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Balancing Act Tube Rolling - Page 20

post #286 of 455
Originally Posted by setamp View Post

To get to 5v, I am turning the control knob to its maximum.  I seem to be getting some variability there as I warmed up the amp for 45 minutes, turned it all the way up which got me barely to 5v then checked it 5 minutes later to be 5.25 v.  Is this indicative of a tube issue - if so, which tube(s)?  Or is it a function of variability in my mains voltage? 

I noticed my meter dips below the zero mark when turned off.  Should it be exactly at zero?  If so, do I set it using the slotted plastic head at the base of t

It could be static electricity that is preventing the meter from going to zero. I have it happen to one my tube tester until the static electricity has been discharged. The screw is the mechanical zero for the meter. You only need to adjust it one time if the amp has been move or shipped from another location.  

post #287 of 455
Thread Starter 

If you run your fingers across the glass/perspex the needle will usually move if it's static.

post #288 of 455

I spoke with Craig.  He felt the needle had shifted in shipment.  It was a simple matter to reset it zero using the slotted screw on the dial. I no longer have to bury the pot to get to 5v.   The variability he felt is due to changed resistance as the tubes warm. 

I love this amp!

post #289 of 455
Would there be any advantage whatsoever to switch to a pair of NOS Mullard 6x4 rectifiers over the ones that came stock?
post #290 of 455

Craig has said no-to-negligible , but if you have a pair you may as well swap them out and let us know your findings.

post #291 of 455
Thread Starter 

setamp has stated:




I am a bit surprised at the difference the rectifiers make in the ECBA.  I can hear a bigger difference in the 6X4 than in many of the 6SN7's I have rolled.




from http://www.head-fi.org/t/479031/6sn7-tube-addicts/3540 post#3452

post #292 of 455

I have no experience with the Mullard tubes but I hesitated in rolling the rectifiers as I had heard there was little to be gained.  Fortunately, I did try other rectifiers and have found them to make in my rig a significant difference. 

post #293 of 455
Thread Starter 

It's a very interesting result actually.


I haven't rolled any rectifiers yet so I can't comment.

post #294 of 455
post #295 of 455

With EC 2A3 the rectifier certainly does make a big difference; with Mullard (Philips Holland in my case) I am getting a different sound signature to say a Sovtek, I thought with EC BA's double regulation this effect would be lessened. 

post #296 of 455
I have tried the nos mullard6x4 and it softened and warmed the sound a little. I switched to some nos tungsol which I thought gave better detail and space.
post #297 of 455


These worked best for me.  My other tubes are Sophia Royal Princess 300b and , NU 68FG

post #298 of 455

Just bought two! Fingers crossed! Thanks for the link. $10 cheaper per tube than flea bay.

post #299 of 455

Got my Genalex 6X4WAs today, and I'm pretty happy with them. I wasn't expecting to hear much of an improvement, if any, but there is a noticeable improvement. How much of an improvement is highly subjective, but to my ears instrument separation shows a marked improvement and perceived soundstage seems to have expanded a touch. Vocal tone also sound more natural to me than stock. I'm still listening to the tracks I'm most familiar with to see what else I pick up on, but I'm quite pleased.


I would definitely give these a try if you're already content with your output/driver selection and are just looking for that last 5-10% (again, subjective). For me, it was definitely worth the $84 investment. Thanks to setamp for the recommendation.


I swapped the stock GE 6X4s back and forth a few times, but these suckers get hot! I called it a day, left the Genalex in, and can't complain.


Edit: For reference, I'm using KR PX-4s with a Mullard ECC32 driver.

Edited by GMF2010 - 6/8/13 at 3:30pm
post #300 of 455

I'm glad they worked for you! 

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