Hi guys, two new important developments, for me at least:
(a) last friday got a response from the engineer who developed my new preamp
(b) yesterday, saturday, I picked up my new custom made 5 pin-XLR cable, that allows me to run balanced into the phono preamp. Will test today, sunday, and report first impressions.
While we wait for (b), let me start by reporting the few thoughts I got from the engineer, and also comment a few things written here over the last few days.
Some additional observations from the engineer of the preamp, I try to translate as good as I can:
- people in the professional world confirmed to him that a balanced generator does not need central tapping, because this is done correctly in the “differential receiver”, in our case in the phono preamplifier. For this to work, the generator (in our case the cartridge) should not have any connection to the ground of the arm or of the turntable. He noted that this was also said by some in this forum.
- he said that with a 5pin-XLR phono cable and the AM Audio phono preamp one can compare the sound in balanced and unbalanced modes by ear
, as all one has to do is move the internal switches for both channels to “MC input balanced”.
- he asked me to report back to him my listening impressions, as he believes that it should sound better in balanced, even in an overall unbalanced system. Hey, will try today!
Now some other comments:
LPspinner wrote:most Moving Coils have an output impedance that approaches zero, so in my book considering this as an “impedance-balanced line” doesn’t seem quite right, at least not without introducing a transformer or impedance matching head amp at the cartridge end.
if the output impedance of a cartridge is the same as its internal impedance, am not sure your first assumption is correct: many MCs have high internal impedances, for example Denon 103s have about 40 Ohm internal impedance, and top end Benz cartridges too, and many others too.
bo-bo wrote:Anyway I have been thinking, and I knew five balanced stages (by heart) when I saw your remark that no five had been mentioned yet. They are:Vacuum State Electronics RTP3, Einstein "the turntables choice (Bal option)", Borbely EB 804, EAR 834P and Manley Steelhead.
Hi bo-bo, the EAR 834P is definitely NOT balanced, it has neither balanced entries nor exits. The top model EAR 88PB is also not a fully balanced model, as it has only balanced outputs, but on balanced inputs. Not even sure about the Manley Steelhead. Anyway, I think we would all agree that there are at least 5 fully balanced models on this planet by now.
lfleib wrote:Hi, I have an unbalanced phono stage that I'm quite happy with. It has a SN ratio greater than 90db with MC or MM, and can drive a power amp with a passive line stage.
My new preamp does not reach a 90db S/N ratio, and I have some sympathy for bo-bo’s reaction. How where these apparent 90db measured anyway? My new phono preamp declares a S/N ratio for MCs of 80.5 dB (weighted A, on a 0.5 mV input, closed at 0 Ohms, with the gain set on maximum), and for MMs of 86 dB (weighted A, on a 5 mV input, closed at 600 Ohms). The devil is in the detail, isn’t it?
Steerpike_jhb wrote:As Carl Sagan said: "If you REALLY want to make an apple pie from scratch, you must first create the universe".
He said a good way of saying profound things. Another one, that I think applies very much to turntable playback theory: "There are no penalties for breaking the laws of physics; the universe is just arranged in such a way that you cannot do it"
Steerpile, I remember having seen early 20th century black and white movies with pies trying to break the laws of physics for a while. But they were creamy, without apples, to increase the effects on people’s faces.
Hey, I will start reading Sagan.