Measuring Amplifiers - Page 40 - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 970Likes
Reply
 
Thread Tools
post #1171 of 1783 Old 07-23-2016, 06:24 PM
AVS Forum Special Member
 
murphy2112's Avatar
 
Join Date: Oct 2005
Location: Chicago, IL
Posts: 1,465
Mentioned: 27 Post(s)
Tagged: 1 Thread(s)
Quoted: 700 Post(s)
Liked: 387
Quote:
Originally Posted by notnyt View Post
I assume you mean something unobtrusive, and not like an oscilloscope? You could always build a small circuit that lights an LED or something when a certain voltage level is reached, shouldn't cost more than $1-2 in components.


I dunno, how much is one of these [oscilloscope]?

It can be measured realtime while listening to music?
murphy2112 is offline  
Sponsored Links
Advertisement
 
post #1172 of 1783 Old 07-23-2016, 06:25 PM
AVS Forum Special Member
 
murphy2112's Avatar
 
Join Date: Oct 2005
Location: Chicago, IL
Posts: 1,465
Mentioned: 27 Post(s)
Tagged: 1 Thread(s)
Quoted: 700 Post(s)
Liked: 387
Quote:
Originally Posted by LTD02 View Post
i haven't seen any simple device that will accomplish this. part of the challenge is that as current increases, the rail voltage can sag. as a result clipping can occur at different voltages depending on how demanding the content is.


on the other hand, just looking for a clipped signal is no good because clipping can be in the content or occurring upstream in the signal chain.


also, speakers are not resistors, so the current demands are frequency dependent. there may be some frequencies where very high voltages can be run with no clipping, while other frequencies will pull lots of current, create significant voltage sag, and have clipping at lower voltage levels.


How do the clip lights work on other amps then? Can't the input signal be compared with the output signal to get rid of false positives?
murphy2112 is offline  
post #1173 of 1783 Old 07-23-2016, 06:49 PM
AVS Forum Addicted Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: Northern Okan range (NW Cascades region)
Posts: 11,105
Mentioned: 244 Post(s)
Tagged: 0 Thread(s)
Quoted: 3918 Post(s)
Liked: 4430
Quote:
Originally Posted by murphy2112 View Post
Can't the input signal be compared with the output signal to get rid of false positives?
That is exactly what the Crown MA's used to do. A deviation of more than 1% was considered clipped.
LTD02, murphy2112 and ja00 like this.
BassThatHz is offline  
Sponsored Links
Advertisement
 
post #1174 of 1783 Old 07-23-2016, 07:05 PM
Newbie
 
Join Date: Mar 2015
Posts: 13
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked: 10
Quote:
Originally Posted by LTD02 View Post
Quote:
Originally Posted by murphy2112 View Post
This may have been discussed before, but is there a way to monitor and measure voltage and current, realtime, while playing music through speakers to know what the levels are and to know when an amplifier is clipping? I'm asking because there are still a boatload of amplifiers on the market today that don't have clipping indicators.

i haven't seen any simple device that will accomplish this. part of the challenge is that as current increases, the rail voltage can sag. as a result clipping can occur at different voltages depending on how demanding the content is.


on the other hand, just looking for a clipped signal is no good because clipping can be in the content or occurring upstream in the signal chain.


also, speakers are not resistors, so the current demands are frequency dependent. there may be some frequencies where very high voltages can be run with no clipping, while other frequencies will pull lots of current, create significant voltage sag, and have clipping at lower voltage levels.
Good to know.. My friend relies on some cheapo eBay clipping indicator like the car audio ones for his system...
murphy2112 likes this.
wafflebroski is offline  
post #1175 of 1783 Old 07-24-2016, 03:01 AM
AVS Forum Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 21,279
Mentioned: 891 Post(s)
Tagged: 1 Thread(s)
Quoted: 3002 Post(s)
Liked: 3753
Quote:
Originally Posted by murphy2112 View Post
How do the clip lights work on other amps then? Can't the input signal be compared with the output signal to get rid of false positives?

while searching around, this article came up:


http://adn.harmanpro.com/site_elemen...r_original.pdf

which appears to have been developed at ae techron?


http://www.aetechron.com/IOC.shtml

seems like the "cheap" approach is to simply use a voltage threshold monitor, but that may not signal clipping under significant stress conditions.


an "input/output comparator" (IOC) appears to be one approach.


this appears to work, but i don't really know anything about circuits/implementation so i can't say whether or not it is practicable.


murphy2112 likes this.

Listen. It's All Good.

Last edited by LTD02; 07-24-2016 at 03:04 AM.
LTD02 is offline  
post #1176 of 1783 Old 07-24-2016, 04:27 PM
Senior Member
 
Join Date: Oct 2014
Posts: 282
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 186 Post(s)
Liked: 168
Rob Elliot has several articles on his site that describe what clipping is and why it's
bad for your speaker drivers:

http://sound.westhost.com/clipping.htm

http://sound.westhost.com/tweeters.htm

He also has a project for the construction of a amplifier clipping indicator:

http://sound.westhost.com/project23.htm

Keep in mind that the fact that the amp is clipping is not what is going to kill your
drivers. What is going to kill them is that when the amp clips, the average power delivered
to the driver increases quite a bit. If the delivered power exceeds the driver's ability
to dissipate the increase in voice coil temperature, the adhesives and insulation of the
coil will fail. Remember too, that depending on a driver's efficiency, anywhere from 92%
to 98% of the power that is delivered to the driver will be dissipated in the coil.
murphy2112 likes this.
sam_adams is offline  
post #1177 of 1783 Old 07-25-2016, 08:48 AM
AVS Forum Special Member
 
Bassment's Avatar
 
Join Date: Aug 2013
Location: Ancaster, Ontario, Canada
Posts: 1,836
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 960 Post(s)
Liked: 389
Quote:
Originally Posted by murphy2112 View Post
This may have been discussed before, but is there a way to monitor and measure voltage and current, realtime, while playing music through speakers to know what the levels are and to know when an amplifier is clipping? I'm asking because there are still a boatload of amplifiers on the market today that don't have clipping indicators.
You could just use a VU meter like the Mcintosh amps have. They're not super accurate as you have to use a fixed output resistance on them, but they will give you a good idea http://www.ebay.com/itm/Precision-VU...1%26rkt%3D1%26

This looks really cool http://www.ebay.com/itm/EVOR04-Color...cAAOSwpDdVAuQ0
murphy2112 likes this.
Bassment is offline  
post #1178 of 1783 Old 07-25-2016, 09:09 AM
Senior Member
 
ja00's Avatar
 
Join Date: May 2013
Posts: 474
Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 225 Post(s)
Liked: 150
The best way to determine is the signal is clipped is to compare the input to the output signal. That IOC is an very elegant way of doing it, however it cannot be implement "outside" the amp, since there is no access to the error amp and output stage junction. The circuit shown on the video is probably your next best cheapy approach. Just make sure to scale the circuit values/components based on your amp. Those transistors are only rated for 45V. So if your rails are higher than this, you will need different transistors.
ja00 is offline  
post #1179 of 1783 Old 07-25-2016, 08:05 PM
AVS Forum Addicted Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: Northern Okan range (NW Cascades region)
Posts: 11,105
Mentioned: 244 Post(s)
Tagged: 0 Thread(s)
Quoted: 3918 Post(s)
Liked: 4430
The last 10-20 posts have been about clip indicators, why they are good things and how to build/buy them, someone should probably create a "clip indicator" thread, before this thread needs an OTCC (Off Topic Comparator Circuit). There's another one for the acronym list thread.
@XBR11
BassThatHz is offline  
post #1180 of 1783 Old 07-25-2016, 08:20 PM
Senior Member
 
ja00's Avatar
 
Join Date: May 2013
Posts: 474
Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 225 Post(s)
Liked: 150
Not sure if this has been asked before, I did a quick search and did not find anything. Let me start by saying I am not familiar with a lot (well most) of amplifiers being tested here, so I am not sure if it is even a question worth asking. My apologies if it isn't.
@notnyt , would it possible for you to measure the frequency response of the amplifiers, especially in the low end of the frequency spectrum. Just thought it might be useful to weed out those that roll off early to use with multiple sealed subs if ULF is the main goal.
ja00 is offline  
post #1181 of 1783 Old 07-25-2016, 08:21 PM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
I've measured FR from all amps tested.
notnyt is offline  
post #1182 of 1783 Old 07-25-2016, 09:02 PM
Senior Member
 
ja00's Avatar
 
Join Date: May 2013
Posts: 474
Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 225 Post(s)
Liked: 150
Quote:
Originally Posted by notnyt View Post
I've measured FR from all amps tested.
Totally missed it then or just misunderstood. Sorry about that. Are those plots your are referring to the ones with the distortion? So the fundamental would correspond to the frequency response?
ja00 is offline  
post #1183 of 1783 Old 08-01-2016, 06:54 PM
AVS Forum Special Member
 
Join Date: Feb 2006
Location: USA
Posts: 3,059
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 1695 Post(s)
Liked: 943
Quote:
Originally Posted by notnyt View Post
I'll update the FP14000 thread once I finish tests with more info.
Were you able test this full range? I'm curious how well it performed distortion wise at the top end.

I'm considering it to run my main L/R speakers.
dwaleke is offline  
post #1184 of 1783 Old 08-01-2016, 07:13 PM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
Quote:
Originally Posted by dwaleke View Post
Were you able test this full range? I'm curious how well it performed distortion wise at the top end.

I'm considering it to run my main L/R speakers.
no time lately, will post results as I have them, sorry.
notnyt is offline  
post #1185 of 1783 Old 08-01-2016, 07:14 PM
AVS Forum Special Member
 
Join Date: Feb 2006
Location: USA
Posts: 3,059
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 1695 Post(s)
Liked: 943
No problem. I know how that goes.

Thanks.
dwaleke is offline  
post #1186 of 1783 Old 10-14-2016, 01:16 AM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
I just tested a Sanway fp14000 with the newer 2 ohm stable power supply. It's a big improvement. Brings it right up with the enhanced clone from botai. I'll do further testing some other time. I just wonder which vendor will be more reliable at this point. This was an older amp I picked up from someone that wasn't working. The PS had a burned trace.

I was running a single channel into a 4.5ohm load, starting at around 4400w, it would run for a few seconds and only drop down to about 3800w. More tests to come at some point..

At least Johnson from Sanway is helpful when something goes wrong, though slow.
dwaleke, Torkild and chrapladm like this.
notnyt is offline  
post #1187 of 1783 Old 10-14-2016, 06:57 AM
AVS Forum Special Member
 
Bassment's Avatar
 
Join Date: Aug 2013
Location: Ancaster, Ontario, Canada
Posts: 1,836
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 960 Post(s)
Liked: 389
Bassment is offline  
post #1188 of 1783 Old 10-14-2016, 11:28 AM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
Quote:
Originally Posted by Bassment View Post
Even the burst is the same? Even with the huge capacitance difference?
The old ones burst just as much as the new ones, just not for as long. I'll have a more thorough comparison later.
notnyt is offline  
post #1189 of 1783 Old 11-03-2016, 08:29 PM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
So I'm trying to measure an NC400.... but it's cleaner than my interface (emu 0404 usb)... even at 1 watt. Might get to see a bit more detail tomorrow after the motu 16a arrives.

Torkild likes this.
notnyt is offline  
post #1190 of 1783 Old 11-04-2016, 02:49 PM
AVS Forum Special Member
 
zeus33's Avatar
 
Join Date: Dec 2012
Posts: 4,257
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1908 Post(s)
Liked: 2072
Quote:
Originally Posted by notnyt View Post
So I'm trying to measure an NC400.... but it's cleaner than my interface (emu 0404 usb)... even at 1 watt. Might get to see a bit more detail tomorrow after the motu 16a arrives.

Sounds about right:

"Distortion at listening levels (1W) is unmeasurable."

http://www.hypex.nl/product/2012-11-...-35/nc400.html


It will be interesting to see if it holds true with the Motu.
zeus33 is offline  
post #1191 of 1783 Old 11-04-2016, 02:50 PM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
Quote:
Originally Posted by zeus33 View Post
Sounds about right:

"Distortion at listening levels (1W) is unmeasurable."

http://www.hypex.nl/product/2012-11-...-35/nc400.html


It will be interesting to see if it holds true with the Motu.
yeah, I'm quite impressed, which doesn't happen too much.
notnyt is offline  
post #1192 of 1783 Old 11-10-2016, 01:16 PM
Member
 
Join Date: Jul 2015
Location: Bucharest, Romania
Posts: 85
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Liked: 18
Quote:
Originally Posted by notnyt View Post
I just tested a Sanway fp14000 with the newer 2 ohm stable power supply. It's a big improvement. Brings it right up with the enhanced clone from botai. I'll do further testing some other time. I just wonder which vendor will be more reliable at this point. This was an older amp I picked up from someone that wasn't working. The PS had a burned trace.

I was running a single channel into a 4.5ohm load, starting at around 4400w, it would run for a few seconds and only drop down to about 3800w. More tests to come at some point..

At least Johnson from Sanway is helpful when something goes wrong, though slow.
Any news regarding testing? Can you tell from the pics I put here if the new power source is the same one as in the amp I got from him ? I never had to chance to thoroughly test it so I cannot know how much it can output...
Also I would like to know if you have any idea how these amps would behave in EIAJ burst tests? I know Powersoft measure the peak output using this test an I would like to know if they take the peak voltage or the mean. Because the M-drive module peaks at around 15Kw and I am curious if that means this amp can peak as much as that one or double.
Also did you get your Speaker Power amps?

Brains are survival engines, not truth detectors
radulescu_paul_mircea is offline  
post #1193 of 1783 Old 11-10-2016, 01:26 PM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
Quote:
Originally Posted by radulescu_paul_mircea View Post
Any news regarding testing? Can you tell from the pics I put here if the new power source is the same one as in the amp I got from him ? I never had to chance to thoroughly test it so I cannot know how much it can output...
Also I would like to know if you have any idea how these amps would behave in EIAJ burst tests? I know Powersoft measure the peak output using this test an I would like to know if they take the peak voltage or the mean. Because the M-drive module peaks at around 15Kw and I am curious if that means this amp can peak as much as that one or double.
Also did you get your Speaker Power amps?
Read the thread, I covered the power measurement stuff in depth. For burst measurements I'm using CEA2010 burst signals and calculating the RMS voltage from the peak-peak measurement then using this to calculate wattage, as it should be. Essentially ( Vpp * 0.707 / 2 )^2 / R. I also take longer sustained measurements with sine waves in my tests. I wrote about some of this here: https://www.avsforum.com/forum/155-di...l#post45085826

I haven't gotten an opportunity to test the enhanced FP1400 further yet, but the important numbers have already been posted. The SP2-12000s I also have not gotten to test, as it requires moving my test rig over to the 240v outlets. I will at some point, but other projects are taking priority in the little bit of free time I actually have. The speakerpower amps are the real deal. I've posted SP2-8000 results already. The 12000s aren't as efficient. I'll see what they do at some point.

Also, the pics you posted were in a different thread. You have the new power supply. I had to search :/

Last edited by notnyt; 11-10-2016 at 01:54 PM.
notnyt is offline  
post #1194 of 1783 Old 11-10-2016, 03:23 PM
Member
 
Join Date: Jul 2015
Location: Bucharest, Romania
Posts: 85
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Liked: 18

You are right, sorry. I should have linked the pic here.
I knew the way you are measuring. I was wondering how the big brands are doing it and your response was spot on. That is cool, thank you.
I should probably get a speakerpower this next summer too to see for myself what POWER really means
Again, thank you.

Brains are survival engines, not truth detectors
radulescu_paul_mircea is offline  
post #1195 of 1783 Old 11-10-2016, 03:47 PM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
Quote:
Originally Posted by radulescu_paul_mircea View Post
You are right, sorry. I should have linked the pic here.
I knew the way you are measuring. I was wondering how the big brands are doing it and your response was spot on. That is cool, thank you.
I should probably get a speakerpower this next summer too to see for myself what POWER really means
Again, thank you.
most provide measurements as I do. Some will list as the bs 'peak watts' rating, and need to be avoided. I don't think any of the big manufacturers are doing this at the moment, but I may not be aware of them all. Keep in mind some mfrs will measure at 1000hz and get high burst ratings, but can't manage that at 100hz and below.

Last edited by notnyt; 11-10-2016 at 03:59 PM.
notnyt is offline  
post #1196 of 1783 Old 11-11-2016, 07:04 AM
Member
 
Join Date: Jul 2015
Location: Bucharest, Romania
Posts: 85
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Liked: 18
For my purpose, I used mostly Powersoft amps and I never felt them like they remained out of juice. Only when I used a more powerful one I realized it could be at limit. But that is only over 30hz . Can't wait to compare the clone with a K8 directly!

Brains are survival engines, not truth detectors
radulescu_paul_mircea is offline  
post #1197 of 1783 Old 11-22-2016, 01:20 AM
AVS Forum Special Member
 
pdxrealtor's Avatar
 
Join Date: May 2005
Posts: 2,678
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 205 Post(s)
Liked: 158
I searched this thread for crest/peavey and didn't come up with any results. Not - is it a lack of supply or time? I saw it looked you were getting an IPR7500 but that's it.

I'm in the market and likely going with crest or peavey's if you're interested in testing one I'll have it shipped your way. If there's already test results and I'm missing them please point them out to me.
pdxrealtor is offline  
post #1198 of 1783 Old 11-22-2016, 02:02 AM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
Quote:
Originally Posted by pdxrealtor View Post
I searched this thread for crest/peavey and didn't come up with any results. Not - is it a lack of supply or time? I saw it looked you were getting an IPR7500 but that's it.

I'm in the market and likely going with crest or peavey's if you're interested in testing one I'll have it shipped your way. If there's already test results and I'm missing them please point them out to me.
gotta catch up on some things, got a new pc coming for my bench since there was just a deal on the high end nuc. My laptop I was using was having issues, so that should be here in a couple days. I have an enhanced fp14000 I bought to test, which I ran some basic tests on. Definitely better than the sanway, but haven't done full work up. Not rushing on that, though. I also need to test my speaker power amps at some point,

If someone wants to send me an ipr2 7500 or anything else I'll test it, but it might be a couple weeks before results between holiday and work stuff.
notnyt is offline  
post #1199 of 1783 Old 11-22-2016, 02:54 AM
Member
 
Join Date: Jul 2015
Location: Bucharest, Romania
Posts: 85
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Liked: 18
Quote:
Originally Posted by notnyt View Post
I have an enhanced fp14000 I bought to test, which I ran some basic tests on. Definitely better than the sanway, but haven't done full work up. .
Oh man, I can't wait to see the tests. I will need 2 fp14K and 2 fp10K to have a full stack and I would love to have some reliable clones.

Brains are survival engines, not truth detectors
radulescu_paul_mircea is offline  
post #1200 of 1783 Old 11-22-2016, 02:57 AM - Thread Starter
AVS Forum Addicted Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 10,399
Mentioned: 332 Post(s)
Tagged: 0 Thread(s)
Quoted: 3882 Post(s)
Liked: 3819
Quote:
Originally Posted by radulescu_paul_mircea View Post
Oh man, I can't wait to see the tests. I will need 2 fp14K and 2 fp10K to have a full stack and I would love to have some reliable clones.
long story short, and off the top of my head, they burst 14kw and sustain 4.8kw for a couple seconds, then 3800w. there are results back in this thread. can't speak on reliability. The sanway will sustain 3800 and is $650 vs $850 shipped, so it's a toss up either way.
notnyt is offline  
Sponsored Links
Advertisement
 
Reply DIY Speakers and Subs

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

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