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In Reply to: RE: Do tube preamps add or take away dynamics posted by airtime on June 08, 2017 at 14:31:42
Think in terms of avoiding info. loss.
Passive control centers exhibit inherently high O/P impedance and poor drive capability. LOW capacitance (read short and unshielded) cabling to the power amp(s) is essential. Notice the lack of flexibility. Also, a pentode voltage gain block at the power amp(s) I/P(s) is helpful, as it allows a high I/P impedance, without adverse CMiller interaction.
An active control center, with or without voltage gain, typically has a lowish to low O/P impedance and decent or better drive capability. Flexibility is present, but "colorations", bandwidth limitations ... may be negatives.
All legitimate options are compromises. Each 'phile decides which way to "jump". We are dealing with yet another perfection is the enemy of the very good situation. A "perfect" solution simply doesn't exist.
Since I like a single point volume control, and the stuff I build is waaaaay too heavy to put onto a stereo chassis, the pre is a useful thing. Gain is a good thing, and since I tri-amp with an active cross over, I like to have one with balanced outputs. It is a matter of of how this is done that can make or break a system.
I tend towards low output Z designs with enough drive to let me ignore silly cables. Just in case it has not been contemplated, the EL84 is a fine signal tube...:)
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
That was perhaps the best explanation of passives vs buffer vs traditional preamp usage I've read. Simple (for the non engineer) and non bias.
I like my CJ preamp very much. It doesn't seem to limit the bandwidth or add coloration to the sound. That is one transparent preamp.
However I was always fond of fooling around with passives. Never had much luck with them and I always came back to the more traditional preamp. Now at least I know why.
Maybe one day when I get REAL bored I'll build that Pass DIY buffer. Again it was only a fun project and not intended to replace anything.
The Mind has No Firewall~ U.S. Army War College.
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