Channelman
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Post by Channelman on Sept 21, 2006 18:25:19 GMT -5
I'll run em thru the sims 'unkstyle' tomorrow...just got in from the pub quiz. Not doing a 2.30am again like last night.
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Channelman
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Post by Channelman on Sept 21, 2006 19:09:18 GMT -5
OK here are the 'unk style' sims of the Ch-Unk circuit. I'm not sure what you are looking for in these...I prefer the swept tone sims. Channelman
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Post by UnklMickey on Sept 21, 2006 23:07:28 GMT -5
hi Channelman,
what i am looking for, are clues to unwanted results.
yes, the tone sweep graphs look prettier, but i think the volume sweep graphs give us info that gets muddled, because of the way the curves converge at low frequencies.
i don't think the 50k below the pot is going to work that well.
it causes the same kind of trouble it did, in series with the wiper.
because of the shape of the curve, when the tone is at minimum and the volume is turned down to -25dB, we see a "boost" at higher frequencies.
this isn't too terrible, because the more complex model shows us of a loss of highs when the volume is reduced.
still, i think it will be a wash at best, or only a slight (net) cut.
also, using a small cap for the treble bleed, and no resistor is giving us a upward slope above 3kHz.
i think this is probably more than we want.
i suspect the shelf with +6dB was plenty.
i'd be more inclined to target making up for the loss of the peak at 3 kHz when the volume is turned down, in the complex model.
i can almost hear JohnH thinking:
"okay guys, this has taken you as far as you need to go.
you have an overall understanding of how things work.
now build it and test it in the real world, without the extra resistors.
then find out what the highest and lowest settings are that work well,
measure the amount of resistance left at the ends of the pot,
and add a resistor of the appropriate amount at each end."
or something like that.
hey, i could be totally wrong, but i suspect the original cap values,
with a 50k~100k on the top, and a 5k~20k either on the bottom, or in series with the wiper,
will probably be where this balances out best.
my guess is, a resistor in series with the wiper will be better, but will be harder to tweak.
the value of the series resistor, for the right amount of cut will first have to be determined.
then, the value for the top resistor will be determined.
either way, i think with some real-world tweaking, this thing does show some promise.
unk
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Post by JohnH on Sept 22, 2006 16:01:20 GMT -5
i can almost hear JohnH thinking: unk Seems I have become a small voice inside Unk's head. So while I'm in here, I think I'll take a look around. The schematic for this place is rather complicated. What are all these coils hanging? I'll just shunt them to ground while I'm here. I like to be helpful. Now what happens if I reconnect this module... Holy SH!T!!..Im outta here....! J
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Post by UnklMickey on Sept 22, 2006 16:14:08 GMT -5
...Seems I have become a small voice inside Unk's head. ... yes,..............one of MANY!
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Post by JohnH on Sept 23, 2006 16:59:40 GMT -5
Question for Channelman - I like your graph output. What Spice package are you using? I use a free one that I downloaded, which works fine but it is clunky.
J
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Channelman
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Post by Channelman on Sept 24, 2006 4:12:00 GMT -5
Question for Channelman - I like your graph output. What Spice package are you using? I use a free one that I downloaded, which works fine but it is clunky. J Hi John, It's a program called Electronic Workbench Version 5.2. It's a bit 'crummy' in some respects but it does what I want. The graphic display 'on screen' is OK but to export them for display purposes I have to do a 'screen capture' and paste it into a graphics package and 'crop' it. Channelman
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Post by UnklMickey on Sept 25, 2006 17:43:55 GMT -5
hi Channelman,
the more i think about this circuit, the less likely i think i'll be able to massage it into a control that i'll like.
the reason i will probably not like it so much, is the way the curve will change, as the volume is adjusted.
there just won't be any getting around that.
(that doesn't mean you won't come up with something you'll like.)
but here's a thought that does appeal to me.
if you take the original circuit, and work with the setting of the pot, the values of the caps, and perhaps even a resistor in series with the wiper,
and got that to give you a similar response at -10dB as you get at 0dB,
using the complex model like you are using in the "treble boost without..." thread,
that would tell us what an improved treble bleed NETWORK would look like.
and IMHO that would be outstanding.
unk
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Channelman
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Post by Channelman on Sept 25, 2006 18:13:12 GMT -5
but here's a thought that does appeal to me. if you take the original circuit, and work with the setting of the pot, the values of the caps, and perhaps even a resistor in series with the wiper, and got that to give you a similar response at -10dB as you get at 0dB, using the complex model like you are using in the "treble boost without..." thread, that would tell us what an improved treble bleed network would look like. and IMHO that would be outstanding. unk @unk I'm not sure what you mean here mate. If you could do a sketch and tell me exactly what you want, then I'll sim it for you. Any one component can be swept in value so you can see the effect of a range of values of caps or resistors, but just one component at once. Channelman
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Post by UnklMickey on Sept 25, 2006 18:15:49 GMT -5
gotta run, for the evening.
i'll explain the idea in more detail tomorrrow.
we don't want you thinking about this all night tonight anyway.
later,
unk
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Post by UnklMickey on Sept 26, 2006 14:50:32 GMT -5
...I'm not sure what you mean here mate.... don't feel alone. i seem to cause an awful lot of that. here's my thinking. 1 -- regardless of minor anomalies in the frequency response of a guitar, we can get the sound we want by judicious use of equalization. 2 -- when a typical guitar volume control is turned down, it changes the shape of the frequency response curve. this makes our equalization wrong for the lower volume. 3 -- if we add a cap between the top and wiper of the volume control, this helps a bit, but the peak shifts to a higher frequency, and becomes too pronounced. so our target should be to create a network that will provide a response curve at reduced volume, that is a close as possible to the curve at 0dB. even if it alters the frequency response a little at 0dB, the ability to keep the response curve constant, when reducing volume, is of great value. we will never get the curves shown above, when the volume is adjusted, but that is the target. initial values: start with resistor "d" @ 0 ohms, cap "a" @ 1nF, and cap "c" @ 10nf, pot "b" value of 500k. decreasing the coupling of this network by increasing the value of resistor 'd' might be desireable, but it might simply make the network less effective. if might also strongly affect the required setting of pot 'b', so for now we might want to just leave resistor 'd' at 0 ohms. START: with the volume set at at max, acquire a single graph, this will be our reference curve. then set the volume to -15dB and sweep pot "b"find the place where the curve most closely resembles the reference curve at volume = 0db. (we will probably be more interested in the relative amplitude of the peak, rather than the position) this is our first approximation. STEP 2: with pot 'b' at the best value found in our first approximation, set the volume for 0db. acquire a single graph, will be our new reference curve. set the volume for -10dB. sweep through values for cap 'a' (i assume sweeping this is possible). select the value for cap 'a' where the curve most closely resembles the curve for 0dB. (here we will probably be more concerned with the position of the peak than the amplitude of the peak). STEP 3: with pot 'b' still at the value found in the first approximation, and cap 'a' at the value we found in step 2, adjust the volume for 0db and get a reference curve. then set the volume for -20dB. sweep through values for cap 'c'.select the value for cap 'b' where the curve most closely resembles the reference curve. (here again, we will probably be more concerned with the position of the peak) LOOP from START through STEP 3, a few times, until no changes need to be made. now that we have determined the optimum values, do a sweep of the volume control. how do the new curves compare with: 1 - a volume control only, with no compensation network. 2 - a single 1 nF cap between the wiper and top of the volume control. anyway, the description is wordy, but i think the process will take less time than the description. if we're lucky, we will have a large improvement on a single treble bleed cap. if not ...., fortunately it's too far across the pond for you to throw things at me. cheers, unk
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Channelman
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Post by Channelman on Sept 26, 2006 18:35:02 GMT -5
>the description is wordy, but i think the process will take less time than the description....unkFirst part is correct....second part no way! Anyway I had a go, following your instructions. The graphs are in the order you asked for them. ___________ REF 1 Volume Set at Max________________ I selected 75% (third one down from top) I selected 500pF (middle of all sweeps) I abandoned the sims here to 'have a think' (and a sleep) since with the Tone now fixed at 75% the value of Cap 'b' has little effect. Cheers, Channelman
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Post by UnklMickey on Sept 26, 2006 19:35:47 GMT -5
sleeping and thinking are both good things!
i've sometimes been accused of doing both at the same time, but not when i'm supposed to be sleeping.
my goodness, did you notice the size and shift of the peak @ volume -20dB?
we went from 7~8dB peak @ volume 0dB,
to a 6 dB peak @ volume -10dB - (very reasonable),
to a ~12dB peak @ volume -20dB - (YIKES!)
i wonder if we might have better luck, by substituing 2 separate resistors for the top and bottom halves of the 'tone' pot.
but i'm not certain what the alignment procedure should be, or where this might lead us.
yeah, sleep and think!
BTW, check your messages. did you get the one i sent?
unk
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Channelman
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Post by Channelman on Sept 28, 2006 8:14:55 GMT -5
OK Unk, after thinking and sleeping I think I've got something near to your 'target' in the earlier post. It may need some fine tweaking but here it is. Channelman
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Post by UnklMickey on Sept 28, 2006 8:34:06 GMT -5
thanks Channelman,
i have already given this a bit of thought, and i'll put a lengthy post together, to share my most recent revelation, and conclusions.
(don't worry no more sims needed!)
again, thanks for all the effort you put into this.
unk
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Post by tacobobbo on Sept 30, 2006 4:03:30 GMT -5
...(the "woman tone" unk; Nah-nah-nah-nah-nah-nah, nah-nah-nah-nah-nah-nah )....
Was wondering whatever happened to my old Journey cd...... Bob
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Post by UnklMickey on Oct 2, 2006 16:00:48 GMT -5
OK Unk, after thinking and sleeping I think I've got something near to your 'target' in the earlier post. It may need some fine tweaking but here it is.... thanks again Channelman. i had intended to write a comprehensive post regarding treble bleed. thus far, i haven't had time to put one together, so i'll just wing it. trying to bend your "improved tone control" into a better treble bleed was doomed from the start. if i had looked more closely at why the treble loss occurs, and how the basic treble bleed functions, i wouldn't have bothered you with the work. in a nutshell, the resistance in series with the cable capacitance increases, as the volume is reduced. this makes a more effective high-cut filter. a simple treble bleed, adds a capacitor in parallel with the resistance from the top of the volume pot to it's wiper. as the pot is rotated from maximum, downward: 1 -- the resistance from top to wiper increases making the effect of the treble bleed cap greater, as the volume is decreased.2 -- as the volume pot is reduced below the point where the resistance above and below the wiper are equal, the effectiveness of the treble bleed cap continues to increase, but the effectiveness of the cable capacitance decreases. because of this, there is only 1 setting of the volume control, where the treble-bleed can be optimized. between this setting and maximum, the treble will be somewhat reduced. below the optimized setting, the treble will be increased. nothing we did, with the bottom end of your tone control would help. in fact, it would tend to be counter-productive. you have already posted a reasonable attempt at a treble-bleed. the values are similar to what i might have imagined. they can probably be optimized a bit, but this will only marginally improve the performance. it won't be great, but better than nothing. in regards to using your original circuit as a tone control.it will, necessarily require a bit of fussing, since changing the volume control, will strongly affect the tone, at full boost, or full cut. there is a way to make this less dependent on the volume adjustment, but you won't like it! you could place a fixed voltage divider where the volume control was. this will allow you to use your circuit to boost or cut the treble. then a simple preamp, to add some gain to compensate for the loss in the divider, and provide a low impedance output, to make the cable capacitance irrelevant. a lower resistance volume control would be after, or between stages, of the pre-amp knowing your (and my) feelings toward batteries in guitars, this probably doesn't much interest you. you will probably rather deal with re-adjusting the tone, when the volume is adjusted. however, i'm sure there is one certain person, who will be at least mildly interested in the concept, of using your tone control with a pre-amp. cheers, unk
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Channelman
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Post by Channelman on Oct 2, 2006 16:46:03 GMT -5
Unk, I agree with all you've said in the above post....don't want to upset anyone else This thread did actually start with me suggesting that combining the 'normal' treble cut tone control in a typical guitar may be improved by combining it with the treble bleed to give greater flexibility. But... the 'target' somehow got moved to trying to design the perfect treble bleed which I think we both agree cannot be achieved without some 'active' electronics. I have configured a similar passive treble control plus a bass cut control in one of my guitars and I like the sound, but you can't please all the people....etc Regarding your suggestion for 'active' plus tone, I think that the signal would need to be boosted before the tone control(s) and then probably buffered to drive the cable capacitance. It could be probably done at a current cost of under 1mA. I have put active electronics in guitars but I don't like changing the pots, so I would put the volume control before the cable driver buffer. I could do with buying some of those J201 FETs and try something out....sims are OK but I like to try it out as well. Channelman
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Post by UnklMickey on Oct 2, 2006 18:28:19 GMT -5
hi Channelman, i read your underlying meaning loud and clear. don't worry about me, i've been involved in quite a few heated debates here, and have a thick skin. i don't take those things, (or myself) too seriously. i don't much care for letting things go that way anymore, and i think between what you have just said, and Rune's RK quote: Whewwww and D@mn. "Can't we all just get along?' - Rodney King. I thought entrophy was the natural resolution of the universe, not implosion. those are all good thoughts to keep the temperature of the forum at the appropriate level. putting the volume in the front-end is an okay idea, but unless you separate the volume from your improved tone control, the volume setting will affect the tone. remember, you can't get any boost with the volume at max, and the cut is deeper as the volume is decreased. if one were to go to the effort of adding the active stuff, it would be nice to also make the tone control less dependent on the volume. if you find a creative way to use typical guitar values for the pots, provide a low impedance output, and make your tone control unaffected by the volume setting, you will have a world beater. as you mentioned, you are reasonably happy with the purely passive application, and i suspect many others will be as well. "but you can't please all the people....etc" or put another way, some folks find a different set of details to be important, that other's set. ............................................differnt strokes fer differnt folks. the target didn't somehow get moved...........i moved it. i hope we've returned it properly to where it belongs. i know this has been somewhat of a singular focus for you, and you've put this on different forums. that's fine, and all. but, don't be a one-trick-pony here at GN2. we have plenty of time and space for you, on this issue, but.... i'm sure you can provide equally interesting points of view on other issues as well. cheers, unk
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Channelman
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Post by Channelman on Oct 3, 2006 9:37:30 GMT -5
>don't be a one-trick-pony here at GN2...unk
Neigh lad, I'm here to stay. ;D (Do ponies neigh?)
>you've put this on different forums....unk
Correct, I wanted to see what sort of response/feedback I got. Now I know it's GN2 for me.
Channelman
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Post by ChrisK on Oct 3, 2006 17:37:14 GMT -5
I most definitely want the tone circuits to precede the volume. The realized curves can often be relatively preserved thru the use of the "volume treble tone preservation mod".
But one can indeed realize downstream frequency dependent boost of the generated voltage at resonance (Tesla).
You bet.
Well, except fer that "low output impedance" part.....
Yeah, 'cuz like the power source lasts forever'ish.
I built a larger pSpice model of a passive guitar inclusive of cable effects and a WAG for the amp input (all are part of a common passive circuit). By using the "LIST" modifier for the .step command, I'm able to step at specified value points inclusive of full scale and 1 Ohm for pots (simulated by two discretes).
I had a ball looking at treble enhancement tone controls and found that, with one exception, sans inductors they all suck.
The one modified one that I came up with that works/sims to my satisfaction is based on the Fender "Grease Bucket" design. I'm able to realize non-peaking (or peaking at about 700 Hz if desired) when all the way to "0", reasonable flat response at about 62 K (for a 500 K pot) and a nice broad treble (well, bandpass) boost around 2 kHz to 4 kHz when all the way up. It really does look like a treble cut/bass cut common control.
Before anyone gets too excited, I did plot the response at the cable and the grid as well, and found that aside from expected attenuation, the curve forms scaled reasonably well. The actual voltage boost occurred at the pickup model's output. Once thru attenuation, well, things were attenuated.
This was all done with the generator having 1 Ohm of series resistance and no parallel capacitance. These most necessary components were realized externally, but the generator reference output was thence most flat (and at 0 dB, and was plotted as THE reference, I might add).
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Post by JohnH on Oct 4, 2006 4:57:00 GMT -5
Neigh lad, I'm here to stay. ;D Channelman This is good John
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Channelman
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Post by Channelman on Oct 4, 2006 8:06:13 GMT -5
Neigh lad, I'm here to stay. ;D Channelman This is good John Thanks for that John. But I think it's a real shame that sumgaifelt he had to go..... definately not what I wanted. Cannot you, Chris, Unk etc (guys who have know him for ages) not get in touch and get him back? Mods & Admin etc must have his Email address. CM
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Post by UnklMickey on Oct 4, 2006 11:15:48 GMT -5
....Cannot you, Chris, Unk etc (guys who have know him for ages) not get in touch and get him back? Mods & Admin etc must have his Email address.... i have been receiving quite a few PMs regarding Sumgai "falling on his sword". for the record:i blame neither Sumgai nor Channelman, for the excessive display of hubris we saw. they both got a bit "puffed up". when things get a bit heated, it's easy for people to go too far. it's a natural human tendency. neither showed any immunity to it. the incident should serve as a lesson in moderation to us ALL.regarding Sumgai's departure: was his prerogative to leave. (although i would have certainly discouraged it.) it is also his prerogative to return. i neither encourage, nor discourage his return. i feel no ill will toward him, but any decision regarding him returning, should be based solely on his own wants and needs. in any case, i believe i speak for all GN2 members, when i: acknowledge Sumgai for his efforts, and many contributions. good luck to him, in all his endeavors. regards, unk
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Post by ux4484 on Oct 4, 2006 15:39:24 GMT -5
hmmm..... Sumgai was(is?) one of the few to really try to make new folks here feel welcome. While I admire all the stuff the rest of you do, Sumgai seemed to be the one most concerned with "community". In an example just the day before, I've rarely been on boards where the members thought it was fun to hang the mods out to dry in the most embarrassing way possible....but here it seem to be fair sport. It's ironic that unk comments on moderation....because he regularly comes down on Chris who IS the moderator. I'm a tech...which means that when something is broke, I find out enough to fix it and do the job and then move on (That's what brought me to JohnA's site in the first place). I would estimate that makes me more tech savvy than 80% of most guitar players. A few of you are clearly engineers and often come down pretty hard on the average joe guitarist stopping by to ask a (simple) question (more so if they make an incorrect statement). I understand you want to make sure everything posted here is right....but what you lose when you do that is a sense of community. If it's more than a bit intimidating for me, I can't begin to imagine what it's like for the person coming here popping the screws off their pickgard for the first time. I like that there are such knowledgeable people here, but it also makes for a very small club. Sumgai was the exception, he tried more than most to put a personal spin on his comments, and could correct people in a non-condescending way. You've lost something (and someone) special.
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Post by JohnH on Oct 4, 2006 18:30:39 GMT -5
Put very simply, I think it would be absolutely great if Sumgai came back. We will miss his enthusiasm and experience. But if that is not possible, them I wish him well.
John
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Post by UnklMickey on Oct 4, 2006 20:39:19 GMT -5
hi Ux4484, in principle i agree with much of what you've said, but there are a few areas where i don't. "Sumgai was(is?) one of the few to really try to make new folks here feel welcome." while i agree, he was one of the few (there are, after all, very FEW of us here), i challenge you to name the many who don't try to make new folks welcome here! while i occasionally give some of the guys a gentle nudge about not explicitly welcoming a first timer, i believe their willingness to help, speaks for itself. accuracy IS important. style over substance, is NOT the answer. if that makes us a small group, so be it. this is the first forum i ever participated in, i have visited others, i find some of them large, but filled with questionable advice. many of their members, eventually find their way to GN2, when the locals at the "big" forums don't have the answers. due to their sheer size, the big forums are more interesting, because of the diversity of the conversations. with the exception of ProjectGuitar, i haven't found any that have more than one member who's advice i find consistently reliable. is it possible to strive for accuracy and do so in a "kinder, gentler" manner? i think so. would i trade accuracy for a hundredfold increase in membership? ...............not a chance. "It's ironic that unk comments on moderation....because he regularly comes down on Chris who IS the moderator." there are many things about my interactions on this forum that could use a bit of self-review, and tweaking. however, your statements about my interactions with Chris, should be framed in the proper context. yes, Chris is A moderator. as are others, most notably Runewalker, who also enjoys sparring with me, almost at much as i do with him. Chris is more highly educated than i am. in that regard he IS my better. but in many ways, i consider us peers. if you see those times when i do get the better of him in our jousts, as "hanging him out to dry", or "coming down on him", i think you may be reading way too much into that. on average, Chris gives as good as he gets, in our exchanges. i sometimes have to read his posts TWICE, just to be sure i've just been burned. he's that good at it! i believe we BOTH benefit by sharpening our skills in our banter. i would NEVER engage in a battle of wits with an unarmed man. therefore, i see no reason whatsoever to quit sparring with Chris! if i thought for a minute, he didn't enjoy the exchanges, i would apologize profusely. unless i hear otherwise from Chris, don't expect our exchanges to cease anytime soon. thought it was implicit, that i included myself, when i said: "the incident should serve as a lesson in moderation to us ALL."i was (and am) suggesting that we should all ( myself included), examine the way we interact in our conversations. recognizing when the tone of a conversation escalates to the point where things could get ugly, and "choosing to dial it down", before it does, will serve us ALL well in the future. "Sumgai ................ could correct people in a non-condescending way" sometimes. and at other times, he could be "abrasive and arrogant". (these are not MY words.) i've been guilty of that myself, but at times, he brought it to the level of an art-form. i have been told by some, they found him obnoxious. i have been told by others, he was a blessing. i have been told by still others, that he was one of the most entertaining people on GN2 i think he was all of those, and all the shades in-between. i believe your closing statement was well put, although, i'll suggest you adjust it slightly: You've We've lost something (and someone) special.
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Post by ux4484 on Oct 5, 2006 8:57:24 GMT -5
A most patient and thought out answer....and I'll give on your last point. While I do like to stop by, I was thinking of myself as an observer, not a member.
On your other points; I have not been here or delved far back enough in every category to be aware of all the history here, I was speaking for what I have seen only. Many sites hang out a "don't feed the newbies" shingle (saves a lot of time typing responses to one hit wonders). I think I indicated that the good outweighs any (of my) impression of bad.
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Post by UnklMickey on Oct 5, 2006 13:10:49 GMT -5
thinking of yourself as an observer, not a member?
we'll have to work on changing that.
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Post by ChrisK on Oct 5, 2006 14:07:05 GMT -5
I've had the absolute luxury of being able to study many disciplines over the years. Most of this was informal, since when I worked on most things, colleges didn't teach them yet. I'm a most interesting blend of genes, a Vulcan (Swedish), a purposely schizophrenic logician (Russian), and Slovak (an observer).
Absolutely!
After all, I'm just a Stranger in a Strange Land.
Indeed!
I love the interchange on this forum. In life, I've had friends few, since for most, there is so little of GeDankengang to discuss.
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