herbert bias which is right?

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crabby

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what is the proper bias the back of the amp says 65ma and ive read about other values else where,like in the manual? which is it?
 
i was told 6l6's sound good in herbert, i have el34 rubys in it now
so if 6l6 ... ma or el34 ... ma
 
I'd suggest to use the values from the official tech page: http://diezelamplification.com/tech-corner.3.0.html

65mA is about right in middle of what is suggested. There is no right or wrong and your ear decides if you like a colder of hotter bias best. So any setting between 60mA and 70mA for EL34 or 6L6 will work, all a matter of taste.
 
I do understand what you're saying and of course I have the older (non-external bias points) so I would of course multiply by 2, and that is indeed what I did.

So, using my amp and the Weber Bias Calculator, I come up with the following ranges:

EL34-
52mA - 60mA (Diezel site gives 60-70mA)

6L6-
62ma - 74mA (Diezel site gives 60-70mA)

this is the confusion I was referring to. Now I did subtract 10% - is this correct for my older style Herbert, or should I not have done that? I am not sure if I should be doing that or not, based upon how I measure (I removed the fuse and measured inside the chassis as the website describes). Am I measuring cathode current or not, is my question, I guess
 
I think I have confused you.

I didn't use any type of bias rite device. I just removed the 3 fuses inside, hooked up my DMM, and adjusted the bias control until i got to my desired bias setting, keeping in mind that I'm working with tube pairs, not individual tubes.

So i'm still not clear if using this method means I should subtract the 10% or not, to derive my proper bias range. Does that make sense?
 
:D

I'm sorry.

Follow the suggestions pairwise (thats what you read). 60-70mA for EL34s. Don't add or substract anything. You are reading the plate current, the value which Peter suggests.
 
No worries at all! I really appreciate the fact that you're trying to help ;)

I guess we're on the same page now, but based upon my situation then, I come up with the following values:

EL34-
58ma - 68mA
6L6-
68mA - 82mA

which still differ from Peter's recommendations. This is where I am confused. I should have my new tubes in a few days, and just want to be sure that I make the correct settings.
 
I've edited a bit - not to confuse more people :)

58-68 is cool. 2mA more or less . . . start with 60, listen, try 65 - then decide, I personally like the colder side, it sounds good and doesn't stress the tubes. If you are looking for something warmer, use the higher side . . .

6L6GTs is a different story though. Peter recommends values lower than the tube manufacturer. It is his experience what they really can handle (I will discuss that with him). Just follow Diezels suggestions - knowing that 70mA for 6L6GTs (say you use Svetlana 6L6, which are known to be strong) is still on the colder side. With Svet 6L6 I'd start with 70mA.
 
You're the best, man. Thank you so very much for all your time.

These are the ones that doug at Doug's Tubes decided most closely represented what I had in my Herbert initially. Do you have any experience with these by any chance? They are Ruby 6L6GCM-STRs, and they look like this:

ruby6l6.jpg
 
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