Sound Quality Vs. Measurements - Page 286 - diyAudio
Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 27th February 2012, 03:15 PM   #2851
diyAudio Member
 
Join Date: Sep 2004
Location: UK
Quote:
Originally Posted by dvv View Post
From my school yard, I could just barely see Watchet. And, across the Bristol Channel, Swansea.

But if you want something really impressive, do go see Ilfracombe. It sits on top of a gigantic boulder, very surreal. When I was there, there were dark storm clouds gathering, which made it even more surreal.
For 10 years in the 80's our family went every year to the summer school at Taunton School. I led a walking group across every which-way of the Quantocks, from the Black Hills to the Blue Ball.

I have just googled the summer school - all gone
  Reply With Quote
Old 27th February 2012, 03:19 PM   #2852
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by dvv View Post
There is no other singular semiconductor manufacturer in the world who has anything like Motorola's 40+ years of experience in power transistors.
I know one. It is called Motoshiba.
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers. -- Plato, 447-367 BCE
  Reply With Quote
Old 27th February 2012, 03:32 PM   #2853
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by Wavebourn View Post
I know one. It is called Motoshiba.
Are you sure they are not called Toshirola?

Ciao T
  Reply With Quote
Old 27th February 2012, 04:05 PM   #2854
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
Quote:
Originally Posted by cliffforrest View Post
For 10 years in the 80's our family went every year to the summer school at Taunton School. I led a walking group across every which-way of the Quantocks, from the Black Hills to the Blue Ball.

I have just googled the summer school - all gone
So is my old school - from 1692, but it's gone now.

All that's left is a forum of ex-students.
  Reply With Quote
Old 27th February 2012, 04:44 PM   #2855
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by ThorstenL View Post
Hi,



Are you sure they are not called Toshirola?
No, I am not sure.
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers. -- Plato, 447-367 BCE
  Reply With Quote
Old 27th February 2012, 06:01 PM   #2856
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Ah yes I remember that cross-licensing with Moto and Tosh. I actually did advise on a discrete power amp and initially wanted the slightly larger devices (3281 etc.) but the Chinese manufacturer pleaded for the next size down. As I was attempting to make incremental changes to a not-entirely-excremental design, so as to not wholly alienate said manufacturer, I didn't do a complete tearup. The design already had complementary bipolar pairs at the input. I think I enhanced the second stages, used "better" output devices, but otherwise did not implement a whole host of ideas I might have considered.

The overall product, a home theater system, was a critical success and a complete flop commercially, owing much to the stupidly poor AV preamp/DVD player sourced from a famously terrible vendor (can you say 41% defects in initial shipments?), but also due to the economic collapse. Either people had money for a 99 dollar Whizzio, or >50k for a full-fledged room. But at the ~6k price "point" as they say, there were few customers. The system included, besides the bad apple piece, a 5.1 channel amp system in the subwoofer, a motorized screen with LCR speakers, a top-line LCD projector for ceiling mounting flanked with rear channel speakers, a universal remote that communicated through a receiver/controller in the screen. The sub electronics cried out for a good DSP-based programmable EQ, but at that point it represented too much of a sea change for the managers, and instead there were five switch-selectable complex EQs for different positions of the screen relative to the wall and ceiling, all done in the analog domain with a sea of modified state-variable biquads. The boards are something to behold.

Oh well, it paid the bills for a while.

As far as high end semantics, I guess my definition is do the best you know how to do. To say simply to "do the best" might presume one knows all and sees all, and I make no such claims. Indeed I am undergoing a huge shift and cascading series of revelations that are quite bracing and challenging. I read part two of the Rees pieces last night and thanked myself for my background in philosophy I can understand SY's impatience with it. But there is something going on, and I don't want to risk violating the Geneva conventions by airing some of the woolier things that could be considered.

Oh these smilies. Who thinks of this stuff?

The first product I'm considering is "yet another" phono preamp, which will employ among other things synthetic "cooled" terminations as at least an option for the cartridge damping resistor, done in a somewhat new way. There's little advantage with MC cartridges with very low inductance, but substantial noise reduction for highish inductance ones. I'd also like to provide variable input capacitance loading, including negative capacitance, very high overload margins with however the option of a very clean symmetrical clipping function, to prevent downstream overload. Fully balanced might be an option, despite the ~fourfold increase in silicon area (or other device proliferation!) for the same noise performance, and despite the very few tonearms etc. that are wired for balanced operation.

Just some thoughts. Actually I've been working on aspects of this for some years now. How the time flies.
  Reply With Quote
Old 27th February 2012, 06:22 PM   #2857
a.wayne is offline a.wayne  United States
diyAudio Member
 
a.wayne's Avatar
 
Join Date: May 2008
Location: Front Row Center
Sounds good Brad, just one question, what's a phono pre-amp ..... ? synthetic "cooled" terminations...
  Reply With Quote
Old 27th February 2012, 06:40 PM   #2858
jcx is offline jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
Self describes it in his Small Signal Audio Design book - his example phono preamp app only gave 1.5 dB noise improvement

basically you use a quiet input op amp and a higher value resistor, with a fixed negative feedback loop gain reducing the effective value of the big R seen by the cart
  Reply With Quote
Old 27th February 2012, 06:46 PM   #2859
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by a.wayne View Post
Sounds good Brad, just one question, what's a phono pre-amp ..... ? synthetic "cooled" terminations...
Synthetic terminations (or more generally synthetic impedances), which "look" like an impedance with a resistive component but have less than a physical resistor's thermal noise over a limited (but usefully large) bandwidth, go way back.

Someone pointed me to a possibly-earliest reference in van der Ziel's classic book from 1954, simply titled Noise. The reference was to a considerably earlier article by Percival in Wireless Engineering, Vol. 16, 237, 1939, which was followed up with a scholarly paper with a whole bunch of other stuff in Physica by Strutt and van der Ziel (Vol. 9, 513, 1942). Oliver mentions impedances with less-than-thermal noise over a restricted bandwidth in his IRE tutorial paper Thermal and Quantum Noise. I saw it first in the Arbel book I like a lot, Analog Signal Processing, and his discussion is of its application to nuclear science instrumentation by the great instrumentation guy at Brookhaven, Veljko Radeka. Pease mentioned it in a column some years ago, and recently Self included the notion along with his particular realization for cartridge loading in his Small Signal Design (along with a remark that he doesn't like the "cooled" part --- but this is the "standard" terminology among the Nuc Sci brethren).

Brad
  Reply With Quote
Old 27th February 2012, 06:52 PM   #2860
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by jcx View Post
Self describes it in his Small Signal Audio Design book - his example phono preamp app only gave 1.5 dB noise improvement

basically you use a quiet input op amp and a higher value resistor, with a fixed negative feedback loop gain reducing the effective value of the big R seen by the cart
Thanks jcx. When applied to some high L low R cartridges that like to see 47k, done right it can yield a substantial improvement. Of course it will be argued that surface noise spoils all of this as soon as the needle is in the groove. But I still think, as does Self, that's it's worth doing. If one is going "all out". Self's particular example in the book is also woefully suboptimal. Good book though, although like much of his writing he's light on historical references. But filling those in is a whole lot of work.

Brad

Last edited by bcarso; 27th February 2012 at 06:54 PM. Reason: afterthought
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Quality Control differences = variations in sound quality? KT Class D 3 4th June 2014 12:02 AM
Sound Card for Measurements Marik Solid State 2 2nd January 2012 08:59 PM
Sound Card Recommendations (For Audio Measurements) dchisholm Equipment & Tools 5 16th July 2011 09:40 AM
How to protect sound card during amp measurements? okapi Everything Else 13 2nd September 2008 03:06 PM
Sound cards - test and measurements jackinnj Everything Else 2 5th July 2003 03:02 PM


New To Site? Need Help?

All times are GMT. The time now is 09:50 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2