Some pictures of Juan Vargas Diaz pcboards
Needing to contact Juan then use vargasmongo@gmail.com
regards,
Carlos
Needing to contact Juan then use vargasmongo@gmail.com
regards,
Carlos
Attachments
Where you can find Dx stuff
Video explain:
https://www.youtube.com/watch?v=iVBal6s9Czk
Regards,
Carlos
Video explain:
https://www.youtube.com/watch?v=iVBal6s9Czk
Regards,
Carlos
Juan Vargas Diaz pcboards
Here you have some pictures.
https://www.youtube.com/watch?v=NzmpCfPQQGc
regards,
Carlos
Here you have some pictures.
https://www.youtube.com/watch?v=NzmpCfPQQGc
regards,
Carlos
We have not Iordan...... about Brazilians building this unit
I am glad some people still build this unit....they like to reduce the bias to to avoid heat (the same as me) as they do not listen Classical Music and the increase of bias will not help modern music actually.
I have asked Zimmer not to provide pcboards anymore..people has not good knowledge (In Brazil) to assemble....they use to complain the sound is distorted because they forget to install fuses and power supply goes througth protective 100 ohms resistor (one per rail)...some increase the voluma and complain the resistor (no fuse) burns
Well.... others forget wire jumpers..and this opens the VBE multiplier and the consequence is the NPN driver goes immediatelly as 42 volts goes to the base.
So.... i concluded (very late conclusion i have to admit, as Hugh Dean concluded that in 2005) that it is not a good idea to sell kits of boards..i ordered Zimmer only to sell assembled and adjusted amplifiers...so....this is the way we are doing.
But!.... people has access to layout..and they can etch at their own home...people that etch their own pcboard, usually (not always) is more skilled and does not give me too much hard work explaining details and giving follow up trying to detect foolishes made in the power amplifier construction....or...builder errors.
Last idea i have is an amplifier with Op amp in the input, driving an output consisted by an EF dual transistor in darlington.... supplies may come from Personal computer junk old supplies or power transformer...everything on board...volume control, tone controls, power supply, regulators, power amplifiers and heatsink..all in one to be sold, IN BRAZIL, assembled and tested.
That's it...i hope you are fine...all of you ...and i do sent you best regards,
Carlos
I am glad some people still build this unit....they like to reduce the bias to to avoid heat (the same as me) as they do not listen Classical Music and the increase of bias will not help modern music actually.
I have asked Zimmer not to provide pcboards anymore..people has not good knowledge (In Brazil) to assemble....they use to complain the sound is distorted because they forget to install fuses and power supply goes througth protective 100 ohms resistor (one per rail)...some increase the voluma and complain the resistor (no fuse) burns
Well.... others forget wire jumpers..and this opens the VBE multiplier and the consequence is the NPN driver goes immediatelly as 42 volts goes to the base.
So.... i concluded (very late conclusion i have to admit, as Hugh Dean concluded that in 2005) that it is not a good idea to sell kits of boards..i ordered Zimmer only to sell assembled and adjusted amplifiers...so....this is the way we are doing.
But!.... people has access to layout..and they can etch at their own home...people that etch their own pcboard, usually (not always) is more skilled and does not give me too much hard work explaining details and giving follow up trying to detect foolishes made in the power amplifier construction....or...builder errors.
Last idea i have is an amplifier with Op amp in the input, driving an output consisted by an EF dual transistor in darlington.... supplies may come from Personal computer junk old supplies or power transformer...everything on board...volume control, tone controls, power supply, regulators, power amplifiers and heatsink..all in one to be sold, IN BRAZIL, assembled and tested.
That's it...i hope you are fine...all of you ...and i do sent you best regards,
Carlos
Attachments
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For you, a High Fidelity lover like me, try to find this book
It is awesome!
A Brazilian sent me as a gift.....a 100 Megabytes file.... i do not know if it is legal or not, reason why i cannot send you.... i receive as a PDF file.
It is about Acoustics...and it looks goes deep into acoustics..... there are several stuff i had not the knowledge about...so..... at least for me, it is a treasure.
I suggest you all to search for it, to buy it from Amazon if possible.
Another great book, mum gave it to me when i was 18 years old (1970), was Audio Cyclopedia, from Howard M. Tremaine.... 2 huge books about audio electronics and all world knowledge about it... several editions made....you can find it in Amazon.... i suppose it is updated because audio technology evoluted a lot since 1970, in special digital media.
My library is huge now a days...almost all good books about audio are there...if i had memory, i would be a wise man..... sadly as memory is something i have lost, i am not...but you can be as you are young.... read the stuff...yep.... read!
There are informations, that we cannot find in books, it is related to practice.... for this stuff you must search for the wise guys, as Hugh Dean, Doctor Self, Cordell and other good guys we have around...not exactly reading their books, but asking them to talk about some subject...ask Hugh about THD, about harmonics.... ask Cordell why FET is better than BGT and where and when it is not....ask Self if THD means audio quality...and why.... ask Pass why Class A can be unbeatable...or how can be beated...if a class AB can match or not...how and when this can happen.... ask Curl about front end...about component choices.... do not even try to find this stuff in their books...ask them.... practice is not inside books...only these men knows.... they are old...ask them before is too late....move!
Acoustics...search for Dudainc
regards,
Carlos
It is awesome!
A Brazilian sent me as a gift.....a 100 Megabytes file.... i do not know if it is legal or not, reason why i cannot send you.... i receive as a PDF file.
It is about Acoustics...and it looks goes deep into acoustics..... there are several stuff i had not the knowledge about...so..... at least for me, it is a treasure.
I suggest you all to search for it, to buy it from Amazon if possible.
Another great book, mum gave it to me when i was 18 years old (1970), was Audio Cyclopedia, from Howard M. Tremaine.... 2 huge books about audio electronics and all world knowledge about it... several editions made....you can find it in Amazon.... i suppose it is updated because audio technology evoluted a lot since 1970, in special digital media.
My library is huge now a days...almost all good books about audio are there...if i had memory, i would be a wise man..... sadly as memory is something i have lost, i am not...but you can be as you are young.... read the stuff...yep.... read!
There are informations, that we cannot find in books, it is related to practice.... for this stuff you must search for the wise guys, as Hugh Dean, Doctor Self, Cordell and other good guys we have around...not exactly reading their books, but asking them to talk about some subject...ask Hugh about THD, about harmonics.... ask Cordell why FET is better than BGT and where and when it is not....ask Self if THD means audio quality...and why.... ask Pass why Class A can be unbeatable...or how can be beated...if a class AB can match or not...how and when this can happen.... ask Curl about front end...about component choices.... do not even try to find this stuff in their books...ask them.... practice is not inside books...only these men knows.... they are old...ask them before is too late....move!
Acoustics...search for Dudainc
regards,
Carlos
Attachments
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I have found a wrong stuff in Juan Pcboard...my mistake
https://www.youtube.com/watch?v=MglTwdQr17s
The CCS control resistor is wrong.... the best value there is 180 ohms instead of 68 or even 82 ohms as published in march 2014 update.
With 82 ohms, some transistors operates at 50 degrées celsius...small ones...and this harm the amplifier performance.
Please, replace it!
Sorry...my fault.
regards,
Carlos
https://www.youtube.com/watch?v=MglTwdQr17s
The CCS control resistor is wrong.... the best value there is 180 ohms instead of 68 or even 82 ohms as published in march 2014 update.
With 82 ohms, some transistors operates at 50 degrées celsius...small ones...and this harm the amplifier performance.
Please, replace it!
Sorry...my fault.
regards,
Carlos
Dx Supply discharge time.... having fun!
Here you have a video:
https://www.youtube.com/watch?v=dObqWZG4imY
Set up conditions you can read in the comments line below Youtube video.
regards,
Carlos
Here you have a video:
https://www.youtube.com/watch?v=dObqWZG4imY
Set up conditions you can read in the comments line below Youtube video.
regards,
Carlos
How a mistake happens...several guys checking..no one have perceived
About this video below:
https://www.youtube.com/watch?v=MglTwdQr17s
The optimized value was 168 ohms... value found in simulator and tested into the prototype pcboard a long time ago....then i have reported to Juan 68 ohms....i reduced 100 as a big mistake..... latter, on a revision in March 2014 i found some transistors too much hot (50 degrées celsius)...... then i have increased to 82 ohms.... this made things better, but making comparison in between some amplifier models i have..i found sound compressed on this unit, due to the excess of current into the differential pair....this made me understand the sequence of errors made...and not detected in the revision...things we perceive when making A to B comparison..without reference we usually do not perceive.
Yes...i do mistakes.
regards,
Carlos
About this video below:
https://www.youtube.com/watch?v=MglTwdQr17s
The optimized value was 168 ohms... value found in simulator and tested into the prototype pcboard a long time ago....then i have reported to Juan 68 ohms....i reduced 100 as a big mistake..... latter, on a revision in March 2014 i found some transistors too much hot (50 degrées celsius)...... then i have increased to 82 ohms.... this made things better, but making comparison in between some amplifier models i have..i found sound compressed on this unit, due to the excess of current into the differential pair....this made me understand the sequence of errors made...and not detected in the revision...things we perceive when making A to B comparison..without reference we usually do not perceive.
Yes...i do mistakes.
regards,
Carlos
Juan Vargas Diaz pcboards are nice...and now with an error found
Your amplifier will sound even better...now without any compression.
https://www.youtube.com/watch?v=NzmpCfPQQGc
regards,
Carlos
Your amplifier will sound even better...now without any compression.
https://www.youtube.com/watch?v=NzmpCfPQQGc
regards,
Carlos
This one was made by Fábio Zimmer, in the south of Brazil
Zimmer is grandson from a German that scaped before WWII.
https://www.youtube.com/watch?v=rgJ7orwiKZc
regards,
Carlos
Zimmer is grandson from a German that scaped before WWII.
https://www.youtube.com/watch?v=rgJ7orwiKZc
regards,
Carlos
Yes dear Juan..... a shame.....i am sorry, my mistake
The amplifier works stable with the previous values...but overheat some transistors that may cause some off set drift and compresses the sound as the current to the differential is out of the "optimum" range.
With 180 ohms we have even new life to the amplifier...it was awesome in sonics before and now much better...try it and listen.
People have not complained about compressed sound..imagine how they gonna fell after modification...they will fell from their chair astonished with the sound.
Video below in the signature line, "unbeatable" is a Dx Super A with a different cascode VAS...not usual or traditional approach there..uses 6 transistors....you can notice the sound....it is using 180 ohms too....the circuit was sold to Nederland and may appear inside a high end amplifier wich brand i cannot tell.
regards,
Carlos
The amplifier works stable with the previous values...but overheat some transistors that may cause some off set drift and compresses the sound as the current to the differential is out of the "optimum" range.
With 180 ohms we have even new life to the amplifier...it was awesome in sonics before and now much better...try it and listen.
People have not complained about compressed sound..imagine how they gonna fell after modification...they will fell from their chair astonished with the sound.
Video below in the signature line, "unbeatable" is a Dx Super A with a different cascode VAS...not usual or traditional approach there..uses 6 transistors....you can notice the sound....it is using 180 ohms too....the circuit was sold to Nederland and may appear inside a high end amplifier wich brand i cannot tell.
regards,
Carlos
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I think I have a bunch of 180 resistors
so I will make the change to see how it responds is amazing because I don't even notice the change on sounds with R4 as 68R I will let you know after I make the changes Regards
Juan