lc audio the end and thd

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km

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Joined 2001
cadaudio.dk
#1
hi.

did any of you measure thd data on this amp? or do you know of such measured specs (website , magazine,...)

we have a bit of discussion (in denmark) about this, partly because of the claim form this site;
http://www.geocities.com/ResearchTriangle/Node/2356/

it seems that simulation on a model of the amplifier gives thd results 200 times worse than those published by lc audio.

a bit of facts would be helpfull for sure (enough bs and crap allready ,,,,)

thanks - k madsen - cad audio dk
 
#3
Who says?

km,

You represent a competitor of LC Audio in the same (very small) country. You have posted some opinions on LC Audio. Perhaps you should leave others to comment on your competitors?


BTW: I do not own any LC Audio products other than their soft start circuit.

Petter
 
#4
hi.

what opinions petter?

i did not write the site i refer to, just asked a few questions and got a bit curious.

my opinion about lc audio and their products is not the issue here and i dont think i have said anything about that , we do not sell hifi amplifiers and such and we are not directly competitors but anyway , ,,,(and i agree for sure)....

i still think i have a valid question and i actually ask here to see if anybody can help with a bit of facts opposed to the rubbish you can see around.

i also think that a comparison of simulated specs and measured specs would be helpfull, just noticed a recent thread about this and mentioning the amp in question.

k madsen - cad audio dk
 
#5
Have you compared the Schematic the site you have linked to with the one from LC Audio.

If you question is made from comparing the measurement from there site with the russian sim.

Maybe you should do a sim yourself (Not to be hard on you), before making any comments.
They do not use the same transistors like the ones in the sim.

So it cannot be compared before the sim is equal to the real world.

Sonny
 
#6
hi.

i did read that the driver transistors is possibly different (the original ones could not be identified).

apart from that i think the schematic is the same.

i do not wish to make a sim , the reason for my posting (if thats unclear in any way) is to ask if anybody here did in fact make thd measurement on actual amplifier.

i think it would be interesting to compare the measured specs with the simulated ones (and if you like to the specs published by lc audio).

if a small difference was detected i dont think that would be interesting , but the claimed 200x is what caused my curiousity.

thd figures is simulated and published for -3 db level , so they do in fact tell what levels are used.

regards k madsen - cad audio dk

ps. i/we could measure thd on an amp we borrowed but i would prefer an (or several) "outsiders".
 
#7
I didn't find level spec. as you did but okay then i looks strange.

You wrote :

I do not wish to make a sim , the reason for my posting (if thats unclear in any way) is to ask if anybody here did in fact make thd measurement on actual amplifier.

It is clear .. sorry for the reply.

You wrote :
ps. i/we could measure thd on an amp we borrowed but i would prefer an (or several) "outsiders".

I really do not understand you.. I think You do have all the equipment to do this. Why not satisfy your couriosity!?

Sonny
 
#9
Hey guys.

I hadn't seen the thread til now.....

Anyway, I own The End Millennium kit based amp. I will try to make the measurements this weekend. I can do it with 4 and 6 ohm load and I quess I will make them at 1W and then at max power (if my dummy load can take it) or as high of a power as possible.

Do you have any special requests of the types of tests. My setup is limited to audio band, but I can make THD and IMD measurements with FFT analyses and visible spectral content (SpectraLab)

Ergo
 
#10
hi.

for best comparisons with simulated specs it would be great if you can measure at -3 db (related to full output).

i think specs for 4 ohm and 8 ohm would be just fine.

additional specs would of course be most welcome.

on the site i referred to you can find specs for different power levels (see under power amplifiers without negative feedback).

i shall look forward to see what you come up with.

k madsen - cad audio dk

ps. grataku i think you would be amazed to see the crap i got from asking same question locally 🙂
 
#11
Well, we shall see what the measurements show. I regard the sound of the amp to be of a very good value for the price. I have listened to it for 1,5 years now and just recently I finished two JLH 96 class A monoblocks and these seem to be the ones that outscore the millennium. I haven't been able to do a decent comparison jet though as my cd player is broken at the moment and I'm waiting for spareparts....

Ergo
 
#12
The End Millennium measurements

First the condirions were.

1) signal source: Sony CDP-XE530 cd player
2) passive voltage divider
3) Sony MDS-JE520 for A/D conversion
4) digital input of CM8738 based soundcard to PC

load was either 6 ohm or 4 ohm non inductive resistive load.

***

The first picture shows the measurement setup base distortion (CD analog out to MD analog in)

http://my.tele2.ee/hifi/millennium/residual.jpg

Also note that the first picture has -130dB range and others have -120dB range

***

1W into 4 ohm load
http://my.tele2.ee/hifi/millennium/4ohm1w.jpg
10W into 4 ohm load
http://my.tele2.ee/hifi/millennium/4ohm10w.jpg
83W into 4 ohm load (-3dB from clipping)
http://my.tele2.ee/hifi/millennium/4ohm83w.jpg

1W into 6 ohm load
http://my.tele2.ee/hifi/millennium/6ohm1w.jpg
1W into 6 ohm load
http://my.tele2.ee/hifi/millennium/6ohm10w.jpg
1W into 6 ohm load
http://my.tele2.ee/hifi/millennium/6ohm83w.jpg

***

The quiesent current in my amp is turned a little higher than specified by LCAudio - it is 300mA

Rgds
Ergo

PS. Oh jeah

this is my The End Millennium : )

http://my.tele2.ee/hifi/millennium/myamp.jpg
 
#14
hi.

"cannot find server"........

any chance you can make a scheme like the one on george krilov site , this way it would be real easy to compare your specs with his simulated ones and the published specs from lc audio?

i will of course try late to see if i can access your files.

bye k madsen - cad audio dk

ps. thanks for your efforts....
 
#16
km, I'll hope you'll see the files this way...

Residual distortion
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1W into 4 ohm
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10W into 4 ohm
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83W into 4 ohm
An externally hosted image should be here but it was not working when we last tested it.

1W into 6 ohm
An externally hosted image should be here but it was not working when we last tested it.

10W into 6 ohm
An externally hosted image should be here but it was not working when we last tested it.

83W into 6 ohm
An externally hosted image should be here but it was not working when we last tested it.
 
#18
The software I used is SpectraLab 4.32

The measurement setup is Sony minidisk player MDS-JE520 which I use for analog digital conversion. Then the signal goes via optical link to Leadtek Winfast 4X soundcard digital input. For the soundcard I use M Audio Dio2448 soundcard drivers which are much more optimized for the job.....

The signal source is usually my Marantz CD67 but as it is broken at the moment I used friends Sony CDP-XE530 player.

Ergo
 
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