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SE design using 10k OPTs
SE design using 10k OPTs
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Old 19th May 2004, 04:05 PM   #1
roundel325 is offline roundel325  United States
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Question SE design using 10k OPTs

I've got a pair of 10K OPTs with 4 and 8 ohm secondaries. I also have a pair of 6l6GCs, with a mess of preamp tubes around. My question is, how can I put these OPTs to use? I think maybe I can run the 6l6s in triode w/ like 350 B+ and get a few watts while staying under their 30w dissapation. Data sheet says in pentode mode I should expect 10-15% distortion with a 4k load. That seems like alot. Will a greater load increase or decrease distortion. Maybe some NFB, but how much? Good idea?

It seems like most designs call for a 5k load or less. Is their some other tube that is happy driving a 10k load? I think maybe I should just build it and find out... What do y'all think?

Wow, this post has an abundance of question marks dosen't it...

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Old 19th May 2004, 04:18 PM   #2
Bryan is offline Bryan  United States
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Hey Jared,

IIRC, a pair of 10K OPT's would work nicely with the 845
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Old 19th May 2004, 04:40 PM   #3
rafalc is offline rafalc  Hong Kong
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Would go great with VT-25 or 801 but very low power around 1W
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Old 19th May 2004, 06:23 PM   #4
Sch3mat1c is offline Sch3mat1c  United States
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One 12AU7 with both sections in parallel?

Problem is you'll need a really, really high voltage to get any power output. No matter what you do.

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Old 15th June 2004, 09:23 PM   #5
elctrifrier is offline elctrifrier  Luxembourg
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10K to 4 and 8 ohms - ok, that is 50 and 35 to 1 turns ratio, which could be translated as 5K to 4 and 2 ohms, but you need to know how many watts they can handle - how big are they?
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Old 16th June 2004, 03:47 AM   #6
Eli Duttman is offline Eli Duttman  United States
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Consider taking a page out of the DECWARE SE84's book. Triode strapping the 6L6s with 100 Ohm resistors will be FINE. You will end up with about 5 BALLSY W. Distortion will be LOW and the damping factor will be HIGH for a SET amp.

A pair of true mid 90s efficient 4 Ohm speakers connected to the 8 Ohm taps might give you a pleasant surprise. 2 Ohm Parker 95s/98s connected to the 4 Ohm taps could be excellent.
Eli D.
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Old 16th June 2004, 05:30 AM   #7
planet10 is online now planet10  Canada
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SE design using 10k OPTs
How big are the OPTs?

10K is often used with EL84, EL95, ECL82, ECL86, ECC80.

It would have to be a substantial OPT for 845s.

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Old 16th June 2004, 06:52 AM   #8
dhaen is offline dhaen  Europe
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You need to establish how much standing current (DC) they can take.

IMO pentodes need fedback to sound reasonable. Triodes are best without.
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