Question about 2.2uf/100ohm on input
Is this important fore curcuit, or only fore DC blocking, and could be removed, if no DC from source?
But this is fun
Probably soon I can do your DX blindfolded, and still have no clew as to how it works
Trying to figure out which parts/components are important
In other words, which components belongs to certain curcuits
Anyway, been through some variations of layout, and ended with more and more below board mounted components
But it got more and more messy, and difficult to draw
So, I decided to try and do it right
I plan to have onboard supply, if I can do it
You know those drawings where you "just fill in the missing parts to see what it is"
Ehh, as you can see, drivers missing
Is this important fore curcuit, or only fore DC blocking, and could be removed, if no DC from source?
But this is fun
Probably soon I can do your DX blindfolded, and still have no clew as to how it works
Trying to figure out which parts/components are important
In other words, which components belongs to certain curcuits
Anyway, been through some variations of layout, and ended with more and more below board mounted components
But it got more and more messy, and difficult to draw
So, I decided to try and do it right
I plan to have onboard supply, if I can do it
You know those drawings where you "just fill in the missing parts to see what it is"
Ehh, as you can see, drivers missing
Attachments
Still working
But I will need to have components in my hands to finish
Found a good source of Sanken I may use
Also been looking at other drivers
Resistors will be new Takman carbon
Carlos
Fore different driver
I suppose I need to watch "current gain" ?
I will stick to 3-4Mhz types, like the TIP41/42
Is it ok to use polystyrene caps fore all small caps, or do I need ceramics?
I will also try to get your later bias adjust curcuit back on the amp board, and only mount sensor transistor on output transistor, if thats ok?
But I will need to have components in my hands to finish
Found a good source of Sanken I may use
Also been looking at other drivers
Resistors will be new Takman carbon
Carlos
Fore different driver
I suppose I need to watch "current gain" ?
I will stick to 3-4Mhz types, like the TIP41/42
Is it ok to use polystyrene caps fore all small caps, or do I need ceramics?
I will also try to get your later bias adjust curcuit back on the amp board, and only mount sensor transistor on output transistor, if thats ok?
Attachments
I see you are on the mood... doing creative job
do not worry about voltage gain into the drivers and output... voltage gain there is 1....in other words...no voltage gain there.
You have current gain..the beta multiplication...but even this is not something to worry, as VAS works with higher current than normal..and this will be enougth, even if you use lower gain transistors.
Well... this amplifier was built and tested, several times, but using TIP41 and TIP42...also BD139 and BD140 was used.... it seems to me can work with the transistor you choice... need to face the rail to rail voltages, and gain from 50 to 200.... with those tested i can guarantee that you will not have surprises.
regards,
Carlos
do not worry about voltage gain into the drivers and output... voltage gain there is 1....in other words...no voltage gain there.
You have current gain..the beta multiplication...but even this is not something to worry, as VAS works with higher current than normal..and this will be enougth, even if you use lower gain transistors.
Well... this amplifier was built and tested, several times, but using TIP41 and TIP42...also BD139 and BD140 was used.... it seems to me can work with the transistor you choice... need to face the rail to rail voltages, and gain from 50 to 200.... with those tested i can guarantee that you will not have surprises.
regards,
Carlos
Re: I see you are on the mood... doing creative job
Yes thanks, good advise
I did decide to do so, when I found my Sankens useless
Then I just now found Sanken near by, and it sort of went off the path
Yeah, I better stick to the original, and I do remember about some problems with using other drivers
So, no Sankens (2SC2922/2SA1216) neither, or would they still be ok, with no surprices ?
Question
Does the bias adjust transistor matter, or should it best be BD139 too?
Also have doubts about bias points "A" - "B" - "C"
Greg suggest to connect bias board to "A" and "B", but as far as I can see "B" has no connection no more
Maybe it should be "A" and "C"?
destroyer X said:
Yes thanks, good advise
I did decide to do so, when I found my Sankens useless
Then I just now found Sanken near by, and it sort of went off the path
Yeah, I better stick to the original, and I do remember about some problems with using other drivers
So, no Sankens (2SC2922/2SA1216) neither, or would they still be ok, with no surprices ?
Question
Does the bias adjust transistor matter, or should it best be BD139 too?
Also have doubts about bias points "A" - "B" - "C"
Greg suggest to connect bias board to "A" and "B", but as far as I can see "B" has no connection no more
Maybe it should be "A" and "C"?
Hi , Carlos. Need a pair of rear channel amps for my "supersym". I have a 26-0-26 trafo , njw0281/0302 (OP) mje15030/31 (drivers).
I have to fit the DX amp , big filter caps (6800uf) , and bridge all on one board (3.5' X 5.5") . I did all the power supply and output section with half the PCB space left. No parts under board and I will include the output coil and isolated ground resistor(10R).
The rest of the amp is all DX (DX compact)
Here are the little VAS/driver heatsinks I will use..
They solder right on board (Attached) I will have this done in a few days , so ..tinitus hold on...
I chose this amp because it is so simple and can be made very compact , it is derived from the famous aska 55 , and perfect to drive my little rear channel 8" speakers.
OS
I have to fit the DX amp , big filter caps (6800uf) , and bridge all on one board (3.5' X 5.5") . I did all the power supply and output section with half the PCB space left. No parts under board and I will include the output coil and isolated ground resistor(10R).
The rest of the amp is all DX
(DX compact)Here are the little VAS/driver heatsinks I will use..
They solder right on board (Attached) I will have this done in a few days , so ..tinitus hold on...
I chose this amp because it is so simple and can be made very compact , it is derived from the famous aska 55
, and perfect to drive my little rear channel 8" speakers.OS
Attachments
Re: Re: I see you are on the mood... doing creative job
Definitely A and C.
http://users.tpg.com.au/users/gerskine/dxamp/media/dx amplifier-dx amplifier schematic-1.png
http://www.diyaudio.com/forums/attachment.php?s=&postid=1835123&stamp=1243051646
http://users.tpg.com.au/users/gerskine/dxamp/media/dx amplifier-dx amplifier vbias board-5.png
tinitus said:
Also have doubts about bias points "A" - "B" - "C"
Greg suggest to connect bias board to "A" and "B", but as far as I can see "B" has no connection no more
Maybe it should be "A" and "C"?
Definitely A and C.
http://users.tpg.com.au/users/gerskine/dxamp/media/dx amplifier-dx amplifier schematic-1.png
http://www.diyaudio.com/forums/attachment.php?s=&postid=1835123&stamp=1243051646
http://users.tpg.com.au/users/gerskine/dxamp/media/dx amplifier-dx amplifier vbias board-5.png
Yes Tinitus...of course you can use other ones
those 2SC2922 i have used dear Tinitus ..they are the best possible option... the first Dx used those ones..i still have them..interesting...i do not use afraid to loose them... those ones are the only super strong ones i have...one more pair from Klaas is still with me..but another type number.
to the VBE multiplier you can use any NPN you find...i love to use those plastic ones..as no insulator is needed.
be confortable to try things...if something strange happened i will help you to fix..sometimes we have surprises when we install a very fast transistor... into the VAS, for instance...those MJ10031 or something alike (Motorola) resulted bad...oscilated... i felt myself scared with so many options you had... afraigthned you make the wrong choice.... you know..some bad luck combination.
Human errors, bad decisions.... can be dangerous.... ship happens (hehehehe)... watch the photo
...........................................................................
Thank you Ostry.
Was the Sony 33 and Aksa project erased...maybe 61 into Rodd Elliot site that made me re-create this nice design that exists since the seventies..all factories have used .... including guitar amplifier factories.... all brands have used that topologie...a good sonic one.... even Sherwood has used...almost all them... inside some STK chips you have this topologie..
I have recalculated, and tried not to use Hugh special resources..and no one of them were included into the Dx amplifier..and have fixed something strange Aksa has..the power on thump.
I can say my toy is the winner into a bass competition with the Aksa..ahahahahahhaha..but loose in all the rest performance points...lost in sound stage, trebles, presence, clarity and focus.
I am glad you like it Ostry.
..........................................
Greg is precise.... he works in a very precise way....i think was a torture for him to work with me..producing boards to me and a site dedicated to the Dx amplifier... i have made several errors..i really think he became mad with me because of my lack of organization... so...he feel shocked when people say that have not understood those A, B and C points.
A and B was used in earlier Dx amplifier schematics...was for a fixed resistance..and from B to C a variable.... those two resistances had made the bias control...there the voltage were developed to put drivers and output transistors into conduction.... the idea was to use enormous heatsink and a fan... not to use VBE multiplier..... this because i had that big heatsink and many guys had too..so.... not really needed the thermal control when we had infinite heatsinks to that power range.
Then i decided to use diodes and them the VBE multiplier.... now a days..only A and C are needed to the VBE multiplier.
Do not worry with that B..it is there only as some historical registration.
regards,
Carlos
those 2SC2922 i have used dear Tinitus ..they are the best possible option... the first Dx used those ones..i still have them..interesting...i do not use afraid to loose them... those ones are the only super strong ones i have...one more pair from Klaas is still with me..but another type number.
to the VBE multiplier you can use any NPN you find...i love to use those plastic ones..as no insulator is needed.
be confortable to try things...if something strange happened i will help you to fix..sometimes we have surprises when we install a very fast transistor... into the VAS, for instance...those MJ10031 or something alike (Motorola) resulted bad...oscilated... i felt myself scared with so many options you had... afraigthned you make the wrong choice.... you know..some bad luck combination.
Human errors, bad decisions.... can be dangerous.... ship happens (hehehehe)... watch the photo
...........................................................................
Thank you Ostry.
Was the Sony 33 and Aksa project erased...maybe 61 into Rodd Elliot site that made me re-create this nice design that exists since the seventies..all factories have used .... including guitar amplifier factories.... all brands have used that topologie...a good sonic one.... even Sherwood has used...almost all them... inside some STK chips you have this topologie..
I have recalculated, and tried not to use Hugh special resources..and no one of them were included into the Dx amplifier..and have fixed something strange Aksa has..the power on thump.
I can say my toy is the winner into a bass competition with the Aksa..ahahahahahhaha..but loose in all the rest performance points...lost in sound stage, trebles, presence, clarity and focus.
I am glad you like it Ostry.
..........................................
Greg is precise.... he works in a very precise way....i think was a torture for him to work with me..producing boards to me and a site dedicated to the Dx amplifier... i have made several errors..i really think he became mad with me because of my lack of organization... so...he feel shocked when people say that have not understood those A, B and C points.
A and B was used in earlier Dx amplifier schematics...was for a fixed resistance..and from B to C a variable.... those two resistances had made the bias control...there the voltage were developed to put drivers and output transistors into conduction.... the idea was to use enormous heatsink and a fan... not to use VBE multiplier..... this because i had that big heatsink and many guys had too..so.... not really needed the thermal control when we had infinite heatsinks to that power range.
Then i decided to use diodes and them the VBE multiplier.... now a days..only A and C are needed to the VBE multiplier.
Do not worry with that B..it is there only as some historical registration.
regards,
Carlos
Attachments
I have wondered about the "thump".
None of my amps ever do it. An original aska 55 / project 61 will "thump". trick is to get input to stabilize first , your zener does it , so will a LED CCS.This one is solved , just add a 22-47R to emitter of VAS tranny , you need to do this anyways as the higher gain transistors like 2sc3503 need to be degenerated unlike BD's or tips , Higher miller cap ..too, 47p - 68p.
I built 2 other DX's (for my daughter) they use the faster 2sa992 (input LTP) and 2sc3503 (VAS) and they nearly match the symasym for clarity AS WELL as having the deep bass. On the other hand , the DX always beat the symasym in bass until I built
a "supersym" (1500KVA + 8 output device monster). DX has "different" type of bass (bootstrap bass), still a real good deal for
a 7 transistor amp.
OS
Thanks tinitus.
I hope you are fine dear Greg... your recovery because of me
will remain for a couple of years... the other one is harder my dear.
I am very sorry about the problems you have faced dear Greg..believe me that i am really sorry... having worries about how you're feeling.
regards,
Carlos
will remain for a couple of years... the other one is harder my dear.
I am very sorry about the problems you have faced dear Greg..believe me that i am really sorry... having worries about how you're feeling.
regards,
Carlos
An externally hosted image should be here but it was not working when we last tested it.
I use to ask folks to measure their supplies under load
Watch this image:
Watch this image:
An externally hosted image should be here but it was not working when we last tested it.
Here is the text about...sorry, my word needs some adjustment
You see, i am testing this supply.
without load the voltage is 50V x 2,
loaded using 7 ohms x 2 resistances,
voltage dropped to 39.8V x 2
Observe both rails are loaded,
so, we have 5.68 amperes each rail.
This can feed an amplifier that will
pump 156 watts each channel, rms,
sinusoidal, continuous and unclipped.
This continuous power will happens
because the voltage drop under high
consumption.. and this is when the
speaker (or load) is 4 ohms.
But… when supply is not hardly
sucked in energy… say…moments
of low volume..musical silent moments,
the pianissimo moments, the supply
will charge the filter condensers and
you will have 50 volts for a peak of
power…not continuous…the supply
cannot keep this voltage continuously,
but you gonna have 248 watts RMS into
the peaks, undistorted power…and
if you accept some distortion you gonna
have your power doubled into the peaks.
And this is an excelent performance.
This supply is able to hold two channels,
each one of them producing 156 watts
rms, over 4 ohms, continuous, undistorted,
sinusoidal with the sinus frequency of
1 kilohertz….a 545 watts supply!
34000 uf will be needed to each rail to
feed two channels with that power..total
filter capacitance will be 68000uf.
Those 250 watts, each channel, are peak
power, transient power, a burst of power,
this will not be continuous, just for a
small moment…a brief burst of power,
but this is translated in our years as
quality and realism,
Carlos
You see, i am testing this supply.
without load the voltage is 50V x 2,
loaded using 7 ohms x 2 resistances,
voltage dropped to 39.8V x 2
Observe both rails are loaded,
so, we have 5.68 amperes each rail.
This can feed an amplifier that will
pump 156 watts each channel, rms,
sinusoidal, continuous and unclipped.
This continuous power will happens
because the voltage drop under high
consumption.. and this is when the
speaker (or load) is 4 ohms.
But… when supply is not hardly
sucked in energy… say…moments
of low volume..musical silent moments,
the pianissimo moments, the supply
will charge the filter condensers and
you will have 50 volts for a peak of
power…not continuous…the supply
cannot keep this voltage continuously,
but you gonna have 248 watts RMS into
the peaks, undistorted power…and
if you accept some distortion you gonna
have your power doubled into the peaks.
And this is an excelent performance.
This supply is able to hold two channels,
each one of them producing 156 watts
rms, over 4 ohms, continuous, undistorted,
sinusoidal with the sinus frequency of
1 kilohertz….a 545 watts supply!
34000 uf will be needed to each rail to
feed two channels with that power..total
filter capacitance will be 68000uf.
Those 250 watts, each channel, are peak
power, transient power, a burst of power,
this will not be continuous, just for a
small moment…a brief burst of power,
but this is translated in our years as
quality and realism,
Carlos
Attachments
I see you sometimes is very agressive with me...i use to notice those things but
i always forgive those things from you, because i know our character differences..cultural differences, life experience also different.
Also i know what you have lived those last years..or last year.... and because of that you turn this way...but inside yourself, without those dirty life facts we hate, you are a gentleman, a cooperator, a valuable man that knows how to recognize people's
character.
It is fine... inside my heart you have a lot of credits... alike a bank account you have to make a lot of ships or bad mood to disturb me.
Relax... even with all that mess i did, we succed Greg..our amplifier is popular...maybe a hundred stereos already built....and we did that.
About the mess i was already punished by the destiny..you do not imagine the troubles i had with another cooperator that used to forget things in a matter of minutes, despite skilled, competent and intelligent... he had no memory..... was a hard work..and this time i was alike in your place, supporting someone doing mess.
I see that in life we pay all we do wrong way.... if i made you suffer, i gonna suffer into almost the same situation.
Those days you're living you will be comparing people all the time long... a revolution...why i have lost such good friend..that wonderfull guy, when this idiot is still alive?
No problems..i have lived all that stuff when i lost mum...now a days a lot of hell bad women still alive bothering family ...my mum was sweet and gone too much early... i still feel angry with that... seems the evil survive for long.
For a very long time i had the intention to delete that "B" and red parts into the layout..but i do not like to give you orders... now a days, those things only confuses...also the VBE multiplier resistance must be 2K2 to make sense with the 750 ohms start up adjustment.
regards,
Carlos
i always forgive those things from you, because i know our character differences..cultural differences, life experience also different.
Also i know what you have lived those last years..or last year.... and because of that you turn this way...but inside yourself, without those dirty life facts we hate, you are a gentleman, a cooperator, a valuable man that knows how to recognize people's
character.
It is fine... inside my heart you have a lot of credits... alike a bank account you have to make a lot of ships or bad mood to disturb me.
Relax... even with all that mess i did, we succed Greg..our amplifier is popular...maybe a hundred stereos already built....and we did that.
About the mess i was already punished by the destiny..you do not imagine the troubles i had with another cooperator that used to forget things in a matter of minutes, despite skilled, competent and intelligent... he had no memory..... was a hard work..and this time i was alike in your place, supporting someone doing mess.
I see that in life we pay all we do wrong way.... if i made you suffer, i gonna suffer into almost the same situation.
Those days you're living you will be comparing people all the time long... a revolution...why i have lost such good friend..that wonderfull guy, when this idiot is still alive?
No problems..i have lived all that stuff when i lost mum...now a days a lot of hell bad women still alive bothering family ...my mum was sweet and gone too much early... i still feel angry with that... seems the evil survive for long.
For a very long time i had the intention to delete that "B" and red parts into the layout..but i do not like to give you orders... now a days, those things only confuses...also the VBE multiplier resistance must be 2K2 to make sense with the 750 ohms start up adjustment.
regards,
Carlos
Hello Max, do you have a suggestion..so post it here
Your cooperation is welcome.
Here is the supply i use together one Dx amplifier channel.
Explain your ideas with how and why... please...if cannot put in english, then write to me in spanish.
I hope not an electronic switching power supply... as i do not like that stuff... also, dear Max, Aksa uses a very simple power supply... i really do not think the audio quality difference is because of the supply.... switching power supply is not welcome..you are welcome..not the switching power supply...if that thing was really good, all good brands would use it..and they do not use..they try and fast they give up about those electronic supplies.
I know the reasons makes Aksa better..but i cannot tell folks...i have used the Hugh sub circuits and i could see i have matched his performance..but was not Dx Amplifier anymore..as a sligtly different, no power on thump Aksa...no more a Dx amplifier... and those modifications where not in the supply.
panzertoo@yahoo.com
regards,
Carlos
Your cooperation is welcome.
Here is the supply i use together one Dx amplifier channel.
Explain your ideas with how and why... please...if cannot put in english, then write to me in spanish.
I hope not an electronic switching power supply... as i do not like that stuff... also, dear Max, Aksa uses a very simple power supply... i really do not think the audio quality difference is because of the supply.... switching power supply is not welcome..you are welcome..not the switching power supply...if that thing was really good, all good brands would use it..and they do not use..they try and fast they give up about those electronic supplies.
I know the reasons makes Aksa better..but i cannot tell folks...i have used the Hugh sub circuits and i could see i have matched his performance..but was not Dx Amplifier anymore..as a sligtly different, no power on thump Aksa...no more a Dx amplifier... and those modifications where not in the supply.
panzertoo@yahoo.com
regards,
Carlos
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