Hi Guys.
I know there are reasons why this design might not work but can you please give me a hand in sorting it out. The first stage uses 1/2 a 12ax7 as shown in diagram. I want to use octals but am happy to use the ax7.
I built it and obviously I am getting the necessary gain but the volume fluctuates..
I could do with some help here.
The riaa is done by bob in his original design but again it is beyond me to fully grasp what i might need to do.
I can read I can listen but being a newbie its a mighty steep hill i climb
I know I could do 2 things.. being using step up trannys or mm cartridge but I just dont want to (have been reading for months now)
Thanks for your help in advance
Nick
I know there are reasons why this design might not work but can you please give me a hand in sorting it out. The first stage uses 1/2 a 12ax7 as shown in diagram. I want to use octals but am happy to use the ax7.
I built it and obviously I am getting the necessary gain but the volume fluctuates..
I could do with some help here.
The riaa is done by bob in his original design but again it is beyond me to fully grasp what i might need to do.
I can read I can listen but being a newbie its a mighty steep hill i climb
I know I could do 2 things.. being using step up trannys or mm cartridge but I just dont want to (have been reading for months now)
Thanks for your help in advance
Nick
Attachments
Many thanks
To Geek and EC..
I had kind of forgotten them on the diagram.. I had placed them in circuit but one wasnt soldered effectively...thats been fixed...
I am experiencing distorted sound (but adequate gain) (distortion may be loading) but the the music stops for a 1/10th of a second with a bass thud then resumes.. for about 3 seconds
Thanks to both of you but i suppose i will have to keep looking/ scratching my head.
I love your DAC EC.. thats very exceptional work.. Pity the Australia dollar buys 1/3 of a Euro..
Nevermind
If anyone has any ideas please feel free to share them
Thanks
Nick
To Geek and EC..
I had kind of forgotten them on the diagram.. I had placed them in circuit but one wasnt soldered effectively...thats been fixed...
I am experiencing distorted sound (but adequate gain) (distortion may be loading) but the the music stops for a 1/10th of a second with a bass thud then resumes.. for about 3 seconds
Thanks to both of you but i suppose i will have to keep looking/ scratching my head.
I love your DAC EC.. thats very exceptional work.. Pity the Australia dollar buys 1/3 of a Euro..
Nevermind
If anyone has any ideas please feel free to share them
Thanks
Nick
still no joy
Hi Geek
Thanks for the suggestions
Changed to a .01 cap to no effect, did the thing with electros no joy
Will now mess with the cathode to ground resistor on the input tube(gain)
Thanks a bunch for your interest.. of what i hear it holds great promise.
Hey Geek do you watch "Corner Gas"?
We have only just got it in australia... A patient of mine is Canadian and lent me the entire series one.. What a great show it is
Regards
Nick
Hi Geek
Thanks for the suggestions
Changed to a .01 cap to no effect, did the thing with electros no joy
Will now mess with the cathode to ground resistor on the input tube(gain)
Thanks a bunch for your interest.. of what i hear it holds great promise.
Hey Geek do you watch "Corner Gas"?
We have only just got it in australia... A patient of mine is Canadian and lent me the entire series one.. What a great show it is
Regards
Nick
Re: still no joy
Hi Nick,
Hmmm, before you start changing things, is perhaps one or more of the tubes themselves buggered?
It is the best show EVER!!!
Given I don't like hockey, I can say I actually watch one thing Canadian besides election results, LOL!
Cheers!
Hi Nick,
duderduderini said:
Hmmm, before you start changing things, is perhaps one or more of the tubes themselves buggered?
duderduderini said:
It is the best show EVER!!!
Given I don't like hockey, I can say I actually watch one thing Canadian besides election results, LOL!
Cheers!
will look into both
OK will order more tubes and also check the grounding/motor boating of ps.
Thanks to both of you for your help.
ps Greg... Its the best tv show i have seen since the good ole days of mash, get smart etc.
The show does Canada proud and and far as intellect goes, its a candle that burns brightly in an ever increasingly dim world.
Cheers and thanks again
Nick
OK will order more tubes and also check the grounding/motor boating of ps.
Thanks to both of you for your help.
ps Greg... Its the best tv show i have seen since the good ole days of mash, get smart etc.
The show does Canada proud and and far as intellect goes, its a candle that burns brightly in an ever increasingly dim world.
Cheers and thanks again
Nick
better
Thanks to all for advice.. i added some more filtration and wired according to audioexpress article re motorboating. Since this is a prototype i at least have prooved its possible but.. need to work on hum, get a regulated ps and figure out riaa.. apart from that everything is dandy!!!!
To EC.. i mistook your id for ec designs who has made a dac for cd player.. i apologise.
If anyone can enlighten me on how to figure riaa then feel free as i think bobs original octal phono amp has now been added to such that it doesnt seem to work well anymore (the sound is shall we say devoid of any bass)
Thanks to all of you
Nick
Thanks to all for advice.. i added some more filtration and wired according to audioexpress article re motorboating. Since this is a prototype i at least have prooved its possible but.. need to work on hum, get a regulated ps and figure out riaa.. apart from that everything is dandy!!!!
To EC.. i mistook your id for ec designs who has made a dac for cd player.. i apologise.
If anyone can enlighten me on how to figure riaa then feel free as i think bobs original octal phono amp has now been added to such that it doesnt seem to work well anymore (the sound is shall we say devoid of any bass)
Thanks to all of you
Nick
AH No worries
I would say a lot do actually. Generally its "no worries mate" but any abbreviation will suffice.
I hope this lesson in the intricacies of the australian myth encourages you to visit EC.. just bring lots of 500V caps and non inductive wirewound resistors when you do.... oh and transformers
Regards
Nick
I would say a lot do actually. Generally its "no worries mate" but any abbreviation will suffice.
I hope this lesson in the intricacies of the australian myth encourages you to visit EC.. just bring lots of 500V caps and non inductive wirewound resistors when you do.... oh and transformers
Regards
Nick
No worries, mate.
Yes, I had heard that you are short on transformer winders. Of course, you can always recycle mains transformers if the laminations haven't been varnish impregnated. First unstack the core. The mains winding is always the inner winding, so count the secondary turns as they come off to find the voltage to turns ratio, measure the wire diameter to find the current density, and then you can rewind for any voltage.
Non-inductive W/W only seem to be readily available in the USA, and 500V electrolytics are fragile things.
I'd quite like to visit Australia and New Zealand but the long haul flight puts me off.
Yes, I had heard that you are short on transformer winders. Of course, you can always recycle mains transformers if the laminations haven't been varnish impregnated. First unstack the core. The mains winding is always the inner winding, so count the secondary turns as they come off to find the voltage to turns ratio, measure the wire diameter to find the current density, and then you can rewind for any voltage.
Non-inductive W/W only seem to be readily available in the USA, and 500V electrolytics are fragile things.
I'd quite like to visit Australia and New Zealand but the long haul flight puts me off.
Re: better
You can check your RIAA values with this calculator: http://www.hagtech.com/equalization.html You'll need to parallel the Rp of the tube with the plate resistor and add that to the RIAA series resistor, then plug those values into the calculator. The first section in your schematic is the 2122 pole, and the second is the 50/500 Hz turnover. You don't have a treble zero at 50kHz, but you could add one. This should let you know if the values are in the ballpark.
Sheldon
duderduderini said:
You can check your RIAA values with this calculator: http://www.hagtech.com/equalization.html You'll need to parallel the Rp of the tube with the plate resistor and add that to the RIAA series resistor, then plug those values into the calculator. The first section in your schematic is the 2122 pole, and the second is the 50/500 Hz turnover. You don't have a treble zero at 50kHz, but you could add one. This should let you know if the values are in the ballpark.
Sheldon
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