I've had it with B&K...Hello Pioneer Elite VSX-49TX

**JonMarsh** · 25 November 2001, 20:37 Sunday

Let us know how it turns out- it's very disappointing to be "into" a piece of gear and have what sounds like a series of lemons. It does lead one to wonder whether there aren't fundamental design or process control issues.

Keep us posted on how you like the Pioneer.

Regards,

Jon

Earth First!
_______________________________
We'll screw up the other planets later....

**Chip** · 25 November 2001, 20:59 Sunday

Yea Jon....ain't it the truth... i really do like the B&K too. I don't think i can complain too much though. I bought the 307 last April and with this now being my "third" one and it's exibiting a slight issue...i'm just tired of it. I paid $2900.00 for the B&K from Tweeter back then. It listed for $3500.00. The new Pioneer lists for $3500.00 as well in Tweeters computer. (Not the $4200.00 on Pioneers site). I'm getting it even steven...not too shabby...and this baby's loaded with every upgrade B&K hasn't delivered and then some.

- Chip

Chip Engle

"Concrete ain't a spectator sport"

<a href="http://www.htguide.com/bilder/index.cfm?fuseaction=arkivbilder&userid=0&selected userid=336" target="_blank">My HT

**Andrew Pratt** · 26 November 2001, 10:53 Monday

keep us posted Chip...oh and I fixed that link

**Lex** · 26 November 2001, 14:57 Monday

I fixed your fix Andrew, so now it brings up something besides a not found, lol.

Awesome receiver Chip! I love Pioneer Elite. I think after you have used this for a month or so, next time you need a product, you too will begin to first check Elite. I own 3 Elite products and love them all, including a 24TX receiver, 301 disc DVD carousel, and an Elite PRO-119 RPTV.

Man, after I kept reading all the features, I was about ready to trade my MC-1!

Cable Guy DVD Collection

**Andrew Pratt** · 26 November 2001, 15:02 Monday

he he well thats team work

I notice they are still quoting power output at 6ohms...

**Chip** · 26 November 2001, 15:45 Monday

"Man, after I kept reading all the features, I was about ready to trade my MC-1!"

Son of a gun is LOADED ain't it? LOL...

- Chip

Chip Engle

"Concrete ain't a spectator sport"

<a href="http://www.htguide.com/bilder/index.cfm?fuseaction=arkivbilder&userid=0&selected userid=336" target="_blank">My HT

**Lex** · 29 November 2001, 01:02 Thursday

I actually took the time to email them about that 6 ohm thing Andrew. Who knows if it will get to the right place, but I tried. I told them it made comparison shopping very difficult when they don't rate their products on a level playing field, not fair.

Got it yet Chip?

Lex

**JonMarsh** · 29 November 2001, 11:56 Thursday

Well, you understand why they do it, don't you? It's to get the highest possible power rating from an average piece of electronics.

Most "budget" electronics are designed for optimum performance with a 6 ohm load, because that gives them a little margin for the vagaries of so called 8 ohm load speakers, without having to spend too much on the power electronics. In fact, this is often a target impedance limit for designing to nominal 8 ohm loudspeakers.

Naturally, it's possible to calculate 8 ohm power from this, but it takes a minute with a calculator to calculate the voltage for X watts at six ohms, then calculate the delivered power at 8 ohms with the same voltage.

How relevant is a power rating into any resistive load? Not especially. What amazes me is how much attention many people pay to the 8 ohm resistive amplifier power ratings, and how little attention is paid to the speaker impedance curves and sensitivity- which has a huge affect on the interaction and ultimate performance of the speaker and amplifier combination, and bears directly on what you need to drive them.

One of the interestingly designed speakers that's gotten a lot of favorable audio press in the last six months is the Joseph Audio RM33si. It's remarkable to me, though, that there is so little comment on the discrepency between it's rated (according to Sterephile, doing a review) efficiency. Stereophile measured a sensitivity of 80 dB, compared with a nominal spec of 88 dB. Now folks, that translates into one heck of a lot of watts required to produce some reasonable SPL! And while I've never been a fan of Klipsch or JBL, for example, I do think reasonable sensitivity is a requirement for most nominally full range designs. Stereoophile noted that on the new Telarc 1812 overture recording, they were able to theramlly shutdown a 300 watt/ch with these 8" three way speakers!

I've been guilty of behavior like this in the past; once I designed a three way transmission line loaded speaker with a 10" woofer nearly six feet tall. It has solid output down to 22 Hz; the first speaker I'd ever built that would do that; the ten was a specially designed part from CTS, with an Xmax of about 12 mm. For it's day, in the 70's, it was awesome. It also took a Phase Linear to drive it, preferably the 700, not the 400!

What's my point? (yes, there is one) With 80 dB sensitivity, it takes 2.83 volts RMS to produce 80 dB at 1 meter. 83 dB is 2 W. 86 dB is 4 watts. 89 dB is 8 watts. 92 dB is 16 watts. 95 dB is 32 watts. 98 dB is 64 watts. 101 dB is 128 watts. 104 dB is 256 wats, and 107 dB is 512 watts.

Now, hardly anyone listens at average levels of 107 dB in their home. But with quality program sources, it's not unusual to have peak SPL's 12 to 20 dB higher than average SPL. An average SPL of 90 dB is prettty typical for serious listening- so we want headroom to 105 to 110 dB for clean peaks. That's a lotta watts we're talking about for some not so unusual SPL's.

Now, going back to my homebrew clones, which didn't cost anything near the selling price of a set of RM33Si's to build. The upper modules are 93 dB sensitive, and the bass cabinets 96 dB efficient. That means my system can hit 93 dB average SPL's with about 1 watt (versus 25 watts for the RM33si), and those 105 to 110 dB peaks will suck down 16 watts. Smokin! Now, if Ayre would just bring out a great, cheap, 25 watt class A zero feedback amp, I'd have all the power I need.

Well, at least I'm doing my part for California Energy efficiency.

Have fun, guys. Good luck with the upgrade, Chip!

Regards,

Jon

Earth First!
_______________________________
We'll screw up the other planets later....

**P-Dub** · 29 November 2001, 14:08 Thursday

Chip: The Pioneer looks like one great receiver. Sorry to hear about all your B&K troubles.

Jon: Another great post. I've been on a sensitivity kick for the last little bit, so I can understand where you're coming from. If I can paraphrase; If your speakers have a high sensitivity rating, say 90db, then you do not require that much power to drive them at normal listening levels. You also have enough reserves for those times when the louder sound levels.

In case anybody missed it, the rule is for every 3dB increase in SPL you need to double the power.

Why Pioneer rates at 6 ohm when everybody rates at 8 ohm seems odd. I mean will people overlook that piece of information. I guess they do.

I bet you get some funny looks from people when you say "I only want a nice 25W/channel amp"

On a side note, is it true that manufacturers, or most receiver brands, only spec the power at 8 ohm for less than a second? I recall reading somewhere that in the past, I think in the 70's, power ratings were 20-20 into 8 ohms for 1 hour.

Paul

There are three kinds of people in this world; those that can count, and those that can't.

**JonMarsh** · 29 November 2001, 18:40 Thursday

Paul,

As far as I know, FTC ratings still require 40% power preconditioning for an hour. The actual measurement at any frequency is done fairly quickly, and is normally specified for the 20Hz to 20kHz frequency range. In the world of power amplifier power supplies, 1 second will give you a lot of "sag", or as much as you're going to get- measuring at any one frequency for longer than that is actually not indicative of performance in any real sense. A second is averaged over 60 line cycles. However much the power supply is going to sag, it will usually do so with tyipcal capcitors and transformers- even atypical ones, such as my homemade monoblocks with 200K uF of filtering.

The real "gimmick" used to be the old "peak power" tests, which only required one cycle at a given freuqency- say, 1msec for 1 kHz. Now that is where you can come up with some crazy ratings! Particularly if you have a weak power transformer, but run higher voltage rails to make up for the sag from internal resistance losses.

A real key is having adequate power supply capacitance. In the seventies I used to hot rod B&O recievers for people, because they looked cool; tweak up the component signal path, and add a special three pin connector on the back which plugged into an outboard box with a slow charge circuit and relay and big capacitor bank. You couldn't believe the looks on people's faces, seeing a B&O reciever driving a Dahlquist DQ10, with puchy, deep bass, and effortless transients. :E The B&O recievers were only rated about 40 watts continuous per channel at eight ohms, but that was because of thermal limitations and power transformer losses, and small filter caps. Beef up the filter caps to a good size reservoir, and an music they worked wonders. They could punch 100 watts for half a second, and in music terms, that worked fairly well.

You may laugh Paul, but on my project list for the next year (after Aragon mods) is a 50 watt Class A zero feedback fully balanced differential power amp. :B (Might as well give it a little headroom

) I've had the front end designed for several years; the power stage design is done on paper, an outgrowth of some consultation I did for another company. I've got an old Quatre DG250 on the way, and may modify it for this app. It's either that or rebuild one of my Aragons, but that would take new power transformers. But it would be a fun conversion to do on an ST.

Best regards,

Jon

Earth First!
_______________________________
We'll screw up the other planets later....

**Chip** · 30 November 2001, 06:24 Friday

"Got it yet Chip?"

Na, not yet.. My guy at Tweeter called his supplier the other day... gonna be a couple weeks. I can wait.. *sigh* lol.. He said he'd call me if it comes in sooner.

- Chip

Chip Engle

"Concrete ain't a spectator sport"

<a href="http://www.htguide.com/bilder/index.cfm?fuseaction=arkivbilder&userid=0&selected userid=336" target="_blank">My HT

I've had it with B&K...Hello Pioneer Elite VSX-49TX

I've had it with B&K...Hello Pioneer Elite VSX-49TX

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