or under rated the amp, the load, tweeters/midranges are
an easier load than woofers. Depending on amplifier build quality [etc] and protection
circuit interaction, you can drive lower impedance if you reduce the power level to
compenstate for a lower impedance.

The PLX can easily drive ordinary HT speakers at very low impedance. Lets say
you wanted to drive 1/2 ohm per channel on surround/rear satellite speakers,
given the content of the sound playing [very low duty cycle] and easy load
[tweeters and midwoofers], that amp would have no issues 'cheating' with low
impedance. I wouldn't drive 1/2 ohm per channel trying to drive some HT subs as
you will place a bigger burden on the amp. This 1/2 ohm scenario is rare,
so even 2 ohm speakers that dip down to 1 ohm is a piece of cake in stereo
mode.

[/QUOTE]
Hummm. :rolleyes:

10-27-06, 01:51 AM

Rich, I own Bryston amps and Crown amps so I am a bit biased. I have not tried QSC. But there is the member Steve Brun...sky (sp) who hangs out in the 20k forum a lot and he drives his Aerials with Bryston amps but if I recall he uses the 7B's which have much more power than the 6B SST. You may want to PM him.

WestCoastD

10-27-06, 01:59 AM

Bryston 9B SST (20 year warranty)

gaderson

10-27-06, 03:46 AM

[QUOTE=thylantyr]People make these claims all the time "A proamp isn't as good because it's designed
for PA use". These generic statements get old and silly. For best results it's better to
compare the two products in question and not compare the two industries trying to
judge SQ as it doesn't work.[/QUOTE]

Uhmm, you do realize that Bryston got it's start making Pro amps for studios (though not PA systems)? They have a complete 'Pro' line that has extras that are useful for installation (rackmount faceplates, pots to adjust input sensitivity, XLR/TRS inputs, etc). Granted I've got 'all pro in my computer/DAW setup (Bryston 4B-ST Pro, to a pair of PMC DB1S (http://www.pmcloudspeaker.com/db1s.html) studio monitors), and love the transparency (at AES (http://aes.org/) I listened to a surround sound set of BB5-XB5A (http://www.pmcloudspeaker.com/bb5xbd.html)s as LCR, and MB2A (http://www.pmcloudspeaker.com/mb2a.html)s as surrounds, THAT is my dream system). And, unless you can hide the speakers away so you don't hear fan noise, 'fan-less' would likely be better. Though I suppose if you're only watching blockbusters the fan noise will be drowned out. Or if you've got lots of background noise as it is (say Highway/Railroad/Young Children).

Rich X

10-27-06, 08:32 AM

[QUOTE=EC]Rich, I own Bryston amps and Crown amps so I am a bit biased. I have not tried QSC. But there is the member Steve Brun...sky (sp) who hangs out in the 20k forum a lot and he drives his Aerials with Bryston amps but if I recall he uses the 7B's which have much more power than the 6B SST. You may want to PM him.[/QUOTE]

Thanks for the tip. I will--he may have a different model of Aerials. I have the 7b's, but the model 9's or 20t's would certainly require more power.

thylantyr

10-27-06, 12:03 PM

The 20 year warranty is attractive, but there is another way to look at the picture.

Hypothetical.

Good 2ch home amp cost - $2000 [20 year warranty]
Good 2ch proamp cost - $750 [no warranty as you bought used]

-- two extreme conditions, great warranty vs. no warranty.

You need five channels.

Cost;
home amp - $10,000
proamp - $3750

1. If the repair cost is $500 on the proamp, then you can have 12 failures
to get to the $10k mark. [$500 is generous].

2. You can buy 13 proamps with that $10k budget, 5 of them you will use, 8 of them are spares.
If you have a failure, you have all these extras amps and downtime is minimal.

In other words, exotic home amps are more like an investment and proamps
are more like disposable amps because they are cheaper. The more expensive
amp doesn't guarantee higher realiability either.

whoaru99

10-27-06, 12:13 PM

Or, you can have some "normal" consumer grade amps that had a 1 year warranty but have lasted 22 years with absolutely no problems - such as my four Yamaha M-series from the early/mid 80's.

IMO, it's not that unusual for a power amp that was used at least semi-responsibly to last a LONG time regardless of what the warranty is.

Espo77

10-27-06, 09:34 PM

Bryston 9BSST 20 warranty and watch out, this amp has the capability of acctually scaring you

scorch123

10-27-06, 10:52 PM

Rich,

I would certainly not look at home theater A/V as an investment. You're unlikely to find much equipment that appreciates in value over time.

Do the research an buy well-designed gear from reputable companies. Pro amps are designed to take a lot of abuse and give you great performance over the long haul. (Yes, I am biased - I use pro amps in my home theater). I thought folks here have also been able to get amps serviced even after buying gear used, as long as it fell under the initial warranty period.

- Steve O.

j8weeks

10-28-06, 12:47 AM

If you can afford them, you can't go wrong with the Bryston amps. They can really crank out the power, and are built like tanks. I have a 4B, a 3B NRB, and a 7BST, and the sound is amazing. The 4B I have is ancient, and I bought it from a musician that toured with it as a bass guitar amp (I guess they were quite popular as a 'pro' amp in the day) I run my 4B bridged/mono to drive a SVS Ultra (water-heater-sized) sub, and it has bottomed the thing out when playing reference-level movies in my theater!

As was mentioned earlier, characteristics of a Bryston amp include a low noise floor, neutrality, musicality, "quickness", muscle, and great control on transients. The amps are high-current, and I haven't had any trouble driving difficult low-impedence speakers.

Good luck!

Monty Williams

10-28-06, 10:47 AM

Get the Bryston's, you know that's what you really want. You'll never have to apologize or second guess your decision to go Bryston.

I started out with a pair of 4BST's and a 5BST and upgraded recetnly to a 6BSST and a pair of 4BSST's. You can find 3BST's on eBay in mint condition with 15 years of remaining warranty for around $850. 5BST's are usually arounf $1150. Those are all 200+ watts/channel into 4 ohms. Each Bryston comes with it's own personal spec/test sheet and they always test out about 10%+ above spec.

I've never heard the QSC's so I can't comment on them, but in my mind, Bryston is a solid choice and most likely the last amplifier you'll ever have to buy.

Rich X

10-29-06, 07:54 PM

[QUOTE=Monty Williams]Get the Bryston's, you know that's what you really want. [/QUOTE]

You are right about that....Though that's certainly not a knock against the QSC's. I probably wouldn't even be considering the pro amp if I didn't already have one myself.

I'm going to give the Brystons another listen this week. Poking around on other threads, Bryston and Aerial seem to be a very popular combination.

J.H.

10-29-06, 08:24 PM

I'm dying to hear peoples thought on QSC amps in Home theater uses? I just bought a PLX-1104 amp and will have it hooked up sometime this week and woould like preview of the sound quality in HTs. Thanks J.H.

Ron Temple

10-29-06, 11:23 PM

I read a post somewhere from a guy who just swapped in an RMX 850 and was very pleased vs. monos (I think). I cant' find the post and since I'm interested in the cheaper RMX 850, it pisses me off. Anyway, Bob Lee told me that it (PLX) will be a better HT solution, less fan noise and distortion. Good Luck.

J.H.

10-30-06, 12:05 AM

[QUOTE=Ron Temple]I read a post somewhere from a guy who just swapped in an RMX 850 and was very pleased vs. monos (I think). I cant' find the post and since I'm interested in the cheaper RMX 850, it pisses me off. Anyway, Bob Lee told me that it (PLX) will be a better HT solution, less fan noise and distortion. Good Luck.[/QUOTE]
Bob told me the same thing. I will know sometime this week hopefully. I'm waiting on my balanced cables to come in and I will be on my way to checking out the QSC for HT use. Thanks for the help J.H.

Rich X

11-07-06, 04:39 PM

Thought I would post an update. I decided to split the difference a little bit.

Bryston 6BSST-C for Left/Center/Right
Bryston 4BSST-C for Surrounds
QSC PLX 1602 for Rears

The amps will be coming in a week or so. Hope I'm happy with it.

Monty Williams

11-07-06, 04:51 PM

Welcome to the Bryston club. I'd be willing to guarantee you'll be happy with them...for a lifetime. And if you ever decide you need to get rid of them you can be assured that they hold their value exceptionally well. I recently sold a Bryston 3BST on eBay and got almost 60% of what it's retail price ($1800) was when it was new 10 years ago.