)Oh, I'll be more than happy to fill 10.000 word with nice things about
the Dx!
)Unfortunately, my estimation are that before next Wednesday it will not be ready for testing up against other amplifiers...
(the final assembling will take at least 2 days...)
On the other hand, I would not have started working on DX if I
wouldn't be convinced that the schematic shows BIG potential!
There are many other options on diyaudio, but it is the DX I choosed, after analyzing the other options!
Of course, in the end, all that it matters is the sound!
I own myself some other amplifiers, in the 500E range...
I am also very curios to do the testing...
Let's wait...
P.S. I am confident that Dx will make a nice figure!
I will post pictures - when ready - from the listening tests...
P.S.S. I have some doubts regarding the pots - from heat, from
other factors they don't degrade in time? Do you think it is better
after let's say 4 weeks to replace them with fixed resistors?
...One more question that bothers me: the input impedance is 39k...
Please detail why have you choosen this value? I am wrong when I
say that the standard industry value is 22k?
A source of lower impedance, beeing injected into a higher one will drive it without
problems..... terrible is when we have this inverted.
Well....as you problems will be sonics... i think you will be happy.
Relate to attenuate something...no problems...Dx can win many amplifiers even having some disadvantage.
But of course...having no protections... will distort screaming alike a crazy pig if over driven....have to work with it bellow the distortion.
You can peak it for sonics...substitute the feedback capacitor with a variable one...adjust it when reproducing FM noises (between station)..peak it for sonics, remove the variable capacitor...measure the one and install a fixed one with the same value.
Dx amplifier is simple, cheap and have nice sonics.
I will repeat...can loose, as was made to be simple and cheap, not to win all other amplifiers.... not to be the best...we have already many others excelent amplifiers...also i have already the best one...the idea was different..simple and cheap with nice sonics.
The difference, some possible disadvantage, if loose in something, will not be significative...or...at least will not justify you the difference of money to have a sligtly better one.
Dx amplifier lost for many here in my home.....and also beated others.
Please, check this same thread...there are a long post about A to B comparison...join your knowledge about this subject with your knowledge...this will result better...more precision.
Blind A to B comparison...simultaneous switching from A to B.... this is the most fair tests i know....the guy cannot know what amplifier is A and what amplifier is B...levels must be the same...example...peaks around 35 watts (as Dx will behave fine and others will behave fine at this same level too)...the same source beeing used.
Then..you will know the beautifull true....complications do not means good sonics.... enormous power also do not means nice sonics....big price means nothing too...equipment beauty is also nothing...and the main lesson we can have.
We are very dangerous...we are not fair into evaluations...we have our myths and beliefs...we use to try to discover, and to give advantage to the ones we "think are better"..... the day people accept that, they will turn more fair..... ourselves must be hardly controled..other guy must prepare the test environment....different folks must evaluate..all them sitted in the same chair.... other, different than the main evaluator (the one that will colect data), and different from the switch operator must decide watching codified numbers...not one can know what means this or that amplifier.
1 second of fade of sonics...without music..will make you fail...simultaneous switching will be needed.
That story that i have listened yesterday the other one and i am listening this one today and i think....... well, better not to think this way.
You will see that Dx amplifier, even with different input impedance..will eat other amplifiers in the breakfast...laughing till fall down from the chair...others told me that in advance.
I will be waiting your evaluation..also the images...please, call my friend Charlie_fd too.
regards,
Carlos
problems..... terrible is when we have this inverted.
Well....as you problems will be sonics... i think you will be happy.
Relate to attenuate something...no problems...Dx can win many amplifiers even having some disadvantage.
But of course...having no protections... will distort screaming alike a crazy pig if over driven....have to work with it bellow the distortion.
You can peak it for sonics...substitute the feedback capacitor with a variable one...adjust it when reproducing FM noises (between station)..peak it for sonics, remove the variable capacitor...measure the one and install a fixed one with the same value.
Dx amplifier is simple, cheap and have nice sonics.
I will repeat...can loose, as was made to be simple and cheap, not to win all other amplifiers.... not to be the best...we have already many others excelent amplifiers...also i have already the best one...the idea was different..simple and cheap with nice sonics.
The difference, some possible disadvantage, if loose in something, will not be significative...or...at least will not justify you the difference of money to have a sligtly better one.
Dx amplifier lost for many here in my home.....and also beated others.
Please, check this same thread...there are a long post about A to B comparison...join your knowledge about this subject with your knowledge...this will result better...more precision.
Blind A to B comparison...simultaneous switching from A to B.... this is the most fair tests i know....the guy cannot know what amplifier is A and what amplifier is B...levels must be the same...example...peaks around 35 watts (as Dx will behave fine and others will behave fine at this same level too)...the same source beeing used.
Then..you will know the beautifull true....complications do not means good sonics.... enormous power also do not means nice sonics....big price means nothing too...equipment beauty is also nothing...and the main lesson we can have.
We are very dangerous...we are not fair into evaluations...we have our myths and beliefs...we use to try to discover, and to give advantage to the ones we "think are better"..... the day people accept that, they will turn more fair..... ourselves must be hardly controled..other guy must prepare the test environment....different folks must evaluate..all them sitted in the same chair.... other, different than the main evaluator (the one that will colect data), and different from the switch operator must decide watching codified numbers...not one can know what means this or that amplifier.
1 second of fade of sonics...without music..will make you fail...simultaneous switching will be needed.
That story that i have listened yesterday the other one and i am listening this one today and i think....... well, better not to think this way.
You will see that Dx amplifier, even with different input impedance..will eat other amplifiers in the breakfast...laughing till fall down from the chair...others told me that in advance.
I will be waiting your evaluation..also the images...please, call my friend Charlie_fd too.
regards,
Carlos
Re: A source of lower impedance, beeing injected into a higher one will drive it with
You are absolutely RIGHT!!!
Carlos, I always wanted to make some suggestions which I
believe can help this thread and the DX:
1. First, let's suppose one is not really interested in using
"cheap" components.. Now, what would you you suggest
replacing (schematic?, pieces? etc) if money would not be
a problem? What one should do to get the maximum value from
DX?
2. I have already saw that Greg updated the web site by
including the voltages schematic. On the other hand, the thread
has many suggestions regarding DX (adjust treble, input
impedance, radiators on TIPs, radiators recommended surface,
what to change if using different input voltages, how to insert
a volume pot, what capacitors can be changed for better bass etc
etc etc)
Unfortunately, these are buried DEEP into 180 pages!...
Would you consider taking the time, "extract" this information and
put it on Greg's site? IT WOULD BE VERY USEFUL!
Thank you!
destroyer X said:
You are absolutely RIGHT!!!
destroyer X said:
Carlos, I always wanted to make some suggestions which I
believe can help this thread and the DX:
1. First, let's suppose one is not really interested in using
"cheap" components.. Now, what would you you suggest
replacing (schematic?, pieces? etc) if money would not be
a problem? What one should do to get the maximum value from
DX?
2. I have already saw that Greg updated the web site by
including the voltages schematic. On the other hand, the thread
has many suggestions regarding DX (adjust treble, input
impedance, radiators on TIPs, radiators recommended surface,
what to change if using different input voltages, how to insert
a volume pot, what capacitors can be changed for better bass etc
etc etc)
Unfortunately, these are buried DEEP into 180 pages!...
Would you consider taking the time, "extract" this information and
put it on Greg's site? IT WOULD BE VERY USEFUL!
Thank you!
buried?...ahahahaha.... 180 pages grave?
Fine..... i like some good mood and some kiddings
Fully agreement!
Your suggestion to produce a short form of instructions are good too, i will produce a meeting with Greg to listen what he thinks about that...i am very well impressed with your idea and i suppose he will be positively impressed too.
But this also worries me....as i have modifications to produce more bass for instance...and i have modifications to more quality in bass...i have to think what is better...... my mind goes to quality...but beeing a cheap and simple amplifier may reach young folks too...and those ones, maybe, will prefer to shake their walls.
Also will scape from the main direction...the philosophy was to make it cheap....not to make it other equipments smasher...not a killer...you know what i mean.... also, there are models provided in the market, and also inside our diy community that are already "Killers"
Also...as you know....difference of sonic quality from the top performer compared to Dx and to other amplifiers are not so big....the sound stage makes the bigger difference, and modifications to increase, or to control sound stage...really...i do not know how to make them.... also i am afraid that no one dominates that knowledge.
There are people that even do not believe that sound stage exists..that is a brain creation made by the listener..something that has not connection with the sonic reproduction...well.... there are some doubts around the theme.
Dx is not the top performer..... if was so special that way i would not publish it to be free, and into the diy community...for sure would be keept in secret, if not only to produce business with it, but also not to compete with my dear friend Hugh Dean from Aspen Amplifiers.
Dx amplifier, the way was published cannot create problems to my friend's sales... as cannot face his product quality and it is a free diy audio project..not decent would be to compete with comercial products..posting something for free..superior to others....not to be sold...and killing comercial products....a very bad behavior...i am not able to do things this way and also i do not want to hehave this way.
If i could do that without use his circuitry methods.... i would made it with the focus to start immediatelly a business and to compete with him using the best possible honest and decent ways.... this is not the sittuation.... no comercial, not competing and i am not eagger to make better than he made (not possible...he used the best possible methods...already made...his copyrigth).... if made to commercial, to business purposes, will not be published opened to wide world as it was made... secret is a need, if not, everybody can make the same and you will have nothing to offer as advantage related others...you will not be able even to "sell the dream" that someone can reach Paradise without die.
This amplifier is very near the maximum of sonics (to that topologie, beeing cheap and using 35 volts)...not too much can be done, as i have tested almost all options you may imagine...all sub circuits, all VAS, mirrored, sinks, CCS, stabilizers, double supply voltages, class G circuits, positive regulated supplies (increasing voltage when you suck current)...and many other tricks i cannot comment, and i made it be best possible...."not entering" Hugh subcircuits and other modifications he made...because copy of something that have copyrigth is not only wrong, but also against the law.
You idea, made suggestion, will be "cooking" inside my brain...all five neurôniums will work full throotle and Greg will help me to decide this subject.
regards,
Carlos
Fine..... i like some good mood and some kiddings
Fully agreement!
Your suggestion to produce a short form of instructions are good too, i will produce a meeting with Greg to listen what he thinks about that...i am very well impressed with your idea and i suppose he will be positively impressed too.
But this also worries me....as i have modifications to produce more bass for instance...and i have modifications to more quality in bass...i have to think what is better...... my mind goes to quality...but beeing a cheap and simple amplifier may reach young folks too...and those ones, maybe, will prefer to shake their walls.
Also will scape from the main direction...the philosophy was to make it cheap....not to make it other equipments smasher...not a killer...you know what i mean.... also, there are models provided in the market, and also inside our diy community that are already "Killers"
Also...as you know....difference of sonic quality from the top performer compared to Dx and to other amplifiers are not so big....the sound stage makes the bigger difference, and modifications to increase, or to control sound stage...really...i do not know how to make them.... also i am afraid that no one dominates that knowledge.
There are people that even do not believe that sound stage exists..that is a brain creation made by the listener..something that has not connection with the sonic reproduction...well.... there are some doubts around the theme.
Dx is not the top performer..... if was so special that way i would not publish it to be free, and into the diy community...for sure would be keept in secret, if not only to produce business with it, but also not to compete with my dear friend Hugh Dean from Aspen Amplifiers.
Dx amplifier, the way was published cannot create problems to my friend's sales... as cannot face his product quality and it is a free diy audio project..not decent would be to compete with comercial products..posting something for free..superior to others....not to be sold...and killing comercial products....a very bad behavior...i am not able to do things this way and also i do not want to hehave this way.
If i could do that without use his circuitry methods.... i would made it with the focus to start immediatelly a business and to compete with him using the best possible honest and decent ways.... this is not the sittuation.... no comercial, not competing and i am not eagger to make better than he made (not possible...he used the best possible methods...already made...his copyrigth).... if made to commercial, to business purposes, will not be published opened to wide world as it was made... secret is a need, if not, everybody can make the same and you will have nothing to offer as advantage related others...you will not be able even to "sell the dream" that someone can reach Paradise without die.
This amplifier is very near the maximum of sonics (to that topologie, beeing cheap and using 35 volts)...not too much can be done, as i have tested almost all options you may imagine...all sub circuits, all VAS, mirrored, sinks, CCS, stabilizers, double supply voltages, class G circuits, positive regulated supplies (increasing voltage when you suck current)...and many other tricks i cannot comment, and i made it be best possible...."not entering" Hugh subcircuits and other modifications he made...because copy of something that have copyrigth is not only wrong, but also against the law.
You idea, made suggestion, will be "cooking" inside my brain...all five neurôniums will work full throotle and Greg will help me to decide this subject.
regards,
Carlos
Attachments
Dx Corporation meeting resolution was to keep the Dx amplifier the way it is
Chairman gave a strong punch into the table and said:
- "It is good enougth!"
Alike Henry Ford said:
"You can have our cars in the colour you want....they will be black!"
Also some of them made comments about your vision dear Namex... but i cannot repeat here.... maybe because the short you had.... they were suggesting new glasses...hehe
regards,
Carlos
Chairman gave a strong punch into the table and said:
- "It is good enougth!"
Alike Henry Ford said:
"You can have our cars in the colour you want....they will be black!"
Also some of them made comments about your vision dear Namex... but i cannot repeat here.... maybe because the short you had.... they were suggesting new glasses...hehe
regards,
Carlos
There are many folks constructing modified Dx amplifiers
Many of them should be.
The main modification people as is to increase power increasing supply voltage.... and some of them also asked reduction in power, using the supplies they have, already made, at their homes.
And many different voltages were already offered, using direct mail, to many folks.
The idea is not to confuse the thread, already pretty crowded....not offering here too much options.... Here the subject is Dx amplifier.... modifications, untested amplifiers may visit this thread after constructed and tested..... well.... finally....guaranteed because tested.
There are modifications, and they are, almost all them, very obvious, controling current excesses, recalculating boot strap current, increasing output pairs, increasing condensers voltages...well.... other tweaks may be needed, depending the destination, for what purpose the Dx amplifier will be constructed for.
Needing to modify, from 15 to 70 volts, to use the supply you have, i will be ready to help...but out from this thread...directly mail to me and i will have the chance to help.
Remember that effective increasings in "sonic power"...the sound you perceive....you will need to increase your power many times.... 4 times minimum.... and also your speaker diafragm surface to compress air will need increasings in area and in amplitude of motion. To go from 50 watts to 100 watts.....hummm, almost nothing will result.... very hard to perceive.... 12 and dozen..almost the same....only the old speaker will suffer with the current increase...will work hot, can melt coil and can distort when reach it's maximum length of movement.... better to associate less powerfull speakers in series and parallel, using many units you will divide the power, will increase also EMF, but will have more sound pressure.... a coil , and an output double "P" (Greek letter) can hold the problem, the consequences , of those increasings.
If you wanna real power, prepare your pockets, as 100 volts symetrical huge supply will be needed and 10 or 20 pairs of transistors will be needed, enormous heatsinks, fan blowers, special cables, switches, connectors, special fuses, special fuse sockets..
This, if you really want to work safe and to install the speaker you wanted in parallell...also prepare pockets to substitute every component, in special condensers and capacitors to higher voltage ratio..... special rectifiers and special electrolitic condensers...... hehe.... and give some kisses to your "almost already lost speaker"...produce some pictures near it as you will need images to remember it after it burns.
But...each one of us with our own mania.... relax and do whatever you want to do... remember that we gonna help you if needed...till the limit of our knowledge.
Plus 100 volts and minus 100 volts can kill you!
Please, only ask those modifications if you are sure you will really construct, as this may need entire recalculations because increasings in power to resistances and so on.....do not give us this work if you are in doubts.
4 already asked modifications...no one have constructed yet.
regards,
Carlos
Many of them should be.
The main modification people as is to increase power increasing supply voltage.... and some of them also asked reduction in power, using the supplies they have, already made, at their homes.
And many different voltages were already offered, using direct mail, to many folks.
The idea is not to confuse the thread, already pretty crowded....not offering here too much options.... Here the subject is Dx amplifier.... modifications, untested amplifiers may visit this thread after constructed and tested..... well.... finally....guaranteed because tested.
There are modifications, and they are, almost all them, very obvious, controling current excesses, recalculating boot strap current, increasing output pairs, increasing condensers voltages...well.... other tweaks may be needed, depending the destination, for what purpose the Dx amplifier will be constructed for.
Needing to modify, from 15 to 70 volts, to use the supply you have, i will be ready to help...but out from this thread...directly mail to me and i will have the chance to help.
Remember that effective increasings in "sonic power"...the sound you perceive....you will need to increase your power many times.... 4 times minimum.... and also your speaker diafragm surface to compress air will need increasings in area and in amplitude of motion. To go from 50 watts to 100 watts.....hummm, almost nothing will result.... very hard to perceive.... 12 and dozen..almost the same....only the old speaker will suffer with the current increase...will work hot, can melt coil and can distort when reach it's maximum length of movement.... better to associate less powerfull speakers in series and parallel, using many units you will divide the power, will increase also EMF, but will have more sound pressure.... a coil , and an output double "P" (Greek letter) can hold the problem, the consequences , of those increasings.
If you wanna real power, prepare your pockets, as 100 volts symetrical huge supply will be needed and 10 or 20 pairs of transistors will be needed, enormous heatsinks, fan blowers, special cables, switches, connectors, special fuses, special fuse sockets..
This, if you really want to work safe and to install the speaker you wanted in parallell...also prepare pockets to substitute every component, in special condensers and capacitors to higher voltage ratio..... special rectifiers and special electrolitic condensers...... hehe.... and give some kisses to your "almost already lost speaker"...produce some pictures near it as you will need images to remember it after it burns.
But...each one of us with our own mania.... relax and do whatever you want to do... remember that we gonna help you if needed...till the limit of our knowledge.
Plus 100 volts and minus 100 volts can kill you!
Please, only ask those modifications if you are sure you will really construct, as this may need entire recalculations because increasings in power to resistances and so on.....do not give us this work if you are in doubts.
4 already asked modifications...no one have constructed yet.
regards,
Carlos
If too much bass is annoying to you
If you have a boomy speaker, or your home acoustic result in mufled sound... also if you use to play using old style turnables, some attenuation into sub sonics and some losses in low end listenable audio may be very interesting.
I have those speakers, also a lot of carpet in my home...furniture with cloth also absorbs high frequencies..... reason why, in my Dx amplifier (you can apply to all amplifiers) i have reduced my input condenser to a very low value.... in my present sittuation the value prefered was 100N...so...i have just removed the bigger condenser in parallel.
Another idea, is to increase treble...as you can correct speakers or audition, the ones increase bass (or filter trebles) reducing bass or increasing treble... or doing both.
You see in the image the 103 capacitor...it will increase treble, but not producing enormous sensitivity into the amplifier... will increase low high frequencies that are normally low level signals...let's say...not more than 15 percent of the entire signal..... one volt of audio will have high frequencies signals under 100 to 150 milivolts...
Those signals are the target...they will be increased and you will have bigger brigth into your reproduction.
BUT.... having some kind of music, where high frequencies are still very loud, you will have some saturation, as they will be amplified till clipping..this is the sub product that turns this use a little bit problematic, depending some care and decision.
I am using 103 in my home, because needed here....the better idea is not to use those capacitors, unless very needed.
regards,
Carlos
If you have a boomy speaker, or your home acoustic result in mufled sound... also if you use to play using old style turnables, some attenuation into sub sonics and some losses in low end listenable audio may be very interesting.
I have those speakers, also a lot of carpet in my home...furniture with cloth also absorbs high frequencies..... reason why, in my Dx amplifier (you can apply to all amplifiers) i have reduced my input condenser to a very low value.... in my present sittuation the value prefered was 100N...so...i have just removed the bigger condenser in parallel.
Another idea, is to increase treble...as you can correct speakers or audition, the ones increase bass (or filter trebles) reducing bass or increasing treble... or doing both.
You see in the image the 103 capacitor...it will increase treble, but not producing enormous sensitivity into the amplifier... will increase low high frequencies that are normally low level signals...let's say...not more than 15 percent of the entire signal..... one volt of audio will have high frequencies signals under 100 to 150 milivolts...
Those signals are the target...they will be increased and you will have bigger brigth into your reproduction.
BUT.... having some kind of music, where high frequencies are still very loud, you will have some saturation, as they will be amplified till clipping..this is the sub product that turns this use a little bit problematic, depending some care and decision.
I am using 103 in my home, because needed here....the better idea is not to use those capacitors, unless very needed.
regards,
Carlos
Attachments
Oh, I forgot to mention one experience:
We've tried to use DX with a portable jukebox... well at half
volume of the jukebox strange things began to happen: pauses, cracks etc
What we found is that probably the input impedance puts "too much
pressure" on the headphone output of the jukebox...
So if anyone will experience such strange behavior, don't panic...
the headphone output of some devices can behave like this... the
problem is not with the DX, but with these small portable devices...
We've tried to use DX with a portable jukebox... well at half
volume of the jukebox strange things began to happen: pauses, cracks etc
What we found is that probably the input impedance puts "too much
pressure" on the headphone output of the jukebox...
So if anyone will experience such strange behavior, don't panic...
the headphone output of some devices can behave like this... the
problem is not with the DX, but with these small portable devices...
The DX has a high input impedance which should not affect the jukebox, so as long as you have your jukebox and DX earths connected correctly maybe the jukebox needs a load to replace the missing headphones, say 47 ohms per channel, and maybe the DX then needs 1k in series with its input to overcome coupling at higher frequencies which the directly connected combination cannot cope with.
Cheers ......... Graham.
Cheers ......... Graham.
I found a brasilian song, an old Bossa Nova
Tom Jobim and Elis Regina singing, that sounds very good with Dx amplifier.
It shows all the amplifier qualities...the deep bass....the clear voices and the extremelly nice, and loud, high frequencies (using 103 in paralell with R10)
The high frequency content, an analogic recording made in the eigthies i think, has clear sonics when metal are hitted.... this produces enormous quantity of lovely harmonics, and this makes the sound very rich....not distorted into the recording...even beeing old tape recording, has that brigth Dx amplifier can reproduce.
If you want..i can upload to you this music...just give me your E Mail adress...the file is 2.5 Megabytes and MP3 to 128K sample.
To reproduce the metals you have...that brass plate we have into the drummer section...the one has metal loosen mouted over the plate...and hitted using a metal brush...hehe....very nice...very clear...the amplifier needs to reproduce a very high frequency without distort to reproduce that clearly.
I am enjoying deeply my amplifier...in special when i could make it adjusted to my speaker and environment...not bass was reduced in intensity using 82N of input capacitor...also treble losses were reduced there.... and 103 soldered in parallel with R10.
The Dx constructors already have received that music...as a sample music...if someone had not received..go to:
panzertoo@yahoo.com
Hummmmm...nice!
regards,
Carlos
Tom Jobim and Elis Regina singing, that sounds very good with Dx amplifier.
It shows all the amplifier qualities...the deep bass....the clear voices and the extremelly nice, and loud, high frequencies (using 103 in paralell with R10)
The high frequency content, an analogic recording made in the eigthies i think, has clear sonics when metal are hitted.... this produces enormous quantity of lovely harmonics, and this makes the sound very rich....not distorted into the recording...even beeing old tape recording, has that brigth Dx amplifier can reproduce.
If you want..i can upload to you this music...just give me your E Mail adress...the file is 2.5 Megabytes and MP3 to 128K sample.
To reproduce the metals you have...that brass plate we have into the drummer section...the one has metal loosen mouted over the plate...and hitted using a metal brush...hehe....very nice...very clear...the amplifier needs to reproduce a very high frequency without distort to reproduce that clearly.
I am enjoying deeply my amplifier...in special when i could make it adjusted to my speaker and environment...not bass was reduced in intensity using 82N of input capacitor...also treble losses were reduced there.... and 103 soldered in parallel with R10.
The Dx constructors already have received that music...as a sample music...if someone had not received..go to:
panzertoo@yahoo.com
Hummmmm...nice!
regards,
Carlos
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