Dx Blame ST together Dx Super A

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#1,703
Are you joking?

500mA of output bias allows a maximum of 1Apk for ClassA output current.
a +-25Vdc PSU probably allows a ClassAB output of around 20W to 25W
That 1Apk equates to <4W of ClassA
That means your amplifier is NOT a ClassA type.
It is a high bias ClassAB with added crossover distortion, due to non optimal ClassAB biasing.
 
#1,704
AndrewT said:
Are you joking?

500mA of output bias allows a maximum of 1Apk for ClassA output current.
a +-25Vdc PSU probably allows a ClassAB output of around 20W to 25W
That 1Apk equates to <4W of ClassA
That means your amplifier is NOT a ClassA type.
It is a high bias ClassAB with added crossover distortion, due to non optimal ClassAB biasing.
Click to expand...
This amplifier has change values ,resistors,capacitors,power supply, so many times.......😕
 
#1,708
I have asked Eduardo Silveira a new recording because the one published

in the previous post was showing saturation in the recording or some problem in the mid range driver or tweeter...it is harshing...not perfect..and this amplifier does not sound this way.

regards,

Carlos
 

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#1,711
Dear Cook77 and Vrystaat, the one build was not me, was Mr. Silveira

from Brazil..... he asked me to remove because he made bad recording and this will harm the brand as audio quality is not fine.

I will ask moderators to remove these videos and Mr. Silveira will make new ones soon....of course i gonna publish them here.

Was not me the builder..i am showing something a friend did with my amplifier circuit but i gonna search for the circuit he used to the meters...i suppose was some germanium diodes or silicon diodes as rectifiers.... some nanofarads as filters and a resistor...not more than that...but i will ask the guy the schematic to post here...the meter driver schematic.

Thank you all by the understanding..will ask moderator to remove these videos...was the video owner that asked me as he perceive it is a shame the audio quality in the recording..he gonna try to make it better..less level, more absortion material around...better light, flat recording without tone controls...well...he will manage to make better audio recording.

regards,

Carlos
 
#1,716
Here you have a video about Eduardo Silveira...i have asked him to make a new video

Because the first one had bad audio recording...harshing sound.

But i am afraid you will not listen the audio..... he used a song that may be blocked...he know nothing about Youtube regulation and international laws.

This amplifier you see, the enclosure and pre amplifier is a Brazilian Quasar made from 1980 to 1988...inside there are Dx Super A modules and also a Dx Supply.... original Quasar pré amplifier is beeing used.... TL071 based circuits...tone control and filters.

regards,

Carlos


https://www.youtube.com/watch?v=cS-Hth9X5DE
 
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#1,717
I just did the 180 ohm swap for R4... I will say this was a solid amp to begin with and I am not sure how to describe the effect I would say less tiring, more transparent...maybe vocals are a little more transparent.

I am running this in a TO-3 version with MJ15015/6 at pretty high idle current. Still one of my favorite amps.
 
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