<PAGE>   1



EXHIBIT 10.60

            WAIVER AND NINTH AMENDMENT TO CREDIT AGREEMENT AND NOTE


         THIS WAIVER AND NINTH AMENDMENT TO CREDIT AGREEMENT AND NOTE ("Ninth
Amendment"), made and entered into as of the 31st day of December, 1996, by and
between GTI CORPORATION, a Delaware corporation ("Company"), and UNION BANK OF
CALIFORNIA, N.A. (successor in interest to Union Bank), a national banking
association ("Bank"),

                              W I T N E S S E T H

         WHEREAS, on December 17, 1992, the Company and the Bank entered into a
Certain Credit Agreement and Note (as amended by those certain First, Second,
Third, Fourth, Fifth, Sixth, Seventh and Eighth Amendments to Credit Agreement
and Note, dated as of May 7, 1993, July 14, 1993, March 24, 1994, June 24,
1994, November 30, 1994, June 29, 1995, December 19, 1995 and February 15,
1996, respectively, the "Credit Agreement") pursuant to which the Bank agreed
to extend to the Company and the Company agreed to accept from the Bank certain
credit facilities more particularly described therein; and

         WHEREAS, the Company and the Bank desire (i) to evidence the waiver by
the Bank of the Company's compliance with certain of the financial covenants
set forth in the Credit Agreement for the fiscal quarter of the Company ended
September 30, 1996, and (ii) to amend the Credit Agreement (A) to extend the
Revolver Termination Date through and including March 31, 1997, (B) to decrease
the maximum availability under the Revolving Loan Facility from Ten Million
Dollars ($10,000,000.00) to Seven Million Five Hundred Thousand Dollars
($7,500,000.00), (C) to modify certain of the financial and other covenants
with which the Company is to comply, and (D) to provide for certain ancillary
matters;

         NOW, THEREFORE, for and in consideration of the premises hereof, and
other good and valuable consideration the receipt and adequacy of which are
hereby acknowledged, the parties hereto hereby agree as follows:

    1.   All capitalized terms used in this Ninth Amendment shall, unless
otherwise defined herein or unless the context otherwise requires, have the
meanings given thereto in the Credit Agreement.

    2.   The Bank hereby waives, for the fiscal quarter of the Company ended
September 30, 1996, and only for such fiscal quarter, compliance by the Company
with the Tangible Net Worth covenant set forth in Subsection 4.02(h) of the
Credit Agreement, the profitability covenant set forth in Subsection 4.02(j) of
the Credit Agreement and the debt service coverage ratio covenant set forth in
Subsection 4.02(1) of the Credit Agreement, and agrees that such noncompliance
shall not constitute an Event of Default under the Credit Agreement or under
the Credit Agreement as amended by this Ninth Amendment.  The waiver here given
is specific to the covenants, and for the fiscal quarter of the Company,
referred to above and shall not operate as a waiver of compliance by the
Company with any other covenants set forth in the Credit Agreement, or in the
Credit Agreement as amended by this Ninth Amendment, or with the covenants
referred to above for any other fiscal quarters of the Company.

     3.   Section I of the Credit Agreement is amended to read as follows:

SECTION I.     THE REVOLVING LOAN FACILITY

1.01.     Availability.  Subject to the terms and conditions of this Agreement,
the Bank shall, from time to time during the period commencing on the Ninth
Amendment Effective Date and ending on March 31, 1997 (the "Revolver
Termination Date"), advance to the Company such revolving loans as the Company
may request under the Revolving Loan Facility (individually a "Revolving Loan"
and collectively the "Revolving Loans"); provided, however, that the
outstanding principal amount of all Revolving Loans shall not exceed in the
aggregate (a) at any given time during the period commencing on the Ninth
Amendment Effective Date and ending on December 31, 1996, the lesser of (I) Ten
Million Dollars ($10,000,000.00), or (ii) eighty percent (80%) of the net
amount owing on Eligible Accounts, or (b) at any other given time, the lesser
of (I) Seven Million Five Hundred Thousand Dollars ($7,500,000.00), or (ii)
eighty percent (80%) of the net amount owing on Eligible Accounts (the
"Revolving Loan Commitment").  Except as otherwise provided herein, the Company
may borrow, repay, and reborrow under the Revolving Loan Facility.  Unless
otherwise directed by the Company, the Bank shall make the proceeds of each
Revolving Loan available to the Company by crediting account no. 4000132123
maintained by the Company at the Bank's San Diego Regional Office.

                                       1
<PAGE>   2



1.02.     Notice of Revolver Borrowing.  The Company shall request the Bank to
make each Revolving Loan by an irrevocable notice to the Bank (a "Notice of
Revolver Borrowing") which specifies:

     (a)  The amount of the requested Revolving Loan, which shall be
Twenty-five Thousand Dollars ($25,000.00) or an integral multiple thereof; and

     (b)  The date of the requested Revolving Loan, which shall be a Banking
Day.

The Company shall give each Notice of Revolver Borrowing to the Bank on or
prior to the date of the requested Revolving Loan, and shall do so by
telephone, telex or telecopy to the Bank's San Diego Regional Office, located
at the address shown in Subsection 8.01(a) hereof, during the hours specified
in Subsection 8.01(b) hereof.  The Company shall immediately confirm each
Notice of Revolver Borrowing in a writing to the Bank in the form appended
hereto as Exhibit A.

1.03.     Interest Rate.  The Company shall pay interest on the unpaid
principal amount of each Revolving Loan as follows:

     (a)  From the date of such loan until the earlier of December 31, 1996 or
the maturity of such loan (whether by acceleration or otherwise) at a rate per
annum equal to the Reference Rate plus one-half of one percent (0.50%), such
rate to change from time to time as the Reference Rate shall change; and

     (b)  From the later of January 1, 1997 or the date of such loan until the
maturity of such loan (whether by acceleration or Otherwise) at a rate per
annum equal to the Reference Rate Plus one and one-quarter percent (1.25%),
such rate to change from time to time as the Reference Rate shall change.

1.04.     Payments.

     (a)  If not sooner repaid, the Company shall repay the aggregate unpaid
principal amount of all Revolving Loans on  the Revolver Termination Date;
provided, however, that on December 31, 1996, the Company shall repay such
portion of the aggregate unpaid principal amount of all Revolving Loans as
shall be necessary to reduce such aggregate unpaid principal amount to an
amount not greater than the amount to which the Revolving Loan Commitment will
be reduced on January 1, 1997.  The Company shall pay accrued interest on the
unpaid principal amount of each Revolving Loan in arrears on the last day in
each calendar month (commencing December 31, 1996), and at maturity (whether by
acceleration or otherwise).

     (b)  The Company may prepay any Revolving Loan, in whole or in part and at
any time, provided that each partial prepayment shall be in a principal amount
Twenty-five Thousand Dollars ($25,000.00) or an integral multiple thereof.

1.05.     Extension Fee.  Upon the execution of the Ninth Amendment, the
Company shall pay to the Bank an extension fee in the amount of Five Thousand
Dollars ($5,000.00)  (the"Extension Fee").

1.06.     Commitment Fee.  Until the Revolver Termination Date, the Company
shall pay to the Bank a commitment fee of one-quarter of one percent (0.25%)
per annum on the average daily undisbursed amount of the Revolving Loan
Commitment during each calendar quarter or portion thereof; provided, however,
that the commitment fee payable in respect of the calendar quarter ending
December 31, 1996 shall be computed at rate of one-eighth of one percent
(0.125%) per annum (the "Commitment Fees).  The Commitment Fee shall be payable
quarterly in arrears on the last day in each March, June, September and
December (commencing December 31, 1996), and at maturity (whether by
acceleration or otherwise).  For purposes of computing the Commitment Fee, the
Revolving Loan Commitment shall be deemed to be (a) for the calendar quarter
ending December 31, 1996, Ten Million Dollars ($10,000,000.00), and (b) for all
subsequent calendar quarters, Seven Million Five Hundred Thousand Dollars
($7,500,000.00), irrespective of whether a shortfall in Eligible Accounts
otherwise limits the aggregate principal amount of Revolving Loans available to
the Company at any given time.

1.07.     Purpose.  Revolving Loans shall be used only for the general working
capital purposes of the Company.


                                       2
<PAGE>   3




1.08.     Facility Account.  The obligation of the Company to repay the
Revolving Loans and to pay interest thereon as herein provided shall be
evidenced by an account or accounts maintained by the Bank on its books
(collectively, the "Facility Account").  The Company hereby authorizes the Bank
to record in the Facility Account:
                                        (a)  The principal amount and the date
of each Revolving Loan

     (b)  The interest rates applicable to each Revolving Loan and the
effective dates of all changes in such rates;

     (c)  The date and amount of each payment of principal, interest or other
expenses made by or on behalf of the Company with respect to each Revolving
Loan; and

     (d)  Such other matters as the Bank shall deem necessary or desirable for
the computation of amounts required to be paid by the Company under this
Agreement or the other Facility Documents.

The Company agrees that all notations made by the Bank in the Facility Account
shall constitute prima facie evidence of the matters noted.

1.09     Other Payment Terms.

     (a)  Whenever any payment due hereunder shall fall due on a day other than
a Banking Day, such payment shall be made on the next succeeding Banking Day,
and such extension of time shall be included in the computation of interest or
fees, as the case may be.

     (b)  The Company shall make all payments hereunder to the Bank's San Diego
Regional office, located at the address shown in Subsection 8.01(a) hereof, in
lawful money of the United States of America and in immediately available
funds.  The Company hereby authorizes the Bank to charge from time to time
against any or all deposit accounts maintained by the Company with the Bank any
amount payable by the Company hereunder not paid when due.

     (c)  If any amounts required to be paid by the Company under this
Agreement or the other Facility Documents (including without limitation
principal, accrued interest and fees) remain unpaid after maturity (whether by
acceleration or otherwise), the Company shall pay interest on the aggregate
outstanding balance of such amounts from maturity until those amounts are paid
in full at a rate per annum equal to the Reference Rate plus five percent (5%),
such rate to change from time to time as the Reference Rate shall change.

     (d)  A11 computations of interest or fees under this Agreement shall be
based on a year of 360 days for actual days elapsed.

1.10.     Security.  A11 amounts due or to become due hereunder a- Secured
and/or supported, as the case may be, by (a) a Security Agreement, dated
December 19, 1996, executed by the Company, (b) a Continuing Guaranty, dated
December 19, 1996, executed by Valor Electronics, Inc.  ("Valor"), which
Continuing Guaranty is in turn secured by a Security Agreement (Chattel
Mortgage), dated October 6, 1992, executed by Valor, (c) a Continuing Guaranty,
dated December 19, 1996, executed by Promptus, which Continuing Guaranty is in
turn secured by a Security Agreement, dated November 16, 1994, executed by
Promptus, and (d) two (2) Security Agreements - Pledge, each dated November 30,
1994, and each executed by the Company.  In addition, and as security for all
Obligations of the Company to the Bank, the Company hereby grants to the Bank a
continuing security interest in:

     (1)  All Deposits in which the Company now or at any time hereafter has 
an interest; and

     (2)  All proceeds and products of, and all accessions to, such Deposits.

1.11.     Banking Relationship.  In consideration of the interest rates payable
with respect to the Revolving Loans, and to afford the Bank the benefit of the
security interest in Deposits granted by the Company to the Bank in Section
1.10 hereof, the Company hereby agrees that it will maintain all of its major
deposit accounts with the Bank until the termination of this Agreement and the
satisfaction in full of all Obligations of the Company arising hereunder.


                                       3
<PAGE>   4




    4.   Subsection 2.02(b) of the Credit Agreement is amended to read as
follows:

     (b)  The Company shall have delivered to the Bank statements in form and
detail satisfactory to the Bank showing the aging and adjustment of the
accounts receivable of the Company, Valor and Promptus (and collections
thereon) as at the end of the semimonthly period most recently ended (or as at
the end of the next preceding semimonthly period if the requested Revolving
Loan is to be made during the first ten (10) days of any such semimonthly
period); provided, however, that the statements of the Company, Valor and
Promptus as at November 30, 1996 shall satisfy the requirement set forth in
this Subsection 2.02(b) in respect of all Revolving Loans requested by the
Company during the period commencing on December 16, 1996 and ending on January
10, 1997; and


    5.   Subsection 3.01(g) of the Credit Agreement is amended by deleting
therefrom the date "December 31, 1994" where it appears in the second line of
such subsection and by substituting in lieu thereof the date "December 31,
1995".

    6.   Subsection 3.01(h) of the Credit Agreement is amended by deleting
therefrom the phrase "the Seventh Amendment" where it appears in the third line
of such subsection and by substituting in lieu thereof the phrase "the Ninth
Amendment".

    7.   Subsection 4.01(a) of the Credit Agreement is amended by the addition
thereto of a new Subsection 4.01(a)(i) to read as follows:

     (i)    Within thirty (30) days after the end of each calendar month, a
copy of the Financial Statement of the Company for such calendar month
Certified by the chief executive officer, the president, the chief financial
officer or the corporate controller of the Company to have been prepared in
accordance with generally accepted accounting principles consistently applied,
except for any inconsistencies explained in such certificate;

    8.   Subsection 4.01(a)(vi) of the Credit Agreement is amended by deleting
therefrom the phrase "Subsections 4.01(a)(ii) and (iv) hereof" where it appears
in the second and third lines of such subsection and by substituting in lieu
thereof the phrase "Subsections 4.01(a)(i), (ii) and (iv) hereof".

    9.   Subsection 4.01(a)(ix) of the Credit Agreement is amended to read as
follows:

     (ix)   Not later than the tenth (10th) day after each of the fifteenth
(15th) day and the last day of each calendar month, but only if Revolving Loans
are then outstanding under the Revolving Loan Facility, statements in form and
detail satisfactory to the Bank showing the aging and adjustment of the
accounts receivable of the Company, Valor and Promptus (and collections
thereon) as at the end of such semimonthly period;

   10.  The first sentence of Subsection 4.01(f) of the Credit Agreement is
amended to read as follows:

The Company will use the Facilities and the proceeds of the Revolving Loans
only for the purposes, and in the manner, specifically set forth in Section
1.07 hereof.

    11.  Subsection 4.01(h) of the Credit Agreement is amended by deleting
therefrom the phrase "Subsection 1.01(a)" where it appears in the sixth line of
such subsection and by substituting in lieu thereof the phrase "Section 1.01".

    12.  Subsection 4.02(g) of the Credit Agreement is amended to read as
follows:

     (g)  Capital Expenditures.  The Company will not, and will not permit any
Subsidiary to, make any expenditures for fixed or capital assets (including,
without limitation, expenditures under capital leases) which would cause the
aggregate of all expenditures for fixed or capital assets made by the Company
and all Subsidiaries (including, without limitation, expenditures under capital
leases) to exceed Ten Million Dollars ($10,000,000.00) during the fiscal year
of the Company ending December 31, 1996, or Five Hundred Thousand Dollars
($500,000.00) during any fiscal year of the Company ending after December 31,
1996.

                                       4
<PAGE>   5




    13.  Subsection 4.02(h) of the Credit Agreement is amended to read as
follows:

     (h)  Tangible Net Worth.  The Company will not permit its consolidated
Tangible Net Worth to be less than:

     (i)  As at the end of the fiscal quarter of the Company ending December
31, 1996, the sum of (A) Thirty-eight Million Dollars ($38,000,000.00), (B)
seventy-five percent (758) of the cumulative consolidated after tax net profits
of the Company for the fiscal quarter of the Company ending December 31, 1996
(without reduction, however, for any consolidated after tax net losses
sustained by the Company for such calendar quarter), and (C) the aggregate
amount of all infusions of equity made on or after October 1, 1996 and on or
prior to December 31, 1996; and


     (ii)  As at the end of any calendar month ending after December 31, 1996,
the sum of (A) Thirty-eight Million Dollars ($38,000,000.00), (B) seventy-five
percent (75%) of the cumulative consolidated after tax net profits of the
Company for the fiscal quarter of the Company ending December 31, 1996, (C)
seventy-five percent (75%) of the cumulative consolidated after tax net profits
of the Company for all calendar months ending after December 31, 1996 and on or
prior to the date of computation (without reduction, however, for consolidated
after tax net losses sustained by the Company for any of such calendar months),
and (D) the aggregate amount of all infusions of equity made on or after
October 1, 1996.

    14.  Subsection 4.02(j) of the Credit Agreement is amended to read as
follows:

     (j)  Net Income.  The Company (I) will not permit its consolidated net
income after taxes for the fiscal quarter of the Company ending December 31,
1996 to be less than One Hundred Thousand Dollars ($100,000.00), (ii) will not
permit its consolidated net income after taxes for any calendar month ending
after December 31, 1996 to be less than One Dollar ($1.00), and (iii) will not
permit its consolidated net income after taxes for the fiscal quarter of the
Company ending March 31, 1997 to be less than Five Hundred Thousand Dollars
($500,000.00).

    15.  Section 4.02 of the Credit Agreement is amended by the addition
thereto of a new Subsection 4.02(m) to read as follows:

Section V.

     (m)  Promptus Net Income.  The Company will not permit the net income
after taxes of Promptus for the fiscal quarter of Promptus ending March 31,
1997 to be less than One Dollar ($1.00).

    16.  The Credit Agreement is amended by deleting therefrom

    17.  The definition of "Bank" set forth in Section 7.01 of the Credit
Agreement is amended to read as follows:

 "Bank" shall mean Union Bank of California, N.A. (successor in interest to
Union Bank), a national banking association.

    18.  The definition of "Banking Day" set forth in Section 7.01 of the
Credit Agreement is amended to read as follows:

"Banking Day" shall mean a day (other than a Saturday or Sunday) on which
commercial banks are open for business in San Diego, California, and "Banking
Days" shall mean two (2) or more such days.

    19.  The definition of "Commitment Fee" set forth in Section 7.01 of the
Credit Agreement is amended to read as follows:

"Commitment Fee" shall have the meaning given to that term in Section 1.06.


                                       5
<PAGE>   6
    20.  The definition of "Facility Account" set forth in Section 7.01 of the
Credit Agreement is amended to read as follows:

"Facility Account" shall have the meaning given to that term in Section 1.08.

    21.  The definition of "Guaranty" set forth in Section 7.01 of the Credit
Agreement is amended by deleting therefrom the phrase "Subsections 1.03(c)(ii)
and (iii)" where it appears in the second line of such definition and by
substituting in lieu thereof the phrase "Subsections 1.10(b) and (c)".

    22.  The definition of "Notice of Revolver Borrowing" set forth in Section
7.01 of the Credit Agreement is amended to read as follows:

"Notice of Revolver Borrowings" shall have the meaning given to that term in
Section 1.02.

    23.  The definition of "Revolver Termination Date" set forth in Section
7.01 of the Credit Agreement is amended to read as follows:

"Revolver Termination Date" shall have the meaning given to that term in
Section 1.01.

    24.  The definition of "Revolving Loan" and "Revolving Loans" set forth in
Section 7.01 of the Credit Agreement is amended to read as follows:

"Revolving Loan" and "Revolving Loans" shall have the meanings given to those
terms in Section 1.01.

    25.  The definition of "Revolving Loan Commitment" set forth in Section
7.01 of the Credit Agreement is amended to read as follows:

"Revolving Loan Commitment" shall have the meaning given to that term in
Section   

    26.  The definition of "Valor" set forth in Section 7.01 of the Credit
Agreement is amended to read as follows:

"Valor" shall have the meaning given to that term in Subsection 1.10(b).

    27.  Section 7.01 of the Credit Agreement is amended by deleting therefrom
the definitions of "Change of Law", "Interest Period", "LIBO Rate" "LIBOR
Revolving Loan" and "LIBOR Revolving Loans", "Notice of Revolver Conversion",
"Notice of Revolver Interest Period Selection", "Reference Rate Revolving Loan"
and "Reference Rate Revolving Loans" and "Yield Rate".

    28.  Section 7.01 of the Credit Agreement is further amended by the
addition thereto of the following definitions in proper alphabetic order:

"Extension Fee" shall have the meaning given to that term in Section 1.05.

"Ninth Amendment" shall mean that certain Ninth Amendment to Credit Agreement
and Note, dated as of______________, 1996, by and between the Company and the
Bank.

"Ninth Amendment Effective Date" shall mean the date on which the Ninth
Amendment becomes effective as provided in Paragraph 33 thereof.

                                       6
<PAGE>   7




    29.  The address of the Bank for purpose of notice set forth in Subsection
8.01(a) of the Credit Agreement is amended to read as follows:

         Union Bank of California, N.A.
         San Diego Regional Office
         530 "B" Street, 4th Floor
         San Diego, California  92101
         Attention; Mr. Richard A. Petrie

The amendment to the Credit Agreement set forth in this Paragraph 29 shall be,
and shall be deemed to be, notice to the Company of the change in the address
of the Bank herein set forth.

   30.  The first sentence of Subsection 8.01(b) of the Credit Agreement is
amended to read as follows:

Each Notice of Revolver Borrowing shall be given by the Company to the Bank's
San Diego Regional Office, located at the address referred to in Subsection
8.01(a) hereof, between 8:30 a.m. and 3:00 p.m., California time, on a Banking
Day.

    31.  Section 8.08 of the Credit Agreement is amended to read as follows:

8.08.     Dispute Resolution.  The Alternative Dispute Resolution Agreement
appended to the Ninth Amendment is incorporated herein and made a part hereof.

    32.  The Credit Agreement is amended by deleting therefrom Exhibits A, C
and D and by substituting in lieu thereof new Exhibits A, C and D in the forms
appended to this Ninth Amendment as Exhibits I, II and III, respectively.

    33.  This Ninth Amendment shall become effective on the date on which the
Bank shall have received the following:

     (a)  This Ninth Amendment, duly executed by the Company;

     (b)  A certificate of the Company's secretary or an assistant secretary,
dated not later than the date of this Ninth Amendment, certifying the following
documents, copies of which shall be attached to or incorporated in such
certificate: (I) resolutions, adopted by the Company's Board of Directors and
continuing in effect, which authorize the execution, delivery and performance
by the Company of this Ninth Amendment and all other documents and instruments
to be executed, delivered and performed by the Company in connection herewith;
and (ii) all other documents evidencing additional corporate action and
governmental or other approvals, if any, necessary for the execution, delivery
and performance by the Company of this Ninth Amendment and all other documents
and instruments to be executed, delivered and performed by the Company in
connection herewith;

     (c)  A certificate of the Company's secretary or an assistant secretary,
dated not later than the date of this Ninth Amendment, certifying the
incumbency and signatures of the officers of the Company authorized to execute,
deliver and perform on behalf of the Company this Ninth Amendment and all other
documents and instruments to be executed, delivered and performed by the
Company in connection herewith;

     (d)  A Security Agreement on the Bank's standard form, dated December 19,
1996 and duly executed by the Company, granting to the Bank a security interest
in the therein described assets of the Company as security for the Obligations
of the Company arising under the Credit Agreement as amended by this Ninth
Amendment and the other Facility Documents;

     (e)  Two (2) Continuing Guaranties, each on the Bank's standard form, each
dated December 19, 1996, one (1) duly executed by each of Valor and Promptus;


                                       7
<PAGE>   8




     (f)  Three (3) Alternative Dispute Resolution Agreements in the form
appended to this Ninth Amendment as Exhibit IV, each dated not later than the
date of this Ninth Amendment, one duly executed by each of the Company, Valor
and Promptus;

     (g)  A certificate of the secretary or an assistant secretary of each of
Valor and Promptus, each dated not later than the date of this Ninth Amendment,
certifying the following documents, copies of which shall be attached to or
incorporated in such certificate: (I) resolutions, adopted by the Board of
Directors of Valor or Promptus, as the case may be, and continuing in effect,
which authorize the execution, delivery and performance by Valor or Promptus,
as the case may be, of such corporation's Continuing Guaranty and Alternative
Dispute Resolution Agreement; and (ii) all other documents evidencing
additional corporate action and governmental or other approvals, if any,
necessary for the execution, delivery and performance by Valor or Promptus, as
the case may be, of such corporation's Continuing Guaranty and Alternative
Dispute Resolution Agreement; together with a certificate of the secretary or
an assistant secretary of each of Valor and Promptus, each dated not later than
the date of this Ninth Amendment, certifying the incumbency and signatures of
the officers of Valor or Promptus, as the case may be, authorized to execute,
deliver and perform on behalf of Valor or Promptus, as the case may be, such
corporation's Continuing Guaranty and Alternative Dispute Resolution Agreement;

     (h)  Evidence that all steps necessary in the opinion of the Bank to
perfect the security interest granted to the Bank by the Security Agreement
referred to in Subparagraph 33(d) of this Ninth Amendment as a first priority
security interest in the assets described therein have been duly taken
(including the filing of all appropriate UCC-2 Financing Statement Change
Forms);

  (i)  The Extension Fee in the amount of Five Thousand Dollars ($5,000.00); and

     (j)  Such other documents and agreements as the Bank may reasonably
request to effectuate the purposes of this Ninth Amendment.

    34.  Except as expressly provided herein, the Credit Agreement is unchanged
and remains in full force and effect.

    35.  This Ninth Amendment shall be governed by and construed in accordance
with the laws of the State of California.


    36.  This Ninth Amendment may be executed in any number of counterparts,
any set of which signed by both parties hereto shall be deemed to constitute a
complete, executed original for all purposes.

         IN WITNESS WHEREOF, the Company and the Bank have caused this Ninth
Amendment to be executed as of the day and year first above written.


<TABLE>
<S>                                                <C>
UNION BANK OF CALIFORNIA,                        GTI CORPORATION
  N.A.

By:      \s\ Richard Petrie                      By:     \s\   Albert J. Hugo-Martinez
         --------------------------                        -----------------------------
Title:   Vice President                          Title:   President and CEO        
         -------------------------                         -------------------------


By:____________________________                    By:___________________________
Title:__________________________                   Title:__________________________

</TABLE>
                                       8
<PAGE>   9
                                   EXHIBIT I
                                  (EXHIBIT A)

                   NOTICE OF REVOLVER BORROWING CONFIRMATION

                                                                          [Date]


Union Bank of California, N.A.
San Diego Regional Office
530 "B" Street, 4th Floor
San Diego, California  92101
Attention:  Mr. Richard A. Petrie

Gentlemen:

    This letter will confirm the Notice of Revolver Borrowing given by GTI
CORPORATION ("Company") to UNION BANK OF CALIFORNIA, N.A. ("Bank") on         ,
199_, pursuant to Section 1.02 of the Credit Agreement and Note, dated as of
December 17, 1992, between the Company and the Bank, as amended (the
"Agreement").  In such notice, the Company requested the Bank to make a
Revolving Loan pursuant to the Agreement and specified as follows:

         (a)  The amount of the requested loan is to be $__________________; and

         (b)  The date of the requested loan is to be _____________________,
199___.

         The Company further confirms to the Bank that, as of the date of this
confirmation, the representations and warranties set forth in Section 3.01 of
the Agreement are true and correct, no Event of Default or Unmatured Event of
Default has occurred and is continuing, and each of the Facility Documents
remains in full force and effect.

Very truly yours,

GTI CORPORATION




By_______________________________
Title:___________________________





                                       9