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In the Forum: Audio Discussions
In the Thread: 250 watts Parallel S.E. advises
Post Subject: 250 watts Parallel S.E. advisesPosted by devo_yan on: 5/16/2018
Hello every body, I live in France and I'm new on this forum.

I'm thinking to build (some months) a mono big Single Ended amplifier (200-300 watts) made with triodes (IDHT or DHT doesn't matter for me) for outdoor professional audio.

Have you got an online store to advise to me for custom output transformers and power transformers ? (I have to admit that I'm more looking for cheap price than high grade =s)

On internet I found "toroidy" that seem to be good.

After many thinking, for final stage I think to use
- 10 parallele 845 (psvane) running at something like 1000V (24 watts per tube in A1). (any other advise ?)
- 2 or 3 845 for driver (running at 1000V too (choke and capacitor coupled))
- 1* 300B (choke and capacitor coupled )for to drive the driver stage (with it's own power supply (400V))
- 1* 6J5 (half 6SN7) (or 6sn7GT with both triodes in parralele) carbon resistors/capacitor coupled to drive the 300B (they will share the same power supply than the 300B)

both power supply with
- center tappered tranformer and full wave tube rectified (5Z3 for 400V, 836 for >1000V)
- LCLC filtered (no solid state regulated)

Every tubes will be self bias and without negative feedback.

How much can I expect it weight ? 100Kg ? More ?
Any advise welcome = )))


I often read that S.E. are not good for to properly drive big basses speakers, do you know why ?

I mean why for example a 300B S.E. could produce wonderfull basses when driving a 5" basic sealed speaker and can't properly drive bigger speaker ? Is it because of the poor damping factor ? (I mean the speakers drive more the amp than the amp drive the speakers ^^)

If yes how to increase it ? Someone told me that I need very high current (like plenty 6c33 in parralele or solid state). But why ? with the output transformer the speaker should already see low impedance, right ?

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