jitae55

Thanks esmit, yes, trying again is about all I can do, although I have now made four attempts using three different sd cards. I also (successfully) made a backup copy of v2.8, just in case. Cheers.

Thanks for the data point, esmit - so, perhaps something other than CPU version as a cause. I had also considered whether the v2.9 image I received may have been at issue - e.g. revisions within the version.

Thanks Jesus, I suspected this might be the case, however no CPU version limitation is listed when purchasing the 2.9 SD card for the microRendu, so I wondered if there may be another cause...

Hi All, On installing the v2.9 sd card there was zero response from my MicroRendu (CPU Name: i.MX6DL, rev 1.3) at power on - no ethernet port led flashing, nothing. I reinstalled my v2.8 card, (works fine) and contacted SGC, who promptly emailed me a copy of the SO v2.9 image, allowing me to burn a copy to an sd locally using Balena Etcher. I wrote the image to a brand new 32GB Samsung Evo plus UHS-1 card, however the microRendu failed per previously - no ethernet port led activity at all. Ditto with a Sandisk card. Reinstalled v2.8 and all is well. I purchased my microRendu directly from Sonore in 2016, so it's definitely an older unit - but as stated, it runs fine on v2.8. I'm wondering if anyone here has had a similar experience and might be able to point me in the right direction. Cheers

re https://www.neutrik.com/en/product/na2m-d0b-tx Note the specifications: Audio transformer 1:1 Impedance ratio: 200:200 Source/load impedance in Ohm: 200/2k, (600/10k) Max. Input level (@ 50 Hz, 1% THD): -3 dBu Transformer saturation at -3dBu - ? potential for significant distortion on transients and heavy bass unless fed low level signal. re atomicbob @ https://www.superbestaudiofriends.org/index.php?threads/wtb-jensen-isomax-pc-2xr.7336/page-2#post-241640

Hi Corvo, re the drop in mains voltage, I presume it is the power company (U.E.) finally responding to my complaint (November 2017!) re the voltage being too high - although I have not received notification of this. I still intend to build the DC blocking circuit (parts finally arrived) - I've read elsewhere that blocking mains DC may be of sonic benefit even in the absence of overt transformer buzz.

Hi all, Just a little feedback. Transformer buzz from my Vidar has dropped to being barely audible with my ear to the chassis. This is not due to any action on my part - however mains voltage has dropped from 246-259 volts to a consistently lower 238-244 volts. This effect would be consistent with transformer saturation at the higher voltage as a cause of the buzz. Maybe someone from U.E. reads C.A.. I don't think I can blame Schiit for U.E.'s poor spec. - although I would be interested to know the max mains voltage Schiit would typically design for. So, back to music - Anesthetize; soaring, dynamic, driving; wish I could drum like that. Cheers

Hello Corvo, I'm also a new member - joined specifically to respond to your post. Your experience with Saga/Vidar sounds similar to my own. Having not had problems with hum or buzz previously (the Schiit duo replaced an aging NAD 7020 receiver), I went through the exercise of changing speaker cable (Supra Classic 4 to zip cord), interconnects (Apature to geric) and power outlets to no avail - and so emailed Schiit for guidance (Jason replied directly). Saga and Vidar were returned to the local distributor for testing. In their listening room the system was totally silent - no hum, no transformer buzz (over the review period anyway...) Other issues such as popping noises (on switching inputs on Saga or muting with Saga in active mode) were also absent. Checking out my domestic power outlets with a simple AVO meter indicated local AC voltages tended to be rather high, fluctuating between 240-259 volts. My local supply company (U.E.) were not inclined to do anything about this (a discussion for another time...). A little research brought up an article by Ben Duncan (a name well known to "older" HiFi News readers), who discusses this issue in the context of transformer specification and problems that may arise due to differences in mains power frequency and voltages across the world (see https://www.soundonsound.com/techniques/identifying-solving-mains-supply-problems ). Worth a read. Having noted the hum coming through the speakers did not necessarily coincide with a cycle of transformer buzzing (i.e. ? ground loop), I found hum through the speakers largely disappeared on lifting the mains ground for either Saga or Vidar. (Changing cables, cable orientation and amplifier orientation and spacing had little to no effect...) Not happy to leave either ungrounded, and since there is nothing like the Hum X available for the Australian market, I built a ground loop isolator per Rod Elliot's article ( http://sound.whsites.net/earthing.htm ). Not only did this resolve the hum through the speakers, but Vidar ran very much cooler. Vidar transformer buzz, however, remains - sometimes totally absent, other times so loud and distracting I just have to switch the system off. I have found I can modulate the buzz by placing my hand on the chassis - or reduce the level of buzz significantly by lifting the front of Vidar off the supporting surface. While I'm tempted to adjust the tension of the transformer mounting bolts and check chassis clearance (warranty?), I believe the variance and cycling of the transformer noise tends to point more toward an electronic issue - perhaps external to the amp. While the transformer issues mentioned in Ben Duncan's article are a possibility, the presence of DC on the mains supply can also cause transformers (particularly toroidals - but also other designs) to buzz. Mains power DC blocking circuitry is evident in power amplifiers produced by a number of manufacturers (e.g. Bryston, LAMM) and a number of individuals and smaller companies are producing "after market" boards and boxes (Google "mains DC blocker"). As far as I can tell from Schiit's photographs, Vidar may not have such mains DC blocking circuitry - and I thought this may be worth investigating. Again, Rod Elliot has written on this subject - not only from the point of investigating the issue, but also with a view to clarifying misunderstandings re such circuits in the DIY community (see: http://sound.whsites.net/articles/xfmr-dc.htm ), and I am currently putting together a circuit per (the much copied by others) Figure 8 from this paper. This is dangerous stuff - electrocution and exploding electrolytic capacitors are real possibilities if you don't know what you are doing. I am NOT encouraging anyone else to build such circuits. Having said that, I have hopes - I would be sad to see Vidar go (great bass!). Cheers