They artistically draw clipped rail-to-rail waveforms on your 'scope, for sure. Some Valium could help that amplifier.
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Damping Factor
- Thread starter Walor
- Start date
Current Drive
ESP Project Pages - High Output Impedance aka current drive. Does it make a difference?
Effects Of Source Impedance on Loudspeakers
ESP - The Effects Of Source Impedance on Loudspeakers. Find out what modifying the amplifier impedance does to loudspeaker drivers.
Some light reading on these topics.
If the Mills and Hawksford paper are posted anywhere, they cover the subject very nicely. There was also a book on the subject by a Finnish guy whose name escapes me.
Under some circumstances, they showed a small reduction in distortion with current drive of some special drivers, though it's difficult to actually get any significant advantage in the real world.
Edit: Mills and Hawksford
- Thread Starter
- #105
Esa Meriläinen: https://www.current-drive.info/
The current amplifier only eliminates the current error. However, a loudspeaker is a much more complicated thing. Mechanics continue to be the main source of distortion.
So stop wasting time tilting at this windmill and go after something useful.
- Thread Starter
- #107
A little less distortion is just a minor matter in my opinion. The main advantage, however, lies in the almost unlimited slope, which no voltage amplifier can offer, even if an equalizer is used. And that's exactly what makes the special sound...
Okay, I won't bother you anymore.
Okay, I won't bother you anymore.
What does "almost unlimited slope" mean? Current is no different than voltage in needing at least N reactive elements for an a N-order filter (slope).
solderdude
Grand Contributor
How do you know when you cannot even hear much above 16kHz or so. It really does not matter if you push in 50kHz + 10dB or so.
The driver won't move any more as the full range speaker can't keep up with that.
You can measure the current being there but it won't matter as it simply cannot move that fast.
So how on earth can the few dB treble lift between say 20kHz and 50kHz even matter ?
You would need A: hires files with actual content above that range. B: a super tweeter because a relative heavy and breaking up full range speaker simply does not have any advantage between 20kHz and 50kHz or so.
First thing you need to do is simulate the exact EQ the current drive does. Then create an equal amount of similar distortion and make a real comparison possible before you chalk it all up to 'current drive magic'.
Doesn't that shorting ring also thwart some of the voice coil's ability to move the cone, too?
A little, yes. But it has a drastic beneficial effect on distortion.
I recently noticed that Avantgarde Acoustic claims to have/use somehing like a current source amplifier https://avantgarde-acoustic.de/en/sound-experience/itron/ for their super expensive horn speaker designs https://avantgarde-acoustic.de/en/products/trio-g3/
To me it looks more like marketing than serious engenering/science and the prices have one 0 too much for my taste. But maybe I am wrong and it at least sounds great for whatever exact technical reason. Presenting Ohm's Law and a high gloss picture of a 5 cent resistor at least looks suspicious to me.
To me it looks more like marketing than serious engenering/science and the prices have one 0 too much for my taste. But maybe I am wrong and it at least sounds great for whatever exact technical reason. Presenting Ohm's Law and a high gloss picture of a 5 cent resistor at least looks suspicious to me.
Lot of marketing hype and simplified explanations ignoring how well voltage amplifiers work in the real world. An ideal voltage amplifier will deliver whatever current is needed, and an ideal current amplifier whatever voltage is required, with the end result on loudspeaker performance being comparable IME/IMO. The idea that their current amplifier perfectly controls the voice coil and all voltage amplifiers are fundamentally flawed when driving voice coils is an interesting stretch...
pogo
Major Contributor
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: GlennGregor
Member
They claim to be the first, however my 1983 Sony TA-F555ES is a Current Drive Integrated Amplifier, so Sony was actually the first. I do believe that Current Drive is superior to Voltage Drive.
The TA-F555ES used a current-signaling scheme internally to route the analog signal from the preamp to the power amp. The power amp is not a current-mode amplifier but a regular class-AB voltage-mode design AFAIK.
GlennGregor
Member
Sony uses a voltage-to-current inverter. Their A.C.T. circuitry has a few stages. They use a Current Drive type attenuator between the pre-amp and power-amp stage. The pre-amp stage is also powered through a constant current shunt regulator.
GlennGregor
Member
Stereo Review did an equipment test report on the Sony TA-F555ES. It’s in the June 83 magazine. I found a .pdf version of it online. Some of the report I don’t understand, but I do understand THD, headroom, and dynamic range. I don’t understand the clipping they talk about, also the second and third order harmonics and some test they did with a phono cartridge to see how quiet the unit was.
For all intents and purposes, your amp is not current drive. We’ve been through this defore:
Current Drive VS Voltsge Drive
I would like to know if anyone has info on Current Drive systems for audio. I have a Current Drive Integrated Amplifier and the sound is amazing. I run a pair of Yamaha S5115HT’s off of it and the music is flawless. These are my house speakers. Their sensitivity is 100. I don’t know if a Current...
www.audiosciencereview.com
Why you still insist it is, is beyond me
solderdude
Grand Contributor
The TA-F555ES has a damping factor of 125 so cannot possibly be a current drive amplifier and is with 100% certainty a voltage drive amplifier (so near 0 ohm output R)
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