Sound Quality Vs. Measurements - Page 439 - 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 17th April 2012, 04:54 AM   #4381
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by dvv View Post
Oddly enough, I was told the exact opposite.
I guess it depends on what you want.

The C-02 is a really minimalist design (Tone controls non-withstanding), folded cascode circuitry and with an MC Stepup Transformer and overall uses lower levels of global NFB.

The C-03 by comparison uses generic (and fairly low grade) Op-Amp's for the Phono Stage and Tone controls (which arguably can be bypassed), has by far more switches in the signal path and all.

But, if you only use the Input switching, volume control and line stage there is likely not a lot between the two.

Quote:
Originally Posted by dvv View Post
Any news of your power amp, Thorsten?
Currently playing with folded cascode VAS (or precisely "VAS-Less") circuitry in the Sim. A bit twitchy for DC stability, but I like the harmonic distribution better. Also have been looking at clipping recovery in the Sim.

Ciao T
  Reply With Quote
Old 17th April 2012, 04:57 AM   #4382
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by ThorstenL View Post


Currently playing with folded cascode VAS (or precisely "VAS-Less") circuitry in the Sim. A bit twitchy for DC stability, but I like the harmonic distribution better. Also have been looking at clipping recovery in the Sim.

Ciao T
A VAS-ectomy?
  Reply With Quote
Old 17th April 2012, 08:08 AM   #4383
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
The key point being that it's moving along - that's what I wanted to hear.

After much simulation, I ended up with classic cascodes at the input, the voltage being stabilizied not by the usual voltage divider, but by a double filtered (22uF/16V tantalum in parallel with 0.1 uF) zener diode. This model returned slightly better results, although the classic method with the voltage divider is said to have a better PSRR. But I reckon I make up for it by using shunt stabilized power supplies for the voltage gain stages.

I am still undecided regarding full electronic stabilization of the current gain stages. It seems there are exactly as many pros as there are cons. It will require splitting a stereo amp into two mono blocs simply because it uses up quite a bit of space. The alternative would be using either one massive (1,000+ VA) toroid, with separate secondaries for each channel, or two separate smaller toroids (500+ VA) for a complete dual mono. Decisions, decisions, ...

As for switches and knobs, don't let it fool you - most of the switches are related to electronically switched inputs, selection of 1 or 2, etc. Of the rest, it has the more or less usual four switches for stereo/L+R (which I consider as essential for properly adjusting balance), loudness, tone in/out and subsonic filter. The two on the extreme right deal with phono type and load and the Rec Out selection, meaning that as far as I am concerned, they may as well not even be there, but thankfully, both have an OFF position - which is where they will stay.

Re: Luxman preamp. What's done is done, there's no turning back. I will have to refresh the preamp, and to do that I'll need its service schematic. I'm hunting for one right now. I can always use that opportunity to beef it up a bit, both using better components and larger capacitors, perhaps exchanging a few critical resistors, things like that. I can't really know until I see its schematic.

All I can say for sure at this point is that its two 3,300/50V uF caps in the power supply will grow in capacity. I have a reasonable stock of both Fischer & Tausche and Panasonic power supply caps, but if I can alway eschew them for something better still. I'm not shy in that way.

Last edited by dvv; 17th April 2012 at 08:13 AM.
  Reply With Quote
Old 17th April 2012, 08:41 AM   #4384
gk7 is offline gk7
diyAudio Member
 
Join Date: Oct 2007
Location: Vienna, Austria
Quote:
Originally Posted by dvv View Post
...I'll need its service schematic. ...
Service manual exeeds the permitted upload size of the forum, I can mail it if you want.
  Reply With Quote
Old 17th April 2012, 08:43 AM   #4385
gk7 is offline gk7
diyAudio Member
 
Join Date: Oct 2007
Location: Vienna, Austria
Easier than mail:
http://www.hal9000.at/tmp/Luxman-C02.pdf
  Reply With Quote
Old 17th April 2012, 01:02 PM   #4386
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
Quote:
Originally Posted by gk7 View Post
Many thanks for your goodwill, but this is for model C-02, and I have C-03, the newer model.

Any luck with that?
  Reply With Quote
Old 17th April 2012, 01:29 PM   #4387
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Dejan,

Quote:
Originally Posted by dvv View Post
Many thanks for your goodwill, but this is for model C-02, and I have C-03, the newer model.

Any luck with that?
Any of the sites that shall not be mentioned here have it...

Link is in a PM.

Ciao T
  Reply With Quote
Old 17th April 2012, 01:37 PM   #4388
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by dvv View Post
The key point being that it's moving along - that's what I wanted to hear.
Not necessarily along, but moving, possibly more sideways or circular, who knows, maybe even funicular...

Quote:
Originally Posted by dvv View Post
I am still undecided regarding full electronic stabilization of the current gain stages. It seems there are exactly as many pros as there are cons. It will require splitting a stereo amp into two mono blocs simply because it uses up quite a bit of space.
Try my way, CLC...

Quote:
Originally Posted by dvv View Post
As for switches and knobs, don't let it fool you
I'm not fooled. I looked at the actual switches in the direct signal circuit, that is how many contacts must be traversed... The C-03 is much worse than the C-02 which I already consider to have "way too many"...

Ciao T
  Reply With Quote
Old 17th April 2012, 02:09 PM   #4389
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
Quote:
Originally Posted by ThorstenL View Post
Hi,



Not necessarily along, but moving, possibly more sideways or circular, who knows, maybe even funicular...



Try my way, CLC...



I'm not fooled. I looked at the actual switches in the direct signal circuit, that is how many contacts must be traversed... The C-03 is much worse than the C-02 which I already consider to have "way too many"...

Ciao T
Amp: Eppur si muove.

CLC: Don't mind if I do. Any ideas? I have a LOT of Fischer&Tausche 10,000 uF/63V and 4,7oo uF/63V caps ....

Switches: Well, thank God I am not the purist you are. I accept my fate stoically.
  Reply With Quote
Old 17th April 2012, 03:06 PM   #4390
Account disabled at member's request
 
Join Date: May 2006
Quote:
Originally Posted by dvv View Post

And I'm still a small timer, Dan d'Agostino uses 118 of them altogether in the voltage gain stages.

I played a lot with the design, trying out different transistors and circuits, and I discovered that using 3 MPSA92/42 trannies reduces high frequency distortion to an extent, nothing spectacular, but it's there. And, being the Motorola/ON Semi affictionado, I just happen (by sheer chance, of course) to have about a suitcase full of them, so matching them is reduced to coffee sipping, cigar puffing, music listening nicely spent time of manual labor.
Is this three trannies in parralel ?? Maybe to replace for higher Ic part ??? Is this in real measured performance or simmed ?? Krell has used this before for the purpose too, but in their case they were looking at near medium levels of Ic I havent counted but in one of their amps they probably used over a 100 of them (six or seven in parallel).
  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 01:02 AM
Sound Card for Measurements Marik Solid State 2 2nd January 2012 09:59 PM
Sound Card Recommendations (For Audio Measurements) dchisholm Equipment & Tools 5 16th July 2011 10:40 AM
How to protect sound card during amp measurements? okapi Everything Else 13 2nd September 2008 04:06 PM
Sound cards - test and measurements jackinnj Everything Else 2 5th July 2003 04:02 PM


New To Site? Need Help?

All times are GMT. The time now is 05:58 AM.


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