Fresh build - ef86 36watt 'thing'

Double-Bubble! Place for discussing the 36W version...

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leslie
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Fresh build - ef86 36watt 'thing'

Post by leslie »

Lots of times Phil and Co. told me that I should build some 36W and finally I did it. It was fun!
What a mighty amp, thanks for warning me!
I have double voltage choice at mains HT 290-275-0-275-290V and at 290V output plates were bit high at 347V but screens were ok at 325V. I tried 275V winding and sound was even better, now is 332V@ anodes and 324 at screens. Power electrolitycs resistors and screen resistors are done like TMB36W in downloads section. Classic 18watt doubled output section and PI. I've done layout ala Brownnote foxy18
I will build one more soon as I catch some time but with some Merlin or clubman ideas to push ef86 with ecc83. I don't have any microphonic problems but we'll see how it goes... I had 173V on anode ef86 and 117V volts on screen with higher HT, now it's even lower about 15V down.
Of course, I winded OT, its complex winding in Partridge/Hiwatt style 50watter, 3.7K

CLIP http://www.youtube.com/watch?v=HQZwXOQy58U in the clip is single 12" G12H30 anniversary 75Hz

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Post by guitar-rocker »

Super clean work Leslie, Congrats on your build!! Looks very nice!
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katopan
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Post by katopan »

Dude, great looking and as usual sounds great too. Different flavour to the 12AX7 preamp, isn't it.
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leslie
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Post by leslie »

Thanks guitar-rocker!

katopan-Yes definately different flavour, I'm in love :D
surely this thing feels different than new ef86 Voxes that came in for service. Next experiment will be low gain ef86 stage pushed with ecc83, it would be nice to retain ef86 harmonics and get rid of it's overly sensitivity, if it's possible. CLIP http://www.youtube.com/watch?v=D0Snhd0nqNs
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katopan
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Post by katopan »

Is your EF86 set up the same as the Vox or have you got different values in there? Mine is the same as an AC15 (even though I've always meant to get back in there and play around). It still sounds very different to the Vox because of how it interacts with the Marshall back end.
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leslie
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Post by leslie »

vox/marshall marriage sounds just perfect to my ears. EF86- a little different, i have about 160V on the anode and about 100V on the screen (still gain is high as you can hear in video) no audible microphony when maxed but its mechanicaly sensitive when I gently tap on it. I have military RFT lot dated '68 so i guess it's tube design but i'll try to go down more, adjust the knee and give it some push with ecc83 in another project.
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leslie
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Post by leslie »

Hey guys, long time no hear.
Here is one more 36W/ef86. this one sports OT with Woden/Drake interlaving pattern. A little fun onstage we had last week, hope you'll enjoy clips and pics.
Cheers to small but powerfull community!

http://www.youtube.com/watch?v=3Brb-3wmj9c

http://www.youtube.com/watch?v=YBykR5Qu0-k

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