Tekton Double Impacts

David_Ten 1-21-2018
I don’t see how a component can somehow ’change it’s spots’ for lack of a better phrase.

Mac48025 1-22-2018
Just to clarify the MZ sounded amazing with my Aric KT 120 amp. It was full of life, energy, speed and dynamics. For some reason when paired with Aric’s 300B it lacked all of those qualites and sounded anemic to me. Your description of anemic matched what I was trying to convey Charles. I thought it was the amp at first and was quite disappointed. Aric suggested that I connect the 300B directly to my DAC and sure enough the 300B came back to life. When Aric’s linestage arrived a few days later it sounded glorious with the 300B....

... To me it’s both a matter of a real drop off in sound and what ones preference in sound is.

While I don’t profess to having a good understanding of the novel ZOTL output circuit which provides a transformer-like impedance transformation without using an audio transformer, it wouldn’t surprise me if the MZ2 does indeed "change its spots" significantly depending on the components it is being used with, and more specifically on the signal levels it is processing and the load impedance it is driving. For example, if the KT120 amp Tom used had higher gain than his and Charles’ 300B amps the 6SN7 output tube in the MZ2 would have been operating at higher signal levels in the latter cases, conceivably resulting in adverse effects on linearity and distortion.

In any event, I suspect that Tom’s last sentence I quoted above pretty much says it all.

Also, BTW, an experiment those using the MZ2 as a preamp may wish to consider doing would be to connect a resistor of say 4 or 8 or 16 ohms, rated to handle 2 watts or more, across the MZ2’s speaker terminals for each channel. I would imagine that would result in a significantly different sonic character compared to simply loading the MZ2’s output circuit with the vastly higher input impedance of a power amp, although I wouldn’t want to speculate as to whether the resulting difference would be for the better or for the worse.

Best regards,
-- Al

P.S: I realized after the editing window closed on my post just above that Laaudionut’s amplifier is the XA60.8, while the last paragraph of my post referred to the XA60.5. However the gain, sensitivity, and maximum power specs of the two amplifiers are identical.

Best regards,
-- Al

First, kudos to Dave (Dlcockrum) for what IMO is an astute, perceptive, thorough, and exceptionally well written review he provided yesterday of his experience with David_Ten’s excellent system. And likewise with respect to the similarly well written comments provided by Laaudionut.

Regarding inline attenuators, for many and probably most applications I would suggest going with the Rothwells rather than the Harrison Labs devices. Based on measurements I recall that one of our members provided here some time ago the resistor values used in the Harrison devices are low enough to be a problem in many systems. Especially if the attenuator is driven from a tube-based component which has coupling capacitors at its outputs.

FYI, resistance measurements I’ve taken of 10 db unbalanced Rothwell attenuators that I have show that they consist of a 22K resistor in series between their input and output, and a 10K resistor in shunt between their output and ground. Therefore, depending on the input impedance of the component whose input they are connected to, the component providing the signal to them would see a load impedance in the rough vicinity of 30K or so. The corresponding numbers for the Harrison Labs attenuator are far lower.

Re the gain questions that have been discussed, first, it’s probably fair to say that among the countless amplifier models that are available gain and maximum power capability tend to have a **loose** correlation. But many examples can certainly be found of lower powered amps having higher gains than higher powered amps.

Charles, it can be calculated from the specified 0.7 volt sensitivity and 8 watt power rating of your Franks that their gain is approximately 21 db when their 8 ohm tap is used to drive an 8 ohm load. IIRC your speakers are nominally 14 ohms, and given the Frank’s output impedance of 1.8 ohms (as stated in a TAS review I’ve seen), their gain from the 8 ohm tap into 14 ohms would be close to a db more than that, or around 22 db.

Re the Pass XA60.5, like most Pass amps it has a specified gain of 26 db, which corresponds very closely to what John Atkinson measured in Stereophile’s review of that amp. Correspondingly, it has a specified sensitivity of 1.1 volts for its rated output of 60 watts into 8 ohms. However its maximum power capability into 8 ohms (after transitioning from class A to class AB) is 130 watts per JA’s measurements, which can be calculated to require an input of about 1.6 volts to be reached.

Best regards,
-- Al

@david_ten @343mps

The visible text of the link in 343's post will work, but what is hidden "underneath" the visible text, which is what the browser is directed to when the link is clicked, has two extraneous characters at the end, namely ">

After clicking on the link, if those two characters are deleted from what appears in the address bar and "enter" is then hit, the intended image will appear.

Regards,
-- Al

Detroit is known for chili dogs🙂 Coney Island style!

As someone who grew up in Coney Island I’d expect that to be quite a treat! Although my own preference in those days was for unadorned Nathan’s Famous hot dogs, at the original Nathan's restaurant :-)

Best regards,
-- Al

JCarcopo, when you use the switcher keep in mind that if a tube amp having output transformers is powered up and does not have speakers or equivalent load resistors connected to its outputs damage to the output transformers and/or output tubes can result. Especially if a signal is being provided to its inputs.

Presumably the switcher connects its unselected inputs to nothing.

Regards,
-- Al

Chris (@Waltersalas), regarding your possible purchase of a Lyngdorf, before doing so I suggest that you contact the manufacturer and ask what the input impedances of its balanced and unbalanced analog inputs are. Those numbers appear to be unspecified for the 3400, while the 2170 has no spec for its unbalanced inputs but a very low 10K figure for its balanced input. Which in turn suggests the possibility that its unbalanced input impedance **might** be only 5K, and if so it would most likely not be a good match for your Allnic H1201 phono stage (1.2K nominal output impedance), and perhaps also for your tube-based Lampizator Atlantic DAC (for which output impedance appears to be unspecified).

Best regards,
-- Al