Amp Internals 2 |
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JR.junior
Old Croc Joined: 14 December 2009 Location: Slovenija Status: Offline Points: 1789 |
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Try reach him via PM box!
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Support the scoop technology, larger mouth plays louder!
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Biggus
Young Croc Joined: 02 May 2010 Location: Market Harborou Status: Offline Points: 1284 |
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He won't be able to PM as less than 10 points.
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WILL*
New Member Joined: 26 January 2013 Location: Vilnius Status: Offline Points: 8 |
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the t.amp TA2400, what did you think about it?
he have 2kW RMS in brigde mode? |
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AudioSystemsEngineer
Registered User Joined: 11 November 2013 Location: London Status: Offline Points: 144 |
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These are an (almost exact) copy of the QSC RMX2400 series.
also appear branded 'c-mark' and 'audiohead'. they are a dual rail Class-G design (a high-speed FET switches the supply rails from ~50V up to ~80V as the input waveform passes a pre-set point). This results in lower power dissipation in the output stages (so they can get away with fewer devices). They use a crow-bar to limit the output current - which is pretty crude. personally, i wouldn't run these into less that 4 Ohms / channel (8 Ohms Bridged) and make sure the clip lights just blink in load sections. (the clip leds sense the error voltage - so they are a pretty good indicator of distortion / when the amp is struggling).
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kedwardsleisure
Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4938 |
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When considering this amp do remember it was for a time about the cheapest amp you could buy, watt for watt.
Yours appears to have Nippon Chemicon capacitors? Never seen those before in one of these, they normally use cheap chinese grenades. |
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Kevin
North Staffordshire |
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AudioSystemsEngineer
Registered User Joined: 11 November 2013 Location: London Status: Offline Points: 144 |
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i hated working on the audiohead 4000 - they didn't follow QSC's design of 3 rails...opting for a nice explody 2 rail solution.
also, the +/- 15V rails for the input signal part are derrived by using 15V zeners + big red-hot resistors. this means you can't run it up on a variac because there isn't enough voltage for the op amps. 2 ways round this... 1. disconnect the resistors and use a seperate 15V psu, or. 2. bypass the resistors with a lower value (but remember to take the bypass off later !! ) I should also mention, if the amp has been run at continuous clipping... the clip LED's or their series resistor will die. |
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studio45
Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3863 |
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LOL! That piece of design genius deserves a prize....
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Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
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JR.junior
Old Croc Joined: 14 December 2009 Location: Slovenija Status: Offline Points: 1789 |
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Support the scoop technology, larger mouth plays louder!
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Earplug
Old Croc Joined: 03 January 2012 Location: Europe Status: Offline Points: 7199 |
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"also, the +/- 15V rails for the input signal part are derrived by using 15V zeners + big red-hot resistors"
Built in obsolescence. I´ve even seen that one in a couple of Crown amps, who you´d think would know better. |
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Earplugs Are For Wimps!
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Tan-2
Registered User Joined: 29 April 2011 Location: Glasgow Status: Offline Points: 255 |
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The simple Zener reg circuit is straight forwards in most circuits and can be up graded with reg's. if them drop feed resistors are to hot then up there wattage or blot them to the chassis has it will aid cooling them down.
Clipping at high levels.. That will sound bad... |
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Logic will get you from A to B. Imagination will take you everywhere.
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bitSmasher
Old Croc Joined: 23 June 2012 Location: Melbourne Status: Offline Points: 2296 |
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"I ran my amp flat out with sine waves until it stopped clipping, now it's burnt in it sounds better" |
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kedwardsleisure
Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4938 |
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nothing wrong with zeners off the dc bus, good enough for Cloud, HH, Carlsbro, QSC, Wharfedale, Behringer, Mackie etc
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Kevin
North Staffordshire |
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