
                                                                   EXHIBIT 10.21



                            STOCK PURCHASE AGREEMENT

                  AGREEMENT, dated as of November 7, 1997, between Ampex
Corporation, a Delaware corporation (the "Corporation") and Edward J. Bramson,
Chairman and Chief Executive of the Corporation (the "Executive").

                             Preliminary Statement.

                  A. On November 6, 1997, the Board of Directors of the
Corporation authorized the Corporation to sell to the Executive up to 175,000
shares of the Class A Common Stock, par value $0.01 ("Common Stock") of the
Corporation, as an inducement to the Executive to remain as an officer and
director of the Corporation, all on the terms set forth in this Agreement; and

                  B. The Corporation and the Executive are entering into this
Agreement in order to evidence the terms of sale to the Executive, and set forth
the terms and conditions thereof.

                  1. Agreement of Sale. The Corporation hereby agrees to sell to
the Executive up to 175,000 shares (the "Shares") of Common Stock, at a price of
$3.3125 per share, upon and subject to the terms and conditions set forth
hereinbelow.

                  2.  Purchase Procedure and Payment.

                  a.       Purchase Procedure.

                           (i) Subject to the conditions set forth in this
         Agreement, (1) the Executive may purchase the Shares at any time prior
         to November 30, 1997 by the delivery of written notice (the "Purchase
         Notice") to the Corporation, and (2) the Purchase Notice shall specify
         the number of Shares to be purchased and shall contain the following
         representations and warranties of the Executive: (u) the Executive is
         acquiring the Shares for his own account and not with a view to, or
         present intention of, distribution thereof in violation of the
         Securities Act of 1933, as amended, and the rules and regulations
         promulgated from time to time thereunder (the "1933 Act") or any
         applicable state securities laws and will not sell or otherwise
         transfer the Shares unless registered or exempt from registration under
         the 1933 Act and such state laws, (v) the Executive is able to bear the
         economic risks of his investment in the Shares for an indefinite period
         of time, (w) the Executive is familiar with the business, financial or
         other condition, assets, liabilities, properties, operations,
         management and prospects

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         of the Corporation, (x) the Executive has had full access to such
         information concerning the Corporation as he has requested and is
         satisfied that there is no material information concerning the
         Corporation of which he is unaware, (y) the Executive has knowledge,
         skill and experience in business, financial and investment matters so
         as to enable the Executive to understand and evaluate the merits and
         risks of an investment in the Shares and form an investment decision
         with respect thereto and (z) acknowledges that a portion of the Shares
         is subject to repurchase by the Corporation under certain circumstances
         as provided below.

                           (ii) Upon receipt of the Purchase Notice and of the
         payment therefor specified below, the Corporation shall deliver to the
         Executive a certificate or certificates representing the Shares being
         purchased, at the Corporation's sole cost and expense. Unless
         registered under the 1933 Act, such certificate or certificates
         representing the Shares sold to the Executive pursuant to this
         Agreement shall bear the following legend:

         "THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED, AND ACCORDINGLY MAY NOT BE OFFERED, SOLD OR OTHERWISE
         DISPOSED OF IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER
         SUCH ACT EXCEPT PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER SUCH
         ACT."

                  b. Payment. The Executive shall pay for the Shares purchased
pursuant to this Agreement by delivery of (i) cash, or a check in good funds
payable to the Corporation, in an amount equal to twenty percent (20%) of the
purchase price ($115,938), and (ii) a promissory note (the "Note") of the
Executive for the balance, and a related pledge agreement (the "Pledge
Agreement"), in form and substance reasonably satisfactory to counsel to the
Corporation. The Note shall bear interest, payable annually on each October 15
during the term thereof and at maturity, at the Applicable Federal Rate (as
defined in the Internal Revenue Code); shall be due and payable in a single
installment on the fifth anniversary date thereof; shall be secured by a pledge
of all the Shares under the Pledge Agreement; and shall otherwise conform to the
terms specified in the resolutions of the Board of Directors of the Corporation
which authorized the sale.

                  3. Assignment and Release. The Executive may assign and
contribute the Shares purchased by him to a corporation or other entity owned
and controlled solely by him ("Nominee"), subject to the Pledge Agreement. The
Nominee shall execute and deliver a promissory note in substantially the form of
the Note executed by the Executive, and shall assume in writing all the
Executive's obligations under the Pledge Agreement, all in form and substance
satisfactory to counsel to the Corporation. Upon receipt of such Note and
assumption agreement, duly executed by the Nominee, the Executive shall be
released from all personal obligations under the Note and Pledge Agreement
except for any claims which have accrued to the date of assignment.

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                  4. Registration Rights. The Corporation hereby grants to the
Executive or his Nominee (as the case may be) the right to cause the Corporation
to register the Shares purchased hereunder for sale under the 1993 Act, on terms
comparable to those contained in the Registration Rights Agreement, dated as of
February 10, 1995, between the Corporation and Sherborne Investment Corporation,
as currently in effect.

                  5. Repurchase Rights. The Corporation shall have the right to
repurchase from the Executive or his Nominee (as the case may be) up to 87,500
Shares purchased by the Executive pursuant to this Agreement, at $3.3125 per
share, if the Executive shall voluntarily resign as both an officer and a
director of the Corporation or shall be terminated for Cause (as defined below),
prior to the first anniversary of the date of this Agreement, or to repurchase
up to 43,750 such shares, at $3.3125 per share, if the Executive shall so resign
or shall be terminated for Cause on or after the first anniversary of the date
of this Agreement and before the second anniversary of the date of this
Agreement, in either case by delivery to the Executive of written notice of
repurchase within 30 days after the effective date of his resignation or
termination. In the event of any such repurchase, the Corporation shall refund
to the Executive (or his Nominee, as the case may be) the amount of cash paid
for such Shares (including any principal or interest payments on the Note) and
return the Note to the obligor against receipt by the Corporation of the
certificate representing the Shares so repurchased (or an equivalent number of
other shares of Class A Common Stock owned by the Executive or the Nominee) and
a new Note in the appropriate principal amount. The Executive shall take all
actions reasonably required in order to cause his Nominee to comply with the
terms of this paragraph 5. The term "Cause" shall mean conviction of a felony
involving acts injurious to the Corporation.

                  6.       Miscellaneous.

                  a. This Agreement may not be modified or amended unless
evidenced in writing and signed by the Corporation and the Executive.

                  b. All notices under this Agreement shall be mailed
(registered or certified) or delivered by hand or facsimile transmission
addressed, if to the Corporation, to it at 500 Broadway, Redwood City,
California 94063, attention, General Counsel, and, if to the Executive, to him
at his office at 590 Madison Avenue, New York, New York 10022, or at such other
address as may be designated in writing by either of them to the other.

                  c. This Agreement shall be governed by and construed in
accordance with the laws of the State of New York.

                  d. This Agreement shall be binding upon and inure to the
benefit of the heirs, successors and assigns of the parties, subject to the
limitations set forth in paragraph 3.

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                  IN WITNESS WHEREOF the parties have executed this Agreement on
the date first set forth above.

                                            AMPEX CORPORATION


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



                                                /s/Edward J. Bramson
                                               ------------------------
                                               Edward J. Bramson


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                                 PROMISSORY NOTE

$463,750                                                        November 7, 1997


                  FOR VALUE RECEIVED,  THE  UNDERSIGNED,  EDWARD J. BRAMSON (the
"Borrower"),  HEREBY  PROMISES  TO PAY to the  order  of  AMPEX  CORPORATION,  a
Delaware corporation  ("Payee"),  on October 15, 2002, the principal sum of Four
Hundred Sixty Three  Thousand Seven Hundred Fifty Dollars  ($463,750),  together
with interest on the principal  amount hereof from time to time  outstanding  at
the rate of 6.34% per annum.  Accrued  interest on this Note shall be payable on
each  October 15 and on the date of each payment of the  principal  hereof until
this Note is paid in full.

                  The Borrower shall have the right,  at any time, to prepay all
or any part of the outstanding principal amount without premium or penalty.

                  The occurrence of any one of the following shall constitute an
Event of Default hereunder:

                  (e) The Borrower shall default in the payment of the principal
of or accrued interest on this Note when due and such default shall continue for
a period of three (3) days after notice from the holder of this Note;

                  (f) The Borrower shall default in the performance of any other
term of this Note and such default shall  continue for 30 days after notice from
the holder of this Note; or

                  (g) The  Borrower  shall  (i) be  adjudicated  a  bankrupt  or
insolvent;  or file a voluntary petition in bankruptcy;  or (ii) any involuntary
petition in bankruptcy  shall be filed against the Borrower which shall not have
been discharged within 60 days.

                  Upon the  occurrence  of an Event of Default,  and at any time
thereafter while such Event of Default is continuing:

                  (a) the  holder  of this  Note may by  written  notice  to the
Borrower  declare all or any part of the unpaid balance of this Note immediately
due and payable,  whereupon  such unpaid balance or part thereof shall become so
due and payable without presentation, protest or further demand or notice of any
kind, all of which are hereby expressly waived,  and the holder of this Note may
proceed to enforce  payment of such balance or part thereof in such manner as it
may elect; and

                  (b) the holder of this Note may proceed to protect and enforce
its rights by suit in equity,  action at law and/or other  appropriate means and
may exercise any and all rights  afforded a secured  creditor  under the Uniform
Commercial Code,  including without limitation,  enforcement of rights under the
Pledge Agreement referred to below.

                  The Borrower hereby agrees to pay on demand  reasonable  costs
and expenses,  including without limitation reasonable attorneys' fees, incurred
or paid by the holder of this Note in enforcing this Note upon the occurrence of
an Event of Default.


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                  The  Borrower  hereby  waives  presentment,   demand,  notice,
protest  and  other  demands  and  notices  in  connection  with  the  delivery,
acceptance or enforcement of this Note.

                  No delay or omission on the part of the holder of this Note in
exercising any right hereunder shall operate as a waiver of such right or of any
other right under this Note, and a waiver, delay or omission on any one occasion
shall not be  construed  as a bar to or waiver of any such  right on any  future
occasion.

                  This Note is subject to the terms and  conditions set forth in
a Stock Purchase  Agreement,  dated as of November 6, 1997, between the Borrower
and the Payee,  including  without  limitation  provisions  with  respect to the
assignment  and  assumption  of this Note,  and is secured by a pledge  with the
Payee of certain Collateral under the terms of a Pledge Agreement, of even date,
between the Borrower and the Payee.

                  All notices  hereunder shall be deemed to have been given when
delivered in person or, if mailed,  when actually  received by the party to whom
addressed.  Such actual receipt shall be presumed if such notice shall be mailed
by registered or certified mail, addressed to any party at its address set forth
below or at any other address  notified in writing to the other parties  hereto,
and if the sender shall have received back a return receipt.

To the Borrower:                    590 Madison Avenue, 21st Floor
                                    New York, NY  10022

To the Payee:                       500 Broadway
                                    Redwood City, CA  94063
                                    Attention: Chief Financial Officer

                  This Note  shall be  governed  by the laws of the State of New
York.

                  IN WITNESS WHEREOF, the undersigned has executed and delivered
this Note as of the date first above written.



                                            /s/Edward J. Bramson
                                            --------------------
                                            Edward J. Bramson

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PLEDGE AGREEMENT,  dated as of November 7, 1997,  between EDWARD J. BRAMSON,  as
Pledgor, and AMPEX CORPORATION, a Delaware corporation, as Pledgee.

                  The Pledgor is entering into this Pledge Agreement in order to
secure repayment of Pledgor's Promissory Note dated the date hereof (the "Note")
to the  Pledgee in a principal  amount of  $463,750,  representing  indebtedness
incurred by Pledgor in  connection  with its  purchase of 175,000  shares of the
Class A Common Stock, par value $0.01 per share ("Common Stock") of the Pledgee,
pursuant  to a Stock  Purchase  Agreement,  dated  of even  date  herewith  (the
"Purchase Agreement"), between the Pledgor, and the Pledgee.

                  1.  Pledge.  As  collateral  security for the due and punctual
payment of the Note, the Pledgor hereby pledges to the Pledgee 175,000 shares of
Common Stock more fully  identified in Schedule A hereto (the "Pledged  Stock"),
together  with the  proceeds  thereof  and,  except as set forth in  paragraph 2
below,  all cash,  securities or other property  distributed in respect of or in
exchange for the Pledged Stock (collectively,  the "Collateral").  Upon delivery
to the Pledgee,  the Pledged Stock shall be accompanied by executed stock powers
in blank or other  instruments  of transfer  satisfactory  to Pledgee.  Upon the
occurrence of an Event of Default,  the Pledgee shall have the right to have the
Pledged Stock registered in the name of the Pledgee.

                  2.  Voting  Rights;  Dividends.  Unless  and until an Event of
Default under the Note shall have occurred and be continuing,  the Pledgor shall
have all voting and consensual  rights with respect to the Pledged Stock for any
purpose  not  inconsistent  with the  terms of this  Pledge  Agreement;  and the
Pledgor  shall be entitled to receive any cash  dividends on the Pledged  Stock,
but any stock dividends and other  distributions of securities or property on or
in exchange for the Pledged Stock shall become part of the Collateral hereunder.
Upon the occurrence and during the  continuance of an Event of Default under the
Notes, all such rights shall vest solely in the Pledgee.

                  3.  Remedies  upon  Default.  If an Event of Default under the
Note shall have occurred and be continuing,  the Pledgee may exercise all rights
of a secured  creditor  under the Uniform  Commercial  Code,  including  without
limitation  the right to sell, at public or private sale,  the  Collateral.  The
Pledgee shall give the Pledgor thirty (30) business days notice of any intention
to make a sale of the Collateral. The proceeds of sale shall be applied first to
the  payment of all  reasonable  costs and  expenses  incurred by the Pledgee in
collecting  the Note and  enforcing  its  rights  under this  Pledge  Agreement,
second,  to the repayment of the Note, and third, any balance shall be paid over
to the Pledgor.

                  4.  No  Waiver.  No  failure  on the  part of the  Pledgee  to
exercise any right or remedy  hereunder shall operate as a waiver  thereof,  and
all remedies hereunder are cumulative.

                  5. Termination;  Release.  This Agreement shall terminate when
the Note has been fully  paid,  at which time the  Pledgee  shall  reassign  and
deliver  to the  Pledgor  such of the  Collateral  as has not  been  sold by the
Pledgee  pursuant  to  the  terms  hereof,   such  reassignment  to  be  without
representation  or recourse  except that the Pledgee  shall  warrant that it has
made no prior sale,  assignment,  pledge or encumbrance of the Collateral.  Upon
repayment  of any  portion of the  principal  of the Note (in an amount not less
than $1,000),  the Pledgee shall release,  reassign and deliver to the Pledgor a
number of shares of the Pledged  Stock equal to the amount so repaid  divided by
2.65 (the product of $463,750 divided by 175,000 shares).


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                  6. Further  Assurances.  The Pledgor agrees to do such further
acts and  things,  and to  execute  and  deliver  such  additional  conveyances,
assignments and instruments as the Pledgee may reasonably  request in connection
with the  pledge of  Collateral  or in order to better  assure and  confirm  the
Pledgee's rights and remedies hereunder.

                  7. Binding Agreement;  Assignment. This Pledge Agreement shall
be  binding  upon and inure to the  benefit  of the  parties  hereto  and to all
holders of the Note and their successors and assigns,  except that Pledgor shall
not be permitted to further pledge or encumber the Collateral. Any transferee of
any of  the  shares  of  Pledged  Stock  shall  take  subject  to all  Pledgor's
obligations  under this Pledge Agreement until such shares have been released or
this Pledge Agreement terminated as provided in paragraph 5 above.

                  8.  Governing  Law.  This  Agreement  shall  be  construed  in
accordance with and governed by the laws of the State of New York.

                                  [END OF TEXT]


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                  IN WITNESS  WHEREOF  the  parties  have  executed  this Pledge
Agreement as of the day first above written.


                                            /s/Edward J. Bramson
                                            --------------------
                                            Edward J. Bramson


                                            AMPEX CORPORATION



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





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                                   SCHEDULE A


                          Description of Pledged Stock


150,000  shares of Class A Common  Stock,  par value  $0.01 per share,  of Ampex
Corporation  registered  in the name of Edward  J.  Bramson  (Certificate  No. A
6131).


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