• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Worlds Best Preamp

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#42
@Kuei
Give it a try, but make sure to NOT skimp on parts quality and to keep the attenuator AFTER the linestage.
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Can you explain me better than the article why to keep the attenuator after the linestage?
Until now I have seen circuits with the attenuator before the linestage.And this to keep the impedance at the input of the amp constant. 😕
 
#43
SY said:
Well, if you have speakers/amps that don't distort asymmetrically, the chances are you won't hear a difference anyway.
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Well actually, I don't think that's quite correct.

IF (big if) you had speakers without asymmetrical distortion, you'd have a better chance of hearing *only* the effects of the source (what comes before the speakers).

On the other hand, IF your speakers do have (and 99.999% of all dynamic drivers DO) have asymmetrical distortion you've got a random situation where the sum or difference effect of the absolute phase of the recording may or may not be euphonic and/or cancelling... and will vary depending on the absolute phase of your playback.

That presupposes as was mentioned earlier that any care whatseover was taken to make the recording itself free of antiphase relationships between microphones - or anti polarity relationships between microphones. (the former referring to absolute phase - although the actual phase relationship between any two mics is important in terms of what gets captured on a stereo recording)

One recording I can suggest for your consideration in terms of absolute phase/polarity is Mickey Hart's Planet Drum. IF and only IF ur system is pretty darn flat, has a really good clean impulse response and your playback gear is also suitably good you may hear some surprising differences in the "mix" when you flip abolute phase (polarity). It's sort of like seeing the mix as having a back and front center, and what is somewhat in back comes to the front, and vice versa as the polarity is flipped. Not a huge effect, but reproduceable and definitely interesting. Try it on the first track.

😀

_-_-bear :Pawprint:
 
#45
Konnichiwa,

resident said:
Can you explain me better than the article why to keep the attenuator after the linestage?
Click to expand...

Because that is how Arthur Loesch designed it and how it sounds best.

resident said:
Until now I have seen circuits with the attenuator before the linestage.And this to keep the impedance at the input of the amp constant. 😕
Click to expand...

But does the Amplifier particulary requires or benefits from a constant impedance (short answer - some do, very few however make much of an issue out of this).

Sayonara
 
#46
Frank,

I don't think you're pulling my leg at all. I'm just saying that those types of semis are optimised for something else other than what you using them for. That they work well for you is great! Damper diodes are pretty common over here perhaps I'll pick up a handful and give them a try... I just don't expect any real difference over using high speed diodes.

Mark
 
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