hye all.i confuse about low power amp like f5,hiraga or jlh.its around 10-20watt and dc supply around 20v.this amp can drive 4 ohm speaker or not?how about bass sound compare solid state amp?what i think when amplifier with low power bass also will low and not loud compare with high watt amplifier.please explain to me.thanks you.
It will drive 4 ohms fine. It is rated at 25W into 8 ohms and 40W into 4 ohms.
It is one heck of a fine amp and should do bass fine. Rember a 400W amp will
only sound twice as loud as a 40W amp. I realy like mine thanks again Mr. Pass.
It is one heck of a fine amp and should do bass fine. Rember a 400W amp will
only sound twice as loud as a 40W amp. I realy like mine thanks again Mr. Pass.
Low power amps require high efficiency speakers to give respectable SPL in the domestic listening environment.
Once you are committed to the high efficiency route to adequate SPL, then any amp can drive any speaker, or at worst, modified to drive any speaker.
Once you are committed to the high efficiency route to adequate SPL, then any amp can drive any speaker, or at worst, modified to drive any speaker.
Hm.
I have a midrange ribbon with 0,16 Ohms and would love to drive it direct for best efficiency.
So it would be absolutely sufficient, if the amp can do a 5 or 6Volts RMS Swing.
But which one can hold the extreme low load, altough it is pure resistive.
I have a midrange ribbon with 0,16 Ohms and would love to drive it direct for best efficiency.
So it would be absolutely sufficient, if the amp can do a 5 or 6Volts RMS Swing.
But which one can hold the extreme low load, altough it is pure resistive.
I think there will be a more efficient driver of course, but my MR Ribbon is 80 inches long and 2 inches wide, what allows levels more than enough for my ears.
Its just the current running trough, which is deciding.
Dont' know the real efficiency, but with preresistors the amplifiers most power will be transformed into heat.
Its just the current running trough, which is deciding.
Dont' know the real efficiency, but with preresistors the amplifiers most power will be transformed into heat.
Why on earth not? If it can radiate a lot of sound with a small amount of power in, it's efficient. Doesn't matter if it's characteristic impedance is 0.16ohm, 8ohm, 16ohm or 6000ohm...
Roscoe
The problem is the power input requires very high current to reproduce the sound output.
That, I suspect, becomes an inherent limitation to the efficiency of the speaker.
That, I suspect, becomes an inherent limitation to the efficiency of the speaker.
😱 At 6V RMS thats 37.5A, with power rails of +- 15V (thats probably the lowest you could get away with for a push pull output stage) the power consumption would be 1125W; you would be better off using a matching transformer.
It's not the speaker efficiency, it's the amplifier, note the power consumption above, for 225W output, I think that is what Andrew is saying.
Andrew was specifically referring to the midrange ribbon efficiency. The amplifier efficiency is only slightly less than 25%, fairly typical for pure class A designs. the efficiency of some of Papa's designs is significantly lower than that.
Roscoe
Roscoe
Yes, you have picked me up correctly.
I am referring to speaker efficiency.
1W into 0r16 requires 400mVac and 2.5Aac.
What SPL does your speaker manufacturer specify for a 1W input signal? 80dB @ 1m or 90dB @1m or 96dB @1m.
I believe that a driver, with this very low impedance, will not be in the mid to high 90s.
But I have not researched the market, partly because I have this inherent engineering led bias that very low impedance cannot co-exist with high efficiency.
But I am willing to hear what others have to say.
I am referring to speaker efficiency.
1W into 0r16 requires 400mVac and 2.5Aac.
What SPL does your speaker manufacturer specify for a 1W input signal? 80dB @ 1m or 90dB @1m or 96dB @1m.
I believe that a driver, with this very low impedance, will not be in the mid to high 90s.
But I have not researched the market, partly because I have this inherent engineering led bias that very low impedance cannot co-exist with high efficiency.
But I am willing to hear what others have to say.
My MR Ribbon offers around 85dB/ 1 W 1m , when used with 4 Ohm Transformers.
( BTW , it is the Apogee Full Range).
But it is hard to get good transformers for 0,16 Output impedance matching at apx 30 Amperes.
When Neodymium Magnets are used and the Ribbon is made with Multitraces ( giving apx 2,5 Ohms) instead of preresistor or transformers, then you get apx 95 dB 1 W 1m.
Basically Ribbons are current driven, the math gives direct relationship between Field Strength, Current and Force and ribbon mass, as far as i know.
I clearly see that the extreme high current is the key, thats why i jumped into the discussion with low power amps, which produce a few volts only, but very fine sounding.
( BTW , it is the Apogee Full Range).
But it is hard to get good transformers for 0,16 Output impedance matching at apx 30 Amperes.
When Neodymium Magnets are used and the Ribbon is made with Multitraces ( giving apx 2,5 Ohms) instead of preresistor or transformers, then you get apx 95 dB 1 W 1m.
Basically Ribbons are current driven, the math gives direct relationship between Field Strength, Current and Force and ribbon mass, as far as i know.
I clearly see that the extreme high current is the key, thats why i jumped into the discussion with low power amps, which produce a few volts only, but very fine sounding.
The problems will raise their ugly head when it comes time to actually move all those electrons to the ribbon. Beyond the massive high current power supply and output stage you will need for this amp, you need low resistance, low inductance wiring and connections. Copper loss, as we call it, will become a significant portion of the load. Much greater than the ribbon impeadance. And, if temperature starts getting involved, your likely to have a non-linear component also. Not to mention the extremely high current slew rate or inductance effects with that type of load.
Not that it can't be done but, most give up in favor of the more traditional methods (higher impeadance drivers or transformers) 😀
Not that it can't be done but, most give up in favor of the more traditional methods (higher impeadance drivers or transformers) 😀
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