Professional Amplifiers

Coll

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Anyone else used a professional amplifier, I just purchased a Crown XLi1500 AB power amplifier and think it is a great idea. Plenty of power at low cost and in the case of this amplifier good sound also. IMO just as good as the Arcam A19 which it replaced.

No hum or hiss which everone warns about and very quiet fans, I can just hear them at about 2 feet from the amp.
 

lindsayt

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I have 4 high end professional amps that were made in the 1980's. I like them a lot. Laughably cheap with plenty of good clean solid state power. They are built like Tiger tanks. About as heavy too. Their strongest area is the bass. Plenty of grip from these high damping factor designs. Weakest area for 3 of them is the fan and transformer noise (from the amp itself, not through the speakers) - which makes them unsuitable for most domestic users. The 4th is silent, but that only has about 75 watts instead of 150 or 300 watts per channel (into 8 ohms continuous less than 1% THD).

Another minor plus for my system is that they are all balanced and have built in volume knobs, which suits my sources.

I'm confident that they could give top end Naim a good run for their money with my sources and difficult to drive speakers.
 

Coll

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Well this Crown model has no hum even from the amp ltself and as I said it is quiet fan wise. It has variable speed fans and even when I have played it for hours at high volume the fans are still running slow . Its great sound wise Im using it with an Audiolab 8200CDQ and Monitor Audio Silver 6 speakers.

But its the cost that is the big plus only £267 including delivery and vat. Also 3 year guarantee. Where else can you get this sort of power for that money not even second hand.

BTW Iuse the balanced inputs so have no idea if it is as good with RCA.It has switchable input sensitivity also so can match almost any preamp.

If fan noise is aproblem there are many ways round this too.
 

andyjm

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It is not just power amplifiers. If you are prepared to do away with the fancy styling, there are many pro audio products which are a fraction of the cost of 'audiophool' products, with equivalent or better performance. Cables are the obvious area, with balanced mic cables available with high quality Neutrik connectors at prices below the post and packing charges of some fancy balanced HiFi interconnects. I have a number of Behringer products, a measurement mic, mixer - great performance at prices that make you think that someone has made a mistake as they are so cheap.
 

davedotco

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lindsayt said:
I have 4 high end professional amps that were made in the 1980's. I like them a lot. Laughably cheap with plenty of good clean solid state power. They are built like Tiger tanks. About as heavy too. Their strongest area is the bass. Plenty of grip from these high damping factor designs. Weakest area for 3 of them is the fan and transformer noise (from the amp itself, not through the speakers) - which makes them unsuitable for most domestic users. The 4th is silent, but that only has about 75 watts instead of 150 or 300 watts per channel (into 8 ohms continuous less than 1% THD).

Another minor plus for my system is that they are all balanced and have built in volume knobs, which suits my sources.

I'm confident that they could give top end Naim a good run for their money with my sources and difficult to drive speakers.

The old pro amps of their day were exceptional beasts, build for power and reliability, their excellent audio performance came practically by default.

The best of the lot to my ears were the Swiss built FM Acoustics, we used to supply FM600 and FM800 to studios to replace their Crowns (Amcron), BGW, Urie and the like. The FMs were pretty expensive, several times the cost of the more widely used models, but very, very good.

I had a nice FM600 that I was desperate to keep for my own use but as often happened in those days, it 'got away'.

Amps of this type and class actually have little in common with modern pro-amplifiers, which are mostly Class D with SMPS. They are fare more lightly built, more powerful and much, much cheaper than there predecessors. I have on occasion recommended them for hi-fi use where high power at low cost has been a requirement.

These suggestions are usually met with indifference, enthusiasts simply do not believe that they can be any good and, one famous case apart, the industry is extremely reluctant to try and test them as hi-fi alternatives.
 

Richard Allen

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davedotco said:
The old pro amps of their day were exceptional beasts, build for power and reliability, their excellent audio performance came practically by default.

The best of the lot to my ears were the Swiss built FM Acoustics, we used to supply FM600 and FM800 to studios to replace their Crowns (Amcron), BGW, Urie and the like. The FMs were pretty expensive, several times the cost of the more widely used models, but very, very good.

I had a nice FM600 that I was desperate to keep for my own use but as often happened in those days, it 'got away'.

Amps of this type and class actually have little in common with modern pro-amplifiers, which are mostly Class D with SMPS. They are fare more lightly built, more powerful and much, much cheaper than there predecessors. I have on occasion recommended them for hi-fi use where high power at low cost has been a requirement.

These suggestions are usually met with indifference, enthusiasts simply do not believe that they can be any good and, one famous case apart, the industry is extremely reluctant to try and test them as hi-fi alternatives.

And, as Dave has said, this is HiFi BS. I too have a pro amp in my rack. An InterM1000. 2U ( 3 3/4" tall ) and I have taken the rack cheeks off and built a wooden sleeve to wrap round it. Looks great. 500 watts a side into 4 ohms, if I use the other 1 I have spare I can bridge them to get 1000 watts into 8 ohms. I'm driving the 1 with an audionote M Zero valve pre and it sounds fine. OK I had to make 2 RCA to XLR converter leads but who cares at the cost.

1 thing to remember with pro amps though. Most of the fans draw air through a gauss filter in the front panel and expel through the rear of the unit. If that filter clogs you can incur thermal shutdown due to the thermocouple on the heatsinks. Once every 6 months, Take the top off and hoover the gauss. 10 minute job and long long service but be sure to disconnect from the mains and leave for 20 minutes or so because the power capacitors are big so they need time to discharge. Other than that, Job Jolly I think.

Just a quick thought. Naim Nait 5Si £900.00 plus for 50 watts a side. 2 pro amps plus preamp £ 1000.00 for 1000watts per side and £100.00 for a wooden sleeve case. The sums don't add up do they.
 

Coll

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Going back to my crown XLi1500 it is a class AB with linear power supply so again I say a bargain at £267 for 340 watts per channel into 8 ohms weighs a lot too.

With regard to my balanced xlr cables they have gold plated terminals and only cost £30 including delivery. They use van damme quadcore cable. When you search on line some of these cables are absolutely ridiculous price.

My Audiolab CDQ 8200 is quite expensive at £999 but dont forget it is a cd player, preamplifier and dac all in one.
 

lindsayt

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attachment.php


The FM Acoustics 800a is one serious looking amp. Look at the size of that transformer and the power supply caps.

I'll be looking out for FM Acoustics amps and will try one if I see one for the right price. Big old pro amps often sell for grin inducingly low prices.

Coll, if you ever get the chance I think you'd find it interesting to compare an amp like this against your modern Crown.
 

Native_bon

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lindsayt said:
The FM Acoustics 800a is one serious looking amp. Look at the size of that transformer and the power supply caps.

I'll be looking out for FM Acoustics amps and will try one if I see one for the right price. Big old pro amps often sell for grin inducingly low prices.

Coll, if you ever get the chance I think you'd find it interesting to compare an amp like this against your modern Crown.
Just got a feeling the above will out class the modern breeds of amps.
 

lindsayt

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Native Bon. Me too. But you don't know for sure till you've tried it. I also suspect such an amp could be a Naim NAP 500 beater - or equaller. Something I'd love to try some day, but owners of NAP 500's are amazingly reticent about doing such a bake-off...
 

Coll

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lindsayt said:
The FM Acoustics 800a is one serious looking amp. Look at the size of that transformer and the power supply caps.

I'll be looking out for FM Acoustics amps and will try one if I see one for the right price. Big old pro amps often sell for grin inducingly low prices.

Coll, if you ever get the chance I think you'd find it interesting to compare an amp like this against your modern Crown.

Wow that is some beast but it would not fit into the space I have for the Crown.
 

davedotco

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Coll said:
lindsayt said:
The FM Acoustics 800a is one serious looking amp. Look at the size of that transformer and the power supply caps.

I'll be looking out for FM Acoustics amps and will try one if I see one for the right price. Big old pro amps often sell for grin inducingly low prices.

Coll, if you ever get the chance I think you'd find it interesting to compare an amp like this against your modern Crown.

Wow that is some beast but it would not fit into the space I have for the Crown.

As I said, it is a very different beast. The FM600 was usually the amplifier of choice for studios, no fan or front slots and 150 wpc 8 ohms nominal. I did try one on my hi-fi, very impressive as I recall, long time ago now.

The FM600 was stupidly expensive, 2 or 3 times the price of the DC300A or BGW750, in modern terms I would say well in excess of £5k.
 
A

Anderson

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What a great topic peeps. The pro audio world seems to have started to cater for the home audio guys. The likes of RCA switchable sensitivity and bare wire connections.

Oh and they measure flat in most cases. I like them.
 

matt49

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All very interesting. I like the idea of these pro amps. Of course the elephant in the room (if you’ll excuse the lame joke) is that having a pro amp involves having an effing great elephant in your room.

One of the odd things about domestic hi-fi is that people have very strong and personal views about what they’re prepared to countenance in their living rooms.

Even weirder is that if something’s marketed and badged as domestic hi-fi, people seem happy to live with huge ugly arrays of the stuff. I’ve never understood how people can live with racks of multiple Naim boxes. Urgh!

Fortunately there’s a thing called a D …

Well, you know where I’m going.
 

Richard Allen

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Another amp to look out for is the Sony Esprit. I used to use a pair bridged to drive big 15" Tannoy Dual Concentrics in the control room. Absolutely superb and virtually bomb proof. I'll bet Davedotco has encountered these as well.
 

Vladimir

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main-thumb-t-28890-50-hjYDjD5R0Cuz83aeSXe4Dl1MvKqRN40j.jpeg

Guaranteed minimum power in watts at 20 Hz-20 kHz with 0.35% THD: 2,565W (20 mS burst, 2-ohm dual per ch.), 1,800W (20 Hz-20 kHz, 2-ohm dual per ch.), 1,800W (1 kHz, 2-ohm dual per ch.), 2,000W (4-ohm dual per ch.), 1,250W (8-ohm dual per ch.), 3,600W (4-ohm bridge), and 4,000W (8-ohm bridge).Frequency Response (at 1 watt, 20 Hz - 20 kHz into 8 ohms): ±0.25 dB.Signal to Noise Ratio (below rated full-bandwidth power, A-weighted): > 110 dB. Total Harmonic Distortion (THD) (at 2 watts into 8 ohms): < 0.1%. Total Harmonic Distortion (THD) Plus Noise (at full rated power): < 0.35%, 20 Hz to 20 kHz.Intermodulation Distortion (IMD) (60 Hz and 7 kHz at 4:1, from full rated output to –30 dB): < 0.35%.Damping Factor (20 Hz to 100 Hz at 8 ohms): > 5000.Crosstalk (below rated power, 20 Hz to 1 kHz): > 80 dB.Common Mode Rejection (CMR) (20 Hz to 1 kHz): 55 dB, typically >70 dB.DC Output Offset (shorted input): < ± 3 mV.Input Impedance (nominal): 10 kilohms balanced, 5 kilohms unbalanced.Maximum Input Level: +20 dBu typical.Network: Onboard HiQnet, compatible with standard 100 Mb Ethercom hardware.Load Impedance: (Note: Safe with all types of loads)Stereo: 1/2/4/8/16 ohms.Bridge Mono: 2/4/8 ohms.Input Sensitivity (referenced to 8 ohm rated output): 1.4V, 32 dB gain, and 26 dB gain.Voltage Gain (referenced to 8 ohm rated output): 37.1 dB to 22.2 dB Required AC Mains: Universal AC input, 100-240VAC, 50/60 Hz (±10%). Maximum AC mains voltage 264VAC.AC Line Connector: Five cordsets supplied with amplifi er (USA, UK, European, Australia, India).Amplifier shall be protected against reactive loads, faults and shorts. If one channel experiences a catastrophic failure, the entire amplifi er will shut down.The front panel shall be cast aluminum, with integrated handles. Cooling shall be dual-zone, microprocessor controlled, continuously variable speed fans, front-to-back airflow.Dimensions shall be EIA Standard 19-in. rack mount width (EIA RS-310-B), 3.5 in. (8.9 cm) high and 16.2 in. (41.1 cm) deep.Net weight shall be 28 lb (12.7 kg). Shipping weight shall be 36 lb (16.3 kg). The amplifier shall be designated the Crown Macro-Tech 5000i.
 

MrReaper182

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matt49 said:
All very interesting. I like the idea of these pro amps. Of course the elephant in the room (if you’ll excuse the lame joke) is that having a pro amp involves having an effing great elephant in your room.

One of the odd things about domestic hi-fi is that people have very strong and personal views about what they’re prepared to countenance in their living rooms.

Even weirder is that if something’s marketed and badged as domestic hi-fi, people seem happy to live with huge ugly arrays of the stuff. I’ve never understood how people can live with racks of multiple Naim boxes. Urgh!

Fortunately there’s a thing called a D …

Well, you know where I’m going.

I think a rack full of Naim boxes looks very sexy.
 

Coll

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Some of the old pro amps were of course very expensive so not much point in getting if your looking for good value unless of course you can get one second hand at a bargain price. But I think if you are buying new today this Crown XLi1500 will take some beating and it does not look too bad either. Have a look on the internet. As a matter of interest I was not to sure if I was doing the right thing but where I purchased it I had a 30 day period to return it for a full refund. I am pretty sure that they also covered return carriage costs also.

Anyway not sending back as I like it very much.
 

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