Sound Quality Vs. Measurements - Page 253 - 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 16th February 2012, 07:31 PM   #2521
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
I could not get to trigger or see anything that looked like ringing after the cutoff. Just random noise.
  Reply With Quote
Old 16th February 2012, 07:40 PM   #2522
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: cambridge ma
Quote:
Originally Posted by ThorstenL View Post
Scott,



What I find interesting in that are a few things.

First numbers are thrown around without any reference level and context.

Without being specific about SPL's involved, frequencies etc. the number alone is meaningless.

Second, instead of a sensible fair use quote something totally different is said instead:


What must be realised is that the adjustment referred to is not a 2nd harmonic adder, but rather adjusts the overall distortion profile of the Amplifier, plus it even affects overall gain if adjusted enough.

So I would expect P3 adjustment to be audible, but not because 0.1% 2nd HD are reduced (or not), but because of other effects it has.

Ciao T
If you choose to think "definately alters the sound" and "things going on below 0.1% are audible" are totally misconstrued by my interpretation so be it. And I did say null not add. This is not the first time he has mentioned it, his amplifiers usually have mostly only low order 2nd's and 3rd's and he has attributed their characteristic "sound" to the relative 2nd's to 3rd's ratio.

The trim would usually add large amounts of inbalance before hitting the stops, I don't see much change in gain for any resonable amount of trim.
__________________
"The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important."
  Reply With Quote
Old 16th February 2012, 07:47 PM   #2523
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by tvrgeek View Post
I could not get to trigger or see anything that looked like ringing after the cutoff. Just random noise.
Current probes are helpful. Sometimes in lieu of that I make a little pickup coil with low-enough inductance to be fast and try to "sniff out" the really high-frequency energy that may be emitted, and which can propagate.

As someone mentioned earlier, the simplest snubbers don't so much snub as they lower the frequency of the ringing, which makes it less likely to propagate.

This thread is long and meandering enough as it is, but someday I will tell the story of the most nearly-disasterous problem with a powered speaker I've had to date. It involved a ceramic cap that was installed in anticipation of the need, with ultra-cheap rectifier diodes, to sometimes need to suppress switching spikes that would have potentially introduced a low-level buzz in the audio. The double failure mode of capacitor and a.c. adapter almost started a fire in a college dormitory room. Had flammable material been nearby it could well have led to fatalities.
  Reply With Quote
Old 16th February 2012, 07:47 PM   #2524
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
Quote:
Originally Posted by Wavebourn View Post
In the post #2493 you write the same, but using more literature language, regarding some certain opamp-style topology, while my answer is more common and precise. In your example resistors loading stages with high output resistance are viewed by the next stage as part of output resistance of the previous one. Balancing such a way power amplification between stages you optimize the whole amp.
Now, THAT'S an answer I wanted to read - thank you!
  Reply With Quote
Old 16th February 2012, 07:55 PM   #2525
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
Quote:
Originally Posted by tvrgeek View Post
Wife said no. Too big for the living room. No to the Sequals, No to the Vandersteins. I should have made the switch when I still had the old Ditton 44's. Now it is small monitors or else.
Serves you right.

Whatever possessed you to change those Dittons? Couldn't you just refresh them, perhaps used still better quality caps, and so forth?

Now you are forver damned to not hearing the bottom octaves.

You might want to try bribery - it worked for me. I told my wife that she loved calssical music so much, it was only right that she should have her own system. So I got her an H/K 680 integrated, a pair of JBL Ti 600 floorstanders which fit in PERFERCTLY in her room, and, in the name of sane economy, a Sony CD/DVD player. Oh man, is she happy, or what!

She was so happy that I was moved to plonk down some serious bread for a pair of serious van den Hul speaker cables.

HiFi bonus, pax in domus.
  Reply With Quote
Old 16th February 2012, 08:53 PM   #2526
a.wayne is offline a.wayne  United States
Sin Bin
 
Join Date: May 2008
Location: Front Row Center
Quote:
Originally Posted by tvrgeek View Post
Wife said no. Too big for the living room. No to the Sequals, No to the Vandersteins. I should have made the switch when I still had the old Ditton 44's. Now it is small monitors or else.
Then build them , what are you currently using ....?
  Reply With Quote
Old 16th February 2012, 09:02 PM   #2527
a.wayne is offline a.wayne  United States
Sin Bin
 
Join Date: May 2008
Location: Front Row Center
Quote:
Originally Posted by tvrgeek View Post
Went looking for the rectifier ringing in the DH120 so I could select proper snubber values. After all, the datasheet for hexfreds say "reduced snubbers" not none. It does not even have the original disk across it.
Hmmm. No ringing. A bit of general noise that is probe cable sensitive, that's all.
OK , are you still going to add snubbers..? did you match your hexfreds ...?

Quote:
Originally Posted by tvrgeek View Post
in contrast to a Rotel 951 with conventional rectifier, cap only snubbers.
So conventional block with snubbers , any thoughts on how this affects the sound vs the hexfreds ...?

Quote:
Originally Posted by tvrgeek View Post
5 mV, .5mS. on the Rotel, 10mV on the Hafler at I think 1ms. I don't have a storage scope, so getting a single shot is not possible. What it does show is the glitch on the conventional supply. It was less stable to trigger on as well. You might have noticed.
Interesting ....
  Reply With Quote
Old 17th February 2012, 01:09 AM   #2528
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
Quote:
Originally Posted by dvv View Post
Serves you right.

Whatever possessed you to change those Dittons? Couldn't you just refresh them, perhaps used still better quality caps, and so forth?

Now you are forver damned to not hearing the bottom octaves.

You might want to try bribery - it worked for me. I told my wife that she loved calssical music so much, it was only right that she should have her own system. So I got her an H/K 680 integrated, a pair of JBL Ti 600 floorstanders which fit in PERFERCTLY in her room, and, in the name of sane economy, a Sony CD/DVD player. Oh man, is she happy, or what!

She was so happy that I was moved to plonk down some serious bread for a pair of serious van den Hul speaker cables.

HiFi bonus, pax in domus.
Ah, but I built a pair of 12" peerless subs, proper electronic crossover etc. Yea, 44's sure did have a nice bottom end. I had to replace the T-2000's years ago with some Seas units. A tad smoother with no crossover change. A friend of mine is still using them with an Acrus amp. Pretty sweet. The cabinets are not up to what I build now, and 40 years have improved driver technology. It would be fun to put in a modern tweeter and rework the crossover. The mid was pretty good too, but they used it too high.
  Reply With Quote
Old 17th February 2012, 01:26 AM   #2529
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
Quote:
Originally Posted by a.wayne View Post
Then build them , what are you currently using ....?
I am building them. I was working on another set when I got distracted by amp design. I was in the middle of a tweeter bake off. I have just about convinced myself that regardless of measurements, I don't like metal domes. Waffling between a Seas Excel or ScanSpeak Revealtors with soft domes. This time I am stepping up the driver budget because I think I know just enough to get some value out of them.

Right now, the living room has first generation Paradigm studio 20's with my own Peerless subs. I have some Kef Q1's in my office, and several pairs I have built I swap in and out of my guest room where I do my serious evaluations. Mostly Seas/Vifa/Dayton based. I really need to get the Q1's out of here. I have done better. I have a pair of slightly modified Tanburgs on my desk. Old and comfortable like well worn shoes. Another project in the works was a set of very narrow towers I priced someone. The narrow baffle is causing me bigger issues than I thought. They are based on the Zaph driver and a Seas metal dome, 6th order effective. Crossover is getting expensive. That is how I decided a more expensive tweeter is easier to use and the crossover savings can pay for the tweeter. Same on the mid. $50 drivers are more expensive to use than $100 drivers.
  Reply With Quote
Old 17th February 2012, 01:34 AM   #2530
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
Quote:
Originally Posted by a.wayne View Post
OK , are you still going to add snubbers..? did you match your hexfreds ...?



So conventional block with snubbers , any thoughts on how this affects the sound vs the hexfreds ...?



Interesting ....
Sound? Well I like both amps, but my wife's super ears did not like the Hafler stock. I doubt the power supply is the main reason, but it is one step. I have a list of changes I plan to make, IPS degeneration and changing the dominant pole to Miller comp. I was using it as my bench amp and wanted to reduce residual distortion. It measured 8 to 13 dB better, so that was a success. Then I got carried away. We have been under the weathers so not in a mood for critical listening.
  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 04:12 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