Eiclone Fixed Bias specs

a DIY, modified Mullard 5-20 monoblock design

Eiclone Fixed Bias specs

Postby justinsweber » Sat Oct 11, 2014 3:24 pm

Im wiring up a fixed bais Eiclone that I plan to use KT88/6500.
The Manual indicates ~ 55ma per tube 550MVs per tube. Was this for the KT88 or EL34s listed int he manual?
Ive seen in other posts that some use 600mv per tube.

So whats the best bias setting?
The Dynaco circuit in the MKIII shows much more distoration if the 6550 is run lower than 70ma.

Given that 30w is ~ 72% of the 42w max for a KT-88 is 600mv/60ma the best choice?
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Re: Eiclone Fixed Bias specs

Postby Shannon Parks » Mon Oct 13, 2014 2:30 pm

justinsweber wrote:Im wiring up a fixed bais Eiclone that I plan to use KT88/6500.
The Manual indicates ~ 55ma per tube 550MVs per tube. Was this for the KT88 or EL34s listed int he manual?
Ive seen in other posts that some use 600mv per tube.

So whats the best bias setting?
The Dynaco circuit in the MKIII shows much more distoration if the 6550 is run lower than 70ma.

Given that 30w is ~ 72% of the 42w max for a KT-88 is 600mv/60ma the best choice?


Justin, I probably set my power tubes to 75% dissipation @ idle. Of course always be monitoring your B+ sag with a new transformer design to make sure your dissipation calc is correct.

For comparison, some current tube amp manufacturers use around 65% and I think a lot of classic tube gear was around 80%.

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