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Vintage threads from the first ten years

Re: Q Ratio... What does it mean to you!!!

9/1/2002 12:25 AM
Tony@Mastertone	Re: Q Ratio... What does it mean to you!!! Guys I got emailed this comment by a frequent browser of the forum.... but he won't post it himself, don't know why.. but for his sake I will keep it anonymous, I shouldn't but I will. Sorry 'anonymous' but you gotta share something like this.... Tone Hello again Tony, As you know I do not post on the PMF but I am an occasional reader. I am responding to you personally for there are times when I cringe if not raise eyebrows at some of the 'claimed expertise' by some posters. If this sounds like I have all the answers and am speaking from a position of greatest authority, then you do not understand that humility and a readiness to learn on my own part are valued attributes to me. A personal view follows - Now I don't wish to embark on a lecture (or a riot), but I wanted to (perhaps) save guys rushing out and buying LCR meters as advised by SK. The pickup coil is a 'real inductor' but it is not a 'pure capacitor' for there are other things going on here. To this end, my view is that the capacitance reading multimeter is not an accurate measuring device for pickup cap. even though some will say it 'approximates' for them. Long back, Al made this point which I am now sure he learned from me ( thanks for taking the credit AL!!!). The usefulness of capacitance reading multimeters ( to my mind) is limited to reading tone cap values ( 'pure capacitors' if you will,) - not pickup cap. values. So how to get a handle on 'Q'? Well for a verybasic 'hands on' grasp of the concept - go play with a parametric equalizer and the manual. Second, understand that an LCR bridge is the prescribed device for obtaining such as L and Q from a pickup coil. Q can be measured AND calculated theoretically with 2pif*L/R, with f =1000Hz. ( 1000 Hz as you point out is the typical measurement 'standard') NOTE! I hope I have this down right here - I avoid formulae in emails - to avoid errors, but I think its correct. I could go further with more math but won't for our mutual sakes. Note again! The measured Q is slightly less because the resistance at 1000Hz is a little more than DC. NO more theory - I hope to have stirred your research a little more. I stress the following - After verifying my propositions with your academic resources, you might choose to post any of the above points as 'provided to me by a friend' if you think it might help others. I prefer to remain unidentified yet trying to be helpful if you understand? regards,.

9/1/2002 12:25 AM

Tony@Mastertone

Re: Q Ratio... What does it mean to you!!!

Guys I got emailed this comment by a frequent browser of the forum.... but he won't post it himself, don't know why.. but for his sake I will keep it anonymous, I shouldn't but I will.

Sorry 'anonymous' but you gotta share something like this....

Tone

Hello again Tony,
As you know I do not post on the PMF but I am an occasional reader.
I am responding to you personally for there are times when I cringe if
not raise eyebrows at some of the 'claimed expertise' by some posters.
If this sounds like I have all the answers and am speaking from a
position of greatest authority, then you do not understand that humility
and a readiness to learn on my own part are valued attributes to me.
A personal view follows -
Now I don't wish to embark on a lecture (or a riot), but I wanted to
(perhaps) save guys rushing out and buying LCR meters as advised by SK.
The pickup coil is a 'real inductor' but it is not a 'pure capacitor'
for there are other things going on here. To this end, my view is that
the capacitance reading multimeter is not an accurate measuring device
for pickup cap. even though some will say it 'approximates' for them.
Long back, Al made this point which I am now sure he learned from me (
thanks for taking the credit AL!!!).
The usefulness of capacitance reading multimeters ( to my mind) is
limited to reading tone cap values ( 'pure capacitors' if you will,) -
not pickup cap. values.
So how to get a handle on 'Q'?
Well for a verybasic 'hands on' grasp of the concept - go play with a
parametric equalizer and the manual.
Second, understand that an LCR bridge is the prescribed device for
obtaining such as L and Q from a pickup coil.
Q can be measured AND calculated theoretically with
2*pi*f*L/R, with f =1000Hz. ( 1000 Hz as you point out is
the typical measurement 'standard')
NOTE! I hope I have this down right here - I avoid formulae in emails -
to avoid errors, but I think its correct.
I could go further with more math but won't for our mutual sakes.
Note again! The measured Q is slightly less because the resistance at
1000Hz is a little more than DC.
NO more theory - I hope to have stirred your research a little more.
I stress the following -
After verifying my propositions with your academic resources, you might
choose to post any of the above points as 'provided to me by a friend'
if you think it might help others.
I prefer to remain unidentified yet trying to be helpful if you understand?
regards,.

9/1/2002 1:18 AM
sk	Hmm, I didn't think I advised anyone to buy an LCR meter. My intent was to answer the question with my experience, and I'm fairly certain it was clear I'm using it for comparative information, and that it is an LCR meter, not a multimeter with capacitance reading. I only know of two,pssibly three,individuals who might lurk here on occasion and be an authority on pickups, one because of a bad experience on another forum (I don't know the details, nor do I care)....... Maybe I'm getting bent over nothing, but I don't like being accused of speaking about something I know nothing about, and that's the feeling I got....... He could at least attack me in person...or directly.....

9/1/2002 1:18 AM

Hmm, I didn't think I advised anyone to buy an LCR meter. My intent was to answer the question with my experience, and I'm fairly certain it was clear I'm using it for comparative information, and that it is an LCR meter, not a multimeter with capacitance reading.
I only know of two,pssibly three,individuals who might lurk here on occasion and be an authority on pickups, one because of a bad experience on another forum (I don't know the details, nor do I care)....... Maybe I'm getting bent over nothing, but I don't like being accused of speaking about something I know nothing about, and that's the feeling I got.......
He could at least attack me in person...or directly.....

9/1/2002 8:03 AM
Dick	Hi guys, I know its not really on the topic,but I was recently given a fairly good digital multimeter (actually from my Avionic engeener relation, Tony), and I was wondering if it is possible to measure Q with this? (I have never done this before, but sounds interesting) Thanks again guys, Dick

9/1/2002 9:32 AM
Tony@Mastertone	Dick If the multimeter can measure inductance as well as resistance then your in business to CALCULATE Q ratio.... 1. Measure the resistance in ohms..(say 6000) 2. Measure the inductance in Henries...(say 2.2) 3. Using your calculator... 2 x Pi x 1000 x (1.5)Inductance / (6000)Resistance Q=2.3 An average Strat measurment for Q is around 2.2 to 2.6 Also Q does not have any units attached. Tone

9/1/2002 9:32 AM

Tony@Mastertone

Dick

If the multimeter can measure inductance as well as resistance then your in business to CALCULATE Q ratio....

1. Measure the resistance in ohms..(say 6000)
2. Measure the inductance in Henries...(say 2.2)
3. Using your calculator...

2 x Pi x 1000 x (1.5)Inductance / (6000)Resistance

Q=2.3

An average Strat measurment for Q is around 2.2 to 2.6

Also Q does not have any units attached.

Tone

9/1/2002 9:20 AM
Tony@Mastertone	SK I agree.... you didn't advise anyone to do anything... as I replied back to 'anonymous' as he wishes to remain, that all of us share willingly our info to mainly novices and interested kids. Its not rocket science and if somethings not 100% correct (in their opinion) then no one is going to die from the consequences... Tone

9/2/2002 3:59 AM
WolfeMacleod	To me, Q ratio or factor = evil. Bleah. Science. Start getting into that stuff, and thats where the art gets lost. Did Leo ever mess with it? Just my opinion. Wolfe

9/2/2002 2:49 PM

Dr Strangelove

Wolfe wrote:

quote:
"[Science is evil]"

Heh.

Science is not Art, shouldn't be confused with it. It's a way of figuring out how and why you did something right. It's just another tool and nobody uses the same tools the same way.

If Science were truly all that bad or irrelevant, you'd pay no attention to the number, direction, or wire gauge of windings on the pickups you make.

-drh
--

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