As HollowState, I also use Clarostat pots (2W).
Those are industrial grade, sealed and offer a great adjustment sensibility. They can be locked also.
Out of curiosity, if you are looking for reliability and longevity, why don't you go KT120?
At a KT88 bias level, or even more those bottle will last you a very long time.
My 2 cents.
Those are industrial grade, sealed and offer a great adjustment sensibility. They can be locked also.
Out of curiosity, if you are looking for reliability and longevity, why don't you go KT120?
At a KT88 bias level, or even more those bottle will last you a very long time.
My 2 cents.
I also tried those:
http://www.mouser.com/ProductDetail...6xssCiY2DepxL1ZtUDZm4uqoDQBMTcvgg1u6C7dOoPQ==
Not bad but not as precised as the Clarostat. They turn too easily.
http://www.mouser.com/ProductDetail...6xssCiY2DepxL1ZtUDZm4uqoDQBMTcvgg1u6C7dOoPQ==
Not bad but not as precised as the Clarostat. They turn too easily.
Hey Mission720. You could try this: 10K Ohm 3590S-2-103L Rotary Wirewound Precision Potentiometer Pot 10 Turns | eBay
They're cheap enough to "try and see"
Cheers.
They're cheap enough to "try and see"
Cheers.
Safe grid bias adjustment as suggested rather than a 'loose' slider. One of our veteran members (forget who) suggested connecting the slider directly to the negative end of the pot, thus making it a variable resistor only. (In that case some recalculation will be necessary; a separate resistor in series on the negative end etc.)
The spec. for the highest value grid return resistor is supposed to be a 'safe' value, thus including worst case tubes. Thus an increased value often works, but at the peril of tube selection. It does of course include all of the resistance mbetween G1-cathode; in this case not overly in excess.
(OT, some history: I remember the days when the first Leak Stereo Twenty amplifiers saw light with all of 820K grid resistors for EL84s, spec then having been < 1meg. They soon had to recall the lot because of tube run-away, and the EL84 spec later changed to 470K maximum for cathode bias.)
The spec. for the highest value grid return resistor is supposed to be a 'safe' value, thus including worst case tubes. Thus an increased value often works, but at the peril of tube selection. It does of course include all of the resistance mbetween G1-cathode; in this case not overly in excess.
(OT, some history: I remember the days when the first Leak Stereo Twenty amplifiers saw light with all of 820K grid resistors for EL84s, spec then having been < 1meg. They soon had to recall the lot because of tube run-away, and the EL84 spec later changed to 470K maximum for cathode bias.)
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.