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To place a secure Internet order for the DD740 at $249 plus shipping click the "Buy Now" button below.


You will be taken to PayPal and may also have the option to pay over 6 months with no interest. Our products are also on Amazon and eBay at slightly higher prices.  (eBay because they offer an international shipping program beneficial to our customers outside the US.)

Our money back guarantee: If the DD740 does not solve your lip-sync problem you can return it for a full refund.  When we first introduced our DD340 (and later DD540) we knew our audio delays "would" solve the lip-sync problem but today with so many different video image sizes (1080P, 4k and 8K) broadcasters sometimes transmit audio  that's "already" delayed. When that happens and the audio delay exceeds the video delay in your system there is  NO product that will delay 4K or 8K video to correct lip-sync. But it "seldom" happens so we're making this "guarantee" to insure the DD740 will either work for you and solve your lip-sync problem or you can return it for a refund (within 30 days so you will have plenty of time to be sure.)

For orders outside the continental United States:


Often local value added taxes (V.A.T.) and duties have to be collected upon delivery in your country. Since you must be present to pay those fees it often delays delivery and may require a trip to collect your shipment.

Because of that inconvenience (and often higher cost) we have listed the DD740 on eBay so you can take advantage of eBay's International Delivery Service which prepays all those costs:

Go to eBay and search for Felston DD740.

Total cost is "usually" less and it is far more convenient.


 100% Satisfaction Money Back Guarantee!

In addition to Felston's one year product warranty offers a 30 day money back return privilege for any reason whatsoever.


To place a phone order, call:
9am to 5pm E.S.T. Monday -Friday

Or mail orders to: LipFix Technology, 5206 Pinestraw Road, Columbia, SC  29206


Building upon the proven DD340 and DD540 digital audio delays which came before it the DD740 includes lip-sync correction features no A/V Receiver offers:

  • Four Digital Audio Inputs: 2 Toslink and 2 Coax

  • 680 ms delay at 48 KHz or 340 ms at 96 KHz

  • 36 Presets (9 per input)

  • Numeric Delay Entry

  • Tweaking in 1 ms and 1/3 ms steps

  • On-the-fly adjustment with no image overlay

 For more product information on the Felston DD740
please visit:

Or download the DD740 Owner's Manual below. We have included the manual for Felston's second generation two input model, the DD540, for those who may be considering a pre-owned unit available from our customers upgrading to the third generation DD740.

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