Velodyne HGS15 (servo sub) with distortion

howie
Junior Member

Posts: 88

Velodyne HGS15 (servo sub) with distortion Oct 24, 2013 5:20:01 GMT -5

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Post by howie on Oct 24, 2013 5:20:01 GMT -5

Seems to have normal output power but emits a noise that sounds like a ripped paper driver cone. Supposedly the amp has been sent back to Velodyne and they say it's OK. I pulled the driver and found that the insulation was hitting the driver and re-stuck it to the cabinet. Besides the usual + and- connections, there is a 4 wire flat cable (serveo control?) going to the driver that was zip tied to the basket. At the zip ti,e the wire insulation was ripped and bare wires were rubbing together. Manually flexing the driver through the voice coil shows no sign that the coil is rubbing. I fixed everything that I could see on the driver yet the scratchy/ticking sound remains. Perhaps it is cominig from the amp but it sure sounds mechanical to me.

mastertech Global Moderator Posts: 3,538	Velodyne HGS15 (servo sub) with distortion Oct 24, 2013 8:44:25 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by mastertech on Oct 24, 2013 8:44:25 GMT -5 Also check to make sure there is no DC on the speaker wires. Have you tried swapping out the speaker with another that you have even if it's not the same size?
	MT

mastertech
Global Moderator

Posts: 3,538

Velodyne HGS15 (servo sub) with distortion Oct 24, 2013 9:17:55 GMT -5

Quote

Post by mastertech on Oct 24, 2013 9:17:55 GMT -5

From the manual:

"The Velodyne subwoofer is designed to operate using the full range audio signal for input
when using the built-in crossover. Some processors/receivers, have a "subwoofer out" jack
that is internally filtered and designed to be used with a conventional amplifier and speaker.
In some rare cases, combining both an external crossover and the one internal to the
subwoofer may result in low output and increased noise. In these installations you may
need to bypass the internal crossover in either the processor or Velodyne subwoofer. In
some installations, simply setting one crossover to a higher frequency (such as 120 Hz) will
restore maximum performance. To bypass the subwoofer's internal crossover when the
unit is being fed a low pass signal from another crossover, simply locate the switch marked
X-over, OUT - IN
on the rear panel of the subwoofer and set to the
OUT
position. This
will eliminate the internal crossover from the signal path.
Note: If not using an external
crossover, you should use the built-in crossover for optimal performance."

MT

howie
Junior Member

Posts: 88

Velodyne HGS15 (servo sub) with distortion Oct 25, 2013 5:08:24 GMT -5

Quote

Post by howie on Oct 25, 2013 5:08:24 GMT -5

Oct 24, 2013 9:17:55 GMT -5 mastertech said:

From the manual:

"The Velodyne subwoofer is designed to operate using the full range audio signal for input
when using the built-in crossover. Some processors/receivers, have a "subwoofer out" jack
that is internally filtered and designed to be used with a conventional amplifier and speaker.
In some rare cases, combining both an external crossover and the one internal to the
subwoofer may result in low output and increased noise. In these installations you may
need to bypass the internal crossover in either the processor or Velodyne subwoofer. In
some installations, simply setting one crossover to a higher frequency (such as 120 Hz) will
restore maximum performance. To bypass the subwoofer's internal crossover when the
unit is being fed a low pass signal from another crossover, simply locate the switch marked
X-over, OUT - IN
on the rear panel of the subwoofer and set to the
OUT
position. This
will eliminate the internal crossover from the signal path.
Note: If not using an external
crossover, you should use the built-in crossover for optimal performance."

Is this from a owners manual or service manual? I'm trying to figure a way to isolate the sound between the amp and driver. The driver has the typical + and- connections but also a 4 wire ribbon which I think has to do with the servo function. I will probably have to find a place on the amp to probe and listen for the noise I hear from the driver.

mastertech
Global Moderator

Posts: 3,538

Velodyne HGS15 (servo sub) with distortion Oct 25, 2013 18:47:28 GMT -5

Quote

Post by mastertech on Oct 25, 2013 18:47:28 GMT -5

I'm going to post in this thread mostly and can be used to apply to your other thread also. First off it's from the user manual. Now these should have a dual voice coil speaker and also has a servo control that monitors cone movement. So this is why all the wires to the speaker. If possible can you post a picture of the back of the speaker so I can see the wire connections?

There is also a gain control board that affects input signal gain and this can affect the other thread sub problem.

I would also suggest you blow the dust off that ESR meter and start some testing as these subs were known to have some cap problems.

MT

howie
Junior Member

Posts: 88

Velodyne HGS15 (servo sub) with distortion Oct 26, 2013 5:25:57 GMT -5

Quote

Post by howie on Oct 26, 2013 5:25:57 GMT -5

Oct 25, 2013 18:47:28 GMT -5 mastertech said:

I'm going to post in this thread mostly and can be used to apply to your other thread also. First off it's from the user manual. Now these should have a dual voice coil speaker and also has a servo control that monitors cone movement. So this is why all the wires to the speaker. If possible can you post a picture of the back of the speaker so I can see the wire connections?

There is also a gain control board that affects input signal gain and this can affect the other thread sub problem.

I would also suggest you blow the dust off that ESR meter and start some testing as these subs were known to have some cap problems.

There is not much to see The driver has the usual + and - connections. The 4 wire ribbon is glued to the back of the cone. It connects to something on the front side of the cone but behind the voice coil dust cover. This sub is obviously old enough to have bad caps. The very first thing I did was a visual inspection for leakers or swollen caps and saw none. Of course that does not mean that the electrolyte has not evaporated over the years. I also looked for indication of board overheating. I saw no visual hot spots. Hmmm, how did you know I even have a ESR meter? Then you probably already know that I have a home brewed test rig that I can use to probe for sound at various points in the sub to test for sound signal. I have already considered pulling the amp again and test all the electrolytics. My meter claims to be able to test them in circuit but I don't do it that way. I pull them to test them. I test each cap twice. Once at room temp and again warmed up slightly with a heat gun. Many caps can fail a bench test but come back to or close to spec in circuit when they are allowed to naturally warm up in use. This explains why a funky SMPS will continue to run if you manage to get it started. The other thing is I don't usually reinstall a used cap. If I'm going through all the trouble of removing them for testing, I usually install new ones. The only additional expense is the caps which are cheap. I look at it like draining the oil in your engine looking for a problem and reusing the oil. Just ain't gonna happen.

mastertech
Global Moderator

Posts: 3,538

Velodyne HGS15 (servo sub) with distortion Oct 26, 2013 8:41:11 GMT -5

Quote

Post by mastertech on Oct 26, 2013 8:41:11 GMT -5

Well since it is suppose to be a dual voice coil speaker along with cone movement detection your description of wire locations was somewhat confusing. I can't see what you see. And without any schematics I can only help if I have visuals to see. If it is a dual voice coil and it was me, I would first be using a known good speaker and connect it to each line, 1 at a time and see if there is a noise on 1 or both or none. Or take the speaker and connect it to a known good amp, 1 channel to each coil and see if you hear the noise. Of course, this is where you need to know which wires are for which and with no picture, I cannot suggest. But you can probably find them with your ohm meter.

MT

howie
Junior Member

Posts: 88

Velodyne HGS15 (servo sub) with distortion Oct 27, 2013 7:48:30 GMT -5

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Post by howie on Oct 27, 2013 7:48:30 GMT -5

I'm trying to decide which end of this to attack this problem from. I can not use this amp on another driver. The amp hums when the servo ribbon cable is not plugged in. Im not convinced driving it with a non servo amp is the best way to test the driver. I'm going to have to somehow probe the amps output and listen for the noise from two places at the same time. It would be nice if I had a second Velodyne here to swap amps with to see if it follows the amp.
Looking at it from a mechanical view, I could remove the dust cover and gauge the clearance around the voice coil. It looks like centering these is done from both ends and may require stuff I don't have available to me. Velodyne says a new driver is $800.00 and to service the old one is over $300.00

howie Junior Member Posts: 88	Velodyne HGS15 (servo sub) with distortion Nov 3, 2013 7:41:38 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by howie on Nov 3, 2013 7:41:38 GMT -5 I also read in another post that the "pizio chip" in the driver is not a replaceable part. Hmmm, I had another post here just before this one that went M.I.A.
	Last Edit: Nov 3, 2013 7:44:08 GMT -5 by howie

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Velodyne HGS15 (servo sub) with distortion Nov 3, 2013 9:10:57 GMT -5

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Post by Admin on Nov 3, 2013 9:10:57 GMT -5

Nov 3, 2013 7:41:38 GMT -5 howie said:

Hmmm, I had another post here just before this one that went M.I.A.

There is another post just before your last one. Or do you mean something else? I have not deleted any posts.

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