I have made some suggestions to B, Cordell about the content of his next book and he liked what i said. I think he is a real gentleman and so much easier to read than Self. He has an open mind, Self seems more enamored with his own work than anything else it seems. I'd say Self is more like J. Curl, stuck with what worked 40 years ago and thinks that is all there is.
Self did characterize the "distortion mechanisms" in his book. 6-7 years ago
his book was the only book.
Same with the amps 5 years ago - just symasym , blameless , and leach.
We have a much broader base now. No one popularized many
of the good 70-80's japanese designs (cascoded luxmans / 3 stage sansui's
AND the NAD CFA's).
None of it is really "new" , some were just "overlooked" because of
a harder design scope.
OS
his book was the only book.
Same with the amps 5 years ago - just symasym , blameless , and leach.
We have a much broader base now. No one popularized many
of the good 70-80's japanese designs (cascoded luxmans / 3 stage sansui's
AND the NAD CFA's).
None of it is really "new" , some were just "overlooked" because of
a harder design scope.
OS
Pete,
I know I am older than you and I can tell you there was a time when most consumers thought that the Japanese amps must be junk, it was just a prejudice against most things made in Japan at one time but I think it was pretty prevalent at one time, So most people overlooked the Japanese designs out of hand even if there were good designs. There was also a time when so much from Japan was touting such low distortion numbers and outrageous power output that peope just didn't believe any of it. Now we know better about the better designs but that was just the way it was.
I know I am older than you and I can tell you there was a time when most consumers thought that the Japanese amps must be junk, it was just a prejudice against most things made in Japan at one time but I think it was pretty prevalent at one time, So most people overlooked the Japanese designs out of hand even if there were good designs. There was also a time when so much from Japan was touting such low distortion numbers and outrageous power output that peope just didn't believe any of it. Now we know better about the better designs but that was just the way it was.
I got me a brand new marantz sr600dc in the late 70's. That thing sounded great and lasted over 20 years with me beating the cr*p out of it.
not this one but like it.
https://www.youtube.com/watch?v=MHsDHNBcJP8
not this one but like it.
https://www.youtube.com/watch?v=MHsDHNBcJP8
marantz sr600dc Had Hdam (my pitchfork diamond buffer amp) running
a FET cascoded symmetrical power amp with a cascoded VAS.
A Jfet spooky amp. ha !
Contrary to Mr. Selfs assessment that a symmetrical is unreliable.
What bunk !
Many of the 70's Japanese amps were the kypton V (3 stage with
Jfet's). Kypton V has a much more reliable LED biased symmetrical VAS.
Would last 50 years with all film caps. 😱
Notice how all the Valve hybrids copied my "GLA". Did that 2 years ago.
Geez !
OS
a FET cascoded symmetrical power amp with a cascoded VAS.
A Jfet spooky amp. ha !
Contrary to Mr. Selfs assessment that a symmetrical is unreliable.
What bunk !
Many of the 70's Japanese amps were the kypton V (3 stage with
Jfet's). Kypton V has a much more reliable LED biased symmetrical VAS.
Would last 50 years with all film caps. 😱
Notice how all the Valve hybrids copied my "GLA". Did that 2 years ago.
Geez !
OS
Nope - just populate caps marked "a" in the driver section.
Damn - wahhhhh , I wanted to have the first ! If I used my old outputs , mine
would be a singin' now ! At least they are done , and have driven 1 pair
of outputs.
Well , you the man .. Terry. (I'm just an occasional builder , at best 😱😱).
OS
I've got boards waiting to test but have become swamped with work and haven't had time to assemble a set yet.
Small progress in symmetry.
I'm looking forward for best resistors values (R8,R9,R10,R11,R13,R14,R17,R18) FOR +/-50V power supply.
Is 47R a good choice ?
I haven't any trimmer smaller value than 500R for R6,R20.Are these ok?
This trimmers controls only the ccs or the offset simultaneously?
I'm looking forward for best resistors values (R8,R9,R10,R11,R13,R14,R17,R18) FOR +/-50V power supply.
Is 47R a good choice ?
I haven't any trimmer smaller value than 500R for R6,R20.Are these ok?
This trimmers controls only the ccs or the offset simultaneously?
Attachments
Besides stability , 47R will do for all the the re's (Q1-4 /7-10). Voltage
really don't matter on the "symetri' " (European type name 😛).
As long as you can get that 50R - 150R range out of those 500's , no
problem there.
Yes, you can affect offset and total VAS I by adjusting
the two CCS's (asymmetrically).
Make sure you fix the Q8 base trace error. R33 trace goes to Q8's
collector. I'll wait till you build it - I have the corrected layout to post
(and add to the first page).
OS
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Q1-4 ? 10-22R will do. This amp is not real "picky" , except
if you have too much gain (22R emitter resistors - terry) 😛
OS
I have to say, this amp is pretty tolerant for offset. Even a pretty big variance in the ccs doesn't through it off much.
Hey , Jeff. We could discuss some "gibberish" here ?
I know what you are saying with the uncalibrated hall current sensors now.
the ones with the built in "wire" (specc'ed conductor) are pre - calibrated.
A trace based one would have to be scaled to the users trace thickness/
width.
ACSxxxx says " motor control" for an app. Motors would surely throw off
quite the EMF. Look to the suggested uses to determine whether a humble
DIY amp would exceed what ever industrial uses there are for the IC.
OS
I know what you are saying with the uncalibrated hall current sensors now.
the ones with the built in "wire" (specc'ed conductor) are pre - calibrated.
A trace based one would have to be scaled to the users trace thickness/
width.
ACSxxxx says " motor control" for an app. Motors would surely throw off
quite the EMF. Look to the suggested uses to determine whether a humble
DIY amp would exceed what ever industrial uses there are for the IC.
OS