PreBee 2 for me?

Ivan303 · 2588

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Offline Paul Joppa

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Reply #15 on: January 31, 2022, 03:49:34 AM
...
Speaking of, I'm assuming tube rolling the 300B in the BeePree is likely more influential on sonics than the Kaiju? Even if only due to the signal being further amplified by the power amp..?
It's complicated  ...  no surprise there! The headroom of the BeePre is pretty substantial, and the tube itself is quite linear, so the actual distortion is very low. And Kaiju does not invert the phase, so the harmonics simply add, and will be  dominated by the Kaiju - unless your speakers are so efficient that it has even greater headroom. But if the sonics are influenced by noise or mechanical resonances of the internal tube strucrture, the preamp may dominate.

Bottom line, I'd just say the sonics are differently influential between the two.

Paul Joppa


Offline Paul Birkeland

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Reply #16 on: January 31, 2022, 04:18:41 AM
The BeePre is earlier in the chain, so yes I would say to use the nicer pair there.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ivan303

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Reply #17 on: January 31, 2022, 04:24:33 AM
the tube itself is quite linear

Even at that uncommon operating point? 

Good to know.






Offline Paul Birkeland

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Reply #18 on: January 31, 2022, 04:32:57 AM
Even at that uncommon operating point? 
If you try to swing 100V peak from a BeePre, that won't be great.  At preamp signal levels, the operating area is linear.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Sp33ls

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Reply #19 on: January 31, 2022, 11:05:02 AM
Thanks to both Paul's for the input!

Not trying to hijack this thread here, but I had a couple quick questions as I'm likely going to place an order for the BP2.

At what point does the low frequencies begin to roll off? I imagine that since this is operating at such a low output (and is so linear) that it doesn't even drop 1dB until probably 20Hz?

And, is the Bottlehead shop open to visitors? I moved to the area not long ago. :)



Offline Paul Birkeland

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Reply #20 on: January 31, 2022, 11:07:46 AM
In stock configuration the BP2 should be about -3dB at 2Hz. With the attenuator upgrade, that will move up to 5Hz, but you could put bigger coupling caps in to move it back down if you'd like. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ivan303

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Reply #21 on: January 31, 2022, 12:01:35 PM
So based on that, if one really doesn't need anything under 10-20 Hz one could halve the size of the output cap and go with something EXPENSIVE?




Offline Paul Birkeland

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Reply #22 on: January 31, 2022, 12:11:24 PM
Well, where would you like the roll-off to start?  -3dB at 5Hz from a coupling caps means the rolloff starts around 50Hz.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Sp33ls

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Reply #23 on: January 31, 2022, 01:14:25 PM
It's complicated  ...  no surprise there! The headroom of the BeePre is pretty substantial, and the tube itself is quite linear, so the actual distortion is very low.

This got me thinkin -- is it all that different sounding from a decent solid state pre then? :) Lol I'm mostly kidding, but am kind of curious how they'd generally compare them since the THD is so low, do you actually end up getting some of those nice second order harmonics injected into the signal?

Every BH kit I've heard has done an amazing job of hitting the sweet spot between tube warmth and accurate tonal fidelity, so I have no doubt it's even better with the BP2. Just made me curious why it works so well in this case (from what I've read).



Offline Paul Birkeland

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Reply #24 on: January 31, 2022, 01:20:55 PM
This got me thinkin -- is it all that different sounding from a decent solid state pre then?
Well, a solid state preamp usually requires many, many discrete components or at least an op-amp (~20 transistors inside one package) to get some gain and decent linear output.  The BeePre and the Moreplay do that with just one active device.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man