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In the Forum: Melquiades Amplifier
In the Thread: Valve Preamplifier for Macondo/DSET
Post Subject: Very interesting, how does it Sound?Posted by Romy the Cat on: 8/5/2020
Hm you are true in the “terra incognita” territory as far as I concern. The preamps are mystery to me. All my attempts to make any decently sounding preamp or even buffer failed. To me Placette was truly God sent and if I got burned that I am looking with fear what will I do.
The idea to make a tube-based preamp is noble one and 10Y is a very good tube. The 30R before the autoformer is good and if you are able to drive it lover with autoformer them it is wonderful, even I am not so comfortable with the ideas of autoformers. The changing preamp output impedance is very bad for the Milquades as each preamp output impedance will change the setting of the input filters. However, if your impedance slides under a few Ohms then it might have no auditable impact at all. You can calculate how your moving output impedance impacts your amp filters. I do not care about the fact that it moves a few Hz up or down. I am care about phase. If you time aligned two channels and move volume of your preamp, then will the changing the preamp output impedance result the channels juts out of alignment? They certainly will BUT the it is possible since the impedance number are so low the timing error will be very much within the margin of errors of your time alignment.
I do not have the answer if the changing of the Rout would be prohibitive in this situation. What I would like you to consider is that in 10 years you will find your DPoLS and then you might realize that your playback can maintain the DPoLS only with let sat 30% of your volume and then the phase micro-shifts kick the system out of DPoLS. I do not mean to “scare” you, juts present you an architectural concept.
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