Bottlehead Forum
Bottlehead Kits => Kaiju Stereo 300B amp => Topic started by: hpleung on January 19, 2022, 09:29:03 AM
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Hi,
I am assuming that Kaiju power output is a lot higher than Mainline. How many more times is the Kaiju more powerful than the Mainline? I get confused as the power rating changes for different speaker/headphone based on its impedance.
Thanks.
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How many more times is the Kaiju more powerful than the Mainline?
The easiest answer to give is that the Mainline is about 600mW but only into typical headphone impedances (it won't do that into an 8 ohm speaker without a different transformer).
The Kaiju is 8000mW and delivers that more happily at lower impedances, but the Kaiju wired for 16 ohms and the Mainline on the low impedance setting aren't super far off in terms of expected load. It would be tempting to say that the Kaiju is more than ten times more powerful than the Mainline, but as you've mentioned the whole difference in intended loading impedance makes the waters a bit murkier.
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PB was posting while I was writing, but here are the underlying calculations.
Speaker amps like Kaiju are designed to transfer maximum power into a speaker load. Kaiju can be wired to drive 8 watts into 2, 4, 8, or 16 ohm loads. Using higher impedance phones is not a problem, but the available power in watts decreases as the load impedance increases. For these higher impedances, maximum voltage is a better measure to use. When wired for 16 ohms, Kaiju can put out 11 volts RMS.
Headphone amps like Mainline are usually optimized for higher load impedances. Mainline can be switched to drive 600mW into 32 or 64 ohms. At higher impedances, it can put out 6.2 volts.
So Kaiju can put out 11/6.2 = 1.8 times as many volts into headphones with impedances over 64 ohms. Power is proportional to the square of voltage, so that's 3 times the power of Mainline.
For impedances around 32 ohms, Mainline should use the lower-impedance setting, which reduces the available voltage to 4.4 volt (half the power) so Kaiju is 6 times the power of Mainline.
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Many thanks for the detailed explanation. I once "exploded" my first Hifiman Susvara headphone because I used a speaker amp (Accuphase E408) - speaker connectors to 4 PIN-XLR converter and accidentally cranked the volume too high. I did not feel I got much of a warning - when the volume increased too high, it distorted the sound for like 3 seconds, then popped.
I now mainly use the Benchmark HP4 for my Susvara but even this will clip every once in a while. This means that it is nearly not powerful enough.
So I am interested to see if the Kaiju could drive the Susvara fully without being too powerful to be damaging. If we could configure the Kaiju to output power that is just slightly higher than the HP4, such that it never clips at my listening level (I know its loud) that would be ideal.
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Many thanks for the detailed explanation. I once "exploded" my first Hifiman Susvara headphone because I used a speaker amp (Accuphase E408) - speaker connectors to 4 PIN-XLR converter and accidentally cranked the volume too high. I did not feel I got much of a warning - when the volume increased too high, it distorted the sound for like 3 seconds, then popped.
The Accuphase can put out like 38V of signal, while a Kaiju wired for 16 ohms will be more like 12V with soft clipping allowing considerably more than that if necessary.
I now mainly use the Benchmark HP4 for my Susvara but even this will clip every once in a while. This means that it is nearly not powerful enough.
The HP4 says 6W at 16 ohms, so a bit less than 10V.
So I am interested to see if the Kaiju could drive the Susvara fully without being too powerful to be damaging. If we could configure the Kaiju to output power that is just slightly higher than the HP4, such that it never clips at my listening level (I know its loud) that would be ideal.
The 16 ohm configuration should be quite nice. Be sure to grab the DC filament upgrade, as the stock Kaiju is not quiet enough for use with headphones.