BIAS QUESTION - HERBERT RETUBE

  • Thread starter Thread starter jelyfinger
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jelyfinger

jelyfinger

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Hello all,
I am doing my first retube on my Herbie which has all Ruby EL34's and have a question on setting the Bias points.
I am retubing Herbie with a matched quad of SED Winged C EL34's which all have a Bias Point of "38". I am also revalving 2&5 with SED "Winged C" 6L6GC which have a Bias Point of 17. I have read everywhere that I should set the bias points on each pair at 60-70ma which is the sum of each pairs bias point. The SED EL34's based on the individual bias points of "38" would be "76" correct? And since the bias point is 76, should I only bias to 70 as stated? Also, the 6L6's having a bias point of "17" each would have a bias point of "34" for the pair correct? That seems extremely low when the site states 6L6's should be biased at 60-70ma as well. Can someone clarify this for me?

Thanks in advance guys! ;)
 
Well, thanks to Uwe for answering my question! Wow...what an incredible difference! My cleans are even more percussive with a piano like chime and sustain for days. I absolutely LOVE the 2 6L6's with the EL34's. Not near as dark...by the way, I also installed a 12AX7 Telefunken NOS Diamond Bottom in V1. My Herbie is like a different animal. :thumbsup: Cheers!
 
Oh, by the way....hats off & special thanks to Peter for having the foresight to design an amp with external bias! :worship: I never realized how valuable that feature was until I retubed & biased my Herbie today! It was a breeze...Thanks Peter!
 
Telefunken NOS Diamond Bottom in V1
Click to expand...

YIKES! How much was that, was it the frame grid one, the ones I've seen go for about 4-600 dollars.
 
Ahh, wasn't a frame grid then, oh well, I was wanting some clips if it was.
 
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