909 Posted September 13, 2007 Report Share Posted September 13, 2007 what's involved in biasing the es-1 properly? the es-1 had a few biasing turning dials that needed some fine finessing and i think he used an electric reading gauge of some sort. others amps i've seen you just flip a switch, but that might not be the same exact thing. Quote Link to comment Share on other sites More sharing options...
n_maher Posted September 13, 2007 Report Share Posted September 13, 2007 electric reading gauge Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted September 13, 2007 Report Share Posted September 13, 2007 You have to adjust the dc output voltage for each of the 4 output tubes. Absolutely no difference between that and a he90 or aristaeus. My all tube amp uses self bias instead, and requires no output bias adjustment. Although there is a phase adjustment that is set basically once for the life of the amplifier. The blue hawaii has dc feedback, and for a range of different tubes the adjustment needs little to no adjustment. Quote Link to comment Share on other sites More sharing options...
909 Posted September 13, 2007 Report Share Posted September 13, 2007 cough, i meant multimeter, cough Quote Link to comment Share on other sites More sharing options...
909 Posted September 13, 2007 Report Share Posted September 13, 2007 You have to adjust the dc output voltage for each of the 4 output tubes. Absolutely no difference between that and a he90 or aristaeus. My all tube amp uses self bias instead, and requires no output bias adjustment. Although there is a phase adjustment that is set basically once for the life of the amplifier. The blue hawaii has dc feedback, and for a range of different tubes the adjustment needs little to no adjustment. self bias and no to little adjustment seems the ideal implementation. is there any reason or benefit to the one that requires user adjustment? Quote Link to comment Share on other sites More sharing options...
Dusty Chalk Posted September 13, 2007 Report Share Posted September 13, 2007 self bias and no to little adjustment seems the ideal implementation. is there any reason or benefit to the one that requires user adjustment? Some manufacturers believe in autobias (or "selfbias") circuits , some don't, it's really as simple as that -- you'd have to poll those manufacturers to see why they do it one way or the other. For examples, I know AudioValve are really proud of their autobias circuits, and I know the Manley Stingray is a really simple design with manual bias. On the one hand, it increases the cost of the amp (compared to the same amp with manual bias), and increases the complexity of the design by some amount (I don't know if this is small or not, but I suspect it is); on the other, a bias pot is really simple. I have no idea how it affects the sound, as I've never heard similar amps, one with autobias, the other with manual bias. Quote Link to comment Share on other sites More sharing options...
Icarium Posted September 13, 2007 Report Share Posted September 13, 2007 He has an easy bias option which basically greatly simplifies the process. I saw it on Neil's es-2. I think its somewhere like 300-800 dollars I forget exactly I'd have to look at the spread sheet again. But basically you hold down down a button which corresponds to a tube and then hit + - to lower that # to 0 which equals biased. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted September 13, 2007 Report Share Posted September 13, 2007 He has an easy bias option which basically greatly simplifies the process. I saw it on Neil's es-2. I think its somewhere like 300-800 dollars I forget exactly I'd have to look at the spread sheet again. But basically you hold down down a button which corresponds to a tube and then hit + - to lower that # to 0 which equals biased. If he went that far for the easy bias, i don't see any reason why he did not finish the job, and have a little single chip micro do the job automatically every 30 minutes, when there is a between the track silence. Servo bias with a 1 minute time constant is way easier and cheaper. Quote Link to comment Share on other sites More sharing options...
Icarium Posted September 13, 2007 Report Share Posted September 13, 2007 Unknown! Quote Link to comment Share on other sites More sharing options...
philodox Posted September 13, 2007 Report Share Posted September 13, 2007 Did you get the optional rivets option? I hear it keeps 909 from your amp like nobodys business. Quote Link to comment Share on other sites More sharing options...
909 Posted September 13, 2007 Report Share Posted September 13, 2007 that's the surprise wtf option at no additional cost post it and it becomes public domain where everyone is entitled to share opinions. Quote Link to comment Share on other sites More sharing options...
Elephas Posted September 14, 2007 Author Report Share Posted September 14, 2007 I've been looking at some "Fluke" brand multimeters. They're expensive! And it seems I would have to learn how to use it and actually do some math calculations, yuck. I will ask Mikhail if any extra "anti-909" defensive measures are available. \ I found an interesting article about tube amplifier bias adjustments: http://www.mesaboogie.com/US/Smith/biasadjust.html Quote Link to comment Share on other sites More sharing options...
n_maher Posted September 14, 2007 Report Share Posted September 14, 2007 I've been looking at some "Fluke" brand multimeters. They're expensive! And it seems I would have to learn how to use it and actually do some math calculations, yuck. You don't need a Fluke, or anything particularly special actually. You should easily be able to find a serviceable meter for $50 or so. Quote Link to comment Share on other sites More sharing options...
n_maher Posted September 14, 2007 Report Share Posted September 14, 2007 i really like my Fluke, though. Me too, but I've got two other meters that also perform just fine for basic functions. I'm guessing that all you're doing during the bias adjustment is measuring voltage, which just about any meter should be able to do with enough accuracy to get the job done. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted September 14, 2007 Report Share Posted September 14, 2007 I use my 7 digit agilent. Got to get it right down into the microvolts for best sound Quote Link to comment Share on other sites More sharing options...
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