How are you Rabbitz....some fingers are better and others not?
Tell me, please, how are you?
Do you have your home coordinates...those informs of global positioning.... Google earth positioning..
Please, send my your location....the place name..not the entire adress..the town and Australia position.
Do this directly Rabbitz, please.
panzertoo@yahoo.com
regards,
Carlos
Tell me, please, how are you?
Do you have your home coordinates...those informs of global positioning.... Google earth positioning..
Please, send my your location....the place name..not the entire adress..the town and Australia position.
Do this directly Rabbitz, please.
panzertoo@yahoo.com
regards,
Carlos
Last january, the Dx amplifier was under testings.
Output coil was used....different values tested...including air core.
Different Current to VAS...different biasing points.
Different rail resistances
R/C filter between differential colectors
Different drivers emitter loads
Many types of input capacitors...different values too
Supression of the 2K2 input resistance was tested too.
regards,
Carlos
Output coil was used....different values tested...including air core.
Different Current to VAS...different biasing points.
Different rail resistances
R/C filter between differential colectors
Different drivers emitter loads
Many types of input capacitors...different values too
Supression of the 2K2 input resistance was tested too.
regards,
Carlos
Attachments
Dx supply is working fine.
I am very proud of this supply...it resulted excelent.
Schematic is the one posted at the home page.
My prototype produces 110 watts undistorted....and could reach 160 watts during short time peaks with reasonable (tollerable, suportable...not enormous) distortion.
regards,
Carlos
I am very proud of this supply...it resulted excelent.
Schematic is the one posted at the home page.
My prototype produces 110 watts undistorted....and could reach 160 watts during short time peaks with reasonable (tollerable, suportable...not enormous) distortion.
regards,
Carlos
Attachments
Hi Andrew,
Re your post#1470 (freq of R Vibracion AM station often DXed in UK). I did not see this before I entered my post#1474.
If the filter were stand alone and separately buffered I might go along with your generalised figure, but over the years I have found that you can hear what would be deemed a sensible input filter when it is simultaneously used in direct connection to differential/input bipolars.
I feel it is likely your figures would better match a fet input stage.
You ask >>It would appear that a lower value of series resistor and possibly higher value of grounding capacitor would both help in lowering the AC impedance seen by the base of the input transistor. Is that correct? <>
I would think that correct, but sometimes there can be oscillation on a previosly stable circuit having only a small stability margin.
You ask >>has anyone tried moving C14 (the Miller comp cap) from the collector of Q1 to the base of Q2? <<
Carlos' amplifier has fewer high gain phase changing stages within the closed loop, and so I see this technique for stabilisation being worse. Carlos checked out to optimise the NFB capacitor value, and so I could imagine connecting another 22pF at the base of Q2 would mean he would need to re-check all capacitor values anyway.
Actually the method of stabilisation you enquire about is more useful for circuits containing additional phase changing devices, like a differential mirror and a Darlington VAS, or more complex output stage complementaries, because it can improve stability.
However Carlos' Dx is already quite stable, so it is better off without any of inner loop phase change that such a C.dom between Q3 collector and Q2 base will cause.
You ask >>
Does it improve the sound?
Would other stability components be required to implement this change? <<
I suggest it would degrade reproduction; and,
This connection will reduce the closed loop bandwidth, but I cannot be sure about stability. Values need to set up in a real life amplifier circuit.
Thus I must echo Carlos' suggestion that you give it a try and let us know.
Hi Nordic,
When you are quite used to the sound of your Dx amplifiers, why not try linking out the 2k2 input resistors beneath the boards and let us know if you hear anything.
Maybe there is that little bit more for you to be happy about, as long as the wisdom teeth are not playing tricks with your hearing.
Cheers ....... Graham.
Re your post#1470 (freq of R Vibracion AM station often DXed in UK). I did not see this before I entered my post#1474.
If the filter were stand alone and separately buffered I might go along with your generalised figure, but over the years I have found that you can hear what would be deemed a sensible input filter when it is simultaneously used in direct connection to differential/input bipolars.
I feel it is likely your figures would better match a fet input stage.
You ask >>It would appear that a lower value of series resistor and possibly higher value of grounding capacitor would both help in lowering the AC impedance seen by the base of the input transistor. Is that correct? <>
I would think that correct, but sometimes there can be oscillation on a previosly stable circuit having only a small stability margin.
You ask >>has anyone tried moving C14 (the Miller comp cap) from the collector of Q1 to the base of Q2? <<
Carlos' amplifier has fewer high gain phase changing stages within the closed loop, and so I see this technique for stabilisation being worse. Carlos checked out to optimise the NFB capacitor value, and so I could imagine connecting another 22pF at the base of Q2 would mean he would need to re-check all capacitor values anyway.
Actually the method of stabilisation you enquire about is more useful for circuits containing additional phase changing devices, like a differential mirror and a Darlington VAS, or more complex output stage complementaries, because it can improve stability.
However Carlos' Dx is already quite stable, so it is better off without any of inner loop phase change that such a C.dom between Q3 collector and Q2 base will cause.
You ask >>
Does it improve the sound?
Would other stability components be required to implement this change? <<
I suggest it would degrade reproduction; and,
This connection will reduce the closed loop bandwidth, but I cannot be sure about stability. Values need to set up in a real life amplifier circuit.
Thus I must echo Carlos' suggestion that you give it a try and let us know.
Hi Nordic,
When you are quite used to the sound of your Dx amplifiers, why not try linking out the 2k2 input resistors beneath the boards and let us know if you hear anything.
Maybe there is that little bit more for you to be happy about, as long as the wisdom teeth are not playing tricks with your hearing.
Cheers ....... Graham.
Yes Nordic...just a link to check...make it in one channel and let the other original
Just link and listen.
You will have an increase in level....carefull not to confuse level of treble with quality of treble.
I am remembering that because i feel very difficult to "separate" those two things when they happens simultaneously...it is normal for us... humans...to perceive the one is louder as better.
Because of that, A to B comparison testings need carefull adjustments related levels.
regards,
Carlos
Just link and listen.
You will have an increase in level....carefull not to confuse level of treble with quality of treble.
I am remembering that because i feel very difficult to "separate" those two things when they happens simultaneously...it is normal for us... humans...to perceive the one is louder as better.
Because of that, A to B comparison testings need carefull adjustments related levels.
regards,
Carlos
Thanks I might try to short it out with a crocodile clip lead..... don't feel like unscrewing it from the heatsink AGAIN.
Ta, for kind wishes... throat still sore, but the uncle put the camera down my nose yesterday, and said it looks OK, considering how long I smoked... Can't wait to have these teeth removed now...
Ta, for kind wishes... throat still sore, but the uncle put the camera down my nose yesterday, and said it looks OK, considering how long I smoked... Can't wait to have these teeth removed now...
Will be good to me when you turn free of those teeth are bothering you
Nordic
You have special passion for audio, in our group of people you are important, a very special man...also you move yourself constantly doing things.... a good constructor, a good researcher.
It is a pitty to watch you this way.....with concerns, some natural fear about the treatment you will face.
Please, let me know the day you turn free of this nigthmare.... for a while go talking as this may bring some relief to you.
You will not face pains..Xylocaine, Novocaine will maintain you confortable.. it is only not a very nice thing to face.... going out from the Doctors keep yourself drugged with Sodium Dipirone and you will feel yourself better.... do not wait Xylocaine effect finishes..go to Dipirone immediatelly... and another one 4 hours latter.
regards,
Carlos
Nordic
You have special passion for audio, in our group of people you are important, a very special man...also you move yourself constantly doing things.... a good constructor, a good researcher.
It is a pitty to watch you this way.....with concerns, some natural fear about the treatment you will face.
Please, let me know the day you turn free of this nigthmare.... for a while go talking as this may bring some relief to you.
You will not face pains..Xylocaine, Novocaine will maintain you confortable.. it is only not a very nice thing to face.... going out from the Doctors keep yourself drugged with Sodium Dipirone and you will feel yourself better.... do not wait Xylocaine effect finishes..go to Dipirone immediatelly... and another one 4 hours latter.
regards,
Carlos
Mr. Erskine was carefull to show the parts are going to obsolescence
This trimpot and resistance were used to bias.....now they have no function and will disappear from the 3D models near future.
This was the method used to "call attention"... and will be substituted to a new image, with those parts clearly supressed, in the future
regards,
Carlos
This trimpot and resistance were used to bias.....now they have no function and will disappear from the 3D models near future.
This was the method used to "call attention"... and will be substituted to a new image, with those parts clearly supressed, in the future
regards,
Carlos
Attachments
It is nice enougth..also the size seems to be good.... the grille, that top cover
was excelent.... produces a huge, a very professional ancient days tube amplifier look....we used to observe the tube heaters over those kind of grilles in the past...as great to watch the ionic blue and that yellow/red colour from the heaters...... i like it Nordic.
It will result pretty when you finish your job.
regards,
Carlos
was excelent.... produces a huge, a very professional ancient days tube amplifier look....we used to observe the tube heaters over those kind of grilles in the past...as great to watch the ionic blue and that yellow/red colour from the heaters...... i like it Nordic.
It will result pretty when you finish your job.
regards,
Carlos
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