The interesting Luxman stage - Page 5 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 23rd May 2002, 12:15 AM   #41
Account Disabled
 
Join Date: May 2002
Default hi till

by active components i meant individual transistors.....a single op-amp may contain up to twenty times the number of transistors in the signal path than the average discrete device power amp.
  Reply With Quote
Old 23rd May 2002, 12:27 AM   #42
Banned
 
Join Date: Apr 2002
Location: Germany, Clausthal
mikek:

Ok, most times this statement is true. But: i tried to build a chain with the less parts as possible, erery channel has except powersupplys now about 4 transistors. I don´t know how much transistors are used in my TDA 1305 DAC, but as i read in DIYOPAMP.PDF from NP, a typical Opamp could be build out of 4 transistors. You see, mostly there will be much more parts in the CDP than in the rest of the chain, but it isn´t necessarily that way. I´ll build another DAC next time, to get rid of some active devices at that place...
  Reply With Quote
Old 23rd May 2002, 02:38 AM   #43
Banned
 
Join Date: Feb 2002
Location: Dallas,Texas
Smile example of pointless misuse of components

Why do I do this.......? The current source feed provides greater rejection of supply noise for the zener since it does not have a zero ohm impedance. This is a common circuit and can measurably increase the rejection of supply noise by the current source. This is not an"example of pointless misuse of components" any more than your post would be called a pointless misuse of this forum.

H.H.
  Reply With Quote
Old 23rd May 2002, 09:17 AM   #44
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Hi, everyone!

The discussion about the specific circuit is totally of track. Maybe I will start a thread about audio gear philosophy.

I think Nelson Pass forgot to divide the DIY's into two groups: those who materialize (is there such a word in english? in swedish we have "materialsera") other ideas and those who materializes their own. Some ideas on the net aren't that good but I think Mr. Pass' ideas are cool, especially the lamp amp!

Since we are of track I would clearify my point of view:

Don't forget to listen to the music!

It's fun to test different gear but some differencies are small, hardly noticable and also not very important in order to enjoy the music.

My attitude is, it's fun to design but I don't need the performance. There are two halves of me, the designing process and the using of the gear.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 23rd May 2002, 11:51 AM   #45
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
"The feedback loop is the coolest thing about this amp. You can use a small film cap and still use low value feeback resistors so as not to run into input capacitance problems with the diff pair feedback input. I have used this several times and I love it." The Sumo Model 9 circa 1980 used this design too. Bongiorno used a 0.1µF cap with a 10M in parallel in the feedback loop. The FET inputs on the 9 had a stated input impedance of 10^12 ohms so the input off-set current was quite low even with the 10M resistor.
"I got very interested in these japanese design with a special stage which connects the diff input stage with the output. Could anyone explain a little bit more of the benefits of this weird connection? " The Lang amplifier in Audio Amateur 2/86 used this technique. The circuit board is still available
http://www.audioxpress.com/bksprods/pcbs/solidstate.htm
The 2/86 article cites a JAES reference that I remember reading, but can't remember the author/date off-hand. The JAES article has a lot of distortion graphs showing the improved performance of this topology.
  Reply With Quote
Old 23rd May 2002, 12:08 PM   #46
Banned
 
Join Date: Apr 2002
Location: Germany, Clausthal
peranders:

You wrote a posting i can agree with fully. Very good comment.

Start this pholosophy thread.

We should keep in mind that Mr Pass has not only ideas which are really worth to use time for understand them, her also seems to be a very tolerant human beeing.

Another point is, Mr Haller writes in a style that is formal provocative, but the content of his postings are often worth reading. We just should overlook the style, maybe the style of speech is correlated with his location, wasn´t his President from the same location, from Texas too?

Theyer socialisation maybe is very different from a european one, but i think he is a "friendly cowboy", he reads the "********" we greenhorns write, and uses his time to write comments. Thats ok.

(PS, if we talk wine, in mr. passes country Mr. Robert Mondavi produces a quite good but expensive Cabernet Sauvignon, my favorite is a same quality Lagrein from Südtirol / Italy made by Joseph Brigl for half the money)
  Reply With Quote
Old 23rd May 2002, 12:18 PM   #47
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
The JAES article you're talking about, can it be the one about error correction?

The AudioXpress link tells me nothing more than there are pcb's available. Somebody who can fill in for me?
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 23rd May 2002, 12:51 PM   #48
Account Disabled
 
Join Date: May 2002
Default pointless misuse....

Hi harryhaller,

on the contrary, the current source whose reference is biased by yet another current diode is suboptimal with respect to supply rail rejection, (which includes rf on the rails), precisely because its rejection immunity decreases with increasing frequency, due to the parasitic inter-electrode capacitances of the jfet current diode.

a much better way is to use two resistors, R1,R2,(see attached), in place of the current diode, and decouple their intersection to the supply rail.......supply immunity now increases with frequency and at less cost....a time constant, (T=C*R2), of the order of two seconds is sufficient.

connecting the capacitor directly across the zener is again sub-optimal, as a comensurately larger component would be required for the same time constant.

on a separate issue....many audiophiles are carefull not to define precisely what is meant in practical terms by the 'simpler is better' concept....the overall lack of consistency boggles the mind......for instance, cascodes seem to fall in and out of favour like autumn leaves, (see recent threads on subject
).
Attached Files
File Type: zip ccs2.zip (4.2 KB, 98 views)
  Reply With Quote
Old 23rd May 2002, 12:55 PM   #49
Account Disabled
 
Join Date: May 2002
Talking hi till...

please do'nt mix our very own knowledgeble harryhaller with george bush.....the latter is inarticulate,incoherent, and generally posseses a lamentable lack of grasp of anything of significance...including his own mother tongue....hhahaha
  Reply With Quote
Old 23rd May 2002, 01:00 PM   #50
Account Disabled
 
Join Date: May 2002
Default hi djk

i think you'll find the connection you've reffered to is infact due to peter blomley....article in wireless world..

i should'nt be too impressed with the japanese disign though....the critical balance of collector current in the double-ended diff. stages, essential for cancellation of even order artifacts), is disrupted by p-n, and jfet diodes which seem to syphon off an imprecisely quantified amount of current from the diff. stages.

Moreover the topology develops a double zero, rapidly followed by a treble(!), pole in its transfer function, all within an octave of the transition frequency.....a recipe for gross instability....these appear not to have been compensated for in the designs?
  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
luxman a-377 jobmeel Swap Meet 0 11th February 2008 07:22 PM
interesting amp & interesting problem m6tt Tubes / Valves 9 14th August 2007 06:28 PM
Interesting output stage idea keantoken Solid State 18 15th November 2006 11:41 PM
Interesting challenge:GU 50 output stage! Le Basseur Tubes / Valves 10 15th October 2004 07:04 AM


New To Site? Need Help?

All times are GMT. The time now is 06:59 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright İ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2