No more Optimus amplifier, increasing bias into the HRII...
... i found that 1 ampere or higher standby bias does not give us any advantage into sound reproduction.... TESTED!
I found was sligthly mufled into higher bias....also i have found the optimized bias point is around 250 miliamperes (as Nordic said..he was rigth!).
Comparisons made, using two identical amplifiers, same parts and same supply, into a single speaker, gave me this result..instead to adjust your stand by bias to 60 to 100 miliamperes, it is better to increase it to 250 to 300 miliamperes because performance was better than lower bias and higher bias.
So.... Optimus is dead....now we have HRII Optimized!
Be happy folks.
Enjoy Dx Amplifier.... sounding near the perfection.
regards,
Carlos
... i found that 1 ampere or higher standby bias does not give us any advantage into sound reproduction.... TESTED!
I found was sligthly mufled into higher bias....also i have found the optimized bias point is around 250 miliamperes (as Nordic said..he was rigth!).
Comparisons made, using two identical amplifiers, same parts and same supply, into a single speaker, gave me this result..instead to adjust your stand by bias to 60 to 100 miliamperes, it is better to increase it to 250 to 300 miliamperes because performance was better than lower bias and higher bias.
So.... Optimus is dead....now we have HRII Optimized!
Be happy folks.
Enjoy Dx Amplifier.... sounding near the perfection.
regards,
Carlos
No more Optimus Amplifier... testing high bias into the HRII
... i found that 1 ampere or higher standby bias does not give us any advantage into sound reproduction.... TESTED!
I found was sligthly mufled into higher bias....also i have found the optimized bias point is around 250 miliamperes (as Nordic said..he was rigth!).
Comparisons made, using two identical amplifiers, same parts and same supply, into a single speaker, gave me this result..instead to adjust your stand by bias to 60 to 100 miliamperes, it is better to increase it to 250 to 300 miliamperes because performance was better than lower bias and higher bias.
So.... Optimus is dead....now we have HRII Optimized!
Be happy folks.
Enjoy Dx Amplifier.... sounding near the perfection.
regards,
Carlos
... i found that 1 ampere or higher standby bias does not give us any advantage into sound reproduction.... TESTED!
I found was sligthly mufled into higher bias....also i have found the optimized bias point is around 250 miliamperes (as Nordic said..he was rigth!).
Comparisons made, using two identical amplifiers, same parts and same supply, into a single speaker, gave me this result..instead to adjust your stand by bias to 60 to 100 miliamperes, it is better to increase it to 250 to 300 miliamperes because performance was better than lower bias and higher bias.
So.... Optimus is dead....now we have HRII Optimized!
Be happy folks.
Enjoy Dx Amplifier.... sounding near the perfection.
regards,
Carlos
So....
Has anyone yet completed a Precision 1, and if so, can you please comment on its performance?
I haven't yet heard of anyone completing one!
Cheers
Stu
Has anyone yet completed a Precision 1, and if so, can you please comment on its performance?
I haven't yet heard of anyone completing one!
Cheers
Stu
Precision 1
Hi Stuey,
I have started building my Precision1 and should be able to finish in a week or two. Are you interested in personal opinions or would you want me to measure distortion, TIM, db/m etc. I am asking because I have access to a scope and signal gen but no distortion analyser or other fancy gear. Also my rail voltage is +-50V for this one. Also I feel hesitant to comment on this thread being called silly by clever people such as AnderwT. You can PM me if you want.
🙂
Hi Stuey,
I have started building my Precision1 and should be able to finish in a week or two. Are you interested in personal opinions or would you want me to measure distortion, TIM, db/m etc. I am asking because I have access to a scope and signal gen but no distortion analyser or other fancy gear. Also my rail voltage is +-50V for this one. Also I feel hesitant to comment on this thread being called silly by clever people such as AnderwT. You can PM me if you want.
🙂
Re: Precision 1
I am here to further my knowledge, not to appear clever.
I have learned a lot while I have been a member, but I still have enormous gaps in my knowledge. I will continue to learn and to offer technical opinion.
I hope I do not offend members deliberately, but sometimes I do make mistakes and I'm generally man enough to admit my errors.
I am clever enough to know and recognise my limitations.Twaksak said:
I am here to further my knowledge, not to appear clever.
I have learned a lot while I have been a member, but I still have enormous gaps in my knowledge. I will continue to learn and to offer technical opinion.
I hope I do not offend members deliberately, but sometimes I do make mistakes and I'm generally man enough to admit my errors.
Cool, great
Here we have been brought up to admit errors we make. Should you want to make a personal remark then you close the door (or email privately) and do not show your dirty laundry in public. Different people have different level of knowledge and I will be the first to acknowledge that I am a very low knowledgable as compared to audio designers. I am sorry if I have offended you AndrewT. My sincere apologies. I always enjoy your remarks and technical knowledge. 🙁
Here we have been brought up to admit errors we make. Should you want to make a personal remark then you close the door (or email privately) and do not show your dirty laundry in public. Different people have different level of knowledge and I will be the first to acknowledge that I am a very low knowledgable as compared to audio designers. I am sorry if I have offended you AndrewT. My sincere apologies. I always enjoy your remarks and technical knowledge. 🙁
Twaksak, personal opinions please! No measurements (unless you want to).
I bought boards some time ago, but due to ill health all my projects have been painfully slow. (I'm half way through a SKA build and have a couple of speaker projects).
I may not even build the P1's unless they get good reviews by builders, but it seems rather strange that I haven't yet seen one comment from a customer! I was going to use them to drive a bass augmenter driver on a pair of Hawthornes.
Cheers
Stuey
I bought boards some time ago, but due to ill health all my projects have been painfully slow. (I'm half way through a SKA build and have a couple of speaker projects).
I may not even build the P1's unless they get good reviews by builders, but it seems rather strange that I haven't yet seen one comment from a customer! I was going to use them to drive a bass augmenter driver on a pair of Hawthornes.
Cheers
Stuey
Measurements means nothing to me.... but listening tests means everything to me
I have found awfull amplifiers measuring very well...also lovely amplifiers measuring very well.
I also have found wonderfull amplifiers measuring very bad..also terrible amplifiers measuring very bad.
A very long, long time buiding several schematics, including some of the best ones in our communitty (understood as , considered as, valued as best ones)...and i have learned that low distortions, nice Fourier analises, linearity ... IMD, THD, and all that stuff as something may be a clue about the amplifier performance...but many times i had surprises, many of them was defective Twaksak (I have build something around 4.3 to 4.7K amplifiers those last 48 years buiding almost 1 amplifier each day).
Measurements, charts, technicall evaluations, graphics, spectrum analisers results, distortion results, linearity graphics, angle graphics...all that will serve only to your personal fun and to ATTRACT boring "instrumentologists" to come here and invade a nice thread made by someone evaluates listening, and they will come to say good things or bad things when all they can say i already know listening...and this is what matters to me.
Your evaluations, or review, comments, comparative tests, listening impressions, your feelings..all that stuff is welcome.
Off course you are free to use our forum the way you want...but i will reserve to myself the rigth to ignore, or not to feed, numbers of graphics or such things that do not contribute to our real world listening evaluation.
Numbers are used manipulated...some distortions are measured using 5 Kilohertz when the real distortions happens at 10 Khz....well.... this serves to industries to fool us... they give us nice numbers and when you listen you may trash the hell thing and will have the risk to have the damn thing spitted out from the trashbox as some trash box does not accept such kind of junk (trash box has pride too!)
Even if my amplifiers measure wonderfull or awfully... i am personally absolutelly not interested, and i am sure will attract boring people to this thread...... we have 3 of them in our forum... cloudy folks!
The first three seconds... after you switch the amplifier on and start to play some music you like, into a speaker you appreciate... this is very important to me..... when times goes passing the brain engage and filter, and filled gaps (MP3) and remove noises, attenuate distortions and clean almost all junk from the recording...we cannot give time to the brain to make ALMOST all amplifier very good....if you feel the amplifier normal when you start to listen THEN IT IS NORMAL....but long listening will make you listen cracked bamboo hitting a stone as something interesting.
regards,
Carlos
I have found awfull amplifiers measuring very well...also lovely amplifiers measuring very well.
I also have found wonderfull amplifiers measuring very bad..also terrible amplifiers measuring very bad.
A very long, long time buiding several schematics, including some of the best ones in our communitty (understood as , considered as, valued as best ones)...and i have learned that low distortions, nice Fourier analises, linearity ... IMD, THD, and all that stuff as something may be a clue about the amplifier performance...but many times i had surprises, many of them was defective Twaksak (I have build something around 4.3 to 4.7K amplifiers those last 48 years buiding almost 1 amplifier each day).
Measurements, charts, technicall evaluations, graphics, spectrum analisers results, distortion results, linearity graphics, angle graphics...all that will serve only to your personal fun and to ATTRACT boring "instrumentologists" to come here and invade a nice thread made by someone evaluates listening, and they will come to say good things or bad things when all they can say i already know listening...and this is what matters to me.
Your evaluations, or review, comments, comparative tests, listening impressions, your feelings..all that stuff is welcome.
Off course you are free to use our forum the way you want...but i will reserve to myself the rigth to ignore, or not to feed, numbers of graphics or such things that do not contribute to our real world listening evaluation.
Numbers are used manipulated...some distortions are measured using 5 Kilohertz when the real distortions happens at 10 Khz....well.... this serves to industries to fool us... they give us nice numbers and when you listen you may trash the hell thing and will have the risk to have the damn thing spitted out from the trashbox as some trash box does not accept such kind of junk (trash box has pride too!)
Even if my amplifiers measure wonderfull or awfully... i am personally absolutelly not interested, and i am sure will attract boring people to this thread...... we have 3 of them in our forum... cloudy folks!
The first three seconds... after you switch the amplifier on and start to play some music you like, into a speaker you appreciate... this is very important to me..... when times goes passing the brain engage and filter, and filled gaps (MP3) and remove noises, attenuate distortions and clean almost all junk from the recording...we cannot give time to the brain to make ALMOST all amplifier very good....if you feel the amplifier normal when you start to listen THEN IT IS NORMAL....but long listening will make you listen cracked bamboo hitting a stone as something interesting.
regards,
Carlos
Personal view as request
Stuey, I will post my personal opinion on sound as soon as completed. My speakers are 300W Sansui Pro with 15" and big tweeter that gives a great sound on anything from low bass to the maximum high frequency. Hope this one works without oscillating or other problems.
Stuey, I will post my personal opinion on sound as soon as completed. My speakers are 300W Sansui Pro with 15" and big tweeter that gives a great sound on anything from low bass to the maximum high frequency. Hope this one works without oscillating or other problems.
Precision One has enormous bass power... and you can increase volume without perceive
distortions.... a huge power...it seems to me can be used to Professional Applications.
Of course it is a full range amplifiers, but despite linear into measurements it shows enormous punch into bass area when dinamically operated (no tones, real music or white noise having the whole spectrum mixed)
regards,
Carlos
distortions.... a huge power...it seems to me can be used to Professional Applications.
Of course it is a full range amplifiers, but despite linear into measurements it shows enormous punch into bass area when dinamically operated (no tones, real music or white noise having the whole spectrum mixed)
regards,
Carlos
Excellent Twaksak. I look forward to your impressions!
I wonder how many boards were sold, as there seem to have been few finished - or at least, none where the owners have posted about it!
Cheers
S
I wonder how many boards were sold, as there seem to have been few finished - or at least, none where the owners have posted about it!
Cheers
S
DX Precision nearly done
I have also been a bit busy and the boards were waiting quite a while for me. I think in the range of about 40 boughts were ordered. I am also curious why nobody posted impressions on their amps. I still have 3 waiting. The first 2 are for a stereo amp rebuild for a friend.
I have also been a bit busy and the boards were waiting quite a while for me. I think in the range of about 40 boughts were ordered. I am also curious why nobody posted impressions on their amps. I still have 3 waiting. The first 2 are for a stereo amp rebuild for a friend.
I have suspections folks have not succeded into the construction....
While building, even Nordic had problems..and he has made the boards...problems about parts position.... the BD139 pins are strange compared to others...so...chances for errors during assembling is very big.
Into the Dx Standard, in Brazil, i had more than 10 failures because folks forgeted to install the external bias control... the circuit was openned and enormous positive voltage entered the positive rail driver and positive output driver resulting in damaged transistors and resistances... this is an example of what happens when non skilled guys try to assemble amplifiers.
I was also surprised why so many have not published results...i suppose they have faced problems...more parts, more dense circuit means more options to errors.
I have built several times, so i am sure it works fine and have no mistery to build....but i could see many folks here, down in Brazil, that made foolishes during construction and have faced enormous off set.
Rail voltage into the output is the main result when people invert transistors...when board is "sick"...not correctly assembled, the main defect that appear is rail voltage appearing as off set.
Also many threads exists, and some comments were posted into Dx Amplifier, my amplifier..... also there are a thread used as group buy to HRII where people has posted comments.... also the thread about DHR Turbo was used to post comments...and obviously the Precision I thread.
I love the sonics...and some local friends too....so... i do not think they did not have published comments because they could felt the amplifier deceptive.... HRII had a lot of comments, a lot of thanks, and sounds almost the same having more basses to the Precision I (dinamically, both amplifiers are flat..but working, with music, facing speakers, all amplifiers shows preferences to basses, or mids or highs...do not ask me how and why because i am still searching for those reasons... 48 years long searching)
The most common reason, i found here, was BD139 and BD140 invertion.
Once again i ensure you the amplifier works, and that it is stable...once again i guarantee that was built several times..but i have never used the board Nico has made.....but he tested, he has assembled the board to test....so..... alike all of you i feel strange this silence...... and my life experience, that shown me people use to hide and silence when fail because ashamed and this is something i understand as a clue that this happened and more than once or twice.... Nico has failed..had problems and started to be suspections about the amplifier and afraigthned because his board.... he felt would be possible a bug into the board...but soon he could see that's no bug existed, no mistake into the board and no error into the design.
During 48 years building...more than 4700 amplifiers made (when i stopped my accounting last year) i could see that several times i have failed and had to assemble again and to search for errors.. and this happened THOUSANDS of times...so i am SURE, we, humans, do such kind of things...and the more experienced you are, the more skilled you are, the more confidence you have about yourself...more "ship" you use to make...i am still doing "ship" a lot here at my home.
HRII have received enormous reviews, very positive ones, without complains, thanks, gratitude and happyness from the folks have built..... Precision I is not different, has more voltage into the supply and a CCS in the place of the bootstrapp.... sonic difference is small...so...if people have loved HRII, for sure they will love Precision I..... i have suspections people faced problems during assembling..and ashamed gone silent and let the boards into the drawer.
Carlos
While building, even Nordic had problems..and he has made the boards...problems about parts position.... the BD139 pins are strange compared to others...so...chances for errors during assembling is very big.
Into the Dx Standard, in Brazil, i had more than 10 failures because folks forgeted to install the external bias control... the circuit was openned and enormous positive voltage entered the positive rail driver and positive output driver resulting in damaged transistors and resistances... this is an example of what happens when non skilled guys try to assemble amplifiers.
I was also surprised why so many have not published results...i suppose they have faced problems...more parts, more dense circuit means more options to errors.
I have built several times, so i am sure it works fine and have no mistery to build....but i could see many folks here, down in Brazil, that made foolishes during construction and have faced enormous off set.
Rail voltage into the output is the main result when people invert transistors...when board is "sick"...not correctly assembled, the main defect that appear is rail voltage appearing as off set.
Also many threads exists, and some comments were posted into Dx Amplifier, my amplifier..... also there are a thread used as group buy to HRII where people has posted comments.... also the thread about DHR Turbo was used to post comments...and obviously the Precision I thread.
I love the sonics...and some local friends too....so... i do not think they did not have published comments because they could felt the amplifier deceptive.... HRII had a lot of comments, a lot of thanks, and sounds almost the same having more basses to the Precision I (dinamically, both amplifiers are flat..but working, with music, facing speakers, all amplifiers shows preferences to basses, or mids or highs...do not ask me how and why because i am still searching for those reasons... 48 years long searching)
The most common reason, i found here, was BD139 and BD140 invertion.
Once again i ensure you the amplifier works, and that it is stable...once again i guarantee that was built several times..but i have never used the board Nico has made.....but he tested, he has assembled the board to test....so..... alike all of you i feel strange this silence...... and my life experience, that shown me people use to hide and silence when fail because ashamed and this is something i understand as a clue that this happened and more than once or twice.... Nico has failed..had problems and started to be suspections about the amplifier and afraigthned because his board.... he felt would be possible a bug into the board...but soon he could see that's no bug existed, no mistake into the board and no error into the design.
During 48 years building...more than 4700 amplifiers made (when i stopped my accounting last year) i could see that several times i have failed and had to assemble again and to search for errors.. and this happened THOUSANDS of times...so i am SURE, we, humans, do such kind of things...and the more experienced you are, the more skilled you are, the more confidence you have about yourself...more "ship" you use to make...i am still doing "ship" a lot here at my home.
HRII have received enormous reviews, very positive ones, without complains, thanks, gratitude and happyness from the folks have built..... Precision I is not different, has more voltage into the supply and a CCS in the place of the bootstrapp.... sonic difference is small...so...if people have loved HRII, for sure they will love Precision I..... i have suspections people faced problems during assembling..and ashamed gone silent and let the boards into the drawer.
Carlos
Attachments
I am happy to tell folks that i am ready to help the ones that failed
giving them some "confidential" assistance, some follow up into my direct mail:
panzertoo@yahoo.com
I also happy to inform you all the amplifier, the Precision I is stable... was tested many times (not with the blue boards!... i had no blue boards here!).
The construction i have made.... p2p was modified several times, as i was tweaking to produce the Precision II.... and this one was not delivered to forum folks, as i have perceived advantages into the power and into the bass....when the Precision I is already very good in power and in the bass area....so... the advantage was not good enougth to deliver another amplifier with that small difference that results alike the "make up" you see in automobiles...they change the lamps and front bumpers and small things and call the "new clothing" as beeing a new car.
The Precision II was using CCS into the drivers, adjusted to 27 miliamperes to each driver.... zener, resistances, condensers and power transistors were used to do this job....the circuit was more and more dense, more and more confused...and the result was that the bass never had such small distortion into very high levels of output voltage...the speaker was "walking alone".... travelling over my ceramic floor and room was shaking...but nothing more than that...treble was the same, mids was the same..dinamics was not the same... resulted a little bit compressed and sounded alike systems using subwoofer.... enormous ammounts of basses.
The idea into the Precision II was a copy made from Electrocompaniet CCS solutions to increase driver current.
Why i am telling you that.... when doing that i have mounted and dismounted the Precision I (was the base to the Precision II, because only the CCS was different)...and did it many times..and have created several schematics, all them sent to Nico to show him progress...and this means..that several times the Precision I was build, dismounted, changed, built once again to compare and always worked great, without unstabilities and failures.
regards,
Carlos
giving them some "confidential" assistance, some follow up into my direct mail:
panzertoo@yahoo.com
I also happy to inform you all the amplifier, the Precision I is stable... was tested many times (not with the blue boards!... i had no blue boards here!).
The construction i have made.... p2p was modified several times, as i was tweaking to produce the Precision II.... and this one was not delivered to forum folks, as i have perceived advantages into the power and into the bass....when the Precision I is already very good in power and in the bass area....so... the advantage was not good enougth to deliver another amplifier with that small difference that results alike the "make up" you see in automobiles...they change the lamps and front bumpers and small things and call the "new clothing" as beeing a new car.
The Precision II was using CCS into the drivers, adjusted to 27 miliamperes to each driver.... zener, resistances, condensers and power transistors were used to do this job....the circuit was more and more dense, more and more confused...and the result was that the bass never had such small distortion into very high levels of output voltage...the speaker was "walking alone".... travelling over my ceramic floor and room was shaking...but nothing more than that...treble was the same, mids was the same..dinamics was not the same... resulted a little bit compressed and sounded alike systems using subwoofer.... enormous ammounts of basses.
The idea into the Precision II was a copy made from Electrocompaniet CCS solutions to increase driver current.
Why i am telling you that.... when doing that i have mounted and dismounted the Precision I (was the base to the Precision II, because only the CCS was different)...and did it many times..and have created several schematics, all them sent to Nico to show him progress...and this means..that several times the Precision I was build, dismounted, changed, built once again to compare and always worked great, without unstabilities and failures.
regards,
Carlos
Stue Request
I have powered up my DX Precision1 and as per Stue request I give acount of my impression. First the differences to the standard DX P1 from Carlos are the input tail current a little bit higher with R8 set to 3K9. My supply voltage +-50Vdc. Bias voltage across emitter resistor at 15mV.
I measured 1mV offset and on my scope see no crossover distortion between 1kHz and 10kHz. The waveform seems more rounded at the bottom that the top. Clipping starts at input voltage of 1.5V on my DX P1.
First listening impression (Mono with other channel still not completed) Immediately treble sounded very clear bells cymbals and flute extremely clear. Voice on the midrange and accoustic guitar catching your ear and the bass very tight but not boomy. I am listening with no preamp straight from my Phillips cdplayer as I prefer to evaluate the amps that I make.
Unfortunately my camera is on the blink and I am not able to post the scope traces. My plan is to use this amplifier in stereo and add a subwoofer and 2 rear channels. My first impressions are that I like this sound.
I have powered up my DX Precision1 and as per Stue request I give acount of my impression. First the differences to the standard DX P1 from Carlos are the input tail current a little bit higher with R8 set to 3K9. My supply voltage +-50Vdc. Bias voltage across emitter resistor at 15mV.
I measured 1mV offset and on my scope see no crossover distortion between 1kHz and 10kHz. The waveform seems more rounded at the bottom that the top. Clipping starts at input voltage of 1.5V on my DX P1.
First listening impression (Mono with other channel still not completed) Immediately treble sounded very clear bells cymbals and flute extremely clear. Voice on the midrange and accoustic guitar catching your ear and the bass very tight but not boomy. I am listening with no preamp straight from my Phillips cdplayer as I prefer to evaluate the amps that I make.
Unfortunately my camera is on the blink and I am not able to post the scope traces. My plan is to use this amplifier in stereo and add a subwoofer and 2 rear channels. My first impressions are that I like this sound.
Thank you Twaksak.... fully agreement into your comments
The amplifier is fine.... it is not perfect, but even beeing not perfect sounds clear and very powerfull.
No amplifier is perfect..even alive sound is not perfect because noises, reverberations, attenuations, echoes and a lot of problems including levels...some instruments are not loud enougth...... good equalized sound from studio sometimes is near perfection to my taste... as levels are more equalized when mixed.
Perfect may be the Maestro position.
thank you by your comments,
regards,
Carlos
The amplifier is fine.... it is not perfect, but even beeing not perfect sounds clear and very powerfull.
No amplifier is perfect..even alive sound is not perfect because noises, reverberations, attenuations, echoes and a lot of problems including levels...some instruments are not loud enougth...... good equalized sound from studio sometimes is near perfection to my taste... as levels are more equalized when mixed.
Perfect may be the Maestro position.
thank you by your comments,
regards,
Carlos
DX P1
Hi Carlos, your Precision1 is very good sounding! I thank you for a great amplifier.
Greetings 🙂 😉
Hi Carlos, your Precision1 is very good sounding! I thank you for a great amplifier.
Greetings 🙂 😉
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