This last picture, the Dx Turbo, my home edition
Is now a days operating with 45 plus 45 volts.
It uses 3 pairs..all transistors absolutelly matched inside 2 percent tollerance...SO...no equalizing resistances are needed.
I'm using emitter resistances to allow me to measure the current into the ouput transistors (all them same time..all them the same gain, so all them will be conduction and i will have all those folks current into the emitter resistance)
One emitter resistance to the PNP emitters....other emitter resistance to the NPN emitters (joined together all them).... as i have two channels in this board..then you have 4 emitter resistances.
I have adjusted, there, to 500 uA to each power transistor... so measurement over each resistance is 335uA (0.000335A).
The best current is three times this one....or 1.5 miliamperes to each power transistor...this reduces distortion.
My decision was to operate with less heat.. accepting some distortions ..because heatsink is not very large.... the amplifier works dead cold!
regards,
Carlos
Is now a days operating with 45 plus 45 volts.
It uses 3 pairs..all transistors absolutelly matched inside 2 percent tollerance...SO...no equalizing resistances are needed.
I'm using emitter resistances to allow me to measure the current into the ouput transistors (all them same time..all them the same gain, so all them will be conduction and i will have all those folks current into the emitter resistance)
One emitter resistance to the PNP emitters....other emitter resistance to the NPN emitters (joined together all them).... as i have two channels in this board..then you have 4 emitter resistances.
I have adjusted, there, to 500 uA to each power transistor... so measurement over each resistance is 335uA (0.000335A).
The best current is three times this one....or 1.5 miliamperes to each power transistor...this reduces distortion.
My decision was to operate with less heat.. accepting some distortions ..because heatsink is not very large.... the amplifier works dead cold!
regards,
Carlos
Here is my home edition..simplified...i accept some risks of oscilations
so i have omitted stop resistors, also have not installed zobel filter...but this is to my own unit..if explode (i will be happy fixing and tweaking.. a good chance to see how stable it is).
For forum folks, i suggest to use zobel filter, also stop resistances and output coil too (because some long length of wire used by some folks)
This one is mine.... i accept the risks.... it is working stable till now (72 hours testing)..... build this one under your own risk!.... the schematic is published at Greg Erskine and also DHR Turbo thread.
regards,
Carlos
so i have omitted stop resistors, also have not installed zobel filter...but this is to my own unit..if explode (i will be happy fixing and tweaking.. a good chance to see how stable it is).
For forum folks, i suggest to use zobel filter, also stop resistances and output coil too (because some long length of wire used by some folks)
This one is mine.... i accept the risks.... it is working stable till now (72 hours testing)..... build this one under your own risk!.... the schematic is published at Greg Erskine and also DHR Turbo thread.
regards,
Carlos
Parallel Transistor Dx-Amp
Hi Dx,
Today i`m success parallel the output transistor by using 2 x fja4210 and 2 x fja4310. Power supply is switching provide output +37.4 0 -37.4 VDC at 15 amp. Large winding toroid core using 6 22 awg at primary and 6 18 awg at secondary.
what i feel is dx amp with 4 power transistor produce more power, hi treble and huge of bass, about the temp? Its cold than 2 output transistor like 3 times cold than before. Its has been running about 5 hours non stop at half volume (btw my mohawk 150 wrms 8 ohm like to come out from the box hehehehe ). I`m not finish the final case yet, tonight i`ll process new board for stereo amp.
I can feel the music and the quality clear treble and deep bass very good at vocal too.
Regars
Azmi.
Hi Dx,
Today i`m success parallel the output transistor by using 2 x fja4210 and 2 x fja4310. Power supply is switching provide output +37.4 0 -37.4 VDC at 15 amp. Large winding toroid core using 6 22 awg at primary and 6 18 awg at secondary.
what i feel is dx amp with 4 power transistor produce more power, hi treble and huge of bass, about the temp? Its cold than 2 output transistor like 3 times cold than before. Its has been running about 5 hours non stop at half volume (btw my mohawk 150 wrms 8 ohm like to come out from the box hehehehe ). I`m not finish the final case yet, tonight i`ll process new board for stereo amp.
I can feel the music and the quality clear treble and deep bass very good at vocal too.
Regars
Azmi.
An externally hosted image should be here but it was not working when we last tested it.
Very good Norazmi...thank you to share the image with us
If you want you can remove the excesses of thermal compound grease using brush and petrol solvent...alike Kerozene, or Gasoline, or some product used to clean paint brushes.
I am glad you have appreciated... the best thing, is that your hairs will became gray and white and your amplifier will continue working...very reliable this one.
- "Dx amplifier, the unit that can works with almost any voltage you have..and will outperform many more complicated schematics..the sophisticated amplifier's eating machine!"
regards,
Carlos
If you want you can remove the excesses of thermal compound grease using brush and petrol solvent...alike Kerozene, or Gasoline, or some product used to clean paint brushes.
I am glad you have appreciated... the best thing, is that your hairs will became gray and white and your amplifier will continue working...very reliable this one.
- "Dx amplifier, the unit that can works with almost any voltage you have..and will outperform many more complicated schematics..the sophisticated amplifier's eating machine!"
regards,
Carlos
Re: Re: Parallel Transistor Dx-Amp
Hi AndrewT,
The most experience person too in DiyAudio
, i`ll post it tomorrow because time now at my country GMT +8:00 is 3:09 AM at morning. Cant test it now, forgot to get the ac voltage at output, yes i know its important too.
I`ll take it tomorrow, here we have ac 240 vac. I`ve test with normal transformer 240 vac to 28 0 28 vac 5 amp, the led power will clip at half volume and large voltage drop, so i choose switching (mosfet IRFP460 x 2 driver) supplies and make transformer using ferrite toroid with 6 22 awg at primary and 6 18 awg at secondary. I use ultrafast rectifier to-220 case x 4 rate at 10 amp each, having choke after diode then go to 8 50v 3300uf on each rail(total 16 pcs).
I`m plan to use 2 dx amp(stereo) with this. I`m just newbie and trying build Dx Amp with great guide by DX A.K.A Mr Carlos very very friendly person teach me step by step sometimes i`m feel my question like a kids. Idiot question ... etc.... SO i`m 100% respect to Mr DX. From what i learn and i remember what my teacher say at school when i was 15 before (now 32). The person whois always teaching another person and share their knowledge will get more knowledge and experience.
Best Regards,
Azmi.
Hi AndrewT,
The most experience person too in DiyAudio
, i`ll post it tomorrow because time now at my country GMT +8:00 is 3:09 AM at morning. Cant test it now, forgot to get the ac voltage at output, yes i know its important too.I`ll take it tomorrow, here we have ac 240 vac. I`ve test with normal transformer 240 vac to 28 0 28 vac 5 amp, the led power will clip at half volume and large voltage drop, so i choose switching (mosfet IRFP460 x 2 driver) supplies and make transformer using ferrite toroid with 6 22 awg at primary and 6 18 awg at secondary. I use ultrafast rectifier to-220 case x 4 rate at 10 amp each, having choke after diode then go to 8 50v 3300uf on each rail(total 16 pcs).
I`m plan to use 2 dx amp(stereo) with this. I`m just newbie and trying build Dx Amp with great guide by DX A.K.A Mr Carlos very very friendly person teach me step by step sometimes i`m feel my question like a kids. Idiot question ... etc.... SO i`m 100% respect to Mr DX. From what i learn and i remember what my teacher say at school when i was 15 before (now 32
). The person whois always teaching another person and share their knowledge will get more knowledge and experience.Best Regards,
Azmi.
AndrewT said:
Re: Re: Parallel Transistor Dx-Amp
Hi AdrewT,
I`ve test it today done, got 16.47 average vac on output and mohawk speaker 150wrms cant take it more, the cone become warm. It has been play at half volume. At this point my distance from the speaker about 2 meter and i can feel the energy of bass deep into my heart.
Regards,
Azmi.
Hi AdrewT,
I`ve test it today done, got 16.47 average vac on output and mohawk speaker 150wrms cant take it more, the cone become warm. It has been play at half volume. At this point my distance from the speaker about 2 meter and i can feel the energy of bass deep into my heart.
Regards,
Azmi.
AndrewT said:
heheheh.... 35 watts is easy for this amplifier
It can be playing that level for whole life..need only a good transformer and heatsink not to melt all stuff.
You can leave it this way and go the Mall, to by some food, and when return go to visit your girl friend...when return the amplifier will be there, playing in a very happy way.
regards,
Carlos
It can be playing that level for whole life..need only a good transformer and heatsink not to melt all stuff.
You can leave it this way and go the Mall, to by some food, and when return go to visit your girl friend...when return the amplifier will be there, playing in a very happy way.
regards,
Carlos
Playing hard... disco music
Hi Dx,
Now i`m take some times setup with proper preparation using +37.4 0 -37.4 15 amps switching supply. Using 12" Alpine speaker full range at 8 ohm, i`ve got 27.1 vac at output speaker its seems to bee peak volume i can play with that supply and its enough to make my friends scream hehehehe. Play it with safe and slowly increase the volume. it has been played at open air at my home at 6:45 pm and nothing melt the amp was doing great and also speaker. The supply running with normal condition too.
Dx your amp is rock, but notice that my friends surprise about the quality of sound produce by this Dx amp.
Regards,
Azmi
Hi Dx,
Now i`m take some times setup with proper preparation using +37.4 0 -37.4 15 amps switching supply. Using 12" Alpine speaker full range at 8 ohm, i`ve got 27.1 vac at output speaker its seems to bee peak volume i can play with that supply and its enough to make my friends scream hehehehe
. Play it with safe and slowly increase the volume. it has been played at open air at my home at 6:45 pm and nothing melt the amp was doing great and also speaker. The supply running with normal condition too.Dx your amp is rock, but notice that my friends surprise about the quality of sound produce by this Dx amp.
Regards,
Azmi
Dx Hrii
I didn't think gray/silver and black would look good.
But I think it looks great.
Kind of looks like an older Goldmund.
Front panel received from Front Panel Express dot com.
You see the old Sansui 2000 faceplate behind the new panel.
The panel size was just a tiny bit smaller than it had to be.
On purpose- better small than too big and have to file down.
the frosted glass in the opening is in the original Sansui receiver
2 green lights = good
Lights recessed behind a smoked glass plate give nice 3-D visual effect.
The back did not come out too good as I had to cut out the top support, caused a bow in the back.
Its not 220V but I left as much original as I possibly could.
Even used the original fuse holders.
The inside is at Post #6071
I didn't think gray/silver and black would look good.
But I think it looks great.
Kind of looks like an older Goldmund.
An externally hosted image should be here but it was not working when we last tested it.
Front panel received from Front Panel Express dot com.
You see the old Sansui 2000 faceplate behind the new panel.
The panel size was just a tiny bit smaller than it had to be.
On purpose- better small than too big and have to file down.
the frosted glass in the opening is in the original Sansui receiver
2 green lights = good
Lights recessed behind a smoked glass plate give nice 3-D visual effect.
An externally hosted image should be here but it was not working when we last tested it.
The back did not come out too good as I had to cut out the top support, caused a bow in the back.
Its not 220V but I left as much original as I possibly could.
Even used the original fuse holders.
An externally hosted image should be here but it was not working when we last tested it.
The inside is at Post #6071
Lovely enclosure Igreen..congratulations
http://www.youtube.com/watch?v=hjcbdDTU5_Y
above link is the introductory slide movie about the series of 14 slide movies i am uploading to youtube.
They gonna be:
- "How to design audio amplifiers using simplified method"
Ohms law only...using the Dx Amplifier as the basic schematic.
I will be uploading those slide movies during those next three days.... two movies already there...in the sequence you gonna have Part 1A, Part 1B, Part 2A, Part 2B......... till you gonna have part 7B (the fourtenth part)
It is basic, to beginners, not to engineers, i supose they will not enjoy the non precise informations posted there...but gonna be very helpfull to the ones needs such kind of basic things.
regards,
Carlos
http://www.youtube.com/watch?v=hjcbdDTU5_Y
above link is the introductory slide movie about the series of 14 slide movies i am uploading to youtube.
They gonna be:
- "How to design audio amplifiers using simplified method"
Ohms law only...using the Dx Amplifier as the basic schematic.
I will be uploading those slide movies during those next three days.... two movies already there...in the sequence you gonna have Part 1A, Part 1B, Part 2A, Part 2B......... till you gonna have part 7B (the fourtenth part)
It is basic, to beginners, not to engineers, i supose they will not enjoy the non precise informations posted there...but gonna be very helpfull to the ones needs such kind of basic things.
regards,
Carlos
How to create, or design, or force to operate an audio amplifier alike the Dx one
Do it by yourself...create and build your own..it is for free..absolutelly for free!
The simple know how used, common send and ohms law is all you need....2 or three neuroniuns full operating will be enougth.
ahahahahah!
Type in youtube:
"how to design an audio amplifier"...and introductory slide movie is there and already 8 from 14 parts uploaded.... fixed schematic as image and narrative explaing all details.
Be happy, the way i am..build, share, enjoy, be friendly and figth against selfish folks.
regards,
Carlos
Do it by yourself...create and build your own..it is for free..absolutelly for free!
The simple know how used, common send and ohms law is all you need....2 or three neuroniuns full operating will be enougth.
ahahahahah!
Type in youtube:
"how to design an audio amplifier"...and introductory slide movie is there and already 8 from 14 parts uploaded.... fixed schematic as image and narrative explaing all details.
Be happy, the way i am..build, share, enjoy, be friendly and figth against selfish folks.
regards,
Carlos
Attachments
This handsome man is TAJ, a very important friend we have
he use to produce schematics for us.... a very nice guy from Canadá.
It is a secret... i would not let you know...but he travelled to Australia and met Greg Erskine and Hugh Dean.
Greg Erskine is another very good looking man, i have a two years old picture of him.... looks alike John Lennon from The Beatles.
Those guys do not give me permission to publish their pictures... even TAJ asked not to publish his real family name.
Despite i cannot understand those things (i am brazilian, another culture, more free, more open) i have to respect.
TAJ had nice moments together dear Hugh Dean...had a Capuccino Coffee together TAJ and his wife.
regards,
Carlos
he use to produce schematics for us.... a very nice guy from Canadá.
It is a secret... i would not let you know...but he travelled to Australia and met Greg Erskine and Hugh Dean.
Greg Erskine is another very good looking man, i have a two years old picture of him.... looks alike John Lennon from The Beatles.
Those guys do not give me permission to publish their pictures... even TAJ asked not to publish his real family name.
Despite i cannot understand those things (i am brazilian, another culture, more free, more open) i have to respect.
TAJ had nice moments together dear Hugh Dean...had a Capuccino Coffee together TAJ and his wife.
regards,
Carlos
An externally hosted image should be here but it was not working when we last tested it.
Dx Corp Logo
Hi Dx,
Its has been 2-3 weeks play arround with dx-amp, its the first model produce by Mr Carlos is it?. Ok now the amp work great running every day and night, i think the sound also perform better than before, i`ve increase the rail voltage to +38 0 -38 vdc using offline smps.
Ok now, i`ve finish the amp build in stereo and of course 2 pair power transistor per board, so i just thinking about the Logo or something for this amp, i would like to suggest if you have time to make Dx Corp logo, maybe can be download from your website so it will easy to print out and put it on the amp box. What ya think?
btw i`ve few question, if the rails increase to +45 0 -45 VDC so what about Q3 (BD139)? It must be change or it can handle the new rails voltage? But i`ve seen MJE340 have high voltage but i`m worried about sound quality. Or maybe better put tip41c? I`ve test for several time on test board, i`ve made 3 pcs dx amp board, 2 already assembly and another one for testing purpose, but i`m suprise with one test yesterday i`m using 2sc4242 N type bipolar tripple diffused as a bias and amazingly the amp more stable and i`ve reduce the bias voltage to 450 mv and still 0 mv at output signal. Sound is very good and output transistor still cool even volume increase and produce 16-18 vac at output.
What is that mean by tripple diffused? fast transistor?
I`ll take some picture tomorrow and i`ll show you when this amp drive mohawk 8" 8 ohm impedance rated 120 wrms and max 240 wrms, this speaker cant handle the power of this amp at +38.4 0 -38.4 15 amps on each rails. The cone just touch the limit (cone touching at bottom) and we can hear it. lol. I think its suiteable for 10" driver i have to try both.
Best Regards,
Azmi
Hi Dx,
Its has been 2-3 weeks play arround with dx-amp, its the first model produce by Mr Carlos is it?
. Ok now the amp work great running every day and night, i think the sound also perform better than before, i`ve increase the rail voltage to +38 0 -38 vdc using offline smps.Ok now, i`ve finish the amp build in stereo and of course 2 pair power transistor per board, so i just thinking about the Logo or something for this amp, i would like to suggest if you have time to make Dx Corp logo, maybe can be download from your website so it will easy to print out and put it on the amp box. What ya think?
btw i`ve few question, if the rails increase to +45 0 -45 VDC so what about Q3 (BD139)? It must be change or it can handle the new rails voltage? But i`ve seen MJE340 have high voltage but i`m worried about sound quality. Or maybe better put tip41c? I`ve test for several time on test board, i`ve made 3 pcs dx amp board, 2 already assembly and another one for testing purpose, but i`m suprise with one test yesterday i`m using 2sc4242 N type bipolar tripple diffused as a bias and amazingly the amp more stable and i`ve reduce the bias voltage to 450 mv and still 0 mv at output signal. Sound is very good and output transistor still cool even volume increase and produce 16-18 vac at output.
What is that mean by tripple diffused? fast transistor?
I`ll take some picture tomorrow and i`ll show you when this amp drive mohawk 8" 8 ohm impedance rated 120 wrms and max 240 wrms, this speaker cant handle the power of this amp at +38.4 0 -38.4 15 amps on each rails. The cone just touch the limit (cone touching at bottom) and we can hear it. lol
. I think its suiteable for 10" driver i have to try both.Best Regards,
Azmi
I cannot make Logo...i do not know how to do such kind of things
The one can produce is TAJ...but the guy use to be very busy... really busy.
Yes..increasing voltage you have to substitute transistors, some of them will not hold the rail to rail voltage..and rail to rail is not really needed into all cases but it is a nice and safe decision..so... catch transistors that can hold rail to rail.
My prefered ones are 2SC4793 and 2SA1837... those are the ones Hugh Dean from Aksa have selected because audio quality.
To the VAS, a better choice will be faster transistors, able to manage rail to rail voltage, more than 5 watts of power (all mid power ones can hold that)... and a good idea is to find transistors that have small capacitance from base to emitter..those are faster ones normally.... i cannot inform the one Hugh uses...it is a secret.
2 pairs to the output when voltage is higher than 42 volts is a good idea and you are already using it.
Yessssss...pictures..... goooood!
Also video uploaded to youtube and link here will good...very, very good.
Tripple diffusion and all that stuff is marketing.... really... say nothing special..do not worry about that.
Use the ones "clever guys use".... and use the ones, "everybody uses"...those are the best specifications,..if people are using and no complain..so..it is good.
regards,
Carlos
The one can produce is TAJ...but the guy use to be very busy... really busy.
Yes..increasing voltage you have to substitute transistors, some of them will not hold the rail to rail voltage..and rail to rail is not really needed into all cases but it is a nice and safe decision..so... catch transistors that can hold rail to rail.
My prefered ones are 2SC4793 and 2SA1837... those are the ones Hugh Dean from Aksa have selected because audio quality.
To the VAS, a better choice will be faster transistors, able to manage rail to rail voltage, more than 5 watts of power (all mid power ones can hold that)... and a good idea is to find transistors that have small capacitance from base to emitter..those are faster ones normally.... i cannot inform the one Hugh uses...it is a secret.
2 pairs to the output when voltage is higher than 42 volts is a good idea and you are already using it.
Yessssss...pictures..... goooood!
Also video uploaded to youtube and link here will good...very, very good.
Tripple diffusion and all that stuff is marketing.... really... say nothing special..do not worry about that.
Use the ones "clever guys use".... and use the ones, "everybody uses"...those are the best specifications,..if people are using and no complain..so..it is good.
regards,
Carlos
Use the transistor you have, or the transistor you want folks!
But use them!
Build something folks!
Enjoy to listen something you have made!
Wanna something with tripple guarantee of reliability...then build a Dx Amplifier.
Guarantee of satisfaction!
...................................................................................................
You can buy Dx rigths, Dx schematics, Dx assistance, Dx follow up, Dx friendship and the joy to listen a Dx amplifier by a very special price,
ZERO!!!.... Dx amplifiers are absolutelly FOR FREE!
But use them!
Build something folks!
Enjoy to listen something you have made!
Wanna something with tripple guarantee of reliability...then build a Dx Amplifier.
Guarantee of satisfaction!
An externally hosted image should be here but it was not working when we last tested it.
...................................................................................................
You can buy Dx rigths, Dx schematics, Dx assistance, Dx follow up, Dx friendship and the joy to listen a Dx amplifier by a very special price,
ZERO!!!.... Dx amplifiers are absolutelly FOR FREE!
Attachments
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