Amplifier Loader Circuit
zingo
Posts: 11,258
As I've been playing around with my 105db sensitive horns, obviously some amps sound better than others, which I was prepared for. One known issue with even good SS amps is that distortion numbers are initially high at low power (where I would be using my horns), but then distortion lowers and SQ increases as power comes up and the amp hits its sweet spot.
My idea is, what if I were to design a circuit, maybe an L-Pad, that would attenuate or load the amp before the speakers, causing you to increase the volume, and thus get into the amps sweet spot on a pair of speakers that other wise would not have. Obviously there could be weird SQ issues with a circuit like this, and it might have weird interactions with the speakers depending on the frequency and impedance, but is there anything I'm overlooking on a simple level?
My idea is, what if I were to design a circuit, maybe an L-Pad, that would attenuate or load the amp before the speakers, causing you to increase the volume, and thus get into the amps sweet spot on a pair of speakers that other wise would not have. Obviously there could be weird SQ issues with a circuit like this, and it might have weird interactions with the speakers depending on the frequency and impedance, but is there anything I'm overlooking on a simple level?
Post edited by zingo on
Comments
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"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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Thanks; I know all about NPs gear and the value of the "first watt" whether SS or tube. Clean, dynamic power is importanr for any speakers, but paring is especially important with high sensitivity speakers because of noise and amp design.
However, and for slightly academic reasons, I'm trying to design a circuit that would load an amplifier, to make it more ideal for driving high sensitivity speakers. I'm sure there are a lot of objections to the idea, but it's intellegence that lets us entertain an idea without accepting it. -
The distortion vs. power behavior described in the first post is intrinsic to many solid state amplifiers. One may use the old series resistor (e.g., a 1 ohm noninductive power resistor) trick on the speaker outputs to lower DF and make an overdamped ss amp sound "like" a tube amp. One can certainly use an L-pad to pad down an amplifier's output - but I doubt that it would yield a marked improvement in the perceived (audible) performance of the amplifier.
The nice thing about an L-pad made with noninductive resistors is that it will (should) function as a purely resistive load (i.e., the impedance won't be frequency-dependent, and there shouldn't be any inductive or capacitive reactance). It will dump the excess power as heat, though. Kind of like putting a governor and big mufflers on a Lamborghini and then using it to commute in town.
Plenty of L-pad calculators on teh webs. -
I have heard people do this with guitar amps. Usually 100watt tube amps. They need to pad it down so it can be recorded in the Sweet Spot.
I would guess the same principle would apply, I would worry about the possible distortion you may add to the signal though.
