rb2013
Author of The 6922 Tube Review
- Joined
- Apr 12, 2013
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Hi Pakultra and thanks for the very interesting advice.
Clearly i am not really serious in my approach for different reasons. Just to start i have no scope to see what is going on in a circuit.
I am just peeping inside famous units of great sound hoping to learn something. A schematic would be much helpful for this.
The parts you have selected i guess are the best available. As you say it is difficult to foresee if they will have any impact on sound.
Maybe it is trivial but for a me a great unit starts with a great power supply.
And in low signal units suppression of all kind of noise (mains noise, diodes noise, EMI/RFI noise) is fundamental.
But again your approach to kill the noise after the transformer is equally good.
A scope more than a ear could show the situation. A scope is much more sensitive than a human ear.
Where will you buy these parts from ? i like the Shaffner filters very much. I could skip on the transformer replacement and try one of these filters.
Maybe the outcome would be even better ?
Just as a reference this is a very good dac from Schiit Audio ... actually their new TOTL dac said to have an exceptional sound.
http://schiit.com/public/upload/general/imagecache_thumbnail_product_gallery_large/yggdrasil_pcb_1000.jpg
Looking at its power supply can give important hints about how a PS for digital euipment must be designed.
A very strong chain clerly cannot have weak links. If all the dac is extremely good the PS must also be very good indeed.
Anyway also dealing with the PS noise at regulators level could work perfectly the same (actually even better ... maybe i am overrating this PS issue).
So my idea is that the same parts (with the right ratings of course) put in a cheaper unit could give some benefits.
For the best units that provide the best sound possible the parts selected can be the best available. Cost is less of a constraint and top sound is the goal.
You see ? no toroidals ... attention to mains filtering and rectifying diodes ... chokes ...
Do you have some pics of your modified U12 ? how are you placing the new PS ?
I would think to a new box for sure. Something bigger with the space for everything inside. The U12 box is already quite full of parts.
Thanks again, gino
Or you could just run one of these right before the U12 or MXU8 - I have and the results are excellent and reversible. And relativly cheap. The Pro version with the Advanced Power Filtering should not be confused with the non-Pro version which will do line by line EMI/RFI filtering.
The Advanced Power Filtering uses both Common Mode and Differential Mode filters, in addition to the EMI/RFI filters.
From Blue Circle on Common Mode Rejection on their excellent and expensive $2,200 BC60X1:
The balanced power outlets offer another advantage. First of all, not only do they share all the filtering of the other outlets, there is alsosome additional filtering on the secondary of the transformer. Another advantage to using balanced power is a phenomenon calledcommon-mode rejection or CMR. This can best be explained visually so refer to the figure below.When the center-tap on the secondary is tied to ground as in the figure above, any noise on one side of the grounded center tap is180˚ out of phase with the noise on the other side. This means that the noise on either side of the center tap will cancel out. Thisadds another level of filtering to these outlets. It also prevents any noise being generated by one component (such as clock noisefrom a DAC) from leaking into the power supply of another component connected to the conditioner. This offers a great advantage tocomponents that are processing very low-level signals, like phonostages
ART PB4x4Pro Power Distribution System with Advanced Power Filtering:
All PRO SERIES models have an additional internal discrete module called APF (Advanced Power Filtering) which filters out digital and dimmer hash as well as any high frequency noise that is above the audio range. Some off-the-shelf add-on modules saturate and lose their filtering effectiveness as the load increases, but by using a high power discrete design we were able to create a filter that stays effective over the full operating range.
By using both Common Mode and Differential Mode topologies in series for the filter design we are able to block virtually all of the unwanted noise that is between the AC line and ground, and also the two sides of the AC line. This has the additional benefit of reducing ground loop problems in your system. High frequency noise currents in particular are highly attenuated in both directions so that any line noise that could be generated by one of your components is not allowed to get back into your main A.C. wiring so if you use a number of PRO SERIES Power Conditioners in your setup, you can distribute and isolate the noisy components from the sensitive components in your system. Additionally, any signals above 10kHz are filtered from the line with over 40dB of attenuation above 100kHz and beyond.
Every PRO SERIES power conditioner is designed with a power capacity of 1800 Watts, surge/spike protection, APF with EMI & RFI filtering, front-mounted unswitched power outlet and an adjustable rear-mounted gooseneck light source for bright illumination behind the rack. The spacing and alignment of the rear outlets to accommodate various size power plugs and AC adapters.
Features:
Not bad for $85
- APF - Advanced Power Filtering
- Power Capacity of 1800 Watts
- Surge & Spike Protection
- EMI & RFI Filtering
- 8 Rear Outlets with Power Adapter Friendly Positioning
- One Front-mounted Unswitched Power Outlet
Non-pro version of the PB 4X4 with EMI/RFI at the AC and between each AC block ($49) - which the Pro version has in addition to the APS: