The official board is the ones, beeing under test, by Nordic
He will present the final product, that was tested and worked fine till today.
Official board from Nordic.
The High Resolution II will be substituted by Dx Precision into this next Christmas...if possible, by me, to produce something even better than this one.
I am afraid i reach the top...the best i can do..but i will try.
So..High Resolution II, blue and green frame, is the last model that will remain as the last one till December.
regards,
Carlos
......................................................................................................
Thank you Razorback
You do not imagine how happy i feel to have "hermanos" de sudamerica in this thread.
regards,
Carlos
He will present the final product, that was tested and worked fine till today.
Official board from Nordic.
The High Resolution II will be substituted by Dx Precision into this next Christmas...if possible, by me, to produce something even better than this one.
I am afraid i reach the top...the best i can do..but i will try.
So..High Resolution II, blue and green frame, is the last model that will remain as the last one till December.
regards,
Carlos
......................................................................................................
Thank you Razorback
You do not imagine how happy i feel to have "hermanos" de sudamerica in this thread.
regards,
Carlos
Hi Nordic,
Good to hear of your success.
Patient fault finding rewarded !
Now the listening tests start all over again.
Hi Sparkle.
CCS for differential tail current plus a mirror leaves the input stage floating. This might seem ideal but removes all node damping with respect to zero AF ground.
I tried many times a CCS in place of tail (and emitter follower) R but never heard any advantage, so thought it better to not overcomplicate and just make best use of simple resistively self damping circuitry.
Hi Carlos.
It is great that others achieve your HR success.
The pleasure and satisfaction of constructors being reward in itself.
Well Done !!!
(Until the next - ultimate one ? )
I remain concerned about mistakes being more catastrophic than might be the case if the VAS has a 22 to 47 ohm series emitter resistor, maybe with a small current limit back to the mirror.
Even D.Self covered this aspect because the follower can overdrive the VAS making it overcurrent via the PNP driver and this through the PNP output transistor. Then once the PNP half overcurrents with failure the upper NPN section can fail too, whereas a VAS based limit would minimise damage.
Cheers ........... Graham.
Good to hear of your success.
Patient fault finding rewarded !
Now the listening tests start all over again.
Hi Sparkle.
CCS for differential tail current plus a mirror leaves the input stage floating. This might seem ideal but removes all node damping with respect to zero AF ground.
I tried many times a CCS in place of tail (and emitter follower) R but never heard any advantage, so thought it better to not overcomplicate and just make best use of simple resistively self damping circuitry.
Hi Carlos.
It is great that others achieve your HR success.
The pleasure and satisfaction of constructors being reward in itself.
Well Done !!!
(Until the next - ultimate one ? )
I remain concerned about mistakes being more catastrophic than might be the case if the VAS has a 22 to 47 ohm series emitter resistor, maybe with a small current limit back to the mirror.
Even D.Self covered this aspect because the follower can overdrive the VAS making it overcurrent via the PNP driver and this through the PNP output transistor. Then once the PNP half overcurrents with failure the upper NPN section can fail too, whereas a VAS based limit would minimise damage.
Cheers ........... Graham.
Graham Maynard said:
thanks for reply .... i have seen few problems at the output related output signal wave....it was not very clear...so, when i have removed the ccs and mounted a zener, like Carlos did, the problem was gone and i had much more clear output signal .... so better to use zener IMHO...
also i can see that you favour resistors up there - it turns that it is also a good option... ccs produce porblems up there.....maybe a ccs in some other form would be the solution beter to what i have tried but i do not know....all in all it is probybly best to use resistor in the leg of the diff. or zener diode like Carlos did.....
good work Carlos and all....
thank you all folks....good support and agreements are always nice
I have to study this VAS.... i will do this near future..to see if it will really kill my output.
For a while, it is not a real danger, i want to see my output burned to move.... i remember i tried that, not only i could not burn but also i was surprised how weak the distortions are into the macimum volume i had.
regards,
Carlos
I have to study this VAS.... i will do this near future..to see if it will really kill my output.
For a while, it is not a real danger, i want to see my output burned to move.... i remember i tried that, not only i could not burn but also i was surprised how weak the distortions are into the macimum volume i had.
regards,
Carlos
Graham, please, tell me how to limit that VAS driver, or limit the VAS output?
Into the first one, it is attacked by current, so, zener will not work there.
But maybe we can do something into the second one.
Can you, please, instruct me to place a limit to avoid problems?
I have not "burns" into the simulator, so..... i do not know how to make that... will try something there, avoiding clipping into the negative rail to happens in advance.
Michael and you told me the problem, i will be happy with the solution too....of course without remove the VAS.... not a solution.... i need protection
regards,
Carlos
Into the first one, it is attacked by current, so, zener will not work there.
But maybe we can do something into the second one.
Can you, please, instruct me to place a limit to avoid problems?
I have not "burns" into the simulator, so..... i do not know how to make that... will try something there, avoiding clipping into the negative rail to happens in advance.
Michael and you told me the problem, i will be happy with the solution too....of course without remove the VAS.... not a solution.... i need protection
regards,
Carlos
Fine!..... one week more and i will check if the amplifier is under danger without
The protection.
I will try to burn the output...using only one transistor, 37 volts and 4 ohms speaker.
Succeeding to burn the output, then i will include into the schematic.
Thank you Graham...very good the solution.... i will check if we have a problem in advance.
I think Ecat had tried high volume.... have you tried Ecat?
regards,
Carlos
.......................................................................................................
Arnis!!!..... hey Microp!!!... were are you?
You have disappeared,
how are you doing.
regards,
Carlos
The protection.
I will try to burn the output...using only one transistor, 37 volts and 4 ohms speaker.
Succeeding to burn the output, then i will include into the schematic.
Thank you Graham...very good the solution.... i will check if we have a problem in advance.
I think Ecat had tried high volume.... have you tried Ecat?
regards,
Carlos
.......................................................................................................
Arnis!!!..... hey Microp!!!... were are you?
You have disappeared,
how are you doing.
regards,
Carlos
Hi Carlos,
It is not high volume which is the problem, but all the other little things that are beyond your control.
Like someone inadvertently causing a momentary short on the output whilst the amp is being driven, or connecting up too low an impedance LS, or a piezo tweeter with insufficient series R, or the centre of a RCA phono inputting RF at the moment the ground connection is lost when being removed, or a transistor in the wrong way due to different pin-out at construction, or a wandering spec of solder, or ......
Without the current limit and having up to say 1mA into the base of the emitter follower from the differential pair, that little transistor could self destruct in an instant (gain >250 and 30V between collector and emitter), or take the VAS and PNP driver out etc.
A single transistor VAS would be more rugged but not as low distortion.
Cheers ............ Graham.
It is not high volume which is the problem, but all the other little things that are beyond your control.
Like someone inadvertently causing a momentary short on the output whilst the amp is being driven, or connecting up too low an impedance LS, or a piezo tweeter with insufficient series R, or the centre of a RCA phono inputting RF at the moment the ground connection is lost when being removed, or a transistor in the wrong way due to different pin-out at construction, or a wandering spec of solder, or ......
Without the current limit and having up to say 1mA into the base of the emitter follower from the differential pair, that little transistor could self destruct in an instant (gain >250 and 30V between collector and emitter), or take the VAS and PNP driver out etc.
A single transistor VAS would be more rugged but not as low distortion.
Cheers ............ Graham.
Hey you two, go away!
Do you have any idea how hard it was for me to get this one working.....?
Lol well it took much less time than the first DX, but I have to buy a bag of transistors for the second channel to replace all the ones I blew....
BTW if much of your music is from mp3s.. build the vanilla DX.... the HDII magnifies all the bad qualities of a bad mp3, while the vanilla blends and overcomes it.
Treble is superb... first amp I heard that makes natural sounding S'es and T's... and beatifull silky sound of two hihat symbals comming together.. out of this world.
I would say there is a bigger diffirence in quality bewteen the HDII and the vanilla then there is a diffirence between the vanilla and my Mauro Penasa chipamp.
Outstanding work Carlos.
Do you have any idea how hard it was for me to get this one working.....?
Lol well it took much less time than the first DX, but I have to buy a bag of transistors for the second channel to replace all the ones I blew....
BTW if much of your music is from mp3s.. build the vanilla DX.... the HDII magnifies all the bad qualities of a bad mp3, while the vanilla blends and overcomes it.
Treble is superb... first amp I heard that makes natural sounding S'es and T's... and beatifull silky sound of two hihat symbals comming together.. out of this world.
I would say there is a bigger diffirence in quality bewteen the HDII and the vanilla then there is a diffirence between the vanilla and my Mauro Penasa chipamp.
Outstanding work Carlos.
audio is never ending story....it is normal that Carlos will produce something new...otherwise i will be worried for him....maybe not better than HRII but new for sure.....he is an ultimate audio junkie.....in a positive way of course....
so Nordic - do not bother - this way you will learn to enjoy the music not the components - because there is allways a better amplifier on the way somewhere.....do not bother
it is nice that you like the amplifier...it is a good job and it needed long time to be made....
i am happy......
Thank you Graham, Ecat, Nordic and Sparkle
I had my mouth wide opened when i listen this amplifier...i have to say that Hugh Dean was over my shouder, inspiring me, when i made this one.
There are some connections with Aspen amplifiers designs..of course, the King of Audio Amplifiers is behind the scenes helping me.
Also Graham was present during those last monthes, in special refered to the Dx Standard, "the Vanilla" as Nordic said.
I was very impressed with the sonics.....
I said:
- "I have made that?.... was me?"
Not really me.... was Hugh inspiring, and Graham supporting.
Sound is exceptional, wonderfull clear nice sonics, to eat thousands, not more hundreds!
I am afraid of those over current protectors, as they tend to turn audio compressed....losses in dinamics is what we gonna pay for that protection i think...but...i have to try...i have to listen, to decide something about.
If someone try to me, i will be extremelly happy and gratefull.
My parts are inside cases, boxes, a mess to re-start electronics rigth now....i was into the roof, helping folks to install Satelite antena to television reception... a lot of things, priorities, here in my life.
I think i will delay to check those things...so...sorry Graham, and sorry to the folks that may have burned output because of overdriven, shorts into the output...EMF generated by crazy Piezos and electrostátics and everything that may kill the output.
Well....not the idea to make something undestructable.... reliable, or reasonable reliable is enougth to me.
If Nordic agree....i feel more confortable to let this testings to the future.
Friends are around...an gentleman, from Australia, sent me another VAS with that overcurrent protection...reading the second transistor emitter current and draining the first VAS base (reducing signal..automatic volume control... automatic gain control..compressive thing.)
I will not be happy to include this or that schematic, i feel it will kill sonics...we will see...future will tell us if we need that care or if it is "in excess".
regards,
Carlos
I had my mouth wide opened when i listen this amplifier...i have to say that Hugh Dean was over my shouder, inspiring me, when i made this one.
There are some connections with Aspen amplifiers designs..of course, the King of Audio Amplifiers is behind the scenes helping me.
Also Graham was present during those last monthes, in special refered to the Dx Standard, "the Vanilla" as Nordic said.
I was very impressed with the sonics.....
I said:
- "I have made that?.... was me?"
Not really me.... was Hugh inspiring, and Graham supporting.
Sound is exceptional, wonderfull clear nice sonics, to eat thousands, not more hundreds!
I am afraid of those over current protectors, as they tend to turn audio compressed....losses in dinamics is what we gonna pay for that protection i think...but...i have to try...i have to listen, to decide something about.
If someone try to me, i will be extremelly happy and gratefull.
My parts are inside cases, boxes, a mess to re-start electronics rigth now....i was into the roof, helping folks to install Satelite antena to television reception... a lot of things, priorities, here in my life.
I think i will delay to check those things...so...sorry Graham, and sorry to the folks that may have burned output because of overdriven, shorts into the output...EMF generated by crazy Piezos and electrostátics and everything that may kill the output.
Well....not the idea to make something undestructable.... reliable, or reasonable reliable is enougth to me.
If Nordic agree....i feel more confortable to let this testings to the future.
Friends are around...an gentleman, from Australia, sent me another VAS with that overcurrent protection...reading the second transistor emitter current and draining the first VAS base (reducing signal..automatic volume control... automatic gain control..compressive thing.)
I will not be happy to include this or that schematic, i feel it will kill sonics...we will see...future will tell us if we need that care or if it is "in excess".
regards,
Carlos
Attachments
Was a nice surprise... i had in my imagination that i could do better than the Dx
standard.... but not so better that way.
Was a big surprise....not more surprise that sound quality now a days.
I have to confess, not being humble, that i am confident that everybody will appreciate this amplifier.
regards,
standard.... but not so better that way.
Was a big surprise....not more surprise that sound quality now a days.
I have to confess, not being humble, that i am confident that everybody will appreciate this amplifier.
regards,
Attachments
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- Not open for further replies.