Single Power ES-1 configuration

[909]

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.

[n_maher]

electric reading gauge

[kevin gilmore]

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.

[909]

cough, i meant multimeter, cough

[909]

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?

[Dusty Chalk]

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.

[Icarium]

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.

[kevin gilmore]

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.

[Icarium]

Unknown!

[philodox]

Did you get the optional rivets option? I hear it keeps 909 from your amp like nobodys business.

[909]

that's the surprise wtf option at no additional cost

post it and it becomes public domain where everyone is entitled to share opinions.

[Elephas]

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

[n_maher]

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.

[n_maher]

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.

[kevin gilmore]

I use my 7 digit agilent. Got to get it right down into the microvolts for best sound