What 300b's are you running?

[johnsonad]

Thanks Deb!  I'm very tempted by those tubes.  Too bad we don't live closer together so I could listen to your stash!

When you get a chance, could you post the current draws for your different tubes?  It would be interesting to see what the KR tubes draw..

[debk]

I have about 5 hours on the KR's now.  They have "opened" up more, very spacious and detailed sounding.  I am very happy I bought these, the best sounding 300b I have tried in the BeePre.

The data sheet that came with the tubes say the filament current is rated at  1.2A.  The actual test data included with the tubes are 1.11A and 1.12A.

I have not had a chance to make any measurements myself.  When I get a chance I will drag it down to Lab (Ok, Basement but Lab sounds better) and make some measurements

Deb

[johnsonad]

Thanks Deb, though it raises more questions and concerns.

PJ, Deb's tubes are drawing less that normal WE spec current.  I called the TubeDepot and all of their tubes in stock draw 1.13 amps or less.  Thoughts??

[Paul Joppa]

... all of their tubes in stock draw 1.13 amps or less.  Thoughts??

So, they don't meet their spec, do they? But it's close. When I have more voltage data, I'll have some thoughts....

The voltage variation is about half the current variation, so 1.13amps is 6% low and the voltage would be 3% high, close enough. Do the numbers, and you'll see that 1.1 to 1.3 amps is a nominally safe range - if we ignore variations in component values and build resistances in individual amps. So I am looking to learn what the build variations may be, and what the tube variations may be, before making any recommendations.

Ignoring the other variations as above, you might think you could say that a 1.3A tube will work. But you can't say a tube model with 1.3A +/-0.5A current draw will work - half of them will draw too much current.

[debk]

Without more data I wouldn't want to try the 1.3A EML.
Though the KR don't quite meet spec they sound very good.

I will try and get you voltage data next week.  My son is coming for a visit this weekend and I probably will not get to it till next week

Deb

[debk]

One other observation about the KR tubes, they are much less microphonic than the Psvane are.

Deb

[johnsonad]

I tried the TJ 300B mesh this weekend.  I enjoyed this tube in my Paramounts but it wasn't the best combo for my BeePre and speakers.  Too light weight, no body or soul.  I only gave them an hour or so but to my ears and system, the EH 300B Gold Grid have been the best sounding tube so far.