interwinding capacitance
is close to 60uuF
Even if I'm off by a factor of 10, the capacitive reactance of a 600uuF cap at audio frequencies is equivalent to an open circuit.
But, seeing all the interest in this measurement, my real question is why is such a low number even an issue for you when the average triode has a grid-cathode capacitance of at least 3pF??
That's 3,000uuF
is close to 60uuF
Even if I'm off by a factor of 10, the capacitive reactance of a 600uuF cap at audio frequencies is equivalent to an open circuit.
But, seeing all the interest in this measurement, my real question is why is such a low number even an issue for you when the average triode has a grid-cathode capacitance of at least 3pF??
That's 3,000uuF
Brett, thanks for the nomenclature clarification.
So, can anybody offer up the measurements of their more pricey chokes? I've been to several websites - Sowter, Bartolucci, Magnequest. They never give these numbers.
Peter - I'm especially curious what the interwinding capacitance of your favorite plate choke is. I also see you again did not reply to my questions. The only conclusions I can draw are: 1) You do not know what the capacitance values of any of the chokes you use are, 2) you do not have any understanding of how the capacitance behaves in an audio circuit, 3) you have no experience or data to support your assertions.
So, can anybody offer up the measurements of their more pricey chokes? I've been to several websites - Sowter, Bartolucci, Magnequest. They never give these numbers.
Peter - I'm especially curious what the interwinding capacitance of your favorite plate choke is. I also see you again did not reply to my questions. The only conclusions I can draw are: 1) You do not know what the capacitance values of any of the chokes you use are, 2) you do not have any understanding of how the capacitance behaves in an audio circuit, 3) you have no experience or data to support your assertions.
Joel,
I don't know whether these chokes are good or not, but I must clarify a misconception:
For LC circuits it is more complex. The self capacitance will cause a gradual falloff in HF, then a rise until resonance. At that point there will be ringing and a greater ouput.
Cheers,
I don't know whether these chokes are good or not, but I must clarify a misconception:
For RC circuits it does of course depend on the impedance of the circuit you are fitting it across. Eg You can put 100n across your speaker terminal with no discernable effect. Now try it between any control grid and deck.
For LC circuits it is more complex. The self capacitance will cause a gradual falloff in HF, then a rise until resonance. At that point there will be ringing and a greater ouput.
Cheers,
Joel
Thank you for your praise. It's especially endearing coming from someone who very recently learnt what is a 3-terminal voltage regulator (i think 14-Jan was the big date but correct me if i'm wrong).
Transformer manufacturers are notoriously shy about the published characteristics of their goods, probably because of the clash between good objective and subjective performance. Reasonable parasitic capacitance seems to be in the region of 200pF for a 100H choke but i have failed to establish strong relationship with perceived sound quality. As i prefer to reuse components for different applications i mostly use interstage/output transformers instead of proper chokes and i don't really have much use for inductance as high as 150H (low Rp valves). The type of core seems to have a much bigger effect on the perceived sound than parasitic capacitance. Using PS chokes and especially swinging chokes is hardly a good idea as no effort to mininise capacitance has been made at all. That said, a really good PS choke is probably very similar to a good plate choke. Unfortunately i have never had the fortune to use a premium PS choke.
cheers
peter
Thank you for your praise. It's especially endearing coming from someone who very recently learnt what is a 3-terminal voltage regulator (i think 14-Jan was the big date but correct me if i'm wrong).
Transformer manufacturers are notoriously shy about the published characteristics of their goods, probably because of the clash between good objective and subjective performance. Reasonable parasitic capacitance seems to be in the region of 200pF for a 100H choke but i have failed to establish strong relationship with perceived sound quality. As i prefer to reuse components for different applications i mostly use interstage/output transformers instead of proper chokes and i don't really have much use for inductance as high as 150H (low Rp valves). The type of core seems to have a much bigger effect on the perceived sound than parasitic capacitance. Using PS chokes and especially swinging chokes is hardly a good idea as no effort to mininise capacitance has been made at all. That said, a really good PS choke is probably very similar to a good plate choke. Unfortunately i have never had the fortune to use a premium PS choke.
cheers
peter
analog_sa said:
TRANSLATION: "I have no idea what the capacitance of any of my transformers is. I was just hoping you wouldn't be able to come back with a number..."
TRANSLATION: "I don't have a clue what these values would do in an audio circuit, and none of my issues of Audio-Mythology has an article on it.
TRANSLATION: "I've never used that choke, or anything like it - so I pulled my comments on it out of my a**."
TRANSLATION: Gee, I could be completely wrong on this argument, and I better back-pedal a little.
Go give your ego a rest man.
I don't think a single figure will indicate how well one will work.
There is not a single capacitor across a single inductor.
Because of winding and layering, a distributed capacitance will exist. This can be reduced by sectionalising.
Here may lay one of the differences between the "cheapies" and the expensive ones.
Cheers,
There is not a single capacitor across a single inductor.
Because of winding and layering, a distributed capacitance will exist. This can be reduced by sectionalising.
Here may lay one of the differences between the "cheapies" and the expensive ones.
Cheers,
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