Anybody using Pro Audio Amplifiers?

warnerwh · « **on:** 28 Oct 2006, 07:38 am »

I ask because I wonder if they could be used in a bi amp setup. It would seem some must be pretty good. In years gone by I remember Crown DC 150 and DC300's were used by alot of audiophile types. Also Bryston amps are from a pro audio company. Does anyone make them without fans? And if not how loud are these fans? Can the fans be replaced with the quiet computer fans? Any feedback with experience whether used for subs or in a bi amp setup would be appreciated. Thanks

Ethan Winer · « **Reply #1 on:** 28 Oct 2006, 03:30 pm »

Warner,

> I ask because I wonder if they could be used in a bi amp setup. <

I have two Crown PowerBase stereo amps in my home studio, bi-amped, driving a pair of very large JBL pro speakers. Between both amps I have more than a KW of power. Okay, cue up a few Tim the Toolman Taylor grunts.

> Does anyone make them without fans? <

Ay, there's the rub. My Crown amps do have fans and they're noisy. So I made a little case for them, with simple air handling that directs the flow out the rear toward a wall covered with absorption. Now they're quiet enough to have in the same room. You can tell when they're on and running, but just barely. Otherwise amps like these should be in a separate room.

--Ethan

JoshK · « **Reply #2 on:** 28 Oct 2006, 04:33 pm »

I use Crown K1 for my soon to be built subs. No fans in the K1/K2.

woodsyi · « **Reply #3 on:** 28 Oct 2006, 04:57 pm »

I use Crown K2 for the subs. It has volume control and selectable ouput voltage to make biamping easy. And as Josh said it has no fan. Another option is digital amps for the woofers. My ICE amps do great with woofers on the 40s.

fredgarvin · « **Reply #4 on:** 28 Oct 2006, 06:21 pm »

I would recommend QSC. In a band I was in we switched from Crown to QSC in our P.A. and the differance was great as far as clarity, dynamics. We ran our mains and our monitors with QSC amps. I haven't used Behringer amps but the Consoles and various effects we used were very nice, so you might check them out as well.

JDUBS · « **Reply #5 on:** 28 Oct 2006, 07:21 pm »

Yep, here's another vote for the Crown K1/K2. I was using a K2 with my JBL cabinets and it was truly awesome! No fan so it was perfectly silent.

-Jim

bpape · « **Reply #6 on:** 28 Oct 2006, 07:49 pm »

I run a Crown on my sub. Tried it on my mains but that just wasn't happening at all - I was just curious. For the sub, the ability to run in parallel mono mode was the clincher for me. My sub needs a TON of juice but presents a load that can go down to around 2 ohms. Most standard amps bridged won't handle the impedance.

For me, fans aren't an issue as the sub amp is outside the room.

Bryan

Rob Babcock · « **Reply #7 on:** 28 Oct 2006, 08:33 pm »

The Behringer A500 has been recieving a lot of buzz as a good pro amp for audiophile apps. I think one of the more mainstream press sources has praised it, too. I might try a couple as cheap as they are (around $180 online).

warnerwh · « **Reply #8 on:** 29 Oct 2006, 09:32 pm »

Thank you guys for the information. I think I'll give one of the Crowns a try.

mjosef · « **Reply #9 on:** 30 Oct 2006, 01:10 am »

I used a Hafler P7000 proamp on the woofers of my RM1s a few weeks ago with great success, had much better dynamic kick and cleaner effortless bass response...the downside of course was the fan noise, which was audible during quieter passages of the music. Now if only I can find some low noise 80mm 120v fans...

fredgarvin · « **Reply #10 on:** 30 Oct 2006, 01:25 am »

I've never used Haflers, wanted to but after Crown, Amber, Peavey and QSC, the QSC just kicked the others. Maybe I'll check a Hafler for my (possible) sub build.

To go with my *new* 626r's. I used to have RM1's and missed 'em!

mjosef · « **Reply #11 on:** 30 Oct 2006, 01:37 am »

A great feature on the Hafler P7000 are the crossovers embedded in the input circuit, comes with 100Hz stock and easily configurable to other frequencies and I think two choices of slopes, 12 and 24 dB. Plus they can be 'taken' out of the circuit by orienting the card for bypass(?).
I picked this one up from Hafler as a B-stock (looked brand new to me) last year.

Ferdi · « **Reply #12 on:** 3 Nov 2006, 12:45 pm »

Hi, I don't remember all the details but in the old days of Harmonic Discord.......

There was a specific type of Crown amp and a QSC amp that was considered very good and even better with some specific mods. The biggest issue that I thought people had was that those pro-amps had fans built in.

Not sure HD is still to be found for those old discussions. Not even sure who did those modifications.

Bob in St. Louis · « **Reply #13 on:** 4 Nov 2006, 07:29 pm »

I was about to start a thread on this very subject after suffering with the "twin hairdryers" in my amp. It was bad enough that I built and installed a tempered, smoked glass door in front of my rack.......

http://home-and-garden.webshots.com/photo/2739744660085868784wRBUAo

However, during quiet movie/audio sequences, it's "still there".

The amp does double duty as H.T. and audio. It is a Legion LSA 900 (900 watts bridged).

So today I decided I'd had enough so I took the cover off and installed those little felt pads, like the ones in your kitchen cabinets, between the fans and the case. It made an improvement of about 2%.

The fans themselves are pretty quiet. I checked them while plugged in, but not bolted to the case. Actually very quiet, just not when they're installed in the case.

So, not to be out-done, I got to thinking.....
The amp has never gotten hot, not even warm. In fact, after extended periods of high SPL from the sub, it's actually cold to the touch.
So I unplugged both fans........

Damn things quiet now. aa

Realising this isn't the best long term solution, I was thinking about "turning the fans down" by installing a resistor internally, or an external 'pot' that I could use in conjuntion with a thermometer (just to keep an eye on it, you know...).
The users manual says that in event of excessive temperature, the fans will engage 'high speed'. I've never heard them "kick into high gear", afraid of what that would sound like.

Any thoughts about either/both ideas?

Bob

Russell Dawkins · « **Reply #14 on:** 5 Nov 2006, 01:02 am »

I'd feel more comfortable about moving at least some air, especially if the air flow is horizontal, through a duct.

I have seen this fan recommended as the best solution for an audible (not even "noisy") fan in a multitrack recorder. If it fits it would be worth trying at $8! Brings the noise down to 20 dB, runs on 7 - 14 V with a current draw of 75 mA and is 3.15 X 3.15 X 1".

http://www.pcpower.com/products/viewproduct.php?show=VCBS

Bob in St. Louis · « **Reply #15 on:** 5 Nov 2006, 05:19 am »

Wow, $8 is a deal.
The strange thing is, except for the label in the center, that fan is exactly like mine. Same plastic housing, four spokes to center hub, all of it is identical. I suppose 'the guts' are better hence the quiet operation.

I'll have to try a couple of those.
Thanks Russell
Bob

Russell Dawkins · « **Reply #16 on:** 5 Nov 2006, 06:27 am »

Bob, I don't know how your fans are mounted, but if its bolts, then there's your sound/vibration transmission path. Try using some sort of adhesive backed dense foam.

I have an exhaust fan over my workbench to take soldering fumes outside and it is not bolted to the wall, for the same reason. It is suspended by a bungee cord and rests against a gasket of foam self-adhesive weatherstripping with gasket cement or something (it's been 14 years) adhering the fan surround surface to the non-adhesive side. It weighs 7 lb, so something similar should be easy for one of these. It works, by the way.

I hate motor noise or any noise of a continuous nature. Detest fridges, dishwashers!

Bob in St. Louis · « **Reply #17 on:** 5 Nov 2006, 12:06 pm »

Quote from: Russell Dawkins on 5 Nov 2006, 06:27 am

I hate motor noise or any noise of a continuous nature. Detest fridges, dishwashers!

HardDrives, PC fans. ect...
Amen brother! Drives me up a wall.

In my post I had mentioned I used the felt cabinet 'pads' but made no difference.
Wonder what a non-hardening 'adhesive' would do???

Bob

Russell Dawkins · « **Reply #18 on:** 5 Nov 2006, 05:55 pm »

Bob, when you say you used felt pads, do you mean just between the fan frame and the chassis of the amp, then bolted the fan back in? If you do, as I said, the bolts are the noise path. In the set up I described, the fan was not bolted, but held against 1/2" thick weatherstripping foam. The foam transmitted little of the bearing noise of the fan.

Bob in St. Louis · « **Reply #19 on:** 6 Nov 2006, 04:42 am »

Quote from: Russell Dawkins on 5 Nov 2006, 06:27 am

....rests against a gasket of foam self-adhesive weatherstripping with gasket cement or something ..... adhering the fan surround surface to the non-adhesive side.

I gotcha now Russell, totally understand. Not a bad idea actually.

Quote

Bob, when you say you used felt pads, do you mean just between the fan frame and the chassis of the amp, then bolted the fan back in?[/quote
Yea, that's what I meant that must be why it didn't help much.

The amps been playing all day, not even warm yet. That's bizarre isn't it???

Bob