SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
                            -------------------------

                                  SCHEDULE 13G
                                 (Rule 13d-102)

                    INFORMATION TO BE INCLUDED IN STATEMENTS
                  FILED PURSUANT TO RULES 13d-1(b), (c) AND (d)
                AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2(b)
                        (Amendment No. ______4______)(1)

                              Electro-Sensors, Inc.

                                (Name of Issuer)

                          Common Stock, $0.10 par value
                         (Title of Class of Securities)

                            ________285233102 ______

                                 (CUSIP NUMBER)

                                 April 25, 2006


             (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

                      /   /     Rule 13d-1(b)
                      /   /     Rule 13d-1(c)
                      /   /     Rule 13d-1(d)


-----------------------------
(1)      The remainder of this cover page shall be filled out for a reporting
         person's initial filing on this form with respect to the subject class
         of securities, and for any subsequent amendment containing information
         which would alter disclosures provided in a prior cover page.

The      information required on the remainder of this cover page shall not be
         deemed to be "filed" for the purpose of Section 18 of the Securities
         Exchange Act of 1934 or otherwise subject to the liabilities of that
         section of the Act but shall be subject to all other provisions of the
         Act (however, see the Notes).







                                                                                                      

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1. NAME OF REPORTING PERSONS:
        I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
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2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                        (A)   X
                                                        (B)
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3. SEC USE ONLY
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4. CITIZENSHIP OR PLACE OF ORGANIZATION UNITED STATES OF AMERICA

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 NUMBER OF SHARES   5.    SOLE VOTING POWER                                                               263,413
   BENEFICIALLY
     OWNED BY
       EACH
     REPORTING
    PERSON WITH

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                    6. SHARED VOTING POWER 0
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                    7. SOLE DISPOSITIVE POWER 263,413
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                    8. SHARED DISPOSITIVE POWER 0
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9.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON                                      263,413

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10.     CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
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11.     PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                                                   8.10%
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12.     TYPE OF REPORTING PERSON* IN
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                      *SEE INSTRUCTION BEFORE FILLING OUT!



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Item 1(a).        Name of Issuer:

                           Electro-Sensors, Inc.

Item 1(b).        Address of Issuer's Principal Executive Offices:

                           6111 Blue Circle Drive
                           Minnetonka, Minnesota 55343-9108

Item 2(a).        Name of Person Filing:

                           Daniel Zeff
                           (the "Reporting Person")

Item 2(b).        Address of Principal Business Office or, if None, Residence:

                           The principal business address of the Reporting
                           Person is:

                           c/o Zeff Holding Company, LLC
                           50 California Street, Suite 1500
                           San Francisco, CA 94111


Item 2(c).        Citizenship:

                           Mr. Zeff is a United States citizen.

Item 2(d).        Title of Class of Securities:

                           Common Stock, $0.10 par value

Item 2(e).        CUSIP Number:

                           285233102

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Item 3.           If this statement is filed pursuant to Rule 13d-1(b), or
                  13d-2(b) or (c), check whether the person filing is a:
                  Not Applicable

                        (a) [ ] Broker or dealer registered under Section 15 of
                        the Exchange Act; (b) [ ] Bank as defined in Section
                        3(a)(6) of the Exchange Act; (c) [ ] Insurance Company
                        as defined in Section 3(a)(19) of the Exchange Act; (d)
                        [ ] Investment Company registered under Section 8 of the
                        Investment Company
                                      Exchange Act;
                        (e) [ ] Investment Adviser in accordance with Rule
                        13d-1(b)(1)(ii)(E); (f) [ ] Employee Benefit Plan or
                        Endowment Fund in accordance with Rule
                                      13d-1(b)(1)(ii)(F);
                        (g)           [ ] Parent Holding Company or Control
                                      Person in accordance with Rule
                                      13d-1(b)(1)(ii)(G);
                        (h)           [ ] Saving Association as defined in
                                      Section 3(b) of The Federal Deposit
                                      Insurance Act;
                        (i)           [ ] Church Plan that is excluded from the
                                      definition of an Investment Company under
                                      Section 3(c)(14) of the Investment Company
                                      Act;
                        (j)           [ ] Group, in accordance with Rule
                                      13d-1(b)(1)(ii)(J).
Item 4.           Ownership.

                  A.  Daniel Zeff


                                                                                                          
(a) Amount beneficially owned:                                                                               263,413
(b) Percent of Class:                                                                                           8.10%
(c) Number of shares as to which such person has:

                      (i)    Sole power to vote or direct the vote:                                          263,413
                      (ii)   Shared power to vote or to direct the vote:                                           0
                      (iii)  Sole power to dispose or direct the disposition of:                             263,413
                      (iv)   Shared power to dispose or to direct the disposition of:
                                                                                                                   0


                                      -4-




                     As calculated in accordance with Rule 13d-3 of the
                     Securities Exchange Act of 1934, as amended, Daniel Zeff
                     beneficially owns 263,413shares of the Issuer's Common
                     Stock, $0.10 par value ("Common Stock"), representing 8.10%
                     of the Common Stock. Mr. Zeff does not directly own any
                     shares of Common Stock, but he indirectly owns
                     263,413shares of Common Stock in his capacity as the sole
                     manager and member of Zeff Holding Company, LLC a Delaware
                     limited liability company ("ZHC") which in turn serves as
                     the general partner for Zeff Capital Partners I, L.P.
                     ("ZCP"), a Delaware Limited Partnership. Mr. Zeff also
                     provides discretionary investment management services to
                     Zeff Capital Offshore Fund ("ZCF"), a class of shares of
                     Spectrum Galaxy Fund Ltd., a company incorporated in the
                     British Virgin Islands.

Item 5.           Ownership of Five Percent or Less of a Class.

                           If this statement is being filed to report the fact
                           that as of the date hereof the reporting person has
                           ceased to be the beneficial owner of more than five
                           percent of the class of securities, check the
                           following: [ ]

Item 6.           Ownership of More than Five Percent on Behalf of Another
                  Person.

                           Each of ZCP and ZCF have the right to receive and the
                           power to direct the receipt of dividends from, and
                           the proceeds from the sale of, the shares of Common
                           Stock held by them.

Item 7.           Identification and Classification of the Subsidiary Which
                  Acquired the Security Being Reported on by the Parent Holding
                  Company.

                           Not Applicable

Item 8.           Identification and Classification of Members of the Group.

                           Not Applicable

Item 9.           Notice of Dissolution of Group.

                           Not Applicable

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Item 10.          Certification.

         By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were not acquired and are not held for
the purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.

                                    SIGNATURE


         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

Dated:  April 25, 2006
                                                   /s/ Daniel Zeff
                                                   ---------------





     Attention:  Intentional  misstatements  or  omissions  of  fact  constitute
Federal criminal violations (see 18 U.S.C. 1001).


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