Bzzzzzzzzzz....
I could suggest a different use for the above boots (it is deep) ... but it would not be
productive.
The "blameless" was worked out in the forums as (built)projects by 2008... Along with the
ground lift , compensation/phase-margin , proper grounding techniques.
Member MJL21193's amp ,"frugalamp" , "supersym" (modular w/ a "blameless"
variant) were all 2009 amps.
There were no DX "blames" at this time.
So who copied who ?
Instead of pushing this fact , help was offered but ignored (me and andrew T.)
The 3 threads above + Self's book offer EVERYTHING you need to know ....
no excuses for a less than perfect result
.
And , real advice would be freely given - that is productive.
OS
I could suggest a different use for the above boots (it is deep) ... but it would not be
productive.
The "blameless" was worked out in the forums as (built)projects by 2008... Along with the
ground lift , compensation/phase-margin , proper grounding techniques.
Member MJL21193's amp ,"frugalamp" , "supersym" (modular w/ a "blameless"
variant) were all 2009 amps.
There were no DX "blames" at this time.
So who copied who ?
Instead of pushing this fact , help was offered but ignored (me and andrew T.)
The 3 threads above + Self's book offer EVERYTHING you need to know ....
no excuses for a less than perfect result
.And , real advice would be freely given - that is productive.
OS
dx super A
I'm here to hear all suggestions .
i'm not a designer engineer and i DON'T KNOW EVERYTHING
I will continue testing all my diy amplifiers
Didn't believe that measurments isn't the truth.
I have repeat measurments in another place with another test equipments.
Results are same and publiced.
The amplifier is playing of course ,the video is on youtube.
I have inspection my board again and again.
Another builder have same overshot ,so it is clear this isn't mine mistake.
No one is in my ignore list because no one is my enemy.
Best regards to all.
Thimios.
I'm here to hear all suggestions .
i'm not a designer engineer and i DON'T KNOW EVERYTHING
I will continue testing all my diy amplifiers
Didn't believe that measurments isn't the truth.
I have repeat measurments in another place with another test equipments.
Results are same and publiced.
The amplifier is playing of course ,the video is on youtube.
I have inspection my board again and again.
Another builder have same overshot ,so it is clear this isn't mine mistake.
No one is in my ignore list because no one is my enemy.
Best regards to all.
Thimios.
You are not in my ignore list too Thimios
Entered, but when i have perceived your good will....then was removed.
If another one builder has the overshot..then we have a problem.
My last post was not dedicated to your Thimios...the target was other guy.
As soon as my pcboards arrives...or even if not arrive, then i will etch and gonna build into the pcboard to see if the trouble goes to the pcboard or to parts....about the design i do not think so, as i do not have overshot in several amplifiers already made.
I had once, some overshot, in the Precision 1... what i cannot remember if this was detected before or after the release... the solution was the adjustment of the output coil ...inductance was increased if i am correct in my memory..also the parallel resistor was tweaked.... sorry, memory is not something that works very good on me.
If you find solution to the overshot..then let me know.
You see..there's not even output coil..maybe was removed...i cannot remember.... what i can remember is that Andrew T suggested to place the output coil nearby the output connectors in the rear panel...maybe this is the reason we cannot see the output coil in the schematic.
Another good suggestion used from him was to place the zobel in two places..one into the pcboard and other into the rear panel.... these guys, sometimes helps a lot... Ostripper helped me about the fly back diodes i am now using.
regards,
Carlos
Entered, but when i have perceived your good will....then was removed.
If another one builder has the overshot..then we have a problem.
My last post was not dedicated to your Thimios...the target was other guy.
As soon as my pcboards arrives...or even if not arrive, then i will etch and gonna build into the pcboard to see if the trouble goes to the pcboard or to parts....about the design i do not think so, as i do not have overshot in several amplifiers already made.
I had once, some overshot, in the Precision 1... what i cannot remember if this was detected before or after the release... the solution was the adjustment of the output coil ...inductance was increased if i am correct in my memory..also the parallel resistor was tweaked.... sorry, memory is not something that works very good on me.
If you find solution to the overshot..then let me know.
You see..there's not even output coil..maybe was removed...i cannot remember.... what i can remember is that Andrew T suggested to place the output coil nearby the output connectors in the rear panel...maybe this is the reason we cannot see the output coil in the schematic.
Another good suggestion used from him was to place the zobel in two places..one into the pcboard and other into the rear panel.... these guys, sometimes helps a lot... Ostripper helped me about the fly back diodes i am now using.
regards,
Carlos
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If you sold the board and the parts - had total control over everything ,
no one would have overshoot. Everyone would have your exact amp.
But , they use the parts they have ... all over the globe. BCxxx grade a-c
grade C can be very high (800Hfe),or low ... grade A (120).
I ran (simulated) your amp with 556b models - 10R/68R for LTP/CM , and it is
at edge of stability by design. For the 556B you use , this is good (sound).
Use a 556c , and overshoot/ringing will be there. The low Re for LTP/CM is good
for low noise , but the design offsets this by using 1.2k/56k for DC/Nfb (higher
noise).
This not MY opinion , but the way transistors work ... no way around it.
Using a huge miller (150p/220p) reduces performance at the VAS.
Subwoofer amps such as .. Project 117 .. use the "monster" miller. Rod elliot says "can not
oscillate under any condition" = 220pF miller.
68p miller with larger degeneration at the input stages does 2 things ,
1. Allows a larger margin for error in device selection (more parts will be stable).
2. The "poor" little input stage will not have to drive such a large capacitance.
Lower THD will result. You can also lower the CCS current for cooler transistors.
Compensation for this amp comes out better (with even better performance)
with (below-resistor/cap values) , even the BCxxx c grade is within limits. In fact , ANY grade
of ANY of the components (LTP/CM/VAS) will make for a very stable amp.
In the "imperfect world" what you are doing here is "trading off" a little
input noise for more stability-wider device selection-VAS performance.
OS
no one would have overshoot. Everyone would have your exact amp.
But , they use the parts they have ... all over the globe. BCxxx grade a-c
grade C can be very high (800Hfe),or low ... grade A (120).
I ran (simulated) your amp with 556b models - 10R/68R for LTP/CM , and it is
at edge of stability by design. For the 556B you use , this is good (sound).
Use a 556c , and overshoot/ringing will be there. The low Re for LTP/CM is good
for low noise , but the design offsets this by using 1.2k/56k for DC/Nfb (higher
noise).
This not MY opinion , but the way transistors work ... no way around it.
Using a huge miller (150p/220p) reduces performance at the VAS.
Subwoofer amps such as .. Project 117 .. use the "monster" miller. Rod elliot says "can not
oscillate under any condition" = 220pF miller.
68p miller with larger degeneration at the input stages does 2 things ,
1. Allows a larger margin for error in device selection (more parts will be stable).
2. The "poor" little input stage will not have to drive such a large capacitance.
Lower THD will result. You can also lower the CCS current for cooler transistors.
Compensation for this amp comes out better (with even better performance)
with (below-resistor/cap values) , even the BCxxx c grade is within limits. In fact , ANY grade
of ANY of the components (LTP/CM/VAS) will make for a very stable amp.
In the "imperfect world" what you are doing here is "trading off" a little
input noise for more stability-wider device selection-VAS performance.
OS
Attachments
Someone send me a message and the message said
He had much better sound when he installed a big capacitor in the input , a 4u7 capacitor, more than 300 volts of insulating voltage in a place we have some millivolts.
What can i say....i said.
Good...i am glad you like it this way.
The guy is Brazilian and does not read in English....overkill naturally, mixed with illusion....what can i do?.. argue with him?... no way.... people beliefs are like faith...it is stronger than rational conversation.
Well... the feeling is to ask the guy to suck a screw till it become a wooden nail...but we have to be educated...at the end, we have our own crazy stuff too.
Then the guy will install that huge capacitor into my amplifier input and people will start to think the circuit designer is mad or mentally retarded.
regards,
Carlos
He had much better sound when he installed a big capacitor in the input , a 4u7 capacitor, more than 300 volts of insulating voltage in a place we have some millivolts.
What can i say....i said.
Good...i am glad you like it this way.
The guy is Brazilian and does not read in English....overkill naturally, mixed with illusion....what can i do?.. argue with him?... no way.... people beliefs are like faith...it is stronger than rational conversation.
Well... the feeling is to ask the guy to suck a screw till it become a wooden nail...but we have to be educated...at the end, we have our own crazy stuff too.
Then the guy will install that huge capacitor into my amplifier input and people will start to think the circuit designer is mad or mentally retarded.
regards,
Carlos
Attachments
Connect your potentiometer case the way shown in this video
06:20 aproximately.
How To Build A Tweed Deluxe Kit - YouTube
regards,
Carlos
06:20 aproximately.
How To Build A Tweed Deluxe Kit - YouTube
regards,
Carlos
Arrived!.... pcboards from Juan Vargas arrived my home
https://www.youtube.com/watch?v=3C48Qt1Ph4M
regards,
Carlos
https://www.youtube.com/watch?v=3C48Qt1Ph4M
regards,
Carlos
I am at work and i am already inspecting with magnifiers
Wonderfull pcboard... very well made...we have worked a lot...in special you Juan.
I could not find any mistake till this moment... and i do think i will not find any technicall error alike long tracks, nearby tracks, danger of magnetic coupling or something alike.
I will assemble to check that overshot...it is not a big problem, but this kind of stuff scares people...and i gonna find the way to remove, or reduce, if i face the overshot at home
I will do it, but slowly as i want to enjoy myself building the best pcboard we have made.
regards,
Carlos
Wonderfull pcboard... very well made...we have worked a lot...in special you Juan.
I could not find any mistake till this moment... and i do think i will not find any technicall error alike long tracks, nearby tracks, danger of magnetic coupling or something alike.
I will assemble to check that overshot...it is not a big problem, but this kind of stuff scares people...and i gonna find the way to remove, or reduce, if i face the overshot at home
I will do it, but slowly as i want to enjoy myself building the best pcboard we have made.
regards,
Carlos
You know Juan...i still have the kit of parts you have sent
to populate the first pcboard you made...that shipment lost....i will populate one pcboard with these parts that are reserved for this purpose.
From Brasil to outside Brasil.... exporting things.... postal system works perfectly..but the opposite, the entrance of gods is complicated.
I cannot remember, but you send two different packages..one had parts and arrived..other had pcboards and have never arrived...that one delayed 6 months to arrive in Francisco hands..from São Paulo..... the problem is Brazilian mail system..inside Brasil things are lost.
Dudainc that very often receive things from Brasil, said he have never lost anything...but something he sent to Brasil have never arrived.... so...there's a problem with that route...from outside Brasil to inside Brasil.
From 2000 to 2010 i have never lost anything shipped to Brasil...but these last years everything changed.
regards,
Carlos
to populate the first pcboard you made...that shipment lost....i will populate one pcboard with these parts that are reserved for this purpose.
From Brasil to outside Brasil.... exporting things.... postal system works perfectly..but the opposite, the entrance of gods is complicated.
I cannot remember, but you send two different packages..one had parts and arrived..other had pcboards and have never arrived...that one delayed 6 months to arrive in Francisco hands..from São Paulo..... the problem is Brazilian mail system..inside Brasil things are lost.
Dudainc that very often receive things from Brasil, said he have never lost anything...but something he sent to Brasil have never arrived.... so...there's a problem with that route...from outside Brasil to inside Brasil.
From 2000 to 2010 i have never lost anything shipped to Brasil...but these last years everything changed.
regards,
Carlos
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I will manage to have some time to assemble
Here you have a video that explains.
https://www.youtube.com/watch?v=B0LkgKN7_6A
regards,
Carlos
Here you have a video that explains.
https://www.youtube.com/watch?v=B0LkgKN7_6A
regards,
Carlos
I have started to assemble.
Here you have it.
https://www.youtube.com/watch?v=ePetsqepbIk
regards,
Carlos
Here you have it.
https://www.youtube.com/watch?v=ePetsqepbIk
regards,
Carlos
Here you can see where you can find Dx Amplifiers
Models shown, all DIY models published in this forum.
https://www.youtube.com/watch?v=iVBal6s9Czk
regards,
Carlos
Models shown, all DIY models published in this forum.
https://www.youtube.com/watch?v=iVBal6s9Czk
regards,
Carlos
Well I finished the Super A. Been playing it most of the morning. Sounds very nice. I have it biased at 200mA per rail and the heatsinks are barely warm. I'm going to leave it there for a while and let everything burn in. I used a Mr Evil/PMI Cap Multiplier for the PSU as I am using the DX power supply for another amp that needs higher voltage. Using a 25-0-25vac Antek transformer and with a one volt drop for the regulator the rails are +/-38.4Vdc.
Here are some pics of the finished amp.
Blessings, Terry
Here are some pics of the finished amp.
Blessings, Terry
Attachments
