Nice design Carlos! I must felicitate you on your "HD-II" amplifier.
I'm wondering how you determined these 180Ohm/220pF values for the lowpass filter in the input. 180Ohm/220pF gives 4MHz (-3dB) corner frequency. Strange!
What about choosing an 5 times larger resistor or capacitor for 600kHz /-3dB?
Just my
Best regards,
Donk
I'm wondering how you determined these 180Ohm/220pF values for the lowpass filter in the input. 180Ohm/220pF gives 4MHz (-3dB) corner frequency. Strange!
What about choosing an 5 times larger resistor or capacitor for 600kHz /-3dB?
Just my
Best regards,
Donk
I decide those things using my ears donk....listening.
The input resistance was bigger...than my main adviser, Doctor Graham Maynard suggest me to reduce...or remove.... was reduced.
I am not a designer, i have expertise into listening tests, A to B comparison and i have knowledge of some basic calculations, alike ohms law and simple things.... i am very ignorant.
But i use to force amplifier to work...stages to work...just that..and sometimes they sound good.
You have not readed the thread...too big, i know that.... because your answer..... made many times before...answered many times before...no problems..welcome.
regards,
Carlos
The input resistance was bigger...than my main adviser, Doctor Graham Maynard suggest me to reduce...or remove.... was reduced.
I am not a designer, i have expertise into listening tests, A to B comparison and i have knowledge of some basic calculations, alike ohms law and simple things.... i am very ignorant.
But i use to force amplifier to work...stages to work...just that..and sometimes they sound good.
You have not readed the thread...too big, i know that.... because your answer..... made many times before...answered many times before...no problems..welcome.
regards,
Carlos
Was a long time ago Donk.... the input resistance was 2K2 i think.... early beginning
of this thread.
Then Graham told me that would be better to reduce it or even to supress it.
And before that i had a voltage attenuator into the input...so... the story is old.
He suggested me to try smaller values, or even to supress the input resistance.
I made a try.... as nothing happened with audio reproduction...i reduced to 180 ohms into the input (Dx Standard).
The reason why the 180 ohms choice was to make more simple to people order parts.... we already have a 180 ohms resistance into the circuit...so... in the place to choice for other value, the decision was made to a value that already existed.
This input filter was never calculated by me.... i have just used values that were used in many other amplifiers.
Graham and Andrew made calculations... filter calculations... i am not good into this matter Donk...because of that i am surrounded by competent folks that use to help me when needed...ahahahha... they are a little bit boring too...because they use to point our errors....no one likes that...but needed.
Well Donk.... have a seat and welcome.... this is a very good place to learn things... if you already have learned a lot may be boring to you ... if not, enjoy a very simple thread.
regards,
Carlos
of this thread.
Then Graham told me that would be better to reduce it or even to supress it.
And before that i had a voltage attenuator into the input...so... the story is old.
He suggested me to try smaller values, or even to supress the input resistance.
I made a try.... as nothing happened with audio reproduction...i reduced to 180 ohms into the input (Dx Standard).
The reason why the 180 ohms choice was to make more simple to people order parts.... we already have a 180 ohms resistance into the circuit...so... in the place to choice for other value, the decision was made to a value that already existed.
This input filter was never calculated by me.... i have just used values that were used in many other amplifiers.
Graham and Andrew made calculations... filter calculations... i am not good into this matter Donk...because of that i am surrounded by competent folks that use to help me when needed...ahahahha... they are a little bit boring too...because they use to point our errors....no one likes that...but needed.
Well Donk.... have a seat and welcome.... this is a very good place to learn things... if you already have learned a lot may be boring to you ... if not, enjoy a very simple thread.
regards,
Carlos
Hi Carlos,
How you know I got out of car to see ?
When my neck was very bad and I had to reverse into a parking space I would get out, study the space and then reverse by mirrors and judgement - not looking.
I would even note distance to reverse, move a stone that same distance from doorframe, and then reverse with door open until door-frame was level with stone. Never bumped anything !
Hi Donk,
Don't forget that any series resistance between a source and first transistor base is also in series with the input potential which simultaneously is the reference for the NFB loop to operate via the differential input stage.
Cheers ........ Graham.
How you know I got out of car to see ?
When my neck was very bad and I had to reverse into a parking space I would get out, study the space and then reverse by mirrors and judgement - not looking.
I would even note distance to reverse, move a stone that same distance from doorframe, and then reverse with door open until door-frame was level with stone. Never bumped anything !
Hi Donk,
Don't forget that any series resistance between a source and first transistor base is also in series with the input potential which simultaneously is the reference for the NFB loop to operate via the differential input stage.
Cheers ........ Graham.
I was kidding.... interesting that you do not have an alarm for nearby objects
An audio oscilator having a big coil... when the coil goes near other metal object, the inductance will change and the audio tone will change too.
And this for you, is very easy to make...you are a real designer.
So... listening the tone you will feel how near you are... but of course will need to switch four different channels....maybe a little complicated because of that.
regards,
Carlos
An audio oscilator having a big coil... when the coil goes near other metal object, the inductance will change and the audio tone will change too.
And this for you, is very easy to make...you are a real designer.
So... listening the tone you will feel how near you are... but of course will need to switch four different channels....maybe a little complicated because of that.
regards,
Carlos
Mr Ras,
baie dankie, just read the E-mail, don't mind if i do.
High time for a discrete headphone amp thread, especially single ended ones that give the simple chippies some competition.
Anything to keep me from using my stash of 200mhz bd139/140s to assemble a DeXtra.
(Carlos, sorry carinho
)
baie dankie, just read the E-mail, don't mind if i do.
High time for a discrete headphone amp thread, especially single ended ones that give the simple chippies some competition.
Anything to keep me from using my stash of 200mhz bd139/140s to assemble a DeXtra.
(Carlos, sorry carinho
)
Oh!.... mastertrap was terrible!...have not followed threads were he use to land
The amplifier was made replacing sub circuits.
In a base of try and error..... let's try this and that..... CCS included, then removed, modified input included... and removed... comparing.
I think i was influenced by Graham Maynard and Hugh Dean... and of course i am not original..... not only me.....but WE are the result of our environment.... we go reading, learning, watching ideas... and all creations are in the reality, combinations of other guy's ideas.... hard to be the first.... only Pass and JLH.... those were very original.... Pass still is.
Yeah Jac the warrior.... even your 'carinho" comes with a protude pointing us (maybe a finger..ahahahah)... a very strong person you are.
Well.... to be inspired into Mistertrap was a hell ofensive....but as this came from you, a dear friend, there's absolutelly no problem.
regards,
Carlos
The amplifier was made replacing sub circuits.
In a base of try and error..... let's try this and that..... CCS included, then removed, modified input included... and removed... comparing.
I think i was influenced by Graham Maynard and Hugh Dean... and of course i am not original..... not only me.....but WE are the result of our environment.... we go reading, learning, watching ideas... and all creations are in the reality, combinations of other guy's ideas.... hard to be the first.... only Pass and JLH.... those were very original.... Pass still is.
Yeah Jac the warrior.... even your 'carinho" comes with a protude pointing us (maybe a finger..ahahahah)... a very strong person you are.
Well.... to be inspired into Mistertrap was a hell ofensive....but as this came from you, a dear friend, there's absolutelly no problem.
regards,
Carlos
Well.... nothing changed... filter remains an interrogation mark
Will it avoid transmissions from Mars to enter the amplifier?
I hope not!
I will be happy to listen transmissions from Mars.
I am still sanding my table...if it is turning better i do not know...but i am turning a hell strong... my arm jumped to 70 centimeters diameter....ahahahaha... half is fat!... and the other half is because the effort i am doing.... in one week i will be small once again..ahahahaha.
regards,
Carlos
Will it avoid transmissions from Mars to enter the amplifier?
I hope not!
I will be happy to listen transmissions from Mars.
I am still sanding my table...if it is turning better i do not know...but i am turning a hell strong... my arm jumped to 70 centimeters diameter....ahahahaha... half is fat!... and the other half is because the effort i am doing.... in one week i will be small once again..ahahahaha.
regards,
Carlos
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Yeah Dear Than.... everything in electronics forms "T" shape filter, or "H" shap
filters....if you start to consider those things you will turn crazy.
Mr Andrew now will open his Enciclopedia about filters.
And i am needing a filter here in home... sanding is producing a lot of dust...i would like to have a filter against dust here.
regards
hohohohoho!
filters....if you start to consider those things you will turn crazy.
Mr Andrew now will open his Enciclopedia about filters.
And i am needing a filter here in home... sanding is producing a lot of dust...i would like to have a filter against dust here.
regards
hohohohoho!
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If my furniture will be pretty or not i have doubts.
But no doubts that i am turning a hell strong making circles using arms alike Karatê trainment.
Clockwise and counter clockwise...both hands...ahahaha.
Karatê Kid II
Tell me the filter is bothering you and i will give it a punch and will sit over the filter after that....hummmm.. smashed!
regards,
Carlos
But no doubts that i am turning a hell strong making circles using arms alike Karatê trainment.
Clockwise and counter clockwise...both hands...ahahaha.
Karatê Kid II
Tell me the filter is bothering you and i will give it a punch and will sit over the filter after that....hummmm.. smashed!
regards,
Carlos
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____A new DX Standard is born____
Carlos! .....You have ruined my life! I cannot stop listening to the music! 14 hours straight yesterday, of music. I almost skipped worked today, can't wait to get home. Sound is beautiful, not the amp but the music, the amp just allowed me to hear the music -- not the electronics and paper cones, if you know what I mean.
Very intimate with the singers, musicians.
Sound is clean, detailed, revealing.
Bass is so tight, clean and imaged. Drums and bass become real instruments in the correct position, and not just the low-frequency background thing. Lot of power into the low notes.
Carlos! .....You have ruined my life! I cannot stop listening to the music! 14 hours straight yesterday, of music. I almost skipped worked today, can't wait to get home. Sound is beautiful, not the amp but the music, the amp just allowed me to hear the music -- not the electronics and paper cones, if you know what I mean.
Very intimate with the singers, musicians.
Sound is clean, detailed, revealing.
Bass is so tight, clean and imaged. Drums and bass become real instruments in the correct position, and not just the low-frequency background thing. Lot of power into the low notes.
Attachments
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