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Old 10th October 2011, 02:50 AM   #3681
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Quote:
Originally Posted by Bassivus View Post
My first tube project.

12B4A Preamp fully dual mono

More pics here: https://picasaweb.google.com/1078196...eat=directlink
Nice job! I like the woodwork.
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Old 10th October 2011, 03:33 AM   #3682
56oval is offline 56oval  Australia
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Quote:
Originally Posted by rvrazvan View Post
And here is my First project . Under construction.
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Great first project ,are you building as pre as well .

There are some great looking very professional work being done in the DIY community .

CHeers
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Old 10th October 2011, 06:43 AM   #3683
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Quote:
Originally Posted by Bassivus View Post
My first tube project.

12B4A Preamp fully dual mono

More pics here: https://picasaweb.google.com/1078196...eat=directlink
Truely beautiful.
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Old 10th October 2011, 08:24 AM   #3684
Stixx is offline Stixx  Germany
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@ quadtech, mhouston, Bassivus:
Thank you...Hvala vam mnogo!

Bassivus: Excellent woodwork! What kind of wood is that?

Last edited by Stixx; 10th October 2011 at 08:27 AM.
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Old 10th October 2011, 11:58 AM   #3685
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Quote:
Originally Posted by Bassivus View Post
My first tube project.

12B4A Preamp fully dual mono

More pics here: https://picasaweb.google.com/1078196...eat=directlink
Your final schematic please.
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Old 10th October 2011, 04:11 PM   #3686
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Quote:
Originally Posted by Stixx View Post
@ quadtech, mhouston, Bassivus:
Thank you...Hvala vam mnogo!

Bassivus: Excellent woodwork! What kind of wood is that?
Its a maple for violin back I got it as the present from a friend who is a Luthier, as well as a special pigments I stained it with
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Last edited by Bassivus; 10th October 2011 at 04:14 PM. Reason: Spelling
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Old 10th October 2011, 11:24 PM   #3687
AJT is offline AJT  Philippines
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finally.....

input tube is a 12BY7, ltp drivers are paralleled 12BH7's, this is a non-global negative feedback amplifier, the KT88's are run as triodes so that the resulting low plate resistance from parallel operation negates the need for global negative feedback.....

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biasing at -47v power consumption was:
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backing down a bit to -50volts yeilded this power consumption and seemed to be stable, no drifting was noticed and the tubes were surprisingly within 2mA of each other....
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setup psu and amplifier block combo for a listening test:
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Old 11th October 2011, 01:53 AM   #3688
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Tony; how many watts do you expect out of it?
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Old 11th October 2011, 04:27 AM   #3689
AJT is offline AJT  Philippines
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Quote:
Originally Posted by mhouston View Post
Tony; how many watts do you expect out of it?

i did not measure, but 75watts into 8ohms i guess......

i did not spend anything on this project, an audiophile friend came to me with an old amp to gut down and a lot of new parts and asked what can be done...of course everything was his idea, i merely did as i was told.....

the only limit imposed was that we use the old irons as these were stripped M6 goss irons....

that is why i decided to go the triode route.....

the output KT88's are not stressed imho so we expect them to last long...
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Old 11th October 2011, 04:53 AM   #3690
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Single end? Why so many caps?
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