Review: DPS II TBC

PRELIMINARY EVALUATION OF THE DPS II TBC Dec. 4/91

More thorough reports than this are available on a paid product evaluation basis. These comments are copyright & may not be used in any publication or for advertising without written permission.

*The DPS II is transparent enough to handle SVHS (400 lines). The output picture information looked quite clean.

*The burst & sync signals were the proper shapes & without ringing.

*While I didn't really have time to put this TBC through its paces, I did notice that it did handle certain unstable input signals without hiccuping; something my Hotronics AH91 TBC does not.

*The ability to store 10 different proc amp settings is a very handy feature.

*The hardware proc amp settings on the board do not come very well tuned up & the accuracy of the unity gain settings for software depend on the board being set up properly. I recommend that a competent service technician set the board adjustments in the customer's machine with a waveform & vectorscope, although I see no reason why factory settings should change if set up properly in the first place because the board is only drawing power from the host computer. The board settings for the most part are simple & logical however DPS should include a couple of pages in the operations manual on what each of the adjustments is for & how a service technician can tune it up.

*Once I had tuned up the board I found that the settings didn't drift very much at all. Cold or hot settings were very stable. This is unlike my Hotronics AH91 TBC.

*There was a slight difference in chroma saturation levels between Y/C in & composite in. Y/C in produced lower levels. There appeared to be no adjustment to compensate for this. Luma levels between Y/C & composite in were identical.

*The proc amp software controls on this TBC were very good & had a large range. It would have been very useful if the video (luma) level control could have gone all the way to black as this would have benefited those who were doing cuts editing without a switcher so that they could do a fade to black. Although 7.5 IRE is the official black pedestal level, it is meant as a minimum output for cameras, not TBC's. On unity setting, a TBC should pass the input signal at the same levels. If this TBC hardware & software were both set to give 7.5 IRE output with no input or zero IRE input, then it would be compressing the video signal not passing it as unity. When the software is set at unity (7.5 IRE) I would suggest setting the hardware to pass a zero IRE signal at zero. The software is confusing to the amateur user & the unity setting for IRE should really say zero.

*As the manual mentions, the freeze is only a field & makes no attempt to interpolate the other field so it jitters & is not suitable for recording. It would have been extremely handy to have a proper freeze with choices of field or frame. Although you can freeze in the Newtek Toaster, you can only freeze one shot between the 2 buffers so you can't easily do 2 freezes to A/B roll. To have 2 freezes on the Toaster you have to save the first one to the drive & recall it. Field interpolation in the Toaster to reduce motion blur is also a tedious task.

*The rewhite balance (color balance) could be very handy for correcting when you forgot to white balance during a shoot. It should be labeled white balance (not color balance) so users don't confuse it with hue (tint). Notice how they didn't spell "colour" the Canadian way. They know where their market is. It's about time that a TBC manufacturer finally came out with a rewhite balance. When I suggested this feature a couple of years ago, the engineers at DPS looked at me as though I was crazy & asked why you would want that feature. I'm glad they were listening but it would occasionally be nice to get some recognition for being the first one to make a suggestion like that. Maybe more companies will recognize my product evaluation/improvement capabilities & hire me as a consultant. I finally found a tape with incorrect white balance & was surprised to find that the color balance control did not completely correct it to the proper white balance but it did help some.

*It's too bad this TBC doesn't have Y/C out. The Toaster doesn't use Y/C but there are lots of other downstream devices that do use Y/C & most recording VCRs work noticeably better with a Y/C input.

*I did not see a Y/C alignment adjustment. This could be handy when processing 2nd or 3rd generation tapes.

*I have adapted my 3000 to use the Toaster & it works just fine. However, the computer would not even turn on with both the DPS II board & the Toaster installed. It would work with either one individually. I suppose that's because the power supply of the 3000 isn't strong enough. Tests conducted on the Kitchen Sync TBC from Digital Creations a month later showed that their unit did successfully coexist with the Toaster in a 3000. Hopefully both will be able to co-exist in the 3000 Tower. With 2.0 Toaster software the Super Denise chip of the 3000 will work.

*When the source VCR fast forward scans, the picture is very stable and retains its color.

*SVHS input jack was a bit intermittent (touchy).

*When using control software you must adjust your computer serial settings to match what the TBC board is using. Maybe DPS II software should offer you serial preferences when opening up.

*I quite frankly thought I might see some major compromises in quality because of the low price. I was pleasantly surprised to find that this unit was quite a solid TBC in keeping with the better than average standards that Digital Processing Systems has set for the rest of the TBCs in its product line up. Rather than cut quality, they have kept the features to a minimum. It wouldn't surprise me to see them introduce a more full featured TBC on a card in the near future. Features such as Y/C out, drop out compensation without the need of an RF input, Y/C alignment adjustment, chroma noise reduction, Faroudja rise time enhancement, more outputs without having to double up on connectors, freeze frame & field, 3.58 feedback, etc. would be welcome additions.

Yours truly,

Doug Hembruff