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Old 14th July 2012, 04:11 AM   #21
disco is offline disco  Netherlands
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Evenharmonics, please stop playing childish word games as they are neither amusing nor a contribution to our hobby.
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Old 14th July 2012, 04:23 AM   #22
Pano is offline Pano  United States
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Get back to the topic. The topic is not each other, it's tubes.
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Old 15th July 2012, 06:01 AM   #23
disco is offline disco  Netherlands
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As there's no truth in audio, making assumptions based on a graphic does not say much.
So, what's the info in post #15?
- does it show the SE at clipping level ?
- what's the story about masking of higher uneven harmonics ?
- is this harmonic content identical for all SE tube amps ? Many of us try keeping harmonics (esp. 2H) down by cancellation through driver choice.
- What about the effects of feedback on the harmonic content?
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Old 15th July 2012, 12:39 PM   #24
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disco, I'll simplify things for you.
Quote:
Originally Posted by disco View Post
Sorry, there's no tube sound.
That's incorrect. Try SET amp vs PP amp.

Quote:
Originally Posted by disco View Post
As there's no truth in audio, making assumptions based on a graphic does not say much.
If you understand what to look at and have experiences with how they correlate to audible sound, you wouldn't be saying that.

Quote:
So, what's the info in post #15?
The fact that you had to ask about this confirms what I suspected.
See below.

Quote:
- does it show the SE at clipping level ?
- what's the story about masking of higher uneven harmonics ?
- is this harmonic content identical for all SE tube amps ? Many of us try keeping harmonics (esp. 2H) down by cancellation through driver choice.
- What about the effects of feedback on the harmonic content?
Post #10 and click on this --> Tube sound - Wikipedia, the free encyclopedia

The difference is subtle but it's there.
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Old 15th July 2012, 10:52 PM   #25
Pano is offline Pano  United States
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You've had one warning and that is enough. Anymore will result in sin bin time.
OT posts have been removed.
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Old 16th July 2012, 02:21 PM   #26
disco is offline disco  Netherlands
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Thank you, clear.

Why I object against the name "tube sound" is because it suggests a relation between the principal components of an amplifier (being tubes) and the existance of an audiable distortion. It's possible (and a goal to many) to make neutral sounding tube amplifiers. So, the term "tube sound" might be appropriate for your (grand-) fathers AM radio receiver suffering from limited bandwith, power sag, intermodulation distortion and the lot but is a degrading name for someones work of merit.

A graphic reproduction of distortion figures is worthless without information about the conditions under which they were derived as it would be open for several readings. Personally I want 3H down to at least 50-60dB and higher uneven possibly to -100 dB. If that would take 18 dB of global feedback and an extra voltage amplifier, so be it. On the other hand (listening for irregularties) on a 4W SE I can tolerate for a -35 dB 2H at clipping levels. No problem as it would come up once every many minutes on my 98 dB loudspeakers. Not as problematic as a too slow slew rate or blocking coupling capacitors.
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Old 16th July 2012, 03:54 PM   #27
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Quote:
Originally Posted by disco View Post
Why I object against the name "tube sound" is because it suggests a relation between the principal components of an amplifier (being tubes) and the existance of an audiable distortion. It's possible (and a goal to many) to make neutral sounding tube amplifiers. So, the term "tube sound" might be appropriate for your (grand-) fathers AM radio receiver suffering from limited bandwith, power sag, intermodulation distortion and the lot but is a degrading name for someones work of merit.
SET and PP amp have audible sound characteristics due to no feedback vs feedback design.

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A graphic reproduction of distortion figures is worthless without information about the conditions under which they were derived as it would be open for several readings.
Please reread post #15. They were all 1 W output.

Quote:
Personally I want 3H down to at least 50-60dB and higher uneven possibly to -100 dB.
I wasn't talking about someone's personal preference.

Quote:
If that would take 18 dB of global feedback and an extra voltage amplifier, so be it. On the other hand (listening for irregularties) on a 4W SE I can tolerate for a -35 dB 2H at clipping levels. No problem as it would come up once every many minutes on my 98 dB loudspeakers. Not as problematic as a too slow slew rate or blocking coupling capacitors.
I was talking about SET amp. It's doesn't use "global feedback".
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Old 16th July 2012, 06:08 PM   #28
disco is offline disco  Netherlands
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Hi, just a quick reply to clear up the air.

Wish you had stated the power output in your post, ruling out that the smallest amp was at clipping level for instance... you're familiar with the fact distortion relates to output power I presume.

I've built since 2002 over two dozen power and pre amplifiers with tubes, from OTL SE to PP. Among them are four SE with overall voltage feedback, I'm sure I'm not the only one here.
To my experience (I've built four EL84 PP, one 6L6 and two KT88 PP) the trade off for PP is in the phase splitter suffering from tube aging and other nasty things happening at higher levels. But heh, I'm not a pro -feeding my tube babies through candy laces- but who is?
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Old 16th July 2012, 07:49 PM   #29
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Quote:
Originally Posted by disco View Post
Wish you had stated the power output in your post, ruling out that the smallest amp was at clipping level for instance... you're familiar with the fact distortion relates to output power I presume.
If you are familiar with amp measurements and their sound, this much explanation from me wouldn't have been needed.

Quote:
I've built since 2002 over two dozen power and pre amplifiers with tubes, from OTL SE to PP. Among them are four SE with overall voltage feedback, I'm sure I'm not the only one here.
To my experience (I've built four EL84 PP, one 6L6 and two KT88 PP) the trade off for PP is in the phase splitter suffering from tube aging and other nasty things happening at higher levels. But heh, I'm not a pro -feeding my tube babies through candy laces- but who is?
Now that bunch of things have been clarified for you, would you rephrase your statement about "no tube sound"?
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Old 16th July 2012, 08:10 PM   #30
rdf is offline rdf  Canada
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Quote:
Originally Posted by ja2dhc View Post
Those THD's are alomost identical to 6N6 pre-amp+Booster (my original post).
Hi ja2dhc, with those solid Spice talents you might consider simulating the pre-amp feeding your amp. It's possible the even harmonics are cancelling out across part of the operating range. See here:

Cancelling Harmonics

Adding 'tube sound' to the front end could actually be reducing it at the speaker terminals.
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