Did some calculations and here are the results.
The whole calculation is for one monoblock.
As I recall, the supply voltage is +/-24V, which is 48V over the rails.
There are 16 output devices, 8 on each side. Two times 4 for the current sources and two times 4 for the outputs.
I refer to Grey’s original schematic:
http://www.diyaudio.com/forums/attachment.php?s=&postid=32776 (Thanks Grey, Nelson)
Source resistors are 0.47ohm. Voltage over the source resistors is 0.35V. So I have 0.745mA times 8 = 5.96A lets say 6A bias.
R19 and R29 are 47k. Feedback resistors are 120k. Input resistors R18 & R28 are 10k.
DC stability resistors from common diff-pair source to outputs are 2.35k (two paralleled 4.7k).
Both absolute and differential DC are extremely low. Diff-DC can be reduced to almost 0 with V2 and absolute DC is 15-17 mV
R1/R4 and R44/R45 are not used.
No C2 and C4.
R12, R34 are 2.2k.
Sinewave 400Hz unbalanced.
Output power is now 18W RMS into 8ohm. With the 4ohm load 14W RMS.
I added another 2.2k parallel to R12, R34 and the results are a bit better:
24V * 2.2A = 52.8W RMS into 8 ohm
10V * 1.7A = 17W RMS into 4 ohm.
These values are measured just before the XY-axis starts showing distortion. That is become a bow or elipse. I can increase volume further before things get out of hand, but to me it seems the XY-axis should be flat all the way before clipping.
I got rid of the severe clipping at 8ohm and the 4ohm tests are better too.
Still not what it should be when burning that much power.
Sorry if I offended someone (sy, moe29…) yesterday. It was late and I was tired. I just wanted to keep the thread on-topic, that’s all. 😉
Here’s a nice peace about Tori for moe29: http://members.aol.com/AKlink8489/musician.htm 😎
/Hugo
The whole calculation is for one monoblock.
As I recall, the supply voltage is +/-24V, which is 48V over the rails.
There are 16 output devices, 8 on each side. Two times 4 for the current sources and two times 4 for the outputs.
I refer to Grey’s original schematic:
http://www.diyaudio.com/forums/attachment.php?s=&postid=32776 (Thanks Grey, Nelson)
Source resistors are 0.47ohm. Voltage over the source resistors is 0.35V. So I have 0.745mA times 8 = 5.96A lets say 6A bias.
R19 and R29 are 47k. Feedback resistors are 120k. Input resistors R18 & R28 are 10k.
DC stability resistors from common diff-pair source to outputs are 2.35k (two paralleled 4.7k).
Both absolute and differential DC are extremely low. Diff-DC can be reduced to almost 0 with V2 and absolute DC is 15-17 mV
R1/R4 and R44/R45 are not used.
No C2 and C4.
R12, R34 are 2.2k.
Sinewave 400Hz unbalanced.
Output power is now 18W RMS into 8ohm. With the 4ohm load 14W RMS.
I added another 2.2k parallel to R12, R34 and the results are a bit better:
24V * 2.2A = 52.8W RMS into 8 ohm
10V * 1.7A = 17W RMS into 4 ohm.
These values are measured just before the XY-axis starts showing distortion. That is become a bow or elipse. I can increase volume further before things get out of hand, but to me it seems the XY-axis should be flat all the way before clipping.
I got rid of the severe clipping at 8ohm and the 4ohm tests are better too.
Still not what it should be when burning that much power.
Sorry if I offended someone (sy, moe29…) yesterday. It was late and I was tired. I just wanted to keep the thread on-topic, that’s all. 😉
Here’s a nice peace about Tori for moe29: http://members.aol.com/AKlink8489/musician.htm 😎
/Hugo
Netlist said:
How are you doing the measurements? Have you ever listened w/o the scope attached? Are you using a differential probe at the output or just looking at 1 side to gnd?
In all my experimentations I noticed that really bad things happen depending on how instruments are connected.
grataku said:
I know what you are talking about.
The scope ground is attached to the star ground of the amp.
Channel A goes to +out, channel B to -out.
Bad things happen when there is offset at the outputs and the ground of the probe is connected to - or + out.
There is no difference in sound or power with or without connected instruments.
BTW, the sound is absolutely beautiful when the amp plays in the “safe” area.
I would like to hear from other people what the scope patterns are in XY-mode.
Did anyone ever perform these tests?
/Hugo
Well, well...Do we really listen to what we hear? Till, please just look up in the booklet what is that "strange noise" in Boys for Pelé... What makes me curius that you haven't noticed the other, much more relevant effect of the used equipment, namely that it modulates the sound of the Bösendorfer by mechanical means. All over the song...
Or just hit the links above:
http://theatreorgans.com/hammond/faq/mystery/mystery.html
http://mixonline.com/ar/audio_tori_amos/
Hmmm....
Or just hit the links above:
http://theatreorgans.com/hammond/faq/mystery/mystery.html
http://mixonline.com/ar/audio_tori_amos/
Hmmm....
Netlist said:
I never used XY-mode. Nelson and maybe Grey or Fred (he never clearly stated whether he got the TexX done). To tell you the thruth, I found your initial post confusing, I never quite understood what the problem was, exactly. Granted I was having breakfast and skimming through the posts...but what is the 'safe' area?
grataku said:
XY-mode is used to look at the phase of a signal.
I can't explain you the exact process of how this works, but if you have a scope that can do XY-mode you should try it.
Connect the left output to the A-channel, and the right output to the B-channel. Apply a sinewave to the amp and calibrate the scope for proper display of the XY-axis. When all is well in phase, and both channels of the amp are driven equally with the same signal you should see a nice straight line from the top left to the bottom right of the scope. When this line becomes a bow or an elipse something is wrong. Don't ask me further technical details, other people here are much more qualified to explain what I mean.
Now, play a nice piece of music, in stereo and look what happens. Very nice indeed! 🙂
With safe area I mean the max volume where the line is still a nice straight line.
To Banfi T. : impressive. The Nexo stuff is indeed superb. I bet they have tons of roadies..and money
/Hugo
I know what the XY mode is, I just never used it. I normally look at input and output waveforms. So the A and B are on the SAME channel, just on the + and - output, right? I'll try that out tonite and let you know.
Read this again: not to make mistakes.Netlist said:
Don't ask me if you can do this with two monoblocks or with the Alephs.
/Hugo - Hard to write manuals.
quoteA:
Originally posted by Netlist
Connect the left (or right) +output of your amp to the A-channel of the scope, which is then your Y-axis, and the right (or left) +output to the B-channel of the scope, which is then your X-axis. Ground of the scope probes is -outputs of the amp.
Read this again: not to make mistakes.
Don't ask me if you can do this with two monoblocks or with the Alephs.
/Hugo - Hard to write manuals.
quoteB:
I know what you are talking about.
The scope ground is attached to the star ground of the amp.
Channel A goes to +out, channel B to -out.
Bad things happen when there is offset at the outputs and the ground of the probe is connected to - or + out.
Ok, thanks for straightening that out. I got confused by your posts (see quoteA and quoteB). However, I don't agree that in this cased is legit to connect the scope ground to the -output.
Originally posted by Netlist
Connect the left (or right) +output of your amp to the A-channel of the scope, which is then your Y-axis, and the right (or left) +output to the B-channel of the scope, which is then your X-axis. Ground of the scope probes is -outputs of the amp.
Read this again: not to make mistakes.
Don't ask me if you can do this with two monoblocks or with the Alephs.
/Hugo - Hard to write manuals.
quoteB:
I know what you are talking about.
The scope ground is attached to the star ground of the amp.
Channel A goes to +out, channel B to -out.
Bad things happen when there is offset at the outputs and the ground of the probe is connected to - or + out.
Ok, thanks for straightening that out. I got confused by your posts (see quoteA and quoteB). However, I don't agree that in this cased is legit to connect the scope ground to the -output.
In the A-quote, a normal commercial stereo amp is in mind.grataku said:
In most of these the -output is connected to ground.
The XY-connection to the scope can certanly be done as described.
In quote B I'm talking about the AlephX. First, we have two monoblocks. Not sure if we can connect both of them star points together through the scope ground. Second, in the X-circuits, we have two identical 'channels' connected together like a bridged amp, but with X added. (That's the simple way I see the X-circuit). This means we have four outputs and only two scope probes. That's why I said not to ask me how to do it with two monoblocks or with the Alephs.
/Hugo
Netlist said:
I give up, I have no idea of what you're talking about. Maybe you ought to revise your simple way of thinking about the X.
grataku said:
Like the time I remembered that the scope is connected to earth, as I put the probe and ground across the output of a bridged amp
grataku said:
Ok, I rarely give up; I make you a drawing of what I want to explain.
Don't blame ME if YOU can't understand what I mean. No offence!!🙂
/Hugo
Netlist, there are not "4 outputs" there are either two outputs referenced to ground, or a single output not referenced to ground, depending on how you want to look at it.
Thanks tiroth,tiroth said:
could you also explain how to measure the two outputs of two AlephX monoblocks with one scope? Connecting the probes to +out and grounds to scope ground? Or connect the probes to +out and probe grounds to -out?
Is my A-quote correct?
I believe there's a big difference in measuring a normal amp, a bridged amp and an X-amp.
/Hugo
"could you also explain how to measure the two outputs of two AlephX monoblocks with one scope?"
with a 2 channel scope, by using two differential probes.
PS I am a little thick-headed, sorry 😉
with a 2 channel scope, by using two differential probes.
PS I am a little thick-headed, sorry 😉
Netlist said:
Hi,
why you need measuring two monoblocks with scope in same time?
If you want measuring phase shift between blocks, just measure phase between two + or - outputs.You can't connecting ground of probe to any output of bridged (x amp). For measuring one bridged output you need two channel scope, with inputs summed, one input reversed.
If you have diff. probe you can measure two blocks with two channel scope.(grataku answered)
Regards
Don't worry, I definitely have the same problem sometimes..grataku said:
Thanks, that's exactly what I wanted to know. I simply couldn't find it in grataku's answer. I'll give it a try (when I have my two monoblocks)moamps said:
Hi,
why you need measuring two monoblocks with scope in same time?
You can't connecting ground of probe to any output of bridged (x amp). For measuring one bridged output you need two channel scope, with inputs summed, one input reversed.
If you have diff. probe you can measure two blocks with two channel scope.(grataku answered)
Regards
/Hugo 🙂
Yes, i admit before this post
http://www.diyaudio.com/forums/showthread.php?postid=172280#post172280
i never heard of Leslie Cabinet. Thanks Banfi.
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