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In the Forum: Audio Discussions
In the Thread: Passive transformer based preamp
Post Subject: Re: Better among worst?Posted by Thorsten on: 11/4/2005
Hi,
 morricab wrote: |
| the unit I tried (the Sonic Euphoria passive) did not live up to my hopes. |
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Given my somewhat loose but existing ties with S&B and with Music First Audio I need to be careful what I am saying. But let me suggest that just winding some wire around a steel core does not make a good transformer. The unit you tried is very cheap, by comparison. There are reasons.
Given that you very much got the same sound, regardless of having the active preamp in line or not suggests quite clearly that you simply used a device with poor quality transformers.
| morricab wrote: |
| 1) Loss of dynamic contrast. I am sure you are aware of this problem. It should not have been such a problem on my system with a 100kOhm input impedance but there it was. This lack of contrast gave the sound a bland sameness that quickly became boring. |
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Steel core transformers without DC bias sound like that. What did you expect? Ever heard a PP Valve Amp? The reasons are in the magnetic core materials behaviour and obvious.
| morricab wrote: |
| 2) Loss of drive to the sound. This I blame on problems in the low frequencies. With time-coherent speakers (pair of Stax ELS F81s) it was easy to hear the bass was now lagging behind the rest of the music spectrum. I think there must be a phase shift occurring to result in such behavior. |
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You are probably right about the phaseshift, it is a direct result of not having enough primary inductance.
| morricab wrote: |
| However, it occurred to me that anyone who is using a non-time coherent speaker (especially a vented system with a high order and thus high phase shift in the bass) might not be as sensitive to these problems. |
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I use timecoherent speakers.
| morricab wrote: |
| Another amazing sounding amp and preamp that I heard recently is from a German company called Einstein. |
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I am quite familar with their stuff. I found it okay but unremarkable sounding. It also had that "stressed out" (strained) sound I have heard from every single OTL that came my way to some degree. You always get the feeling that there is a lot of hard work going on to keep things on track.
The least offending OTL Amp's in that sense where Atmasphere.
| morricab wrote: |
| Their 6C33C based OTL amps called "The Final Cut" are loosely based on a circlotron theme but the details are not forthcoming from the company except to say that it is a new variation. |
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It is not much of a variation. It is a pretty straightforward Circlotron with a lot of extra claims.
| morricab wrote: |
| The preamp called simply "The Tube" is fully differential and interestingly has no input selector switch in the signal path. It simply activates the filament and heater of the input tube to whichever channel was selected. |
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Yes. And to make up for all that effort they fit a generic Alps "High End" pot as volume control and they use it in the mode that demonstrably causes a lot of non-linearity with that particular device and brand.
I suspect that if you find Einstein "amazing sounding" you are listening for something in music reproduction that I personally pay little attention to and you ignore the things that bother me. Well, different strokes for different blokes.
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