diyAudio (
-   Tubes / Valves (
-   -   SE design using 10k OPTs (

roundel325 19th May 2004 05:05 PM

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...


Bryan 19th May 2004 05:18 PM

Hey Jared,

IIRC, a pair of 10K OPT's would work nicely with the 845:D

rafalc 19th May 2004 05:40 PM

Would go great with VT-25 or 801 but very low power around 1W

Sch3mat1c 19th May 2004 07:23 PM

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.


elctrifrier 15th June 2004 10:23 PM

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?

Eli Duttman 16th June 2004 04:47 AM

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.

planet10 16th June 2004 06:30 AM

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.


dhaen 16th June 2004 07:52 AM

You need to establish how much standing current (DC) they can take.

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

All times are GMT. The time now is 10:04 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 18.75%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio