Other Gear > Headphones
Audeze LCD 4 - Which amp?
Paul Birkeland:
The methods for reducing harmonic distortion in a zero feedback directly heated SET amplifier are generally more detrimental to the sound than they are helpful.
Deke609:
Thanks PB. I think I'll stop with the tweaking for a while. With the impedance switching board, balanced speaker outs, and some signal wire shielding, I've pretty much scratched my tweaking itch. Maybe down the road a bit I'll play with capacitors.
But for now I have the BeePre on order. I plan to do the flux band mod you discussed on another thread, and go a little crazy with shielding the signal wire with grounded copper and where possible some MCF5 film - just for S & G's. And I'll cover with non-conductive tubing/wrap any shielded section that could possibly come into contact with a component.
Paul Birkeland:
I'd be a little cautious withe modifications on our higher end kits. The signal wiring and a fair amount of the AC wiring is shielded already and arranged reliably and out of the way.
The copper tubing I put in the Neothoriator did double duty as a shield and as a support for a bunch of less than rigid twisted pairs of our solid core Teflon jacketed wire. In the BeePre, these wires are secured to the chassis and won't move. These wires also take a gentle curve down the center of the amp that won't be so easily done with copper tubing.
Deke609:
Thanks PB. Wiring paths will not be changed - for the main section through the middle, I'll be using refridgerant copper tubing, which is very soft, unlike regular copper plumbing, and I will form it to match the specified curved path. For trickier spots, I'll use 1/8 or 3/16 OD copper braid, depending on the width of wire to be shielded. I will be very careful in the build process and take my time.
cheers,
Derek
Deke609:
--- Quote from: Doc B. on October 18, 2018, 02:44:26 PM ---You don't need a preamp with the Stereomour II. The BeePre is super quiet in terms of power supply, but there is the potential issue of microphonics in the directly heated 300Bs if you can't put the preamp somewhere where it will be isolated from external vibration.
OK, the disclaimers are out of the way. Sonically it could be a very nice combination. Let us know when you are ready to order. ;)
--- End quote ---
So, the BeePre w/ BeeQuiet has been up and running for a week. Caps and JJ 300Bs are nowhere near to broken in, but from the first switch on it has sounded superb paired with my SII. Build is stock except for (1) teflon 4 pin sockets, (2) copper shielding around as much of the signal wire as I could manage and some sections of the power wiring (refridgerant copper tubing for long sections, and copper braid everywhere else -- sometimes both), and (3) copper flux bands on the transformers. Flux band and shielding is wired to chassis ground.
It is still early days, but the change in SQ is dramatic. Doc is right, the SII doesn't need the BeePre, but boy do they ever get along well. For me, adding the BeePre in front of my SII has already had as much of an impact as the Shunt Reg upgrade (my favorite of the 3 Stereomour upgrades). With the Shunt Reg upgrade added, the SII really started to punch. With the BeePre, it is punching harder and now has SERIOUS BITE! The dynamics are incredible. This is in addition to greater clarity/detail and "openness".
So far, I mostly prefer to listen with the BeePre wide open. This may be pushing it into distortion - but if so, it is a very euphonic distortion, particularly for rock. For classical and some jazz I turn down the Coarse attenuator by a click.
I am impressed by everything about the BeePre, including the very clever layout and implementation of the schematic. There's a lot of stuff going on in this amp -- it not only all fits, but does so in a way that makes amateur assembly possible and fun. Bravo!
cheers,
Derek
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