The Tube CAD Journal, Electrostatic Headphones Amps -Part 2- Pg = 2

From: "Saved by Internet Explorer 11" Subject: The Tube CAD Journal, Electrostatic Headphones Amps -Part 2- Pg 2 Date: Wed, 8 Apr 2015 09:53:46 -0700 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_0022_01D071E1.E7D91BD0" X-MimeOLE: Produced By Microsoft MimeOLE V6.1.7601.17609 This is a multi-part message in MIME format. ------=_NextPart_000_0022_01D071E1.E7D91BD0 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.tubecad.com/Classic_Articles/page3.html =20 =20 =20 =20 =20 The Tube CAD Journal, Electrostatic Headphones Amps -Part 2- Pg = 2=20 =20 =20

=20 =20

"clean sound." Each group obviously desires sound = which=20 simulates the original, but each rejects the elusive and=20 unmeasureable distortions which characterize the tube type = preferred=20 by the opposition camp. A new type of tube, none of which = has been=20 put on the market for many years, might be the thing which = could=20 reconcile these diverse views of listeners who all look for = the same=20 thing but seek it in different ways.
The requisites for = such a=20 new tube can be listed readily:

1.=20 Low internal impedance, such as is offered
= by the=20 triode.
2. High power sensitivity of the tetrode so as = to =20
minimize drive problems.
3. Lower = harmonic and=20 intermodulation
distortion = than either=20 triode or tetrode at both
high and = low=20 levels of operation.
4. Sufficiently high efficiency to = permit=20
adequate output without undue hulk or=20 cost.

Since no such tube is available, the only = recourse is=20 to seek a mode of operation of existing type tubes to = approximate=20 the desired qualities and then to see whether the theory is=20 justified by listening tests.

Linearizing the Output=20 Stage
The=20 physical difference between the triode and tetrode is, of = course.=20 The screen grid. This gives the tetrode its efficiency on = the one=20 hand, but also increases the plate resistance and = contributes toward=20 the "tetrode sound" which is so violently disliked by triode = favorers. Therefore, the screen grid seems to be the element = which=20 gives the tetrode its advantages and its disadvantages = compared to=20 the triode. In fact, when the screen is connected to the = plate, the=20 resultant tube is a triode which is excellent in many = respects=20 though handicapped by limited power output and low = permissible=20 dissipation. Control of the screen is a logical step toward=20 extracting the favorable attributes of the tube and = discarding the=20 unfavorable.


	Experimentally it was found that the goal of = improved=20 operation could be achieved through energizing the screen = with DC=20 through a special winding on the output transformer and = combining=20 the effects of both plate and screen current in the output=20 transformer. This is illustrated at (A) in Fig. 1 with an=20 alternative and simpler method shown at (B). It has been = found that=20 the screens must be fed from a low-impedance source or the = benefits=20 of this arrangement cannot be realized. This eliminates the=20 possibility of doing the same job with resistive bridge = networks or=20 voltage dividers.


	Fig. 1.=20 Arrangements for energizing the screen grid to improve tube=20 linearity.


	The screen load impedance is somewhat = critical if=20 optimum results are desired. As the ratio of screen load = impedance=20 varies from zero (tetrode operation) to unity (triode=20 operation), important effects show up: 1. The = internal=20 impedance takes a sharp drop and then = levels=20 off. 2. Maximum undistorted output drops = slightly =20 at first, then decreases rapidly. 3. = Intermodulation=20 distortion at high level operation drops = to a=20 minimum and then soars upward. 4. = Low=20 level IM decreases somewhat and then holds = almost=20 level.


	<=20 PREVIOUS


	pg.=20 2


	NEXT=20 ><= /FONT>


	www.tubecad.com Copyright =A9 2000=20 GlassWare All Rights Reserved =

= ------=_NextPart_000_0022_01D071E1.E7D91BD0 Content-Type: image/gif Content-Transfer-Encoding: base64 Content-Location: http://www.tubecad.com/Classic_Articles/_blnk.gif R0lGODlhAQABAID/AMDAwAAAACH5BAEAAAAALAAAAAABAAEAAAICRAA7Ymxua2ltZyNnaWYNAAA= ------=_NextPart_000_0022_01D071E1.E7D91BD0 Content-Type: image/gif Content-Transfer-Encoding: base64 Content-Location: http://www.tubecad.com/Classic_Articles/img0.gif R0lGODlhjgIZAPf/AAAAgP///wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAHtzBCH5BAEBAP8ALAAAAACOAhkA QAj/AAEIHEiwoMGDCBMqXMiwocOHECNKnEixosWLGDNq3Mixo8ePIEOKHElSYICTJTuiHLgSQMuK L2OmnFkygEmbLm+iPMmzJ06XPn8WjCkUaFGgBF8eJMrUJk+jPVk+NTp06FSaWDUSlZq168yrXsMq 9Cl1ZVCoZY9uTRoUbFSxcM+yNSsXKliDb9HqbKt0rtK8aQNTdatzr92+cBMvzfuW8VXAfP8eVUy5 suXLmDNr3sy5s+fPoEOLHk26tOnTqFOLBCy66U28ON323fl6Ml22r1VbnP0zNlnBi8fi5joc4W3i SE2mlYlUqO/iukO6Tn5c9mTqzmlHT8h6u/fv4MOL/R9Pvrz58+jTq1/PfvxU39cfNn6PuL38tjXN 4rVa1/hv+6i9VxiAnnUHWn256WXYgtQ1KNhTdCGYHm8sJdiShMlxl+CGGQbX4YW9IXehg2VZReB9 Y/VmnYogRngYVe7dtRuGma2F3YbWmYjcjR/Gxx6FymUIIkN/VVgijmqpiKSIxDFn4Y4jnphicdVl Z2Vuxx0pnoxSdunll2Capl2YZJZp5plopqnmmmy26eabcMYp55x01mnnnXjmqad0pLW4I0U25vTm c4JKx6KOiNJI454b+clhnT7CxGVns/0J6KFBxgmkoEM+Cdt+FW76KJWEeiokpoU+uqiUlY5Kp4Gx EU16oI9VYmmrrfphCV9OWdq3KaFbxYdhqRxK2GunhSL7nHMdNmumscACe2uVTgl5nqz3rWqZZCI6 duVcXFl57H++JmmkstX6lyK53JK6pKk7FYWqXVSe2S6Pjg64F7HNkQfrRZHWmF2T0jp4b4+61kvg rxYqmSmiyX7asIenvpsssQM/3Km27dlYK6exJcwjdOAFzOjJKKccl8ost+yynti+LPPMNNds8804 56xzRAEBADs= ------=_NextPart_000_0022_01D071E1.E7D91BD0 Content-Type: image/gif Content-Transfer-Encoding: base64 Content-Location: http://www.tubecad.com/Classic_Articles/img12.gif R0lGODlhpgDFAPf/AAAAAHtzBP///wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAHtzBCH5BAEBAP8ALAAAAACmAMUA QAj/AP8JHEiwoMGDBwEoXMiwocOHECNKnAgRIYCBFxFq3Mixo8eECwWIFABgJMmFH1OqXIlRYcGM /2CynEmz5EiKOBvepMkzJUqBMIO67EmUoM2TD5E6FAmRac6fRXkOjYmxZdSoR5XqjOh0qdaQO6te teoRatCWMo1WzeiSLVuqMaeWNdn1KU66JA2mJQqVY9+zaMcKzoq3sGG8Jfe+LMqwY8OEYl9WFEy5 ZmW/cjf2hcv5sufBn9X6DA3aaGPRlBVXVm2RtOvXcV+z1jsbtu3bKlGa1ag7M+7fwIMLJ117+MfN QCMbn6nQMGGTvpdbzAxYOm/odu+GtR44ufe4xW3b/+T6tXn58U3zog7+s3p09jfTy096/qjM8J93 f0fePfbFtrEB9d97FtGVXU6I6SXcX8rxZ91zh0WInWO/8Vcdd7fhxx51ymEIm4biecibaZuBmJuI Jor4YYrEsajii/kl5yKMK82I4lQX0iighEzxeJKO4EUmlI2r+WikkUSOZWGH4CUpFXZJkTefV0wp KN5pQkpW4lBD/hfgkMcdKSaSiw2moVwXEghffAdOBF1rqalpWpYCArnjmPF9p9lq+OnXmZ2pyXYi oH+m5SScxA1qZ3iHWpnoaIRGKumklFZq6aU0Nipde0xmiuSRml7mJ5jcQYjnmKHyhWaDcn7IpldT 6v9UX5u0PgWZngKedtaudVIlVG6nBmtgmRVyiKuDa54kLGJZqZZqbjgK2WqppkaIY07GcYorpiw9 y5ekD20bqIferoZWiZ6VKxW37Lbr7rs6qpvhquJyKy9u0dYbb7UkWXuvVFiitpdEw6FXa5T70hkg hoQdnF6VDBtb6LSuGbyUlPTJR26+nCGL76tbxcpQXSND3OmV7vVXY1lhgjwyxrDSZ/J6APtkaIfR 8Srjfh0PXGt9JIP1sHr6Atxnyr32dCi/y/p4s6qtPuaoYlInG7TD5m1HM1ZHIx0kufE1zabWxF5F 8cIdzwlj1mJPq6nHJAqMacmFBVx0aHCTlTa8irYzeNy/9goKKd/mVtx3pgoOLKrgxwF6X9nP/gsi 4EqOGKPhgxOupOQ2a+7555M21haB4YJu//rpqKeuOruUV8xx6y1OVumooTPN9I8Jy6022LPSOvON b+0H+1xQYg0W2cBVrbuWZxcJ9HlXWyzr8Jq9rnLBLgud8fYy39e8mcujfTiijmVvnsjadx93sY/r ueTO8OssvmbmS5/+9A+3vyCX0jKmZN3GO96wtoY3u/GMed9zXvQcNsCyJY9/wlub2Or2OweijFiG SuC82ua2glmvXQQj34totzoCZquEliEXCpmDIkKl6WRYaeGi1qO/cTEsUrNRF/X8ssIe+vBB8Puh ECm1wzhNjXBF5JPX3pVEPinMXrKb3QeJaKoqNvFvVIOhBCV0uyuWhV6dyZvVuAiqfXlNjP8Vqt/P iKaiKWqwYsULIPIepD/vMYxZAWQbGzf0vj/l6o1YmSCevKiyNAFyMPV7HvqyRshcKQyNcFygIrkn qz020Y2EbFZTYIY/KrERkkZ84hsZ1TJJcrJkeaQVZvroM12t5ZVf6lkpBTnI9XENi+FjZdqC5yu9 +SWOL1uk/dhWQ7N17ZGku5avvKRMMWoySsKM3pu0WJNjHvBr6wokLVFlQaPhMnzYXJBzUumcbjLH bTljkgE/ZqBU6nGPfmSMNfcWzuU0zJ0Nu5WZjobMNoZtgsdjTaooRsJ6Pmib0KmgCc85z2s6EkUI xd2ejNk5DIYOoPF01Oa+Sc/aocp7OFF84t+eOLcoavSCX1xiCSmHRl32kHOZG6LlHtU4mfIQczW1 6UzxNr540ZCnOGWZ4xbztMLRVKhAKmpRS3NUCs0QZwtVGuOQ6tOHYjNyU3XqUCe6uKBqVaf6BGpO wWrL/BC0kWRNq1rXylW1CJStIYofV9H60ozuFK54zate9//K17761az4DGxE5opEEIKRrmZzV0GZ yEQI2tVxArznITcEThdai4trW2eOmuSQTTmNTJk6bFnviE94RuyMk02XGn2nUDry8lcQXW2bpkkt pWqpVBG1lmv12corJiaa0AMaXQsKSuJIMrjCDOH+XutLex4XuFIy54pQ6yJSlvKU90Nl/k4qG4ll kGqOFV0srfrL51JSu+rjrussuju56Ux+Z7MPdM9Lt2LiC5POgiWAYumW3h5ImsjdLjVdx9ykZVOb ucVsVAmMzEbeLsFLnS5vQeLbdrozQdJdLzhTi0jZzpa2C45dg2PbO9a29pLhbS5ulSVIRt71vrlE LEYimphwm043neIarHNpad0H1nF2y+JlW9lH0tq9s3gZrq1DV5rUH9d1Y8VdHWJl3EYZ4nXKesVy XrW81fbp0MpVdV+IU3jDp4p5wGQu1VbPfLcDq3nNL66cCnEoQqO+Ga4cBt9f98znPu9znX4GLJUD zZ2AAAA7 ------=_NextPart_000_0022_01D071E1.E7D91BD0 Content-Type: image/gif Content-Transfer-Encoding: base64 Content-Location: http://www.tubecad.com/Classic_Articles/img10.gif R0lGODlhjQICAPf/AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAHtzBCH5BAEBAP8ALAAAAACNAgIA QAg8AAEIHEiwoMGDCBMqXMiwocOHECNKnEixosWLGDNq3Mixo8ePIEOKHEmypMmTKFOqXMmypcuX MGPK/BgQADs= ------=_NextPart_000_0022_01D071E1.E7D91BD0--