From: chrisc@gold.gvg.tek.com (Chris Christensen)
Newsgroups: rec.audio.pro
Subject: The merits of Power amps!  was: Peavey, etc!
Date: 11 Dec 92 22:26:10 GMT
Organization: Grass Valley Group, Grass Valley, CA

In article <1992Dec8.174420.9361@ac.dal.ca> cullen@ac.dal.ca writes:

(NOTE;  the text IS heavily edited!)

Mr. Cullen and I trade jabs!
 
My coment suggested that he suffers from Peaveyitus

>No, the rational belief that they still don't know what they are doing.

I submitt an change in my diagnosis:  "Peavyaphobia"

Those who suffer fromt it are deluded to believe that thair
imformation on the topic is the right information.....This .phobia can
have one of many prefixes and applies to all facets of life, as we
know it!  :-)   

And for-the-record:  I will never ask anyone to believe anything I say. 
It's up the the readers of this forum to decide.
 
This paragraph described my fondness of heavy amps!

>I like heavy quality amps: Bryston, McIntosh. However, I have a problem
>with amp racks that have 210 pounds of amplifiers and only have three
>amps in them, when it comes time to move them.

My amp racks weigh in at 250 lbs each....I have a CS-1200, CS-800 and
Ramsa WP-9220 plus the Rane Xover.

>>>How are you measuring power?
>>>I believe that the "800" rating is really 400 W per channel both channels
>>>loaded to 4 ohms.
 
>My point was that he asked for 800W. That's kind of unspecific.
>And no, but I only drive one cabinet per amp channel, if at all
>possible.

I agree that the original poster was talking in simple terms. 
I usually run two or three drivers per amp channel.  I am
reconfiguring the system so my normal system will have no more than
two drivers per amp channel (and present a 4 ohm load).
 
We then go at the weight issue and I speak of running a 2500 watt P.A
from one wall outlet!

>Nothing is _wrong_ with a heavy amp, but I do not want to lift the
>rack on to stage, or roll it on the truck or or otherwise expend energy
>in gas, money, time, or a wrenched back moving the goddamned things.

Yea I do complain about it to.  I do have a lift gate on the sound
truck that mitigates the lifting issue.  And I rarely work a job where
I an required to lift an amp rack alone so two of us usualy can manage
the racks without a lot of problem......

>P=V*I P=120*20 P=2400W available RMS. This means that obviously
>you are not driving it very hard, as you can't make power out of thin air,
>meaning that you can get away with 2500W instantaneous out of the storage
>caps, but you can't get long term power that way. 

We _are_ talking about audio here aren't we.  Crest factors of about
12 dB and even if it's compressed we don't sustain long term power. 
It is my firm belief that the storage and supply cabablities of the
caps in the supply contribute a great deal to the "goodness" of amps
with linear power supplies.

Also I do count on the fact that a circuit breaker will pass more than it's
rated current.  It does have to time to cool a bit.....  In between
peaks!  :-)

>Besides, assuming your triamped CS800 rig, on most source, you are only 
>really pushing real power to the bins and mids, with very little power
>going to the highs.

Of course you're right here,  and as noted above I run a CS-1200,
CS-800 and the Ramsa.  BUT.....Don't forget the conversion efficency
of my nasty and heavey linear supply amps!  Use a factor of %50 when I
request amp power.  So I count on each amp rack consuming 5000 _peak_ 
watts.

>Although, if you want to talk about real fear, I do shows for an audio
>company that's all Carver 1.5's. The last show I did was 3 1.5s on
>one fifteen amp circuit. *Shiver*

I would expect that the amps are loafing along and or the speakers are
incredibly efficient or you are doing soft shows or, or....

>>What's wrong with a three space amp? Are you limited in rack space?

>No, but I am limited in vehicle space. The smaller and lighter the gear
>is, the less you have to spend to move it around. If the racks are small 
>enough to fit in a station wagon, then you don't have to rent a cargo van.
>The same applies to any show, ie. there's a big difference between renting 
>a cube van for a week, and renting a five ton for a week.

Point noted.  But for the record I suggest you don't damn the amps for their 
weight and or size without applying you own personal situation to the
discussion!

>> And you feel that the silkscreened numbers and a rotart pot on a QSC
>> is better?  I don't use or rely on the accuracy of panel markings or
>> attenuators.  I line up my system with a meter.

>No, but they don't claim (QSC) to be marked with sensitivity ratings.
>Oh, and they only have 2 numbers, 0 and 11 (which I think is a Spinal
>Tap take off) to indicate off and full on, where mine always sit.

Not a problem,  I do the same.  But still won't rely on the panel
markings of any amp if I am forced to use the markings,  and I have
had specific situations to do that.

The discussion led to the Peavey DDT circuit.

>That's not what i'm trying to say. I am trying to say that 1, when the 
>DDT circuit is bypassed, the amp sounds better, and 2, some limiters 
>sound better than others. DDT is one of the others.

The DDT circuit on the late model Peavey amps does not bypass when the
DDT defeat switch is thrown.  The circutry is is always in circuit.
The act of DDT is only defeated.  The amp can't sound different?

>But, could you hear any top end? If not, I would say that that's a detection
>of the problem. And reducing gain is what comps/limiters do, but possibly
>this could be done more effectively with adjustable limiters in line after 
>the crossover. And, with a dead short, I would rather see the amp shut down, 
>than keep trying to drive it.

You missed my quick description of how the DDT works.  The DDT in a
Peavey amp senses the feedback loop of the amplifier.  If the circuit
senses an upset in the loop (for ANY reason) is starts to reduce the
input signal.

This is totally different than that a normal compressor or limiter
does.  It's the same NET effect but the DDT is inside the feedback loop of
the amp!  It's a gteat place to have that kind of protection.

The short that I was driving wasn't a dead short.  It was a driver
shorted out.  There is a difference.

>>>tech rider, the first item is *NO EQUIPMENT MANUFACTURED BY PEAVEY 
>>>CORPORATION IS AN ACCEPTABLE SUBSTITUTE FOR ANY ITEM IN THIS RIDER*.

>> I don't know why you have chosen to be so imovable and inflexiable.  I
>> have supplied sound for many touring acts that have come through our
>> town and the real pro's size up the system and usually are skillfull
>> enough to make it work.  

>I think that the key phrase here is "make it work". I have used CS800s

My description wasn't intended as a performance compromise statement.

>and CS1200s on gigs before, but I don't want to. The purpose of the rider 
>is to make sure we get gear to provide an optimum performance, and not 
>just "make it work". The real purpose of the clause is to prevent some
>boob from going down to the local music hole in the wall and saying
>I have this gig, so give me anything you have and I'll make it make noise
>for them.

I have supplied sound to many performers.  Riders are great and
wonderful but have to be put into perspective.  I have done shows with
Donovan.  His rided called out six large bins and thousands of watts
per side for all shows.  Even the club gigs that I supplied sound on.
The seating was 150, and it was just him and his guitar.

The show happened,  it was great and I did it with my Peavey amps!

More discussion on Quality of OSC, Peavey, etc.

>It all depends on what you're after. The last gig I did with peavey product
>was the Nova Scotia Celtic Festival. I got shafted and had to do the 
>smallest stage. Since I was house tech, I had to create (no info, as usual)

I am sorry you got shafted,  or that you feel you got shafted.  I will
regret doing a job and not bid on it again if I would rather not do
it.  But I try very hard to keep my attidude in line and do what I am asked.....

>PA requirements out of thin air, and when i finally got some info, I needed
>3 amps and console plus what was already on the list. This is 2 days before 
>the gig, mind you, in the busiest summer that Hfx has ever seen. My buddy 
>Brad says "no problem, I can get anything" which is fine, as he's providing
>everything else over and above house stuff. He shows up the day of the gig,
>and in the five ton is this BIG black box. As I'm wheeling the box down the 
>ramp, I say "Wkat the FUCK is in this, dimmers?". At which point, he turns 
>with a weird little grin on his face and says "No, that's your amp rack, 

It is to your credit that you did pull it off.

>its Frank's monitor rack." Lo and behold, 2 CS1200s and a CS800.
>Using a Bose 802/302 rig, (which, oddly enough works quite well for 
>folk/celtic/accoustic, although useless for anything else) really pointed 
>out to me:
>1: the CS1200 sounds much better than the 800
>2: They both sound better with DDT off
>3: The QSC sounds better than both.
>4: I hate Bose almost as much as Peavey

Oh my! Peaveyphobia and Bosephobia all in one gig!  I see now why you
are tweeked! I hope you recover from the infection soon,  I'm
surprised that the hospital let's you log onto the NET.......  :-)

Did you have the QSC and Peavey in a side by side direct comparison?

>By the way, that rack weighs 300 pounds.

Ah!  it's only 50 lbs heavier than mine's!
 
>> Have a nice day!
>Ditto 8) 

My intent is not to flame, though it may read that way in print! :-)
-- 
Chris Christensen                  The opinions I express are my own,
chrisc@gold.gvg.tek.com            and sometimes they are wrong!
916-478-3419 FAX 916-478-3887      After all, I *AM* only human.
Newsgroups: rec.audio.pro