A look inside a Lane Poor MM5.

[ModulusMK]

David,
I agree that it makes no difference to you and me but it did make a difference to Lane and I'm sure that's where the confusion comes in where ModulusMK and Henry P are somehow misinterpreting what Lane was saying (which is why I mention it.)

I hear no audible difference too except excess noise, but in the measurements belwar made there is difference in the peak freq. Without the shielding wire it is higher for about 1.5kHz.
Henry explained that as balanced (without shielding to ground) and normal signal. In the balanced mode I did get a lot of noise... and I use active electronics w/bypass switch. Where he didn't get noise at all. On the drawing only signal ground is connected to jack, pots's housings also are not grounded and shielding from pickups goes to cavity. Nothing other than this about grounding.
So there might be something that is missing here (generally speaking).

[ModulusMK]

Basses don't have balanced circuitry. And it's still ground. I also run my shields separate from the coils, but guess what? One end of the coil connects to the shields and ground at the output jack! If it doesn't do so sooner. There is no problem with connecting the grounds and shields together on the back of a pot, since it all goes to the same place, a few inches away.

Yeah, no difference where shielding connects with ground.
I'm not sure what Lane thought with this... and how really is.
However belwar's measurements show the diff.

[David Schwab]

On the drawing only signal ground is connected to jack, pots's housings also are not grounded and shielding from pickups goes to cavity. Nothing other than this about grounding.
So there might be something that is missing here (generally speaking).

If you don't ground a shield, then you are better off not having one in the first place. Shields work because they are grounded. Otherwise they are noise antennas!

[ModulusMK]

If you don't ground a shield, then you are better off not having one in the first place. Shields work because they are grounded. Otherwise they are noise antennas!

Yeah I'm aware of that... maybe it's the thing to have balanced signal up to the jack... but what's the point when it doesn't matter where you connect shield and ground and after that use regular cable. And that are the pots shielded or not. Why is that important to Lane...

[David King]

I think Lane was simply following establish shielding protocol: one path to ground.
He may also have foreseen the troubles old-school repair folks would have when dealing with a floating ground active buffer system which was where Lane and WAM were headed with the AP 1x1 and the AP 2x1 preamps. He wanted them to get used to the idea that shield was different from PU (-).

[David Schwab]

Why is that important to Lane...

I think he was mixed up about grounds.

[David King]

To change the subject slightly,
Did you all read those sheets I posted yet?

"4k turns x 2 precision machine wound match(0.1%) common axis twin coils, hand assembled and shielded to 100% with .001" brass and or copper foil, output cable junction included"

Well assuming 4k turns is right we should have an easy time determining awg.


I understand if we still need to talk ad-infinitum about grounds and shields.

[ModulusMK]

To change the subject slightly,
Did you all read those sheets I posted yet?

"4k turns x 2 precision machine wound match(0.1%) common axis twin coils, hand assembled and shielded to 100% with .001" brass and or copper foil, output cable junction included"

Well assuming 4k turns is right we should have an easy time determining awg.)

Yes! I paid attention on that but was so in this shielding thing I forgot to write about that, haha. You have these scans for a long time?
So we have good info from that. DCR is known so we can get the AWG.
The coils should be in series, while getting over 6-7K DCR.

[David Schwab]

Well assuming 4k turns is right we should have an easy time determining awg.

Looking at the DC resistance vs. turns, I say it's 42 AWG. 40 AWG at that turn count wound would be about 5.5~6K for both coils in series.

[ajawamnet@comcast.net]

Here's something interesting - impedance sweep of a LP M4.0W

This is an old pup that I had lying around; never installed.

Runs off the WT3 scale

check this out:

Freq Impedance Phase
1.029 8638.192 1.750
1.059 8638.192 1.750
1.091 8638.192 1.750
1.122 8638.192 1.750
1.155 8638.192 1.750
1.189 8638.192 1.750
1.224 8638.192 1.750
1.260 8638.192 1.750
1.297 8638.192 1.750
1.335 8624.951 2.668
1.374 8624.951 2.668
1.414 8624.951 2.668
1.456 8624.951 2.668
1.498 8624.951 2.668
1.542 8624.951 2.668
1.587 8624.951 2.668
1.634 8624.951 2.668
1.682 8624.951 2.668
1.731 8624.951 2.668
1.782 8624.951 2.668
1.834 8624.951 2.668
1.888 8624.951 2.668
1.943 8624.951 2.668
2.000 8591.016 2.546
2.059 8591.016 2.546
2.119 8591.016 2.546
2.181 8591.016 2.546
2.245 8591.016 2.546
2.311 8591.016 2.546
2.378 8591.016 2.546
2.448 8591.016 2.546
2.520 8591.016 2.546
2.594 8591.016 2.546
2.670 8733.073 1.405
2.748 8733.073 1.405
2.828 8733.073 1.405
2.911 8733.073 1.405
2.997 8733.073 1.405
3.084 8733.073 1.405
3.175 8733.073 1.405
3.268 8733.073 1.405
3.364 8398.033 0.617
3.462 8398.033 0.617
3.564 8398.033 0.617
3.668 8398.033 0.617
3.775 8398.033 0.617
3.886 8398.033 0.617
4.000 8732.399 -0.783
4.117 8732.399 -0.783
4.238 8732.399 -0.783
4.362 8732.399 -0.783
4.490 8732.399 -0.783
4.621 8732.399 -0.783
4.757 8450.194 -1.534
4.896 8450.194 -1.534
5.040 8450.194 -1.534
5.187 8450.194 -1.534
5.339 8819.177 -1.289
5.496 8819.177 -1.289
5.657 8819.177 -1.289
5.823 8819.177 -1.289
5.993 8381.349 -1.118
6.169 8381.349 -1.118
6.350 8381.349 -1.118
6.536 8381.349 -1.118
6.727 8281.629 -0.483
6.924 8281.629 -0.483
7.127 8281.629 -0.483
7.336 7976.455 -0.495
7.551 7976.455 -0.495
7.772 7976.455 -0.495
8.000 7865.689 2.104
8.234 7865.689 2.104
8.476 7865.689 2.104
8.724 7939.407 2.136
8.980 7939.407 2.136
9.243 7939.407 2.136
9.514 8132.559 1.563
9.792 8132.559 1.563
10.079 8169.897 0.648
10.375 8169.897 0.648
10.679 8069.310 1.128
10.992 8069.310 1.128
11.314 7928.609 1.584
11.645 7928.609 1.584
11.986 8068.424 0.706
12.338 8068.424 0.706
12.699 8229.327 1.520
13.071 8229.327 1.520
13.454 8736.955 2.585
13.849 8736.955 2.585
14.254 8693.210 4.094
14.672 8800.440 4.544
15.102 8800.440 4.544
15.545 8498.132 4.342
16.000 8693.845 3.327
16.469 8693.845 3.327
16.951 8789.472 3.479
17.448 8889.821 0.462
17.959 8560.518 0.969
18.486 8560.518 0.969
19.027 8560.083 0.167
19.585 8253.033 0.879
20.159 8290.305 0.252
20.749 8230.995 -0.706
21.357 8085.457 -0.846
21.983 8010.113 0.466
22.627 8024.929 1.400
23.290 8257.462 1.732
23.973 8342.211 1.675
24.675 8351.080 1.579
25.398 8406.702 1.106
26.143 8565.890 1.632
26.909 8372.842 2.685
27.697 8393.261 3.661
28.509 8271.641 4.296
29.344 8326.683 4.476
30.204 8394.113 2.495
31.089 8308.273 2.275
32.000 8508.158 1.747
32.938 8335.520 0.902
33.903 8308.714 3.167
34.896 8322.450 3.458
35.919 8243.154 3.571
36.971 8390.290 1.672
38.055 8466.000 2.030
39.170 8399.581 2.392
40.317 8421.619 2.871
41.499 8251.202 4.168
42.715 8256.335 4.673
43.967 8469.684 4.425
45.255 8539.187 4.551
46.581 8455.218 2.989
47.946 8317.890 1.355
49.351 8300.890 1.291
50.797 8318.631 1.211
52.285 8317.292 2.250
53.817 8165.521 3.008
55.394 8067.976 3.956
57.018 8031.355 5.616
58.688 8108.512 8.253
60.408 8189.402 7.890
62.178 7985.360 7.394
64.000 7994.650 5.304
65.875 7870.359 5.116
67.806 8201.685 5.506
69.792 8469.436 5.304
71.838 8459.268 4.270
73.943 8462.656 4.108
76.109 8539.586 4.727
78.339 8594.967 5.504
80.635 8549.326 5.587
82.998 8489.007 5.144
85.430 8527.255 5.040
87.933 8448.945 5.527
90.510 8252.201 6.444
93.162 8331.405 6.162
95.892 8603.591 5.188
98.701 8574.568 5.538
101.594 8333.919 6.429
104.571 8118.523 6.741
107.635 8299.818 6.478
110.789 8652.874 5.587
114.035 8978.318 5.210
117.377 8878.856 6.170
120.816 8864.027 7.181
124.356 8790.483 8.099
128.000 8782.204 8.424
131.751 8374.735 9.053
135.611 8115.701 9.399
139.585 8299.981 9.414
143.675 8506.043 9.494
147.885 8635.869 9.152
152.219 8749.188 9.152
156.679 8768.337 9.904
161.270 8520.936 10.592
165.995 8381.220 10.351
170.860 8492.221 10.758
175.866 8764.493 10.734
181.019 8838.154 10.809
186.324 8888.618 11.653
191.783 8804.245 12.274
197.403 9090.635 12.233
203.187 9251.563 12.346
209.141 9446.375 12.805
215.269 9423.908 12.488
221.577 9247.732 13.378
228.070 9264.384 14.652
234.753 9365.874 16.112
241.632 9327.597 16.122
248.712 9123.171 16.447
256.000 9016.622 16.574
263.501 9118.172 16.929
271.223 9363.165 16.712
279.170 9490.165 16.597
287.350 9534.433 16.095
295.770 9280.224 17.657
304.437 9132.043 19.077
313.358 9318.789 20.138
322.540 9459.035 20.552
331.991 9587.468 20.837
341.719 9565.303 20.941
351.732 9812.276 21.928
362.039 9813.474 22.137
372.647 9721.034 22.731
383.567 9671.686 23.377
394.806 9809.905 23.877
406.375 10039.694 24.030
418.282 10319.538 23.740
430.539 10146.771 25.593
443.155 9975.268 26.686
456.140 10101.517 27.068
469.506 10512.747 26.972
483.264 10652.254 28.367
497.424 10708.850 29.303
512.000 10714.320 29.511
527.003 10725.967 30.157
542.445 11110.317 30.420
558.340 11302.256 29.898
574.701 11345.423 30.086
591.541 11206.558 31.164
608.874 11288.049 33.483
626.715 11605.175 34.440
645.080 12018.267 34.252
663.982 12220.431 33.849
683.438 12594.669 33.707
703.464 13462.734 34.487
724.077 13903.926 36.045
745.294 13961.244 37.828
767.133 13747.514 38.070
789.612 13694.672 38.098
812.749 14016.279 38.209
836.565 13701.447 39.035
861.078 13759.687 39.749
886.309 14489.975 40.792
912.280 15084.030 41.516
939.012 15453.955 42.006
966.527 16156.256 42.938
994.849 16681.644 44.077
1024.000 17148.356 43.983
1054.005 17950.197 44.065
1084.890 60690.185 43.246
1116.680 81541.189 42.661
1149.401 77550.795 43.393
1183.081 21163.259 45.200
1217.748 20811.301 45.061
1253.431 25141.341 43.493
1290.159 27150.994 42.564
1327.964 27414.175 43.814
1366.876 27501.735 42.819
1406.929 33646.502 41.039
1448.155 42111.609 40.218
1490.589 49768.770 40.384
1534.266 57206.011 41.528
1579.224 68782.265 43.257
1625.499 66089.548 42.941
1673.129 48260.348 43.144
1722.156 58546.132 44.974
1772.619 67214.209 42.216
1824.561 82000.724 40.382
1878.024 232040.638 35.283
1933.055 300219.569 32.205
1989.697 293982.733 33.415
2048.000 944621.923 35.253
2108.011 1243157.469 34.117
2169.780 1146564.756 30.484
2233.360 140684.214 31.006
2298.802 316248.352 31.646
2366.162 408239.924 31.616
2435.496 401678.334 31.575
2506.862 294659.605 28.846
2580.318 1091007.531 27.825
2655.927 1839257.308 27.355
2733.752 1800965.935 23.055
2813.857 1868277.592 18.665
2896.309 1858890.842 18.849
2981.178 1324027.100 20.975
3068.533 341961.434 20.449
3158.448 365311.840 18.903
3250.997 441139.236 17.380
3346.259 3698577.400 16.042
3444.312 5122242.522 14.540
3545.238 4826999.836 14.852
3649.121 588164.573 16.284
3756.049 577575.225 15.299
3866.109 315491.684 13.760
3979.395 373734.713 11.688
4096.000 479853.327 7.590
4216.022 908962.257 7.109
4339.561 1002606.883 8.526
4466.720 791049.395 7.516
4597.605 372236.367 8.062
4732.325 243939.555 7.640
4870.992 274640.255 4.475
5013.723 568187.423 2.490
5160.637 650008.448 4.270
5311.855 541030.366 6.918
5467.504 2559842.252 6.654
5627.714 3814360.367 3.604
5792.619 3743475.991 1.675
5962.355 772079.539 1.182
6137.066 745153.731 1.695
6316.896 282435.458 2.320
6501.995 213485.708 5.096
6692.518 331389.271 5.711
6888.623 1124691.433 5.875
7090.476 1155375.291 4.659
7298.242 803905.591 3.038
7512.097 371045.062 1.712
7732.218 408495.100 2.305
7958.790 331303.662 2.462
8192.000 218000.186 3.262
8432.044 230466.482 1.740
8679.122 526008.678 1.858
8933.439 2927637.490 0.779
9195.209 2895953.164 0.192
9464.649 1886952.021 -0.556
9741.985 725007.915 0.250
10027.447 621647.607 0.764
10321.273 368036.135 1.877
10623.710 358840.553 1.621
10935.008 150812.392 2.353
11255.428 534761.294 2.924
11585.238 773191.759 2.093
11924.711 748033.128 -1.868
12274.132 196265.732 -1.173
12633.791 198421.907 -0.189
13003.989 232549.646 0.223
13385.035 283614.016 -0.552
13777.247 258734.242 -1.042
14180.951 143608.805 -1.787
14596.485 139693.980 -1.209
15024.194 938767.316 -0.656
15464.437 1792277.195 0.417
15917.579 1771420.419 1.494
16384.000 681082.885 1.212
16864.088 270993.244 1.141
17358.243 399782.360 1.362
17866.879 400570.243 1.578
18390.418 161557.216 0.632
18929.299 138032.934 0.826
19483.969 115957.924 -0.129
20054.893 116023.345 -0.216
20642.546 70678.945 -0.400

[David King]

Wayne,

Thanks,
This line: "3444.312[Hz] 5122242.522[Ohms] 14.540[º] " seems significant for having the highest impedance?
The plot seems to leave the graph screen just when things were getting interesting..

What's the typical phase relationship one sees when doing a sweep of a "typical pickup"?

[ajawamnet@comcast.net]

No clue...

Here's some excel charts of this.

the phase actually looks fairly coherent, figuring the scope of the issue (lots of f'ing wire on magnet)

the thing that gets me is the impedance; my wife said it looks like a mountain range out west... and that's a log scale.

I wonder how well any of these measurements are as any indication of how well any pick up loads a preamp input.

I saw guys using typical LCR meters... not sure how accurate that'd be. I got the Extech, a BK, and ton of others; they all vary as to accuracy/thing being measured.

for instance i get 26nF on the BK and 15nF on the Extech using a 1K freq. measuring the capacitance might be futile using simple LCR meters

But the inductance is close on both - around 1.664 H at 1Khz with a Q of ~1.3

So go fig...

hey dave - check out marketturd when you get a chance.

WAM

Marketturd Quarterly - rants for Prehensile Chimps
Wayne Mitzen - Portfolio

[ajawamnet@comcast.net]

All you guyz need to get one of these imp sweepers.

Not bad... I have a VNA for RF stuff; this is pretty cool tho.

I talked to the guy that did it for dayton audio, he's the exCarvin dude at Trueaudio ( True Audio: Audio Spectrum Analyzer and Loudspeaker Design Software ). He assured me that it'll measure any passive device within reason.

I've tested it on some RC and LC stuff and it works damn good for a $99 USB device.

I'd say get yur yerself a cheap ass netbook with one of these and have a blast. And it's great for speaker cabs (what it was designed for).

Dayton Audio - WT3 Woofer Tester

[ajawamnet@comcast.net]

A better scaling

A better scaling for the vert axis

[David King]

Wayne,
That impedance plot looks more like a harmonic spread with a regular waveform up the decades. Could that be an artifact of something else in the signal chain?
I'd have to see some other pickup scans to understand what it could possibly mean.

I like your studio shots; Bench vise for MP3 compression. Is that an old panasonic DAT transport?