Velodyne ULD 18 questions / help

I was under the impression the series 1 amps are the same for the series 1 ULD 15 or 18 and same for series 2
Series 1 have the DIN cable between the amp and sub
Series 2 have an RCA connection from the amp to the sub
This third wire is how the amp interacts with the subs servo control
Both series are 400 watt class D amplifiers

The ULD 12 had the built in amplifier with a separate crossover/servo control

I never changed the frequency crossover in the amp. Its a matter of changing a capacitor on the circuit board in side the amplifier. Its not a plug and play change out but a solder job.

I got rid of mine years ago when Velodyne refused to support the product line anymore. Not many techs want to deal with them because of the servo control. A simple re-foam is not going to work like a conventional driver.

The ULD 18 was one of the best subs ever made for music and so many of them are unusable because Velodyne will no longer service them

Too bad

You are correct about Velodyne tweaking each amp and driver as a set. I do know the main difference between series 1 & 2 are that the series 1 has the DIN style cable from the amp to the sub. The series 2 uses an RCA style connection.

The tweaking Velodyne is referring to would be the amp/subwoofers servo control interaction. You will need to find a tech versed in making these adjustments. Thats where it became to time consuming to find a tech and didn't want to deal with sipping the amp and driver out. So I sold mine.

Velodyne is absolutely no help. They act like they never heard of the ULD series subs and will not support the product at all.
I'm more or less done with anything Velodyne