<SUBMISSION>
<ACCESSION-NUMBER>0001144692-11-000003
<TYPE>4/A
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20110414
<FILING-DATE>20110421
<DATE-OF-FILING-DATE-CHANGE>20110421
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>BRONSON STEVEN N
<CIK>0001000383
<STATE-OF-INCORPORATION>FL
<FISCAL-YEAR-END>1231
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4/A
<ACT>34
<FILE-NUMBER>000-30083
<FILM-NUMBER>11774599
</FILING-VALUES>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>QUALSTAR CORP
<CIK>0000758938
<ASSIGNED-SIC>3695
<IRS-NUMBER>953927330
<STATE-OF-INCORPORATION>CA
<FISCAL-YEAR-END>0630
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>3990-B HERITAGE OAK COURT
<CITY>SIMI VALLEY
<STATE>CA
<ZIP>93063
<PHONE>805-583-7744
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>3990-B HERITAGE OAK COURT
<CITY>SIMI VALLEY
<STATE>CA
<ZIP>93063
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>BKF CAPITAL GROUP INC
<CIK>0000009235
<ASSIGNED-SIC>6282
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4/A
<ACT>34
<FILE-NUMBER>000-30083
<FILM-NUMBER>11774600
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>ONE ROCKEFELLER PLAZA
<CITY>NEW YORK
<STATE>NY
<ZIP>10020
<PHONE>2123328400
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>ONE ROCKEFELLER PLAZA
<CITY>NEW YORK
<STATE>NY
<ZIP>10020
</MAIL-ADDRESS>
<FORMER-NAME>
<FORMER-CONFORMED-NAME>BAKER FENTRESS & CO
<DATE-CHANGED>19970829
</FORMER-NAME>
<FORMER-NAME>
<FORMER-CONFORMED-NAME>BAKER FENTRESS & CO ET AL
<DATE-CHANGED>19940714
</FORMER-NAME>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2011-04-14</periodOfReport>

    <dateOfOriginalSubmission>2011-04-19</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000758938</issuerCik>
        <issuerName>QUALSTAR CORP</issuerName>
        <issuerTradingSymbol>QBAK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000009235</rptOwnerCik>
            <rptOwnerName>BKF CAPITAL GROUP INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>225 N.E. MIZNER BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 400</rptOwnerStreet2>
            <rptOwnerCity>BOCA RATON</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33432</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001000383</rptOwnerCik>
            <rptOwnerName>BRONSON STEVEN N</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2011-04-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>179</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1573400</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These shares of Qualstar Corporation common stock were purchased by BKF Capital Group, Inc. in an open market transaction.</footnote>
        <footnote id="F2">BKF Capital Group, Inc. is the owner of 1,515,700 shares of Qualstar Corporation's common stock. Steven N. Bronson as the Chairman and President of BKF Capital Group, Inc. may be deemed a beneficial owner of the shares of Qualstar Corporation held by BKF Captial Group, Inc. Additionally, Mr. Bronson as the sole owner of BA Value Investors, LLC is the beneficial owner of 57,700 shares of Qualstar Corporation's common stock.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Steven N. Brosnon, President</signatureName>
        <signatureDate>2011-04-21</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Steven N. Bronson</signatureName>
        <signatureDate>2011-04-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
