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Old 15th November 2012, 09:33 AM   #11
Merlinb is offline Merlinb  United Kingdom
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Quote:
Originally Posted by DF96 View Post
Better to have valves and circuits which add nothing. 'Personality' is fine in a guitar amp but undesirable in a music reproduction system.
Then why use valves at all? A transistor amp will have less colour at a fraction of the cost...
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Old 15th November 2012, 09:55 AM   #12
SY is offline SY  United States
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Why drive a '57 T-Bird? A new Honda will get you to the same place at a fraction of the cost.
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Old 15th November 2012, 09:58 AM   #13
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Hi!

You should select the input tube based on the requirements it has to full fill in terms of gain and driver capability. This heavily depends on the overall circuit. I agree with previous posters about 12AX7 or similar not beeing the best suited to drive an output tube.

Lower rp tubes unfortunately often have too low mu. I found the 6N7 (both halves paralleled) a good compromise. Considerable gain at reasonably low rp for small output tubes

Best regards

Thomas
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Old 15th November 2012, 10:06 AM   #14
DF96 is offline DF96  England
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Quote:
Originally Posted by MerlinB
Then why use valves at all?
In my case it is a combination of nostalgia, and finding that my attempt at designing and making a solid-state power amp failed due to both output oscillation and loop oscillation. Used properly, valves can do as good a job as SS - in the sense that the music is not noticeably damaged.

I have little sympathy for those who strain for 0.001% THD using SS, or for those who seem happy with 10% THD using valves. Both seem to miss the point.
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Old 15th November 2012, 11:06 AM   #15
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My main reason for me wanting a single ended amp is because I once owned a Fatman 182, though it proved unreliable in the end, the sound was superb. Even my wife enjoyed it, she said it was like listening to a favourite cd for the first time. It had KT88 output valves and I think 6NP1 triodes. I want something that will sound as good but using a readily available triode here in the UK.
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Old 15th November 2012, 11:27 AM   #16
Merlinb is offline Merlinb  United Kingdom
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Quote:
Originally Posted by SY View Post
Why drive a '57 T-Bird? A new Honda will get you to the same place at a fraction of the cost.
Actually that supports my argument, rather than countering it.
If absolute fidelity is your goal (e.g., a fast efficient car), why use valves (e.g., T-Bird)? Answer: fidelity has surprisingly little to do with enjoyment...
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Old 15th November 2012, 11:33 AM   #17
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Go for one octal pretube per channel.

That gives you the option to play with 2-stage/parallel/1-stage+CF without having to hacksaw the chassi.

For the rest you need first to decide on what you need, mostly depending on your speakers and listening habits.
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Old 15th November 2012, 11:38 AM   #18
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Quote:
Originally Posted by Merlinb View Post
Actually that supports my argument, rather than countering it.
If absolute fidelity is your goal (e.g., a fast efficient car), why use valves (e.g., T-Bird)? Answer: fidelity has surprisingly little to do with enjoyment...
I converted the ferrari to model T in my setup by resistor loading the mosfets .

4P1L driver and resistor loaded mosfets for output.

Makes any other tube amp look like energyclass A+ .
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Old 16th November 2012, 03:13 AM   #19
Bigun is offline Bigun  Canada
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Quote:
Originally Posted by DavesNotHere View Post
just build an amp to where they have both sockets and a/b it.
+1
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Old 16th November 2012, 03:22 AM   #20
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Quote:
Originally Posted by Merlinb View Post
Actually that supports my argument, rather than countering it.
If absolute fidelity is your goal (e.g., a fast efficient car), why use valves (e.g., T-Bird)? Answer: fidelity has surprisingly little to do with enjoyment...
When going to absolute fidelity I prefer to combine tubes with SS devices.

Such marriage produces the best results.
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