<PAGE>

                                                                    Exhibit 4.19

                   FIFTH AMENDMENT TO NOTE PURCHASE AGREEMENT
                            AND SENIOR DISCOUNT NOTES

         This Fifth Amendment to Note Purchase Agreement and Senior Discount
Notes dated as of March 25, 2002 (this "Amendment") is by and among Ampex Data
Systems Corporation (the "Issuer"), Ampex Corporation (the "Guarantor"), the
entities identified as "Purchasers" on the signature pages hereto (the
"Purchasers"), and DDJ Capital Management, LLC as agent (the "Holders' Agent")
for the Purchasers and the other holders from time to time of the Senior
Discount Notes (defined below).

         WHEREAS, the Issuer, the Guarantor, the Purchasers and the Holders'
Agent are parties to a certain Note Purchase Agreement dated as of November 6,
2000 (as amended, the "Note Purchase Agreement") with respect to Senior Discount
Notes of the Issuer in the original aggregate face principal amount at June 1,
2001 of $8,919,555.56 (the "Senior Discount Notes"); and

         WHEREAS, the parties have entered into (i) an Amendment to Note
Purchase Agreement and Senior Discount Notes, dated as of May 30, 2001 (the
"First Amendment"), pursuant to which, among other things, the stated maturity
date of the Senior Discount Notes was extended from May 30, 2001 to August 31,
2001, (ii) a Second Amendment to Note Purchase Agreement and Senior Discount
Notes, dated as of August 13, 2001 (the "Second Amendment"), pursuant to which,
among other things, the stated maturity date of the Senior Discount Notes was
extended from August 31, 2001 to October 31, 2001, (iii) a Third Amendment to
Note Purchase Agreement and Senior Discount Notes, dated as of October 26, 2001
(the "Third Amendment"), pursuant to which, among other things, the stated
maturity date of the Senior Discount Notes was extended from October 31, 2001 to
March 31, 2002, and (iv) a Fourth Amendment to Note Purchase Agreement and
Senior Discount Notes, dated as of January 31, 2002 (the "Fourth Amendment"),
pursuant to which, among other things, the restrictions on the ability of the
Issuer and the Guarantor to incur indebtedness and grant liens were amended; and

         WHEREAS, the Issuer and the Guarantor have requested that the
Purchasers and the Holders' Agent agree to further amend the Note Purchase
Agreement and the Senior Discount Notes to, among other things, modify the
payment provisions with respect to the Senior Discount Notes and extend the
final maturity date of the Senior Discount Notes to December 31, 2004; and

         WHEREAS, the Purchasers and the Holders' Agent are willing to amend the
Note Purchase Agreement and the Senior Discount Notes as requested on the terms
and subject to the conditions set forth herein;


                                       1

<PAGE>

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
set forth herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto do hereby agree
as follows:

         1. Capitalized terms used herein without definition shall have the
meanings set forth in the Note Purchase Agreement.

         2. Section 1.1 of the Note Purchase Agreement is hereby amended by
adding the following new terms, and/or amending and restating the following
existing terms:

         "'Asset Sale' means (a) any sale, lease, conveyance or other
           ----------
disposition by the Guarantor or any Restricted Subsidiary (other than to the
Guarantor or a Restricted Subsidiary and other than directors' qualifying
shares) of any assets (including by way of a sale-and-leaseback) other than in
the ordinary course of business or (b) the issuance or sale of Capital Stock
(other than Disqualified Stock) of any Restricted Subsidiary, in the case of
each of (a) and (b), whether in a single transaction or a series of related
transactions, to any Person (other than to the Guarantor or a Restricted
Subsidiary and other than directors' qualifying shares); provided, however, the
following transactions shall not be deemed Asset Sales: (i) the sale of accounts
receivable (or participations therein) by the Guarantor or any Restricted
Subsidiary in connection with any Permitted Receivables Facility; and (ii) the
sale of Capital Stock or Indebtedness or other securities of an Unrestricted
Subsidiary by the Guarantor or any Restricted Subsidiary."

         "`Available Cash Flow' means, with respect to any relevant period:
           -------------------

                  (i) the aggregate amount of royalty payments and license fees
received in cash by the Guarantor and its Subsidiaries under the Royalty
Agreements during such period, plus
                               ----

                  (ii) Net Cash Proceeds received during such period from any
Asset Sale involving any assets of the Guarantor or the Issuer, or any Capital
Stock of the Issuer, during such period, minus
                                         -----

                  (iii) the aggregate amount of scheduled quarterly payments of
interest accrued by the Guarantor on the Hillside Contribution Notes pursuant to
Section 2.3(a) of the Hillside Agreement during such period and actually paid by
the Guarantor during such period or within thirty (30) days following the end of
such period, minus
             -----

                  (iv) the lesser of (x) the minimum amount of principal
payments required to be paid by the Guarantor in respect of the Hillside
Contribution Notes pursuant to Section 2.3(b) of the Hillside Agreement during
such period and actually paid by the Guarantor during such period or within
thirty (30) days following the end of such period, and (y) $750,000, minus
                                                                     -----


                                       2

<PAGE>


                 (v) the minimum amount of principal payments required to be
paid by the Guarantor in respect of the Hillside Contribution Notes pursuant to
Section 2.5(b) of the Hillside Agreement during such period and actually paid by
the Guarantor during such period or within thirty (30) days following the end of
such period (provided that in no event (x) shall the aggregate amount of
payments made in respect of the Hillside Contribution Notes pursuant to Section
2.5(b) of the Hillside Agreement during any fiscal year exceed the lesser of (A)
20% of Net Income of the Ampex Group (as such terms are defined in the Hillside
Agreement) during the prior fiscal year and (B) $1,000,000, and (y) shall any
payments be made in respect of the Hillside Contribution Notes pursuant to
Section 2.5(b) of the Hillside Agreement prior to December 31, 2003), minus
                                                                      -----

                  (vi) mandatory pension payments required to be paid by the
Guarantor during such period that are not funded by Hillside under the Hillside
Agreement and are actually paid by the Guarantor during such period or within
thirty (30) days following the end of such period, minus
                                                   -----

                  (vii) mandatory payments required to be paid by the Guarantor
during such period under employee supplementary pension plans of the Guarantor
or any Subsidiary created prior to 1992 and currently in effect and actually
paid during such period or within thirty (30) days following the end of such
period, minus
        -----

                  (viii) the aggregate amount of withholding, income, property
or other taxes, licenses or fees required to be paid by the Guarantor during
such period in connection with the conduct of the business of the Guarantor or
to maintain its existence and actually paid by the Guarantor during such period
or within thirty (30) days following the end of such period, minus
                                                             -----

                  (ix) the aggregate amount of operating expenses (including,
but not limited to, expenditures incurred in developing, issuing, maintaining
and enforcing patents and collecting royalties but excluding dividends and
distributions to holders of Capital Stock of the Guarantor and payments in
respect of Indebtedness for Borrowed Money not expressly permitted under Section
8.6 hereof) required to be paid by the Guarantor during such period and actually
paid by the Guarantor during such period or within thirty (30) days following
the end of such period, minus
                        -----

                  (x) the aggregate amount of incentive payments to employees
engaged in collecting royalties required to be paid by the Guarantor during such
period and actually paid by the Guarantor during such period or within thirty
days following the end of such period and which in no event shall exceed 3% of
the net royalties received by the Guarantor during such period, minus
                                                                -----

                  (xi) the aggregate amount of payments required to be paid by
the Guarantor in respect of accrued liabilities during such period (including
payments in respect of existing indebtedness but expressly excluding payments in
respect of the Senior Discount Notes, the New 12% Notes and the Hillside
Contribution Notes) and



                                       3

<PAGE>


actually paid by the Guarantor during such period or within thirty days
following the end of such period."

         "`Disqualified Stock' means (a) any preferred stock of any Restricted
           ------------------
Subsidiary, and (b) any Capital Stock which by its terms (or by the terms of any
security into which it is convertible or for which it is exchangeable) or upon
the happening of any event (i) matures or is mandatorily redeemable pursuant to
a sinking fund obligation or otherwise, or (ii) is redeemable at the option of
the holder thereof, in whole or in part, in each case on or prior to the Final
Maturity Date, including without limitation the Guarantor's 8% Noncumulative
Convertible Preferred Stock and 8% Noncumulative Redeemable Preferred Stock
issued effective as of July 2, 1998 outstanding on February 28, 2002, and any
subsequent refinancings thereof, provided, however, that the aggregate
liquidation value of all outstanding securities issued in any such refinancings
shall not exceed the aggregate liquidation value of the Noncumulative Redeemable
Preferred Stock outstanding on July 2, 1998."

         "`Final Maturity Date' means January 5, 2005."
           -------------------

         "`Hillside' means Hillside Capital Incorporated."
           --------

         "`Hillside Agreement' means the Agreement dated as of December 1, 1994
           ------------------
(effective November 22, 1994), as amended through the date hereof, by and among
the Issuer, the Guarantor, Hillside and certain other parties named therein,
which provides, among other things, that if Hillside shall make requested
contributions to certain employee benefit plans of the Guarantor, the Guarantor
shall issue Hillside Contribution Notes to Hillside and the Issuer and other
Subsidiaries of the Guarantor shall guarantee the payment of such Hillside
Contribution Notes."

         "`Hillside Contribution Notes' means the promissory notes required to
           ---------------------------
be issued to Hillside by the Guarantor pursuant to the Hillside Agreement to
evidence required pension contributions made by Hillside in respect of certain
employee benefit plans of the Guarantor.

         "`Mandatory Redemption Date' means any Quarterly Redemption Date or any
           -------------------------
Special Redemption Date."

         "`Net Cash Proceeds' means, with respect to any Asset Sale by any
           -----------------
Person, the aggregate cash or cash equivalent proceeds received by such Person
(including any cash payments received by way of deferred payment pursuant to, or
monetization of, a note or installment receivable or otherwise, but only as and
when received) in connection with such Asset Sale, net of (i) the amount of any
Indebtedness which is required to be repaid by such Person or its Affiliates in
connection with such Asset Sale, plus (ii) all fees, commissions and other
expenses incurred (including without limitation, the fees and expenses of legal
counsel and investment banking, accounting, underwriting and brokerage fees and
expenses) by such Person in connection with such Asset Sale, plus
                                                             ----



                                       4

<PAGE>


(iii) adequate provisions for taxes, including income taxes, attributable to the
Asset Sale or attributable to required prepayments or repayments of Indebtedness
with the proceeds of such Asset Sale, plus (iv) amounts reasonably provided by
the Guarantor or any Restricted Subsidiary of the Guarantor as a reserve against
any liabilities associated with such Asset Sale, including, without limitation,
pension and other post-employment benefit liabilities, liabilities related to
environmental matters and liabilities under any indemnification obligations
associated with such Asset Sale, plus (v) dividends or distributions or other
amounts payable to Persons holding a beneficial interest in the assets sold or
to holders of minority interests in a Restricted Subsidiary or other entity as a
result of such Asset Sale."

         "`New 12% Note Indenture' means the Indenture dated February 28, 2002
           ----------------------
between the Guarantor and the New 12% Note Trustee with respect to the New 12%
Notes."

         "`New 12% Note Security Agreement' means the Collateral Security
           -------------------------------
Agreement dated February 28, 2002 between the Guarantor and the New 12% Note
Trustee, pursuant to which the Guarantor has granted in favor of the New 12%
Note Trustee for the benefit of the holders of the New 12% Notes, a second
priority Lien on the rights of the Guarantor under the Royalty Agreements."

         "`New 12% Note Trustee' means State Street Bank and Trust Company, as
           --------------------
Trustee under the New 12% Note Indenture, together with any successor or
replacement trustee acting in such capacity."

         "`New 12% Notes' means the 12% Senior Secured Notes issued by the
           -------------
Guarantor under the New 12% Note Indenture in the initial aggregate principal
amount of $49,217,300 plus such additional aggregate principal amount of New 12%
Notes as may be issued from time to time in payment of interest on the New 12%
Notes."

         "`Permitted Receivables Facility' means (a) the existing accounts
           ------------------------------
receivable facility established by Congress Financial Corporation in favor of
the Guarantor, the Issuer and certain other Subsidiaries of the Guarantor, as
evidenced and governed by, among other things (i) a Loan and Security Agreement
and a Pledge Agreement, each dated as of May 5, 1994, as amended through the
date hereof, between Ampex Finance Corporation and Congress Financial
Corporation, and (ii) an Inter-Company Loan Agreement among the Guarantor, the
Issuer, certain other Subsidiaries of the Guarantor and Ampex Finance
Corporation, and (b) any new accounts receivable facility entered into by the
Guarantor or any of its Restricted Subsidiaries in connection with any
amendment, modification, restatement, refinancing or replacement of the existing
accounts receivable facility described in clause (a) above, which new accounts
receivable facility shall be in such form and shall contain such terms as shall
be reasonably acceptable to the Holders' Agent; provided that (x) the aggregate
principal amount of the Indebtedness (and/or contingent liabilities) of the
Guarantor and/or the Issuer in connection with the existing or any new
receivables facility shall not exceed $4,000,000



                                       5

<PAGE>

at any one time outstanding, (ii) the final maturity date of such new
receivables facility and any Indebtedness arising thereunder shall be not
earlier than May 31, 2004, (iii) the interest rate payable by the Guarantor and
its Subsidiaries in respect of any Indebtedness incurred under any such new
receivables facility shall not exceed the "Prime Rate" (as publicly announced
from time to time by JPMorgan Chase Bank) plus 3% per annum, and (iv) any Liens
granted to secure the obligations of the Guarantor or the Issuer in respect of
the existing receivables facility or any new receivables facility shall not
extend to the Colorado Facility or to any related Property of the Issuer subject
to the Lien in favor of the Holders' Agent under the Colorado Deed of Trust or
to any of the Guarantor's rights under the Royalty Agreements."

         "`Quarterly Redemption Date' has the meaning set forth in subsection
           -------------------------
2.1(d)(i) hereof."

         "`Reserve' has the meaning set forth in subsection 2.1(b)(iv) hereof."
           -------

         "`Restricted Subsidiary' means each direct or indirect Subsidiary of
           ---------------------
the Guarantor other than an Unrestricted Subsidiary."

         "`Special Redemption Date' has the meaning set forth in subsection
           -----------------------
2.1(d)(ii) hereof."

         "`Unrestricted Subsidiary' means Ampex Holdings Corporation, MicroNet
           -----------------------
Technology, Inc., Ampex Finance Corporation and their direct and indirect
Subsidiaries."

         3. Section 2.1 of the Note Purchase Agreement is hereby amended by
deleting existing Section 2.1 in its entirety and replacing it with the
following new Section 2.1:

         "2.1 Issuance of Senior Discount Notes. The Issuer has authorized the
              ---------------------------------
issuance and sale of its Senior Discount Notes in an aggregate principal amount
at May 31, 2001 of up to $8,919,555.56 pursuant to and in accordance with the
terms of this Agreement. The terms of the Senior Discount Notes shall be as
follows, with such changes thereto, if any, as may be approved in writing by the
Purchasers, the Guarantor and the Issuer:

                  (a) Principal Amount. The Agreement originally contemplated
                      ----------------
         that the Senior Discount Notes would be issued on November 6, 2000 at
         an aggregate Issue Price of $8,000,000 and with an aggregate Accreted
         Value at May 31, 2001 of $8,919,555.56. The Senior Discount Notes were
         actually issued on November 7, 2000 at an aggregate Issue Price of
         $8,000,000, and with an aggregate Accreted Value as of June 1, 2001 of
         $8,919,555.56. As of March 15, 2002, the aggregate outstanding
         principal amount of the Senior Discount Notes (including accrued and
         unpaid interest added to the Accreted Value of the Senior Discount
         Notes in accordance with Section 2.1(b) below and after giving effect
         to


                                       6

<PAGE>


payments of principal and interest received prior to March 15, 2002) totals
$9,378,151.92.

                  (b)      Interest.
                           --------

                           (i) During the period from the original Issue Date of
                  November 7, 2000 through June 1, 2001, no interest accrued on
                  the Senior Discount Notes and, instead, the Senior Discount
                  Notes accreted in value from their original aggregate Issue
                  Price of $8,000,000 to their full Accreted Value of
                  $8,919,55.56.

                           (ii) From June 2, 2001 through March 15, 2002,
                  interest accrued on the full Accreted Value of the Senior
                  Discount Notes (less principal payments received) at the rate
                  of 20% per annum (based on an annual period of twelve 30 day
                  months and compounding on October 31, 2001).

                           (iii) On March 15, 2002, the total amount of accrued
                  and unpaid interest in respect of the Senior Discount Notes
                  through such date was capitalized and added to the full
                  Accreted Value of the Senior Discount Notes.

                           (iv) From and after March 16, 2002, interest shall
                  accrue in respect of the outstanding principal balance of the
                  Senior Discount Notes at the rate of 20% per annum (based on
                  an annual period of twelve 30 day months) and the Issuer and
                  the Guarantor shall cause to be paid to the Holders on the
                  fifteenth day of February, May, August and November of each
                  year (each such date being referred to herein as an Interest
                  Payment Date") an amount equal to the lesser of (x) the
                  aggregate amount of accrued and unpaid interest (excluding
                  interest which has been capitalized and added to the
                  outstanding principal balance of the Senior Discount Notes
                  pursuant to subsection 2.1(b)(iii) above or subsection
                  2.1(b)(v) below) owing in respect of the Senior Discount Notes
                  and (y) 100% of the Available Cash Flow for the fiscal quarter
                  most recently ended prior to such Interest Payment Date (less
                  the amount of any optional interest prepayment made on the
                  Senior Discount Notes during the fiscal quarter most recently
                  ended); provided that the Issuer and the Guarantor may retain
                  an amount equal to 5% of Available Cash Flow for each fiscal
                  quarter to establish a working capital reserve (the "Reserve")
                  until the aggregate amount of such Reserve totals $2,500,000,
                  and thereafter 100% of Available Cash Flow shall continue to
                  be applied to payments of interest and the redemption of the
                  Senior Discount Notes as provided in this Agreement.



                                       7

<PAGE>


                           (v) If, as of any Interest Payment Date, (x) the
                  Available Cash Flow for the fiscal quarter most recently ended
                  prior to such Interest Payment Date less the portion of such
                  Available Cash Flow permitted to be contributed to the Reserve
                  pursuant to subsection 2.1(b)(iv) above is less than (y) the
                  aggregate amount of interest due on such Interest Payment
                  Date, then, on such Interest Payment date, the portion of such
                  aggregate interest payment which is not paid in cash pursuant
                  to subsection 2.1(b)(iv) above shall be capitalized and added
                  to the outstanding principal balance of the Senior Discount
                  Notes.

                  (c) Default Interest. If (i) the Issuer shall fail to redeem
                      ----------------
         any portion of the Senior Discount Notes required to be redeemed on any
         Mandatory Redemption Date or on the Final Maturity Date, or (ii) an
         Event of Default shall have occurred and be continuing and the Senior
         Discount Notes shall have been accelerated pursuant to Sections 9.2(a)
         or 9.2(b), then interest shall accrue on the outstanding principal
         balance of the Senior Discount Notes at the Default Rate from such
         Mandatory Redemption Date or the date of occurrence of such Event of
         Default until all required payments are remitted to the Holders' Agent,
         and shall be due and payable in full immediately upon demand.

                  (d) Mandatory Redemption. The Senior Discount Notes shall be
                          --------------------
         subject to mandatory redemption as follows:

                           (i) on the fifteenth day of February, May, August and
                  November of each year (each such date being referred to herein
                  as a "Quarterly Redemption Date") the Issuer shall be required
                        -------------------------
                  to redeem all or a portion of the Senior Discount Notes by
                  making a scheduled redemption payment in cash equal in amount
                  to the lesser of (x) the aggregate outstanding principal
                  amount of the Senior Discount Notes plus all accrued and
                  unpaid interest through such Quarterly Redemption Date, and
                  (y) 100% of Available Cash Flow for the fiscal quarter most
                  recently ended prior to such Quarterly Redemption Date less
                  the portion of such Available Cash Flow applied to the payment
                  of interest on the Senior Discount Notes pursuant to
                  subsection 2.1(b)(iv) above less the portion of such Available
                  Cash Flow permitted to be contributed to the Reserve pursuant
                  to subsection 2.1(b)(iv) above less the amount of any optional
                  redemption payment made in respect of the Senior Discount
                  Notes during the fiscal quarter most recently ended; and

                           (ii) on the earlier to occur of (x) a Change of
                  Control and (y) an Asset Disposition (the date of occurrence
                  of any such event being hereinafter referred to as a "Special
                                                                        -------
                  Redemption Date"), the Issuer shall be required to redeem all
                  ---------------
                  of the Senior Discount Notes by making a scheduled redemption
                  payment in cash equal in amount to the aggregate



                                       8

<PAGE>

                  outstanding principal amount of the Senior Discount Notes plus
                  all accrued and unpaid interest through such Special
                  Redemption Date.

                  (e) Voluntary Redemption. The Senior Discount Notes may be
                      --------------------
         voluntarily redeemed by the Issuer at any time, in whole or from time
         to time in part, without premium or penalty, in accordance with the
         provisions of Section 6.1 hereof.

                  (f) Final Maturity. Notwithstanding anything to the contrary
                      --------------
         set forth herein, in the event that any Senior Discount Notes shall
         remain outstanding on the Final Maturity Date, the Issuer shall be
         required to make a payment in cash on the Final Maturity Date equal in
         amount to the aggregate outstanding principal amount of the Senior
         Discount Notes plus all accrued and unpaid interest through the Final
         Redemption Date.

                  (g) Payments on the Senior Discount Notes. All payments due in
                      -------------------------------------
         respect of each Senior Discount Note shall be paid to the registered
         Holder of such Senior Discount Note as of the date such payment is due
         in accordance with the payment instructions provided in writing to the
         Issuer by such Holder. The Issuer shall pay the outstanding principal
         balance of each Senior Discount Note and all interest thereon
         (including, if applicable, interest at the Default Rate) in money of
         the United States that at the time of payment is legal tender for
         payment of public and private debts, by wire transfer of immediately
         available funds."

         4. Section 6.1 of the Note Purchase Agreement is hereby amended by
deleting existing Section 6.1 in its entirety and replacing it with the
following new Section 6.1:

         "6.1     Voluntary Redemption.
                  --------------------

                  (a) The Senior Discount Notes will be subject to voluntary
         redemption at any time after the Closing Date, in whole or in part, at
         the option of the Issuer at a price equal to the outstanding principal
         balance of the Senior Discount Notes which are being redeemed, plus
         accrued and unpaid interest thereon through the Designated Voluntary
         Redemption Date. If the Issuer elects to redeem Senior Discount Notes
         pursuant to this Section 6.1, at least 1 business day but not more than
         3 business days before the date that the Issuer elects to redeem the
         Senior Discount Notes (such date being referred to herein as the
         "Designated Voluntary Redemption Date"), the Issuer shall notify the
          ------------------------------------
         Holders' Agent and each Holder of Senior Discount Notes set forth in
         Issuer's books and records in writing that the Issuer elects to
         voluntarily redeem all or a portion of the Senior Discount Notes. Such
         notice shall be irrevocable and shall identify (i) the Designated
         Voluntary Redemption Date and (ii) the principal amount of Senior
         Discount Notes to be redeemed on such Designated Voluntary Redemption
         Date.



                                       9

<PAGE>

                  (b) Once notice of a voluntary redemption of the Senior
         Discount Notes is given to the Holders, the principal amount of Senior
         Discount Notes set forth in such notice shall become due and payable on
         the Designated Voluntary Redemption Date, together with all accrued and
         unpaid interest thereon through the Designated Voluntary Redemption
         Date. If the Issuer fails to redeem the principal amount of Senior
         Discount Notes specified to be redeemed as of any Designated Voluntary
         Redemption Date, interest shall continue to accrue on such principal
         amount of Senior Discount Notes until the Holders of the Senior
         Discount Notes receive full payment of such principal amount, together
         with all accrued and unpaid interest thereon through the date of
         payment."

         5. Section 6.3 of the Note Purchase Agreement is hereby amended by
deleting existing Section 6.3 in its entirety and replacing it with the
following new Section 6.3:

         "6.3 Redemption Payments. On or prior to any Redemption Date, the
              -------------------
Issuer shall segregate money sufficient to pay the principal amount of Senior
Discount Notes to be redeemed on such Redemption Date, together with all accrued
and unpaid interest thereon through such Redemption Date. If the Issuer fails to
redeem the principal amount of Senior Discount Notes to be redeemed on any such
Redemption Date, interest shall continue to accrue on such principal amount of
Senior Discount Notes until the Holders of the Senior Discount Notes receive
full payment of such principal amount, together with all accrued and unpaid
interest thereon through the date of payment."

         6. Sections 6.2, 7.1, 9.1(a), 9.2(a), 9.2(b), 9.6, 10.1(b) and 14.1(a)
of the Note Purchase Agreement are hereby amended by replacing the term
"Accreted Value" with the phrase "outstanding principal balance" everywhere that
such term is used in such Sections of the Agreement.

         7. Section 8.1 of the Note Purchase Agreement is hereby amended by
deleting existing Section 8.1 in its entirety and replacing it with the
following new Section 8.1:

                  "8.1 Borrowing. Create, incur, assume or suffer to exist any
                       ---------
         liability for Indebtedness for Borrowed Money except: (a) the Senior
         Discount Notes; (b) up to $50,000,000 aggregate outstanding principal
         amount of New 12% Notes, plus such additional amount of New 12% Notes
         as may be issued from time to time in payment of interest on the New
         12% Notes; (c) purchase money Indebtedness and Capital Leases; (d)
         Indebtedness of any Restricted Subsidiary to the Guarantor or to any
         other Restricted Subsidiary of the Guarantor and Indebtedness of the
         Guarantor to any Restricted Subsidiary, in each case, incurred in the
         ordinary course of business and consistent with past practices; (e)
         Indebtedness of the Guarantor and its Subsidiaries under any Permitted
         Receivables Facility; (f) Indebtedness of the Guarantor and its
         Subsidiaries in respect of the Letters of Credit listed on Schedule
                                                                    --------
         8.1(f) attached hereto; and (g) Indebtedness of the
         -----



                                       10

<PAGE>


         Guarantor or any Subsidiary to Hillside arising pursuant to the terms
         of the Hillside Agreement and evidenced by Hillside Contribution Notes
         and any guarantees thereof, provided that aggregate outstanding amount
         of all such Indebtedness under the Hillside Agreement, the Hillside
         Contribution Notes and all guarantees thereof shall not exceed (i)
         $7,800,000 at any time prior to December 31, 2002, (ii) $15,000,000 at
         any time prior to December 31, 2003, and (iii) $18,000,000 at any time
         prior to December 31, 2004."

         8. Section 8.2 of the Note Purchase Agreement is hereby amended by
deleting existing Section 8.2 in its entirety and replacing it with the
following new Section 8.2:

                  "8.2 Liens. Create, incur, assume or suffer to exist any Lien
                       -----
         upon any of its Property, whether now owned or hereafter acquired,
         except (i) Permitted Liens, (ii) Liens on the rights of the Guarantor
         under the Royalty Agreements securing the obligations of the Issuer
         under the New 12% Note Indenture and the New 12% Notes pursuant to the
         New 12% Note Security Agreement, provided that such Liens pursuant to
         this clause (ii) shall be junior in priority and subordinate to the
         Liens in favor of the Holders' Agent pursuant to the Guarantor Security
         Agreement, (iii) Liens on the receivables of the Guarantor and its
         Restricted Subsidiaries securing obligations under any Permitted
         Receivables Facility (provided that such liens shall not extend to any
         rights of the Guarantor under the Royalty Agreements), (iv) Liens on
         cash collateral or receivables of the Guarantor and its Subsidiaries
         securing obligations in respect of the Letters of Credit listed on
         Schedule 8.1(f), (v) Liens on assets of the Guarantor or any of its
         ---------------
         Restricted Subsidiaries securing obligations under the Hillside
         Agreement and in respect of the Hillside Contribution Notes (provided
         that (x) the security agreement evidencing such Liens shall be in form
         and substance reasonably acceptable to the Holders' Agent, and (y) such
         Liens shall not extend to (A) the Colorado Facility or any related
         Property of the Issuer subject to the Liens in favor of the Holders'
         Agent under the Colorado Deed of Trust, or (B) the rights of the
         Guarantor under the Royalty Agreements)."

         9. Section 8.6 of the Note Purchase Agreement is hereby amended by
deleting existing Section 8.6 in its entirety and replacing it with the
following new Section 8.6:

                  "8.6 Payments of Indebtedness for Borrowed Money. Make any
                       -------------------------------------------
         payment or prepayment on account of any Indebtedness for Borrowed Money
         other than on the Senior Discount Notes, except that (a) the Guarantor
         may issue additional New 12% Notes in payment of interest on the New
         12% Notes, (b) the Guarantor and its Subsidiaries may make regularly
         scheduled payments of principal and interest (but no prepayments other
         than revolving credit prepayments that may be re-borrowed by the
         Guarantor or a Subsidiary under




                                       11

<PAGE>



         such facility) on account of Indebtedness under any Permitted
         Receivables Facility, (c) the Guarantor and its Subsidiaries make
         payments in respect of drawings made under the Letters of Credit listed
         on Schedule 8.1(f), (d) the Guarantor may make scheduled quarterly
         payments of interest on the dates and in the amounts required to be
         made in respect of the Hillside Contribution Notes pursuant to Section
         2.3(a) of the Hillside Agreement, (e) the Guarantor may make the
         minimum scheduled principal payments (but no prepayments or payments
         out of "Surplus Cash" (as such terms are defined in the Hillside
         Agreement)) required to be made in respect of the Hillside Contribution
         Notes pursuant to Section 2.3(b) of the Hillside Agreement, provided
         that the aggregate amount of such principal payments made during any
         period of four consecutive fiscal quarters shall not exceed $750,000,
         (f) the Guarantor may make the minimum principal payments (but no
         prepayments or payments out of "Surplus Cash" (as such terms are
         defined in the Hillside Agreement)) required to be made in respect of
         the Hillside Contribution Notes pursuant to Section 2.5(b) of the
         Hillside Agreement, provided that (x) the aggregate amount of such
         principal payments made during any fiscal year shall not exceed the
         lesser of (A) 20% of Net Income of the Ampex Group (as such terms are
         defined in the Hillside Agreement) during the prior fiscal year, and
         (B) $1,000,000, and (y) no such principal payments shall be made prior
         to December 31, 2003, (g) the Guarantor and its Subsidiaries may make
         regularly scheduled payments of principal and interest (but no
         prepayments) on account of Indebtedness permitted under Section 8.1
         above (excluding the New 12% Notes, the Hillside Contribution Notes and
         Indebtedness under the Permitted Receivables Facility), and (h) the
         Guarantor and its Subsidiaries may make payments of principal and
         interest on account of intercompany Indebtedness owing from (i) the
         Guarantor to any of its Restricted Subsidiaries, (ii) any of the
         Guarantor's Subsidiaries to the Guarantor, or (iii) any of the
         Guarantor's Subsidiaries to any of the Guarantor's Restricted
         Subsidiaries."

         10. The Note Purchase Agreement is hereby amended by the addition of
new Schedule 8.1(f) in the form attached as Schedule 8.1(f) to this Fifth
    --------------
Amendment.

         11. The Senior Discount Notes are hereby amended to the extent
necessary to cause all of the terms and provisions of the Senior Discount Notes
to comply with the terms and provisions of the Note Purchase Agreement, as
amended by this Fifth Amendment.

         12. The Guarantor hereby acknowledges, confirms, ratifies and agrees
that (i) pursuant to the provisions of Article XIV of the Note Purchase
Agreement, the Guarantor has guaranteed the obligations of the Issuer under the
Note Purchase Agreement and the Senior Discount Notes, (ii) as security for the
obligations of the Issuer and the Guarantor under the Note Purchase Agreement,
the Guarantor has granted to the Holders' Agent for the benefit of the Holders,
pursuant to the Guarantor Security Agreement, a security interest in all of the
right, title and interest now owned or hereafter




                                       12

<PAGE>


acquired by the Guarantor in various royalties, license fees, receivables and
other payments as set forth therein, and (iii) the Note Purchase Agreement and
the Guarantor Security Agreement are presently and, after giving effect to this
Amendment, will continue to be valid and binding obligations of the Guarantor
enforceable in accordance with their respective terms.

         13. This Amendment shall become effective on the date that each of the
following conditions has been fulfilled to the satisfaction of the Holders'
Agent, provided that any or all of the following conditions may be waived, in
whole or in part, by the Holders' Agent in its sole discretion:

                  (a) The Issuer, the Guarantor, the Purchasers and the Holders'
         Agent shall have executed and delivered to the Holders' Agent an
         original of this Amendment;

                  (b) The Issuer and the Guarantor shall have delivered to the
         Holders' Agent, copies of the Hillside Agreement and all amendments
         thereto, which copies shall be certified as being true, correct and
         complete by an Officer of Guarantor;

                  (c) All Indebtedness and other obligations of the Issuer and
         the Guarantor in respect of the SCI Notes, the SCI Loan Agreement, the
         SCI Guarantee Agreement and the SCI Security Agreement (as such terms
         are defined in the Third Amendment) shall have been repaid in full, all
         Liens securing such Indebtedness and other obligations shall have been
         released, and the Issuer and the Guarantor shall have delivered to the
         Holders' Agent, copies of all documents relating to the repayment,
         termination and release of all such notes, Liens and agreements; and

                  (d) The Issuer and the Guarantor shall have executed and
         delivered to the Holders' Agent such additional documents as the
         Holders' Agent may reasonably request, each of which additional
         documents shall be in form and substance reasonably satisfactory to the
         Holders' Agent.

         14. Each of the Issuer and the Guarantor further covenant and agree to
deliver to the Holders' Agent as soon as practicable but in any event no later
than April 30, 2002, an executed copy of the security agreement and all related
documents relating to the Liens granted to Hillside to secure the obligations of
the Guarantor and its Subsidiaries with respect to the Hillside Contribution
Notes, which documents shall be in form and substance reasonably satisfactory to
the Holders' Agent, and shall include a release by Hillside of any right of
Hillside to obtain a Lien on the Colorado Facility. Each of the Issuer and the
Guarantor covenants and agrees that the failure of the Issuer and the Guarantor
to deliver to the Holders' Agent such documentation on or before April 30, 2002,
shall constitute an Event of Default under the Note Purchase Agreement.




                                       13

<PAGE>

         15. Each of the Issuer and the Guarantor acknowledges, represents and
warrants that neither the Issuer nor the Guarantor has any claim, cause of
action, defense, or right of set off against the Purchasers or the Holders'
Agent, and, to the extent that either the Issuer or the Guarantor has any such
rights, each of the Issuer and the Guarantor hereby releases, waives, and
forever discharges the Purchasers and the Holders' Agent (together with their
predecessors, successors and assigns) from each action, cause of action, suit,
debt, defense, right of set off, or other claim whatsoever, in law or in equity,
known or unknown against the Purchasers or the Holders' Agent.

         16. This Amendment may be executed in counterparts, each of which shall
be an original and all of which shall constitute one and the same agreement.

         17. This Amendment shall be governed and construed in accordance with
the laws of The Commonwealth of Massachusetts. If any provision of this
Amendment is in conflict with a statute or rule of the law of The Commonwealth
of Massachusetts, or is otherwise unenforceable for any reason whatsoever, such
provision shall be deemed null and void to the extent of such conflict or
unenforceability, but shall be deemed separable from and shall not invalidate
any other provisions of this Amendment.

         18. This Amendment contains the final, complete, and exclusive
expression of the understandings between the parties regarding the transaction
contemplated by this Amendment.

         IN WITNESS WHEREOF, each of the undersigned parties through their
authorized representatives has executed and delivered this Amendment as an
instrument under seal as of the date set forth above.

                                      "ISSUER"

                                      AMPEX DATA SYSTEMS CORPORATION


                                      By:  /s/ Craig L. McKibben
                                         -----------------------------------
                                           Name:  Craig L. McKibben
                                           Title:       Vice President

                                      "GUARANTOR"

                                      AMPEX CORPORATION


                                      By:  /s/ Craig L. McKibben
                                         -----------------------------------
                                           Name:  Craig L. McKibben
                                           Title:       Vice President




                                       14

<PAGE>

                                "PURCHASERS"

                                B III CAPITAL PARTNERS, L.P.

                                By:  DDJ Capital III, LLC, its General Partner
                                By: DDJ Capital Management, LLC, Manager

                                 By:/s/ David J. Breazzano
                                   --------------------------------------------
                                     Name: David J. Breazzano
                                     Title: Member

                                B III-A CAPITAL PARTNERS, L.P.

                                By:  GP III-A, LLC, its General Partner
                                By: DDJ Capital Management, LLC, Manager

                                 By:/s/ David J. Breazzano
                                   --------------------------------------------
                                     Name: David J. Breazzano
                                     Title: Member

                                State Street Bank & Trust, solely in
                                its capacity as Custodian for
                                General Motors Employees Global
                                Group Pension Trust as directed by
                                DDJ Capital Management, LLC, and not
                                in its individual capacity

                                By:
                                   --------------------------------------------
                                    Name:
                                    Title:

                                "HOLDERS' AGENT"

                                 DDJ Capital Management, LLC, in its capacity as
                                 Agent for the Purchasers and the other holders
                                 from time to time of Senior Discount Notes

                                By:/s/ David J. Breazzano
                                   --------------------------------------------
                                           Name:
                                           Member



                                       15

<PAGE>


                                 Schedule 8.1(f)
                                       to
                             Note Purchase Agreement
                    dated as of November 6, 2000, as amended

                          Outstanding Letters of Credit
                          -----------------------------
<TABLE>
<CAPTION>
----------------------- ----------------------------------------- ------------------- -----------------------
        Issuer                        Beneficiary                    Face Amount         Expiration Date
----------------------- ----------------------------------------- ------------------- -----------------------
<S>                                  <C>                            <C>                      <C>

----------------------- ----------------------------------------- ------------------- -----------------------
     First Union                   Martin/Campus, LLC                $778,680.00               3/03

----------------------- ----------------------------------------- ------------------- -----------------------
     First Union                   Martin/Campus, LLC                $115,697.33               3/03

----------------------- ----------------------------------------- ------------------- -----------------------
     First Union               135 East 57th Street, LLC             $248,672.50              4/02*

----------------------- ----------------------------------------- ------------------- -----------------------
     Wells Fargo                     National Union                  $411,000.00               6/02

----------------------- ----------------------------------------- ------------------- -----------------------
</TABLE>


* This Letter of Credit is in the process of being extended through April of
2003.


                                       16