from post1098
statements:
a.)
this amp is the best example of Self's 'Blameless' topology.
b.)
No it's not.
c.)
According to Self blame is a three stage sch.
d.)
Please note that the Blameless configuration has three stages;
e.)
it is the Lin that has two.
Which statement is causing the problem?
What is the argument about?
statements:
a.)
this amp is the best example of Self's 'Blameless' topology.
b.)
No it's not.
c.)
According to Self blame is a three stage sch.
d.)
Please note that the Blameless configuration has three stages;
e.)
it is the Lin that has two.
Which statement is causing the problem?
2 donpetru,
... If an audioamp develop DC voltage at output, dependant on output power, it must horrible distort, and you should measure it and repair this fault... it is not inherent behavior of topology.
Small asymmetric distortions can generate small DC offset (additionally to "normal" DC offset). Its not need to be horrible
. I think that for example 0,1% second harmonic can generate few milivolts additional offset (depending on output power). It may be interesting way to measure such "special" kind of distortions - just using low pass filter and DC meter.
Dear Boedy,
nice work. These pcb's have (hopefully) plated through holes?
It looks like the pcb's outline layer has been converted/merged to copper layers - maybe you need to cut the pcb's and remove the outline copper to avoid short circuits.
The bom list will take some days...
BR, Toni
Noise of audio amplifiers is usually measured with a 10Hz to 20kHz bandwidth.
A weighting is often used.
So the two figures to use would be 121dB 10Hz to 20kHz
and 127dB A weighting.
But these are very exceptional, making me believe that the measurement bandwidths don't comply with the norm.
Attached picture from VP-7723D datasheet showing built in filters.
Maybe my fault: Is "PSOPHO A" the same as "A-weighted"?
Measured 125db not 127db. Do you mean 121 db "unweighted" should correspond with 127 db "A-weighted" otherwise the filters are not the correct ones?
BTW: the measurements are from lab setup where the cable routing was optimized. I hope but don't expect the same noise figures from the ready made amplifier - we will see soon...
BR, Toni
Maybe my fault: Is "PSOPHO A" the same as "A-weighted"?
Measured 125db not 127db. Do you mean 121 db "unweighted" should correspond with 127 db "A-weighted" otherwise the filters are not the correct ones?
BTW: the measurements are from lab setup where the cable routing was optimized. I hope but don't expect the same noise figures from the ready made amplifier - we will see soon...
BR, Toni
Attachments
Last edited: