The DD-3T sees the DD-3 augmented with tap tempo functionality while the direct output jack has been moved beside the main output jack to make life easier (it's the little things).
Otherwise, the circuitry is unchanged from the classic DD-3 box. You'll still have 12.5 to 800ms of delay. The Hold function, which allows you to save up to 800ms of audio and effectively loop it, returns, but has been renamed as the Short Loop function. And the DD-3T comes in the trademark Boss metal enclosure with rubber footswitch. And it's the same set-up controls-wise as its predecessor with Mode, Time, Feedback, and Effect knobs controlling the effect.
Like the DD-3T, the DD-8 comes in the usual tough Boss enclosure and rubber footswitch setup. Replacing the DD-7, Boss says the DD-8 is their most advanced compact series delay – and it sure has a whole host of clever features.
For a start, it has 11 modes of delay, most of which are self-explanatory. There is Loop, Analogue, Standard, Tape, Warm, Reverse, +Rv (adds reverb to delayed signal), Shimmer (pitchshifts the delayed signal), Mod (modulation), Warp and GLT.
Now, Warp and GLT are really something different. In Warp mode, hold down the footswitch to create swell as the effect's level and feedback increase. This could be a really expressive feature. The GLT mode messes with your delayed signal to add glitchy, "machine gun" effects, which if you turn the Feedback and Time controls up will give you a more extreme effect.
The DD-8 has stereo inputs and outputs, tap tempo functionality and an onboard looper. An external footswitch can be connected to control the tap tempo and looper, or you could hook up an expression pedal to control the effects other parameters on the fly.
The Boss DD-8 costs £140 street (€159, $175 approx) and is available now. As is the DD-3T, which you can pick up for £122 street (€139, $150 approx).
See Boss for more details.