i just tried to change it sorry i was putting three different threads up late at night - 🙂bad idea
Audio labs of main manufacturers often use PA amps for listening tests. At least, the two I did some work with. But on the whole, it would be better to reverse it: use hifi amps to power loudspeakers based on professional drivers. At living room conditions, good PA drivers may distort an order of magnitude less than audiophile drivers do in the same price category.
For example: for my latest project I am using a coaxial midwoofer from PHL, the 3491-14. It is 94dB/W efficient (half space). For the working range of this driver, distortion never gets above 1% at 63W input. That equates to about 109dB at one meter of midrange energy. Put some decent compression driver behind it and you will never play at more than 1W at home for the mid, and some milliwatts for the compression driver. (Driver distortion increases almost linearly with input power). Professional amps are too powerfull in this context and will mostly operate in their relatively high noise region. The gain structure is all wrong, in other words.
For example: for my latest project I am using a coaxial midwoofer from PHL, the 3491-14. It is 94dB/W efficient (half space). For the working range of this driver, distortion never gets above 1% at 63W input. That equates to about 109dB at one meter of midrange energy. Put some decent compression driver behind it and you will never play at more than 1W at home for the mid, and some milliwatts for the compression driver. (Driver distortion increases almost linearly with input power). Professional amps are too powerfull in this context and will mostly operate in their relatively high noise region. The gain structure is all wrong, in other words.
That's an interesting concept ... 🙂
On another note can you tell me more about how the Audio labs used PA gear for listening tests?
Some Hifi stuff comes standard with a P.A. style amp. If you buy a set of JBL M2 speakers, they are standard powered by a Crown Itech 5000HD, and the dsp of that amp is used as crossover. If you want an other amp, you need to find the crossover yourself it seems. They are sold like studio monitors, but mostly used as hifi speakers for big rooms by the customers. I did install a pair in a big fancy hall in a castle a few weeks ago. The amps have fan noise altough so they are in that case in a small sideroom of that hall just behind the speakers where the noise is no issue. And that is the biggest pitfall for pro audio amps in hifi situations. The cooling fans can make a lot of noise you don't want. And pro audio amps are in general class D amps, which are clean sounding, but not everybody's cup of tea. I prefer other amps for myself.
its a bit fustrating that in many cases the pro amps would just need firmware with a lower minimum fan speed to be silent and or better tempreature monitoring. This would also cause them to last longer in pro enviroments as they usualy spend a lot of the time on with no signal so running the fans slower would result in less dust ingress and longer lasting fans.
They need amplifiers for all kinds of testing and the general perception I encountered amongst engineers is that all good amplifiers sound alike. So they prefer the ones that can take a beating.
Hello AA,
I have 5 subs total in my home theater/stereo listening set up. 4 of them are referred to as "Infra-bass" subs, 1 set incorporating 2 10" CSS drivers and the other set 2 12" CSS drivers. Each set of subs (4 total) are driven by modified Adcom GFA-5800's and are used primarily for HQ sound preproduction. These are also used for HT reproduction. Not lacking in low end output per se, I still felt a little extra from the LFE output channel (not being used prior) on my processor would be an interesting addition. I had already purchased a Dayton audio HTS545HE-4 Kraken 21" driver and built what I would deem a dedicated HT LFE output sub using a GSG Audio Full Marty Enclosure Kit. This thing's a beast! I didn't want to shell out another $1000-$1500.00 dollars getting another Adcom. I had done a great deal of reading too and wondered after reading a lot, that I might try a PA style amp. I settled on the Crown, XLS-2502 DriveCore 2 Series amplifier for about half of what a used Adcom would run and it has 4 times the power!. Happy to report, in this configuration, it sounds "really" amazing! Driving this monster with more than I could ever imagine was a great move. The amp rarely gets the fans going and by that time, there is no way you can hear them anyhow. Even with all the bass I had already heard using the 4 subs mentioned above, adding this amp with all this cool running power was a huge "Two Thumbs Up"! As with all things, spend a little to get a quality PA amp as you would if buying anything, you get what you pay for. Not thinking I would go with anything less than a Crown or QSC. Not sure I could say the same for some of the totally overrated (and OVER-RATED) PA amps on the market.
Steve
I have 5 subs total in my home theater/stereo listening set up. 4 of them are referred to as "Infra-bass" subs, 1 set incorporating 2 10" CSS drivers and the other set 2 12" CSS drivers. Each set of subs (4 total) are driven by modified Adcom GFA-5800's and are used primarily for HQ sound preproduction. These are also used for HT reproduction. Not lacking in low end output per se, I still felt a little extra from the LFE output channel (not being used prior) on my processor would be an interesting addition. I had already purchased a Dayton audio HTS545HE-4 Kraken 21" driver and built what I would deem a dedicated HT LFE output sub using a GSG Audio Full Marty Enclosure Kit. This thing's a beast! I didn't want to shell out another $1000-$1500.00 dollars getting another Adcom. I had done a great deal of reading too and wondered after reading a lot, that I might try a PA style amp. I settled on the Crown, XLS-2502 DriveCore 2 Series amplifier for about half of what a used Adcom would run and it has 4 times the power!. Happy to report, in this configuration, it sounds "really" amazing! Driving this monster with more than I could ever imagine was a great move. The amp rarely gets the fans going and by that time, there is no way you can hear them anyhow. Even with all the bass I had already heard using the 4 subs mentioned above, adding this amp with all this cool running power was a huge "Two Thumbs Up"! As with all things, spend a little to get a quality PA amp as you would if buying anything, you get what you pay for. Not thinking I would go with anything less than a Crown or QSC. Not sure I could say the same for some of the totally overrated (and OVER-RATED) PA amps on the market.
Steve
https://www.crownaudio.com/en/products/xls-1502 would be a good match for your 4 ohm Maggies. Plenty of power, good damping factor for tight bass. I have run mine in a triamp setup powering double 15's per side for years. Sounds good and I have never heard the fan.
thread title fixedIs anyone replacing the fan? I like the old AShly FTX 2001 amps. I use them in the basement, and they're installed in a back room, so the fan noise isn't an issue. My upstairs system's amp when goofy so I put one in there too which was an improvement, but the fan noise is a little much. What's a good 120V replacement that's quite.
Thanks!!
Thanks!!
Sorry I am seeing this so late. A friend and I had a somewhat small sound reinforcement company in the '80's. All rock, indoor and out. We built so many DH220/DH500 kits!!! We had 6 rolling racks of them. 500's on subs and mids, 220's on 2" horn loaded TAD drivers.
Studiomaster mosfet 1000 500watts a side 1000 watt mono bridge very nice sounding mosfet amp if you can find one
Maybe you need a special amp version with low voltage output but high current output - go to
https://www.diyaudio.com/community/threads/direct-drive-ribbon-amp.46986/
otherwise this amp modules could be a good approach (in used condition often cheap offers to find)
https://web.archive.org/web/20150316014727/http://www.bkelec.com/MODULES/amplifiers.htm
https://www.albs.de/Spec/DAC-MOSII-120-240-360_Info.pdf
https://www.albs.de/DAC_MOS II 120_240_360.htm
An Impedance plot of your Magnepan model would be helpful.
I haven't good experiences with PA power amplifier from currently manufacturing due the fact, that Class-D and SMPS is usual from today's models.
Older PA amp versions with 50/60Hz transformers and Class AB output stages from power amp section are sometimes good for home audio concerning sound character - e. g. this one from French brand "POWER" :
https://www.diyaudio.com/community/...er-models-from-the-old-uk-brand-power.153646/
also the PA300 (Elektor diy project)
https://www.diyaudio.com/community/threads/pa300-elektor-amp.10311/
https://www.elcircuit.com/2012/04/300w-power-amplifier-elektor.html
https://www.reber.si/ojacevalniki/PA300/PA300.htm
Maybe old models from Lab Gruppen does also provide good sonic character