EML 300Bs in BeePre

[Doc B.]

We put a pair of EML 300Bs in my BeePre today. The filament voltage with the stock cathode resistor value of 4 ohms was a little low as we expected it would be, about 4.68V. We calculated that a 100 ohm resistor rated for about 2W installed in parallel with the existing cathode resistors would get the resistance down to about 3.84 ohms and bring the filament voltage up very close to 5V. Unfortunately we didn't have a 100 ohmer handy, so we put a 120 ohm 5W in. The result was pretty good with the filament voltage rising to 4.8, just within the required +/- 4% spec'd by EML. So a 100 ohm resistor in parallel with the existing parallel 8 ohm cathode resistors should be just about perfect.

Microphony is similar to the EH 300Bs, perhaps slightly better or at least more confined to higher frequencies. But the sound is very different than the EHs. If you have a system that tends toward being bright and bass light I think the EMLs will be a really good choice. I suspect they might be a good choice for taming digital nasties. In our system they are very strong on the bass end and so far we are feeling the treble is not the best match we've heard for our ribbon tweeter. We'll run them in for a while and report any changes in sonics.

[johnsonad]

Thanks Dan!

[johnsonad]

To start with, this is NOT a Bottlehead recommended mod.

I went ahead a bought a pair of standard EML 300B's to try in my BeePre.  The arrived safe and sound from Jac in Germany in about two weeks.  I had to play around with values to get mine within the specified 4% filament specs and ended up with a paralleled 47 Ohm on one side and a 56 Ohm resistor on the other. 

The EML's have much less mechanical microphany when compared to the EH Gold Grids.  Sound wise they are really hard to describe and I couldn't quite get my head around the sound.  As a reference, I use Altec Model 19 two way speakers (horn and BR).  Horns can be bright but after my crossover rebuild and damping the piss out of the horns, they sound wonderful.  I listen in the near field and my system frequency response is posted in other threads on this forum.  Back to sound, the highs are not as prominant as with the EH's.  They have a wider and deeper sound stage.  The soundstage extends much further forward and even around me.  Imaging is great and with that forward sound stage instruments and singers could be placed forward of the speakers, nearly holographic.  This was a little much for my head to understand as I'm used to everything being behind the speakers and prefer it this way.  Out of phase too was holographic and I heard things behind my head that startled me more than once.  In my system, the mid and lower bass were improved over the EH's but I didn't notice any extension in the lower bass. 

I don't feel after about 25 hours on them that they are are a great match for my system and my listening preference.  300B's are so damn expensive to tube roll and I really had hoped these would work. If anyone is interested in them, send me a PM.  I would rather they went to a Bottlehead before I put them up on AA.

[johnsonad]

After hearing the differences that cap rolling can have in my S.E.X. amp it got me thinking that I didn't give the EML's a fair shot and that I could have had a bad cap and tube combo.  So a few days ago I put a pair of Auricaps in the BeePre and ran the EML's in 100 hours.  I can now say that the EML's sound very nice from top to bottom.  I'm going to play around with the caps a little more but the EML's are staying.

Dan, have you put any more hours on your pair?