That is just the star ground point - it is supposed to be connected. Note that a large thick ground jumper from that bridge point up to the ground point near the output transistors where the 100nF C17 to ground goes is needed.
ESP sells the PCBs and that comes with the full and correct schematic and customer support.
You won't find any ESP PCB print.
His other account, halojoy, last active in 2005. I challenge you to find his latest account (hello Carl)
after long Time
Hallo Everybody.
Years back now i have bought DX Boards like PCB showed #7558 cucicu.
Mine are original Chinese Pirates Boards- Sorry for this- i don't know it better
this Time, Uncle Charly!
After study on Gregs BIG DX Web Presentation i see all is fine with Board.
I read along the Thread and stuffed the Board with good Resistors from HiFi-
Collective UK.
For Input i choose the strong BC639/640- reversed pinout.
Also the TIP41/42 are from good known Seller Profusion, the SA SC from
German Seller Schuro and than i put in Faked Hitachi 669- very bad!- replaced with STM BD139 now. I could later compare with original bought from Tech DIY.
Than i hooked it up for setup with 10R 10W Resistor and could only set Bias to 185mV across Resistor- That brings me in big twice.
I looked again every Part, soldering point, Schematic, Board- all good.
Than i put it in Corner for Years now!!
Last week i hooked it up again, measuring every Voltage point, like advice on
Gregs side.
So i found out that the TIP got to low voltage on 33R resistor ~ 0,6..7V, between both A - C ~ 1,5V......hmmmmm?
All other is right.
I think reduce the Bias Pot, so bridge the 2k and Bias goes to ~ 0,250mV.....
hmmm.
What about the R13- 2,7k?- bridge them and Voltage goes to over 2V now.
Ahaaah!
Set the Bias Pot now, bridge again R13- ah- lower Voltage ~ 1,3V.... here is
the point- but really don't know why it doesn't work with R13?
I placed a 100R in now to have a resistance here- could be a mistake 100R?-
should be higher or so- i don't know.
But the Amp is working now....he....he!
The Heat sink must be bigger to dissipate 90-100mA.
I like the dynamic in Sound and the springily Bass- it's touching!
My Advice here is now: There is a Fault in Schematic- or what is it?- a stroke
against pirates?
Me don't like to wrote in this long thread here, but Greg gives the only contact directly to Carlos, so i end up here.
Hope it can help Others here not give up frustrated.
On my wish list is the DX Super A with TIP35/36- if i find Time.
There are coming out so many new good ideas Amplifier- APEX, Bigun, vzaichenko- jwilhelm, mooly, abetir, shaan and so on since last year.
Not to forget Nelson Pass with his Birthday Gift and the last stroke opened
M2 for diy.
So my Solder Iron have to glow now..... so many short time.....hechel.......hechel......what is to do as next?????.....ah.......so on!
Bangla H 50+
Hallo Everybody.
Years back now i have bought DX Boards like PCB showed #7558 cucicu.
Mine are original Chinese Pirates Boards- Sorry for this- i don't know it better
this Time, Uncle Charly!
After study on Gregs BIG DX Web Presentation i see all is fine with Board.
I read along the Thread and stuffed the Board with good Resistors from HiFi-
Collective UK.
For Input i choose the strong BC639/640- reversed pinout.
Also the TIP41/42 are from good known Seller Profusion, the SA SC from
German Seller Schuro and than i put in Faked Hitachi 669- very bad!- replaced with STM BD139 now. I could later compare with original bought from Tech DIY.
Than i hooked it up for setup with 10R 10W Resistor and could only set Bias to 185mV across Resistor- That brings me in big twice.
I looked again every Part, soldering point, Schematic, Board- all good.
Than i put it in Corner for Years now!!
Last week i hooked it up again, measuring every Voltage point, like advice on
Gregs side.
So i found out that the TIP got to low voltage on 33R resistor ~ 0,6..7V, between both A - C ~ 1,5V......hmmmmm?
All other is right.
I think reduce the Bias Pot, so bridge the 2k and Bias goes to ~ 0,250mV.....
hmmm.
What about the R13- 2,7k?- bridge them and Voltage goes to over 2V now.
Ahaaah!
Set the Bias Pot now, bridge again R13- ah- lower Voltage ~ 1,3V.... here is
the point- but really don't know why it doesn't work with R13?
I placed a 100R in now to have a resistance here- could be a mistake 100R?-
should be higher or so- i don't know.
But the Amp is working now....he....he!
The Heat sink must be bigger to dissipate 90-100mA.
I like the dynamic in Sound and the springily Bass- it's touching!
My Advice here is now: There is a Fault in Schematic- or what is it?- a stroke
against pirates?
Me don't like to wrote in this long thread here, but Greg gives the only contact directly to Carlos, so i end up here.
Hope it can help Others here not give up frustrated.
On my wish list is the DX Super A with TIP35/36- if i find Time.
There are coming out so many new good ideas Amplifier- APEX, Bigun, vzaichenko- jwilhelm, mooly, abetir, shaan and so on since last year.
Not to forget Nelson Pass with his Birthday Gift and the last stroke opened
M2 for diy.
So my Solder Iron have to glow now..... so many short time.....hechel.......hechel......what is to do as next?????.....ah.......so on!
Bangla H 50+Attachments
Hallo X and cucicu.
The Resistor is R13 where i have placed a 100R now- you can located it on pic- the one
with longer legs now.
I don't know if it is the right resistance size, but it works.
cucicu the L shape is 40 x 40 x 4mm thick.
I have seen your 100W ultimate Amp- or different- build with L shape in case, clever
way to minimize case size.
Cheers Bangla.
The Resistor is R13 where i have placed a 100R now- you can located it on pic- the one
with longer legs now.
I don't know if it is the right resistance size, but it works.
cucicu the L shape is 40 x 40 x 4mm thick.
I have seen your 100W ultimate Amp- or different- build with L shape in case, clever
way to minimize case size.
Cheers Bangla.
Hi Bangla,
No need to change the value of R13. the problem may be with VR3 viper. Also check R24 ,Q 8,related track, any short etc. if Vr3 viper open voltage accross A-C will less than 1.8V.Voltage between A and C =( 0.6/Vr3)(Vr3+R24)
So carefully check these 3 components and related tracks. Adjust the viper and measure the resistance across Vr3. If it is not changing replace Vr3 or check the track layout
BR
joshvi
No need to change the value of R13. the problem may be with VR3 viper. Also check R24 ,Q 8,related track, any short etc. if Vr3 viper open voltage accross A-C will less than 1.8V.Voltage between A and C =( 0.6/Vr3)(Vr3+R24)
So carefully check these 3 components and related tracks. Adjust the viper and measure the resistance across Vr3. If it is not changing replace Vr3 or check the track layout
BR
joshvi
Last edited:
Hallo Joshvi.
Thank you for advise.
I have checked VR3 again- it shows 886 Ohm now, also the dark Halko 2k is ok.
The measured Voltage between A - C bevor change R13 was ~ 1,3V and after is now
~ 2,4V.
I can adjust via VR3 different bias current now wich is stable ringing around 50-60mV
across bias point.
Also the offset crosses to zero and runs light to - (minus)1-3mv and regulated them self.
I have running the Amp over any hours and all is stable.
With my basic knowledge i really don't know why the Amp is doing it so.
For me it's a bit mysteriously.
The points where i have to solder the thermal BD139 i have checked 3 or more times and write with pen B - C- E point, and now again.
I only could hope any other- mused about this and can analyzing the reason.
Cheers Bangla.
Thank you for advise.
I have checked VR3 again- it shows 886 Ohm now, also the dark Halko 2k is ok.
The measured Voltage between A - C bevor change R13 was ~ 1,3V and after is now
~ 2,4V.
I can adjust via VR3 different bias current now wich is stable ringing around 50-60mV
across bias point.
Also the offset crosses to zero and runs light to - (minus)1-3mv and regulated them self.
I have running the Amp over any hours and all is stable.
With my basic knowledge i really don't know why the Amp is doing it so.
For me it's a bit mysteriously.
The points where i have to solder the thermal BD139 i have checked 3 or more times and write with pen B - C- E point, and now again.
I only could hope any other- mused about this and can analyzing the reason.
Cheers Bangla.
Hi Bangla,
The viper of Vr3 is connected to one of the end point.When you adjust the viper to one end , depends up on the point you connected the viper, resistance becomes zero.So the base and emitter of Q8 is shorted and no current will flow through Q8 (cut off).
Please check R12 also. Are you sure it is 2.2k ? if you put 33k or 22k instead of 2.2k the same will happen.
I didn't see any thing wrong with this schematics. Problem may be with your board.
Best Regards
Joshvi
The viper of Vr3 is connected to one of the end point.When you adjust the viper to one end , depends up on the point you connected the viper, resistance becomes zero.So the base and emitter of Q8 is shorted and no current will flow through Q8 (cut off).
Please check R12 also. Are you sure it is 2.2k ? if you put 33k or 22k instead of 2.2k the same will happen.
I didn't see any thing wrong with this schematics. Problem may be with your board.
Best Regards
Joshvi
Bangla.
Where is Carlos? Uncle Charlie, the "old man"?????
I see he has not been active since the 14th of December 2016? Hope he is well? Not been arrested and a political prisoner or worse, dead. Watched a YouTube vid where he went on about Brazil situation then gone! I want to purchase from him the very simple and inexpensive amp board and instruction manual only available through purchase. I don't want to be bleeding cow and food for the fishes (pirrana) and get that 80% build. I am as he describes, "like a dog chasing tail"! Too much info, builds,changes, dead links, etc, for a beginner to find solid info to build one of these. Any help, active links, contact info, would be greatly appreciated. Thanks his web site won't open for me! Wonder if gov. shut him down?
I see he has not been active since the 14th of December 2016? Hope he is well? Not been arrested and a political prisoner or worse, dead. Watched a YouTube vid where he went on about Brazil situation then gone! I want to purchase from him the very simple and inexpensive amp board and instruction manual only available through purchase. I don't want to be bleeding cow and food for the fishes (pirrana) and get that 80% build. I am as he describes, "like a dog chasing tail"! Too much info, builds,changes, dead links, etc, for a beginner to find solid info to build one of these. Any help, active links, contact info, would be greatly appreciated. Thanks his web site won't open for me! Wonder if gov. shut him down?
No, i am fine...alive and free.
I am just concentrated, 100 percent focused into sells i am making in Brazil for Brazilians only.
This is going fine, almost 400 units sold, built by me with my bare hands (and soldering iron of course).... it is doing great as i have to pay my daughter's University as sweet honey is studying to be a Medical Doctor and we are paying 2000 USD each month to the University..... crazy stuff!
Amplifier is a more modern version of Dx Amplifier, deeply tuned with some CCS included in a such way it can operate from plus and minus 6 volts to plus and minus 42 volts DC...output power goes above 100 Watts RMS
This amplifier i am not sharing schematic, it is not a DIY design and i am giving schematic only for customers, not only the main unit schematic but some special accessories.
It has a linear Supply with 40.000 uf/50 volts filter filled with tradicional snubbers, inductors, RF filters, voltage equalizers (to electrolitic capacitors) and some more features..indicators, rectifiers...very nice unit.
Amplifier is High End, distortion is low and i was seelling by a promotional price...very low...amplifier 70 USD assembled each channel and supply able to feed two channels under 4 ohms loads costing 50 USD.... some second harmonics only...and small..bellow 0.011% THD full power.
I repeat...not seeling outside Brazil and contact is made in Youtube... youtube video comments.
Interesting is some filters added.... a way to convert the unit to subwoofer operation, and full range input and also mids and treble input...the idea is to them to build a 4 amplifiers unit.... 2 amplifiers for woofer and 2 amplifier to mids and treble..each one of them with it's own volume potentiometer.
No tone controls due to that arrangement, simple and good.....the other idea is not to use passive filters into the output..no low impedance crossover to speakers.....output from power amplifier goes directly into dedicated drivers.
Schematic is secret..will not share...sorry.
Daugther has a band Aid...this is tradition here when girls enter University..they remove hairs and put the Band Aid as a sign they win the terrible race to beat thousands in a competition to enter the University... this is a great goal here.
THis is all i gonna talk about the subject....i have no interest to see China (and others) producing my stuff, as usually they do...reason why i am not more publishing in DIY because it is a display to foreigners pirates to come to copy good stuff.
Yes...alike US we are having problems with global government, socialism and things alike...we may start a civil war soon
I am having fun....i bougth an awfull Sony Shake system (i need the speaker and to tell the truth to Brazilians)..i use it to show them these systems are no good...and having them is easier to convince them this is no good...no counter argument can come to say this system is good whle i have one and i can put it under more modern laboratory and measure..they respect uncle Charlie.
Missing Hugh Dean... great guy....missing a lot Hugh Dean...my dear teacher.
Also i bought a small scooter and having fun nearby my home...the wind in my hairs are delicious.
Sound and image to see my prefered movie "These magnificent men and their flying machines" is now a days the best...with a giant screen covering the wall.
I cannot sell here..... because of that, as i am now a days retired, i am concentrated in Brazil... will not accept
orders from outside Brazil and from outside my youtube channel that has 9000 subscribers now a days
https://www.youtube.com/watch?v=aYr4t5566wo
regards,
I am just concentrated, 100 percent focused into sells i am making in Brazil for Brazilians only.
This is going fine, almost 400 units sold, built by me with my bare hands (and soldering iron of course).... it is doing great as i have to pay my daughter's University as sweet honey is studying to be a Medical Doctor and we are paying 2000 USD each month to the University..... crazy stuff!
Amplifier is a more modern version of Dx Amplifier, deeply tuned with some CCS included in a such way it can operate from plus and minus 6 volts to plus and minus 42 volts DC...output power goes above 100 Watts RMS
This amplifier i am not sharing schematic, it is not a DIY design and i am giving schematic only for customers, not only the main unit schematic but some special accessories.
It has a linear Supply with 40.000 uf/50 volts filter filled with tradicional snubbers, inductors, RF filters, voltage equalizers (to electrolitic capacitors) and some more features..indicators, rectifiers...very nice unit.
Amplifier is High End, distortion is low and i was seelling by a promotional price...very low...amplifier 70 USD assembled each channel and supply able to feed two channels under 4 ohms loads costing 50 USD.... some second harmonics only...and small..bellow 0.011% THD full power.
I repeat...not seeling outside Brazil and contact is made in Youtube... youtube video comments.
Interesting is some filters added.... a way to convert the unit to subwoofer operation, and full range input and also mids and treble input...the idea is to them to build a 4 amplifiers unit.... 2 amplifiers for woofer and 2 amplifier to mids and treble..each one of them with it's own volume potentiometer.
No tone controls due to that arrangement, simple and good.....the other idea is not to use passive filters into the output..no low impedance crossover to speakers.....output from power amplifier goes directly into dedicated drivers.
Schematic is secret..will not share...sorry.
Daugther has a band Aid...this is tradition here when girls enter University..they remove hairs and put the Band Aid as a sign they win the terrible race to beat thousands in a competition to enter the University... this is a great goal here.
THis is all i gonna talk about the subject....i have no interest to see China (and others) producing my stuff, as usually they do...reason why i am not more publishing in DIY because it is a display to foreigners pirates to come to copy good stuff.
Yes...alike US we are having problems with global government, socialism and things alike...we may start a civil war soon
I am having fun....i bougth an awfull Sony Shake system (i need the speaker and to tell the truth to Brazilians)..i use it to show them these systems are no good...and having them is easier to convince them this is no good...no counter argument can come to say this system is good whle i have one and i can put it under more modern laboratory and measure..they respect uncle Charlie.
Missing Hugh Dean... great guy....missing a lot Hugh Dean...my dear teacher.
Also i bought a small scooter and having fun nearby my home...the wind in my hairs are delicious.
Sound and image to see my prefered movie "These magnificent men and their flying machines" is now a days the best...with a giant screen covering the wall.
I cannot sell here..... because of that, as i am now a days retired, i am concentrated in Brazil... will not accept
orders from outside Brazil and from outside my youtube channel that has 9000 subscribers now a days
https://www.youtube.com/watch?v=aYr4t5566wo
regards,
Attachments
Last edited:
Good news
Thanks for assuring us that you are OK. How much$ for your lovely daughter! Lol, just joking. I am too a pervert old man. You have gained weight from your previous pic/ vids. Happens when you sit on but and solder boards all day! 400+ is a lot of soldering time. If I understand your post, there is no way to purchase your amps outside Brazil? I want one- see PM I sent you- would rather not purchase pirate amps from China or jim_jim if pirate also? I want the whole enchilada, not 80% hacked cow distraction for the fishes one!
Thanks for assuring us that you are OK. How much$ for your lovely daughter! Lol, just joking. I am too a pervert old man. You have gained weight from your previous pic/ vids. Happens when you sit on but and solder boards all day! 400+ is a lot of soldering time. If I understand your post, there is no way to purchase your amps outside Brazil? I want one- see PM I sent you- would rather not purchase pirate amps from China or jim_jim if pirate also? I want the whole enchilada, not 80% hacked cow distraction for the fishes one!
What about this one
Just put a bid in but not sure if it is right one, or which DX version it is? If it will come anywhere near the original sound quality wise? Any advice would be very welcome before I pay for it! I concerned by the need for a jumper on backside of board? Like it was not done correctly? Thanks. This will be my first amp that I have to populate myself.2X Class AB 60W Push-pull Stereo Audio Power Amplifier DIY Kits BASED ON DX-AMP | eBay
Just put a bid in but not sure if it is right one, or which DX version it is? If it will come anywhere near the original sound quality wise? Any advice would be very welcome before I pay for it! I concerned by the need for a jumper on backside of board? Like it was not done correctly? Thanks. This will be my first amp that I have to populate myself.2X Class AB 60W Push-pull Stereo Audio Power Amplifier DIY Kits BASED ON DX-AMP | eBay
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