Konnichiwa,
I would do it like that, as the Bulk of the PSU current flows in that stage and any signal current impressed will be proportionally larger in this stage as well.
Neither of course. Always consider where the current will flow and where you want it to flow.
Think of current/energy as a bucket of water poured out somewhere. On a perfectly flat and level surface it spreads evenly. Start placing the slightest indentions and the bulk will flow with direction. Place full bullwarks and "shore fortifications" and you will be able to direct a huge flow that would "saturate" your "plain with dug channels" making sure nothing is wasted or available to cause problems elsewhere.
Now replace "indention" with "impedance" and "bullwark" with "insulation" and "water" with "current". Clearer?
I personally would split each filter resistor into 2 seperate ones with 1/2 Value and then would use one each (impedance) for both negative and positive line, making the filter symmetrical. The signal reference ("ground") appears at the last filter cap negative terminal.
I wish people would get rid of this straw ("ground") they clutch.
Remember, ground isn't....
Sayonara
Marinos said:
I would do it like that, as the Bulk of the PSU current flows in that stage and any signal current impressed will be proportionally larger in this stage as well.
Marinos said:
Neither of course. Always consider where the current will flow and where you want it to flow.
Think of current/energy as a bucket of water poured out somewhere. On a perfectly flat and level surface it spreads evenly. Start placing the slightest indentions and the bulk will flow with direction. Place full bullwarks and "shore fortifications" and you will be able to direct a huge flow that would "saturate" your "plain with dug channels" making sure nothing is wasted or available to cause problems elsewhere.
Now replace "indention" with "impedance" and "bullwark" with "insulation" and "water" with "current". Clearer?
I personally would split each filter resistor into 2 seperate ones with 1/2 Value and then would use one each (impedance) for both negative and positive line, making the filter symmetrical. The signal reference ("ground") appears at the last filter cap negative terminal.
I wish people would get rid of this straw ("ground") they clutch.
Remember, ground isn't....
Sayonara
Hi kuei,
I think I've got the idea.
Splitting the resistor the characteristics off the filter remain (cutoff frequency, ripple factor,..) remains the same ?
In the case of LC filter with L for both lines ( + and -) do the 2 Ls summup and the filter calculations are based on the sum ?
Having "lowest ripple" and impedance as the only target of a PSU is achievable in many ways. I (as GAK and many others I believe) am confused when the PSU time comes. Are there any basic rules for it?
For example
- which should be the roll off frequency of a filter block ?
- which should be the resonance frequency and Q factor for a LC filter ?
- when does a decoupling filter really decouple ? (I'm sure it is not like throw in as much capacitance as you can and you've done it).
Sorry for my inaccurate terms ........ but I hope you've got the meaning of my questions. I also understand that there are no easy answers to the subject. Are there ?...
I think I've got the idea.
Splitting the resistor the characteristics off the filter remain (cutoff frequency, ripple factor,..) remains the same ?
In the case of LC filter with L for both lines ( + and -) do the 2 Ls summup and the filter calculations are based on the sum ?
Having "lowest ripple" and impedance as the only target of a PSU is achievable in many ways. I (as GAK and many others I believe) am confused when the PSU time comes. Are there any basic rules for it?
For example
- which should be the roll off frequency of a filter block ?
- which should be the resonance frequency and Q factor for a LC filter ?
- when does a decoupling filter really decouple ? (I'm sure it is not like throw in as much capacitance as you can and you've done it).
Sorry for my inaccurate terms ........ but I hope you've got the meaning of my questions. I also understand that there are no easy answers to the subject. Are there ?...
Konnichiwa,
In essence yes, but you get added common mode noise filtering.
In principle - yes. You can add a neat trick, make the choke one choke with two sections wound as a "really bad" (high leakage inductance) 1:1 transformer. Gives compact but effective filtering not only for differential mode 100/120Hz noise but also for common mode noise, especially if both sections in turn are wound for a minimal shunt capacitance (very high resonance).
Yup. As so many other things. You can do a lot of things in different ways. It often pays to have a good hard how it's done in truely legendary commercial gear. Gives good ideas what is easy, reliable and simple, without being too expensive....
Yes, unless you are spectucaluray good in "tuning gear" by ear and have endless amounts of time always a RC section as final section, this removes most of the Regulator/LC filter ringing sound. In poweramp's that of course becomes difficult.
Depends.
Low to very low on both. Implies large chokes and large cap's.
I use the term "decoupling" in any case where we want to isolate several branches of a (+B) circuit from being modulated by the signal current in one branch as much as possible. This implies first that the "decoupling" RC/LC circuit must reject audio band signals with a pretty substantial rate. If you look at the suggested circuit from my Phono, we have a 100uF Cap or a regulator as the final output of the PSU (before we enter what is really the signal circuit). With 22uF/1k you have a -3db point at 7Hz and a -20db point at 70Hz.
This means any noise from the PSU (or reaction from the psu to a signal related current change) is rejected by > 20db @ 100Hz. This means at 100Hz our signal circuit for the output stage is DE-COUPLED from the PSU by over 20db. BTW, for the first stage the "decoupling is more like > 60db @ 100Hz.
I am unware of anyt subject where sensible questions have sensible answers that are simple, life, the universe and all the rest are inherently complex I'm afraid.
Sayonara
Marinos said:
In essence yes, but you get added common mode noise filtering.
Marinos said:
In principle - yes. You can add a neat trick, make the choke one choke with two sections wound as a "really bad" (high leakage inductance) 1:1 transformer. Gives compact but effective filtering not only for differential mode 100/120Hz noise but also for common mode noise, especially if both sections in turn are wound for a minimal shunt capacitance (very high resonance).
Marinos said:
Yup. As so many other things. You can do a lot of things in different ways. It often pays to have a good hard how it's done in truely legendary commercial gear. Gives good ideas what is easy, reliable and simple, without being too expensive....
Marinos said:
Yes, unless you are spectucaluray good in "tuning gear" by ear and have endless amounts of time always a RC section as final section, this removes most of the Regulator/LC filter ringing sound. In poweramp's that of course becomes difficult.
Marinos said:
Depends.
Marinos said:
Low to very low on both. Implies large chokes and large cap's.
Marinos said:
I use the term "decoupling" in any case where we want to isolate several branches of a (+B) circuit from being modulated by the signal current in one branch as much as possible. This implies first that the "decoupling" RC/LC circuit must reject audio band signals with a pretty substantial rate. If you look at the suggested circuit from my Phono, we have a 100uF Cap or a regulator as the final output of the PSU (before we enter what is really the signal circuit). With 22uF/1k you have a -3db point at 7Hz and a -20db point at 70Hz.
This means any noise from the PSU (or reaction from the psu to a signal related current change) is rejected by > 20db @ 100Hz. This means at 100Hz our signal circuit for the output stage is DE-COUPLED from the PSU by over 20db. BTW, for the first stage the "decoupling is more like > 60db @ 100Hz.
Marinos said:
I am unware of anyt subject where sensible questions have sensible answers that are simple, life, the universe and all the rest are inherently complex I'm afraid.
Sayonara
Hi Keui,
Considering the characteristics of this filter techically adequte for the specific design, the decision to alter the values eg. 47uF/500R (nearly identical characteristics) has more to do with sonics or affects seriously the whole design ?
I can undestand that bigger capacitors are bad but taking in consideration your article http://www.fortunecity.com/rivendell/xentar/1179/theory/seamptheory/SEAmplifiertheory.html resistance also has a limit.
For example with the all passive RCRCRCRCRC supply the PSU impedance becomes very high. Is the 1:10 perfectionistic and trading this rule (when you must) for smaller capacitors is sonically preferable ?
A big thank for your really helpful response...
Considering the characteristics of this filter techically adequte for the specific design, the decision to alter the values eg. 47uF/500R (nearly identical characteristics) has more to do with sonics or affects seriously the whole design ?
I can undestand that bigger capacitors are bad but taking in consideration your article http://www.fortunecity.com/rivendell/xentar/1179/theory/seamptheory/SEAmplifiertheory.html resistance also has a limit.
For example with the all passive RCRCRCRCRC supply the PSU impedance becomes very high. Is the 1:10 perfectionistic and trading this rule (when you must) for smaller capacitors is sonically preferable ?
A big thank for your really helpful response...
Konnichiwa,
The 1k/22uF is actually based on "the lowest value cap I can get away with. Increasing capacitor values means using larger capacitors. This is not always a good idea.
No, the impedance is that of a 100uF Capacitor.
The 1:10 is for transformer loaded stages. You cannot simply take that forward to Resistor Loaded ones.
Sayonara
Marinos said:
The 1k/22uF is actually based on "the lowest value cap I can get away with. Increasing capacitor values means using larger capacitors. This is not always a good idea.
Marinos said:
No, the impedance is that of a 100uF Capacitor.
Marinos said:
The 1:10 is for transformer loaded stages. You cannot simply take that forward to Resistor Loaded ones.
Sayonara
About the RIAA network of this DC phono
Hi! there!
I am wondering if the R12 and R13 will affect the performance of this RIAA network? If they won't affect the RIAA curve, I prefer smaller values. Can I just keep the ratio of R12/R13, and change it to the other values I want??
I had built a DC phono too, 5842 dc 5842 and transformer coupling to the next stage, no caps all the way!! of course, the RIAA network was constructed between these two 5842 stages. Although it sounds good, but I am not sure that if the RIAA network is precise enough, if somebody can help me, I will put this circuit on for you to refer.
Thanks a lot!!
Hi! there!
I am wondering if the R12 and R13 will affect the performance of this RIAA network? If they won't affect the RIAA curve, I prefer smaller values. Can I just keep the ratio of R12/R13, and change it to the other values I want??
I had built a DC phono too, 5842 dc 5842 and transformer coupling to the next stage, no caps all the way!! of course, the RIAA network was constructed between these two 5842 stages. Although it sounds good, but I am not sure that if the RIAA network is precise enough, if somebody can help me, I will put this circuit on for you to refer.
Thanks a lot!!
Thanks a lot!!
Hi!
I will try to post my circuit on, and please help me to calculate if my RIAA network is correct or not.
Thanks a lot!!
By the way, if the tube of input stage change to 5842, how will the correct RIAA network will be??
And if I prefer the smaller values of R12 and R13, how should I calculate them?
Hi!
I will try to post my circuit on, and please help me to calculate if my RIAA network is correct or not.
Thanks a lot!!
By the way, if the tube of input stage change to 5842, how will the correct RIAA network will be??
And if I prefer the smaller values of R12 and R13, how should I calculate them?
There are limitations on how low can r12 get and for the 6SL7 the values shown are probably optimal. By using a 5842 you can really go lower though.
R12 is in series with the parallel combination of Rp (44k for 6SL7 and 1k7 for 5842) and R9 (220k as shown and dramatically lower for 5842). Whatever value this calc produces is in turn in parallel with r13 from the point of view of riaa. Normally r12 is chosen to be a lot higher than Rp so as tube variations have little effect on riaa accuracy. You can just measure Rp of the actual tube in use of course.
All this is greatly explained here
although it is not for the same RIAA topology.
Ro = rp || 20K plate resistance = 2.9K || 20K = 2.5K ohms
Hi!
I just read the page that you suggested, and something that I can not really understand, t
he first is what does this "Ro = rp || 20K plate resistance = 2.9K || 20K = 2.5K ohms" means?? How can I get correct Ro? how to calculate it?? what does " || " mean?
Second, since my circuit is DC coupled, the 0.1 uF and 1M that follow up the RIAA network do not exist in my circuit, can I just remove them and neglect them? and if I do so, will there any parameters of V2 affect the components of this RIAA network?
It almost clear, thanks for your kind help!!
Hi!
I just read the page that you suggested, and something that I can not really understand, t
he first is what does this "Ro = rp || 20K plate resistance = 2.9K || 20K = 2.5K ohms" means?? How can I get correct Ro? how to calculate it?? what does " || " mean?
Second, since my circuit is DC coupled, the 0.1 uF and 1M that follow up the RIAA network do not exist in my circuit, can I just remove them and neglect them? and if I do so, will there any parameters of V2 affect the components of this RIAA network?
It almost clear, thanks for your kind help!!
Re: Ro = rp || 20K plate resistance = 2.9K || 20K = 2.5K ohms
Konnichiwa,
Exactly what is written.
As suggested above.
|| = parallel in shorthand.
Only if you accounted for the fact that your 2nd stage cathode requires to be lifted to a DC potential of the gridbias plus anode voltage of preceeding stage. No matter how done, doing so is usually a much worse idea than having an 0.1uF coupling cap, as the cathode loop must
Shouldn't.
Sayonara
Konnichiwa,
biogeoff said:
Exactly what is written.
biogeoff said:
As suggested above.
biogeoff said:
|| = parallel in shorthand.
biogeoff said:
Only if you accounted for the fact that your 2nd stage cathode requires to be lifted to a DC potential of the gridbias plus anode voltage of preceeding stage. No matter how done, doing so is usually a much worse idea than having an 0.1uF coupling cap, as the cathode loop must
biogeoff said:
Shouldn't.
Sayonara
About Ro....
Hi!
Thanks for your detail answer, but I still can not understand how can I get the correct Ro, can you describe the equation for me, I don't know how the value 2.5K was calculated.
Ro = rp || 20K plate resistance = 2.9K || 20K = 2.5K ohms
Does this "||" sign has some kind of special mathematic meaning that I don't know...................
Thanks a lot!!
Hi!
Thanks for your detail answer, but I still can not understand how can I get the correct Ro, can you describe the equation for me, I don't know how the value 2.5K was calculated.
Ro = rp || 20K plate resistance = 2.9K || 20K = 2.5K ohms
Does this "||" sign has some kind of special mathematic meaning that I don't know...................
Thanks a lot!!
Butting in on an old post here since I'd like to make this and I have a few questions.
Kuei responded earlier in the post that:
I haven't been able to find anyone that sells Audyns in the US and the VAT plus shipping overseas makes these a bit cost prohibitive. Anyone know where I can find Audyns in the US or that can recommend a reasonably suitable substitute for the 2.2uF coupling cap (not Mundorfs-- too expensive)?
Also, Kuei recommended silver / mica for the 10n and 1n (are these really in nanofarads?) caps in the circuit. Again, these are a bit expensive, so are there any other that would make a good substitute? Maybe metallized poly film (MKSE / PPMF)?
Last one...
I'm planning in using JJ electrolytics in the PSU since they seem to have the best bang / buck ratio. Are there any other 47uF / 500V electrolytics you'd recommend in their place that are in the $8.00 range? Also, if I bypassed the electrolytics, what values would I use?
Meaning of life, anyone? Fermat's last theorem? Unified field theory equation?
"Always with the questions", as my grandfather says...
Thanks,
Kofi
Kuei responded earlier in the post that:
I haven't been able to find anyone that sells Audyns in the US and the VAT plus shipping overseas makes these a bit cost prohibitive. Anyone know where I can find Audyns in the US or that can recommend a reasonably suitable substitute for the 2.2uF coupling cap (not Mundorfs-- too expensive)?
Also, Kuei recommended silver / mica for the 10n and 1n (are these really in nanofarads?) caps in the circuit. Again, these are a bit expensive, so are there any other that would make a good substitute? Maybe metallized poly film (MKSE / PPMF)?
Last one...
I'm planning in using JJ electrolytics in the PSU since they seem to have the best bang / buck ratio. Are there any other 47uF / 500V electrolytics you'd recommend in their place that are in the $8.00 range? Also, if I bypassed the electrolytics, what values would I use?
Meaning of life, anyone? Fermat's last theorem? Unified field theory equation?
"Always with the questions", as my grandfather says...
Thanks,
Kofi
Kofi Annan said:
I'd recommend Motor Run caps that sell on ebay...they're a much better value, IMO.
Here's the seller I use
Remember...motor RUN...not motor START.