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Old 29th December 2011, 01:23 AM   #681
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Quote:
Originally Posted by flatheadmurre View Post
Higher B+- is on the list for next version including a bigger chassi.

Specs say 250 is ok for dissipation over 30w.

I have some industrial stepdown toroids 400-240 run it backwards some nice chokes and the recipe says +-250.

Fixed bias is cheating .
Why fixed bias is cheating ? You will shorten the life of the output tubes with high dissipation , ( like 30W or over ) trying to get more power , you are "cheating " the amp by doing that , and its better to make it with another way . BTW no one tell us what is the output impedance of the amp ? I know its high but how ?
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Old 29th December 2011, 01:43 AM   #682
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Quote:
Originally Posted by Dimitris AR View Post
Why fixed bias is cheating ? You will shorten the life of the output tubes with high dissipation , ( like 30W or over ) trying to get more power , you are "cheating " the amp by doing that , and its better to make it with another way . BTW no one tell us what is the output impedance of the amp ? I know its high but how ?
Just a joke

Fixed is the common way.

This has been an experiment in different aproaches of OTL.

Ive now been running it:

Katod bias ~5w

Mozener bias ~10w

Fixed bias ~20w

Mixed bias ~14w

The appealing with non fixed bias is the plug and play concept.
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Old 29th December 2011, 10:56 PM   #683
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Quote:
Originally Posted by flatheadmurre View Post
Just a joke

Fixed is the common way.

This has been an experiment in different aproaches of OTL.

Ive now been running it:

Katod bias ~5w

Mozener bias ~10w

Fixed bias ~20w

Mixed bias ~14w

The appealing with non fixed bias is the plug and play concept.
Its ok with the joke , as for the amp sorry but I don't get it right , how much power you get now and what is the dissipation power for the output tubes ? , and what kind of bias you use now ? .
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Old 29th December 2011, 11:09 PM   #684
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Im back to katodbias but with a mosfet assisted zener for the moment.

Gives me ~10w no adjusting needed.

Amp was giving best THD at 45w disipation but now im down to 30w not wanting to make bigger hole in the ozonlayer .
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Old 29th December 2011, 11:39 PM   #685
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Nice , 10 watts is quite good , you are runing the 6C33c in the half of its maximum power , something similar with me, I am runing the PL36 at 5.5 W ( each one ) when max power dissip. is 13W . I suggest to use the 6SN7 as PI / driver and parallel the two sections , this will give you a good driver for your amp .
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Old 29th December 2011, 11:58 PM   #686
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I agree on the 6sn7 for PI its on the to do list.

I modified my PSU added a couple of small chokes and some more C.

I Have 7 huge 6800uF RIFA Elyts i want to use but they just dont fit the chassi.

I think its time to assemble and enjoy.

And start planning for the next one
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Old 30th December 2011, 12:06 AM   #687
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How much capacitance for each rail now ? . And what is the next plan ?
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Old 30th December 2011, 12:26 AM   #688
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7x680uF+680 between + and -

I have a box of E130L another of PL36 and a 9pin surprice.
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Old 30th December 2011, 12:33 AM   #689
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E130L I think its similar to EL136 , it would be so nice in an new OTL amp !! .
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Old 30th December 2011, 12:39 AM   #690
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E130L I think its similar to EL136 , it would be so nice in an new OTL amp !! .
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