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. ____________)(1)

                              Electro-Sensors, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)



                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)



                                    285233102
--------------------------------------------------------------------------------
                                 (CUSIP NUMBER)


                                  May 16, 2007
--------------------------------------------------------------------------------
             (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)
                   /X/   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).









                                                                                                    


--------------------------------------------------------------------------------------------------------------------
        NAME OF REPORTING PERSONS: Daniel Zeff
        I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
--------------------------------------------------------------------------------------------------------------------
        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                        (a)   X
                                                                                        (b)
--------------------------------------------------------------------------------------------------------------------
        SEC USE ONLY
--------------------------------------------------------------------------------------------------------------------
        CITIZENSHIP OR PLACE OF ORGANIZATION        United States of America
--------------------------------------------------------------------------------------------------------------------
    NUMBER OF             SOLE VOTING POWER                                                                 176,990
      SHARES
   BENEFICIALLY
     OWNED BY
       EACH
     REPORTING
   PERSON WITH
--------------------------------------------------------------------------------------------------------------------
                          SHARED VOTING POWER                                                                     0
--------------------------------------------------------------------------------------------------------------------
                          SOLE DISPOSITIVE POWER                                                            176,990
--------------------------------------------------------------------------------------------------------------------
                          SHARED DISPOSITIVE POWER                                                                0
--------------------------------------------------------------------------------------------------------------------
        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON                                        176,990
--------------------------------------------------------------------------------------------------------------------
        CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
        CERTAIN SHARES*
--------------------------------------------------------------------------------------------------------------------
        PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                                                      5.3%
--------------------------------------------------------------------------------------------------------------------
        TYPE OF REPORTING PERSON*                                                                                IN
--------------------------------------------------------------------------------------------------------------------



--------------------------------------------------------------------------------------------------------------------
        NAME OF REPORTING PERSONS: Spectrum Galaxy Fund Ltd.
        I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
--------------------------------------------------------------------------------------------------------------------
        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                        (a) X
                                                                                        (b)
--------------------------------------------------------------------------------------------------------------------
        SEC USE ONLY
--------------------------------------------------------------------------------------------------------------------
        CITIZENSHIP OR PLACE OF ORGANIZATION        British Virgin Islands
--------------------------------------------------------------------------------------------------------------------
     NUMBER OF            SOLE VOTING POWER                                                                  56,846
      SHARES
   BENEFICIALLY
     OWNED BY
       EACH
     REPORTING
   PERSON WITH
--------------------------------------------------------------------------------------------------------------------
                          SHARED VOTING POWER                                                                     0
--------------------------------------------------------------------------------------------------------------------
                          SOLE DISPOSITIVE POWER                                                             56,846
--------------------------------------------------------------------------------------------------------------------
                          SHARED DISPOSITIVE POWER                                                                0
--------------------------------------------------------------------------------------------------------------------
        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON                                         56,846
--------------------------------------------------------------------------------------------------------------------
        CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
        CERTAIN SHARES*
--------------------------------------------------------------------------------------------------------------------
        PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                                                      1.7%
--------------------------------------------------------------------------------------------------------------------
        TYPE OF REPORTING PERSON*                                                                                CO
--------------------------------------------------------------------------------------------------------------------



                                     - 2 -


--------------------------------------------------------------------------------------------------------------------
        NAME OF REPORTING PERSONS: Zeff Capital Partners I, L.P.
        I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
--------------------------------------------------------------------------------------------------------------------
        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                        (a) X
                                                                                        (b)
--------------------------------------------------------------------------------------------------------------------
        SEC USE ONLY
--------------------------------------------------------------------------------------------------------------------
        CITIZENSHIP OR PLACE OF ORGANIZATION        Delaware
--------------------------------------------------------------------------------------------------------------------
     NUMBER OF            SOLE VOTING POWER                                                                 120,144
      SHARES
   BENEFICIALLY
     OWNED BY
       EACH
     REPORTING
   PERSON WITH
--------------------------------------------------------------------------------------------------------------------
                          SHARED VOTING POWER                                                                     0
--------------------------------------------------------------------------------------------------------------------
                          SOLE DISPOSITIVE POWER                                                            120,144
--------------------------------------------------------------------------------------------------------------------
                          SHARED DISPOSITIVE POWER                                                                0
--------------------------------------------------------------------------------------------------------------------
        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON                                        120,144
--------------------------------------------------------------------------------------------------------------------
        CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
        CERTAIN SHARES*
--------------------------------------------------------------------------------------------------------------------
        PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                                                      3.6%
--------------------------------------------------------------------------------------------------------------------
        TYPE OF REPORTING PERSON*                                                                                PN
--------------------------------------------------------------------------------------------------------------------




                                     - 3 -




--------------------------------------------------------------------------------------------------------------------
        NAME OF REPORTING PERSONS: Zeff Holding Company, LLC
        I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
--------------------------------------------------------------------------------------------------------------------
        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                                        (a) X
                                                                                        (b)
--------------------------------------------------------------------------------------------------------------------
        SEC USE ONLY
--------------------------------------------------------------------------------------------------------------------
        CITIZENSHIP OR PLACE OF ORGANIZATION        Delaware
--------------------------------------------------------------------------------------------------------------------
    NUMBER OF             SOLE VOTING POWER                                                                 120,144
     SHARES
   BENEFICIALLY
     OWNED BY
       EACH
     REPORTING
   PERSON WITH
--------------------------------------------------------------------------------------------------------------------
                          SHARED VOTING POWER                                                                     0
--------------------------------------------------------------------------------------------------------------------
                          SOLE DISPOSITIVE POWER                                                            120,144
--------------------------------------------------------------------------------------------------------------------
                          SHARED DISPOSITIVE POWER                                                                0
--------------------------------------------------------------------------------------------------------------------
        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON                                        120,144
--------------------------------------------------------------------------------------------------------------------
        CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
        CERTAIN SHARES*
--------------------------------------------------------------------------------------------------------------------
        PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                                                      3.6%
--------------------------------------------------------------------------------------------------------------------
        TYPE OF REPORTING PERSON*                                                                                OO
--------------------------------------------------------------------------------------------------------------------




                                     - 4 -




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:

                           This statement is filed as a joint statement pursuant
                           to Rule 13d-1(k) promulgated under the Securities
                           Exchange Act of 1934 (the "Exchange Act") by Zeff
                           Capital Partners, I, L.P., a Delaware limited
                           partnership ("Capital"), Zeff Holding Company, LLC, a
                           Delaware limited liability company ("Holding"),
                           Spectrum Galaxy Fund Ltd., a company incorporated in
                           the British Virgin Islands ("Spectrum") and Daniel
                           Zeff, an individual ("Zeff") (Capital, Holding,
                           Spectrum and Zeff are hereinafter collectively
                           referred to as the "Reporting Persons"). Zeff
                           provides discretionary investment management services
                           to Zeff Capital Offshore Fund, a class of shares of
                           Spectrum. Zeff is the sole manager and member of
                           Holding, which in turn serves as the general partner
                           for Capital. Accordingly, the Reporting Persons are
                           making a group filing because, due to the
                           relationship between them, the Reporting Persons may
                           be deemed to constitute a "group" for the purposes of
                           Section 13(d)(3) of the Exchange Act.

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

                           The address of the principal place of business and
                           principal office of each of the Reporting Persons is:

                           50 California Street, Suite 1500
                           San Francisco, CA 94111
Item 2(c).        Citizenship:

                           Zeff is a United States citizen. Spectrum is
                           organized under the laws of the British Virgin
                           Islands. Capital and Holding are organized under the
                           laws of the State of Delaware.

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

                           Common Stock, par value $0.10("Common Stock")

Item 2(e).        CUSIP Number:

                           285233102





                                     - 5 -



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:                                                                               176,990
(b)  Percent of Class:                                                                                           5.3%
(c)   Number of shares as to which such person has:
            (i)        Sole power to vote or direct the vote:                                                176,990
            (ii)       Shared power to vote or to direct the vote:                                                 0
            (iii)      Sole power to dispose or direct the disposition of:                                   176,990
            (iv)       Shared power to dispose or to direct the disposition of:                                    0


B.  Spectrum

(a)  Amount beneficially owned:                                                                               56,846
(b)  Percent of Class:                                                                                          1.7%
(c)   Number of shares as to which such person has:
            (i)            Sole power to vote or direct the vote:                                            56,846
            (ii)           Shared power to vote or to direct the vote:                                            0
            (iii)          Sole power to dispose or direct the disposition of:                               56,846
            (iv)           Shared power to dispose or to direct the disposition of:                               0


                                     - 6 -


C.  Capital

(a)  Amount beneficially owned:                                                                              120,144
(b)  Percent of Class:                                                                                          3.6%
(c)   Number of shares as to which such person has:
            (i)            Sole power to vote or direct the vote:                                           120,144
            (ii)           Shared power to vote or to direct the vote:                                            0
            (iii)          Sole power to dispose or direct the disposition of:                              120,144
            (iv)           Shared power to dispose or to direct the disposition of:                               0


D.  Holding

(a)  Amount beneficially owned:                                                                              120,144
(b)  Percent of Class:                                                                                          3.6%
(c)   Number of shares as to which such person has:
            (i)            Sole power to vote or direct the vote:                                           120,144
            (ii)           Shared power to vote or to direct the vote:                                            0
            (iii)          Sole power to dispose or direct the disposition of:                              120,144
            (iv)           Shared power to dispose or to direct the disposition of:                               0



                                    As calculated in accordance with Rule 13d-3
                           of the Exchange Act, Zeff beneficially owns 176,990
                           shares of the Issuer's Common Stock, representing
                           5.3% of the Common Stock. Zeff does not directly own
                           any shares of Common Stock. Zeff's beneficial
                           ownership is comprised of 120,144 shares of Common
                           Stock held by Capital and 56,846 shares of Common
                           Stock held by Spectrum. Zeff beneficially owns the
                           shares of Common Stock held by Capital in his
                           capacity as the sole manager and member of Holding,
                           which in turn serves as the general partner Capital.
                           Zeff beneficially owns the shares of Common Stock
                           held by Spectrum in his capacity as investment
                           manager to Zeff Capital Offshore Fund, a class of
                           shares of Spectrum.


                                     - 7 -


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.

                           Capital has the right to receive and the power to
                           direct the receipt of dividends from, and the
                           proceeds from the sale of, the 120,144 shares of
                           Common Stock held by it, which power is exercisable
                           by Mr. Zeff as sole manager of Holding, Capital's
                           general partner.

                           Spectrum has the sole power to receive and to direct
                           the receipt of dividends from, and the proceeds from
                           the sale of, the 56,846 shares of Common Stock held
                           by it, which power is exercisable by Mr. Zeff as
                           investment manager.

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.

                           Please see Exhibit 1, Joint Filing Agreement.

Item 9.           Notice of Dissolution of Group.

                           Not Applicable


                                     - 8 -



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: May 18, 2007              /s/ Daniel Zeff
                                 ----------------------------------
                                 Daniel Zeff


                                 ZEFF HOLDING COMPANY, LLC

                                 By: /s/ Daniel Zeff
                                 Name: Daniel Zeff
                                 Title: Manager


                                 ZEFF CAPITAL PARTNERS I, L.P.
                                 By: Zeff Holding Company, LLC,
                                 as general partner

                                 By: /s/ Daniel Zeff
                                 Name: Daniel Zeff
                                 Title: Manager


                                 SPECTRUM GALAXY FUND LTD.

                                 By: /s/ Dion R. Friedland
                                 Name: Dion R. Friedland
                                 Title: Director


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



                                     - 9 -


                                                                       Exhibit 1



                             Joint Filing Agreement



         In accordance with Rule 13d-1(k) under the Securities Exchange Act of
1934, as amended, the undersigned hereby agree to the joint filing on behalf of
each of them of a statement on Schedule 13G (including amendments thereto) with
respect to the Common Stock of Electro-Sensors Inc., and that this Agreement be
included as an Exhibit to such joint filing. This Agreement may be executed in
any number of counterparts all of which taken together shall constitute one and
the same instrument.

In witness hereof, the undersigned hereby executed this Agreement this 18 day of
May, 2007.

                                 /s/ Daniel Zeff
                                 -------------------------------
                                 Daniel Zeff


                                 ZEFF HOLDING COMPANY, LLC

                                 By: /s/ Daniel Zeff
                                 Name: Daniel Zeff
                                 Title: Manager


                                 ZEFF CAPITAL PARTNERS I, L.P.
                                 By: Zeff Holding Company, LLC,
                                 as general partner

                                 By: /s/ Daniel Zeff
                                 Name: Daniel Zeff
                                 Title: Manager


                                 SPECTRUM GALAXY FUND LTD.

                                 By: /s/ Dion R. Friedland
                                 Name: Dion R. Friedland
                                 Title: Director



                                     - 10 -