Just testing my D.I.Y. project audio amplifiers.
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These devices are D.I.Y. Audiophile Experimental Audio Amplifiers.
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produced between 1978-79′
pulse power supply
ruler flat frequency response
2×70w sinus
filters for low’s & high’s
high end class
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This is demonstration of what an ACE-amplifier can do. It was done as a project in the course ETI022 Analog Project at LTH in Lund.
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Class-D is an extremely efficient (85% or more of the actual input power is converted to audio), and highly linear (good-sounding) way to amplify an audio signal. The music in this particular video unfortunately does NOT sound good, because of the cheesy mic in the camera that I used to shoot the video with. It does sound excellent to the ears in real-time.
I was able to get better than 3 Watts of average power to the speaker, using only a single TC4428 MOSFET gate-drive IC. The IC itself has dual inverting/non-inverting drivers, and I used both in a full-bridge topology to drive the speakers through low-pass filters, with a cutoff frequency of 25kHz.
The audio is playing through the speaker in the Ibanez amplifier, which has been disconnected from the rest of the amp.
The waveform shown in the beginning of the video is a classic Pulse-Width Modulation signal…where the duty cycle of the square wave varies in proportion to an analog signal (the audio input from a CD player or something). When the high-frequency carrier (200kHz) square wave is filtered out, it leaves the audio waveform which then drives the speakers.
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C-Audio Pulse 4×300 with new-style IGBT gate transformer.
Shows the palarver start up sequence which i suppose is useful for avoiding the largest explosions.
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My FM single conversion pulse counting FM Receiver has the semiconductor lineup as follows. Frequency converter is 1 40673 Dual channel FET. The oscillator is 1 BF244B Single Channel FET. The IF stages are 10.7MHZ and uses 3 40673 dual channel FET making a total of 3 IF stages. The limiter is 1 2N3819 Single channel FET. The discriminator is 2 0A91 Germanium diodes configured as a voltage doubler detector. Due to the high IF responce this receiver gives super stereo performance through my home made stereo decoder.
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http://www.reverb-store.co.uk/product-detail.asp?prod=1624
Line 6 Spider Jam Guitar Amp at Reverb.
The Line 6 Spider Jam™ gives you hundreds of coveted guitar sounds, sound-on-sound looping and the best band in the world right at your fingertips!
A member of the infamous Spider™ family, Spider Jam shares some popular family jewels like 200+ artist-created presets, 150+ song-based presets, 12 Line 6 original amp models and seven Smart Control FX, including reverb and delay. Its full of fan favorites but Spider Jam also features some new, unique characteristics —
— like over 100 ribcage-rattling Endless Jam tracks and drum loops played by LA and Nashvilles top session musicians slamming the drums, thumping the bass and hacking away at guitars. These arent robotic, computer-generated jam tracks — youll feel your pulse racing while youre jamming with top players in killer tunes that explode out of the speaker in vivid, uncompressed audio. Play for days over the Endless Jams and, with sound-on-sound loop recording, save your scorching solos right into Spider Jam.
Cooking at 75 watts, Spider Jam offers rhythm-section chemistry, hundreds of amazing guitar tones and all your recorded creations pushed out of a 12″ Celestion® Custom speaker and a 2″ tweeter — this things got so much bang for your buck we should issue it with a health warning.
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After reverse engineering the original, I think I have finally got it to work. Next comes the three condenser rings and then to build the pickup combs to match.
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This is not power on thump..the amplifier is already switched on…. supply is there, almost 55 Volts symetrical…when i switch the computer “on” then the PC audio system send an enormous pulse….observe, condensers charged..voltage at 55V and will remain this way for several miliseconds..time enougth to burn a wrong transistor…. and have not burned the BD139 and BD140..because 80 volts of VCE is the guaranteed voltage..of course the transistor can hold more voltage..imagine if it will burn with 81 volts..factory would be very stupid producing transistors this way.
This is the Dx Blame ST, using 55V, because supply has drop..the Dx Blame ES and Dx Blame ST, the standard schematic is using 35V and limit is plus 10 percent.
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