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Posted

I have a failed Velodyne DD15 sub which (it would seem) has a failed plate amp.  Spare parts are no longer available for this model.

 

Since I don't use any of its inbuilt DSP is it a reasonable plan of action to connect the speaker level input terminals directly to the driver by-passing the large slab of electronics?  [Not sure if the driver is still OK.]  Then use an external amp to do the driving and my DEQX to do the EQ.  I have an unused ME75 power amp rated at 120wpc, but that may not have enough grunt.  But buying an external plate amp of considerable power might make it cost prohibitive with no guarantee of the whole thing sounding any good. 

 

In its original form the sub has servo control and I suspect some hidden low level EQ to give it a flat response prior to the user level DSP EQ,  Sophisticated and expensive at the time.

 

I have low ability and low tolerance of anything like working on electronics, so anything other than simplistic is probably out of the question.  My immediate reaction is to toss it and buy something new or just re-calibrate my remaining sub to take over sole duties.

 

Any ideas?

 

 

Posted
1 hour ago, aechmea said:

is it a reasonable plan of action to connect the speaker level input terminals directly to the driver by-passing the large slab of electronics?  Then use an external amp to do the driving and my DEQX to do the EQ

Yes

 

1 hour ago, aechmea said:

I have an unused ME75 power amp rated at 120wpc, but that may not have enough grunt. 

It won't ... but it will do fine for testing the driver and building some EQ.

 

1 hour ago, aechmea said:

In its original form the sub has servo control

It will be ok to leave this off.

 

1 hour ago, aechmea said:

and I suspect some hidden low level EQ

All subwoofers have this.... whether it is a vent, or a horn, or increasing the LF signal level (or a combination) .... there is something which makes the driver keep playing at the same level as the frequency decreses.

 

You will need to design some EQ of your own....  start by straightening out the response (with something like a linkwitz-transform filter ... or a "low shelf" filter) ... and then add a low pass, and then perhaps a high pass.

  • Like 1
  • 3 weeks later...
Posted
On 03/05/2023 at 9:46 AM, aechmea said:

I have an unused ME75 power amp rated at 120wpc, but that may not have enough grunt.

 

On 03/05/2023 at 11:39 AM, davewantsmoore said:

It won't ... but it will do fine for testing the driver and building some EQ.

but 120W would go close to at least adequate...

Subs are a bit different...but the pro amp running my TD18's died a while ago, and I've made do with my Rotel HT multi channel amp running the TD18s and the PSEs with around 55W RMS per channel and it's sounding fine.

 

Sure, ideally a bigger amp would be preferred, particularly if you're applying EQ...but better a smaller amp than throwing it into landfill!

 

Mike

Posted

Interesting to stumble across this thread. I’ve a Rel R328 that has met a similar fate - seemed to have some but minimal output on the low level connection but no output at all via the high level Rel connection. 

Posted
8 hours ago, almikel said:

but 120W would go close to at least adequate...

Depends on the efficiency of the driver.

 

Your TD18 is up there with as efficient as it gets for a subwoofer driver .... but the driver in question (Velodyne), looks much less so.

Posted
On 03/05/2023 at 11:46 AM, aechmea said:

I have a failed Velodyne DD15 sub which (it would seem) has a failed plate amp.  Spare parts are no longer available for this model.

 

Since I don't use any of its inbuilt DSP is it a reasonable plan of action to connect the speaker level input terminals directly to the driver by-passing the large slab of electronics?  [Not sure if the driver is still OK.]  Then use an external amp to do the driving and my DEQX to do the EQ.  I have an unused ME75 power amp rated at 120wpc, but that may not have enough grunt.  But buying an external plate amp of considerable power might make it cost prohibitive with no guarantee of the whole thing sounding any good. 

 

In its original form the sub has servo control and I suspect some hidden low level EQ to give it a flat response prior to the user level DSP EQ,  Sophisticated and expensive at the time.

 

I have low ability and low tolerance of anything like working on electronics, so anything other than simplistic is probably out of the question.  My immediate reaction is to toss it and buy something new or just re-calibrate my remaining sub to take over sole duties.

 

Any ideas?

 

 

No you won't be able to connect the driver directly to an external amp, without using a inductor in series with the positive lead. This is as a result of what is called back EMF ( Electro Magentic Force ) that will if used without an inductor, likely cause the external amp to fail. In the circumstance I would advise contacting Velodyne for repair or advice: https://www.velodyneacoustics.com/en/repair-and-spare-parts/  

Posted (edited)

@davewantsmoore @almikel Thanks guys.  I still haven't decided; other life is getting in the way.

 

In the interim I have adjusted the volume on the remaining sub to take over duties, but that is suitable for just one XO point (50Hz).  Its "at the seat" response is pretty flat there, whereas at say 80Hz there is a biggish trough.  80Hz +/- is where the failed sub did its thing.

 

@crtexcnndrm99 I don't think that we are alone. 

My second Velodyne wouldn't start after a couple of years saying that it was "too hot"; it hadn't been on!  All electronics replaced as it has a huge cube of surface mounted devices.  Still working, cross fingers.

A few years later my first then decided to drop volume by about 6dB.  Countered by upping the input volume.  Worked for a few more years but now is the dead one.

There are over 10 years old but even so...

One wonders how good the electronics design/build of subs really is.

 

Thanks @stereo coffee.  I have already contacted Velodyne in Aus who contacted the Velodyne parent.  The Germans said that they could look at it, if it was returned to Germany.  Imagine the cost of that.  Cheaper to replace with a new one.  Velodyne Aus agreed.

 

 

Edited by aechmea
  • Like 1
Posted
2 hours ago, aechmea said:

@davewantsmoore @almikel Thanks guys.  I still haven't decided; other life is getting in the way.

 

In the interim I have adjusted the volume on the remaining sub to take over duties, but that is suitable for just one XO point (50Hz).  Its "at the seat" response is pretty flat there, whereas at say 80Hz there is a biggish trough.  80Hz +/- is where the failed sub did its thing.

 

@crtexcnndrm99 I don't think that we are alone. 

My second Velodyne wouldn't start after a couple of years saying that it was "too hot"; it hadn't been on!  All electronics replaced as it has a huge cube of surface mounted devices.  Still working, cross fingers.

A few years later my first then decided to drop volume by about 6dB.  Countered by upping the input volume.  Worked for a few more years but now is the dead one.

There are over 10 years old but even so...

One wonders how good the electronics design/build of subs really is.

 

Thanks @stereo coffee.  I have already contacted Velodyne in Aus who contacted the Velodyne parent.  The Germans said that they could look at it, if it was returned to Germany.  Imagine the cost of that.  Cheaper to replace with a new one.  Velodyne Aus agreed.

 

 

You might be able to send the sub to Velodyne in Australia ,

Astron Electronics

62 Macquarie Street

Liverpool

Phone: 02 9821 2190

 

Who should be able to test and if needed then send the plate amp, or install a new one, rather than sending the whole sub overseas. 

 

 

Posted
On 20/05/2023 at 8:34 AM, davewantsmoore said:

Depends on the efficiency of the driver.

 

Your TD18 is up there with as efficient as it gets for a subwoofer driver .... but the driver in question (Velodyne), looks much less so.

agreed...and in my case I'm certainly not attempting to use my TD18s as subs...in their small enclosures there's no question I'd need loads more power to have them operate as subs.

 

On 20/05/2023 at 8:46 AM, stereo coffee said:

No you won't be able to connect the driver directly to an external amp, without using a inductor in series with the positive lead. This is as a result of what is called back EMF ( Electro Magentic Force ) that will if used without an inductor, likely cause the external amp to fail. In the circumstance I would advise contacting Velodyne for repair or advice: https://www.velodyneacoustics.com/en/repair-and-spare-parts/  

what factor of back EMF will cause the amp to fail?

An inductor in series with the driver will just introduce a 1st order passive low pass filter.

 

Of course back EMF is a real thing - decades ago I ran a dynamo light on my bicycle - manually spinning the dynamo wheel without the circuit connected, and the dynamo wheel ran freely slowing down from internal friction. Connect the circuit/light and manually spinning the dynamo you could feel the back EMF resistance in the dynamo, and it would stop much more quickly.

 

Speaker drivers are essentially motors, but the back EMF they generate won't cause an amp to fail.

Low impedance speaker loads can cause amps to fail (through drawing too much current), as can highly capacitive speaker loads (sending the amp into oscillation).

 

Mike

  • Like 2
Posted
On 20/05/2023 at 8:46 AM, stereo coffee said:

No you won't be able to connect the driver directly to an external amp, without using a inductor in series with the positive lead. This is as a result of what is called back EMF ( Electro Magentic Force ) that will if used without an inductor, likely cause the external amp to fail.

Likely ?

Or "almost certainly never" ?

 

Hint: the later.

 

If I was to say "well, it depends on the amp" ... people would read that and think "oh, so it's possible, so we won't do it then".   Reality:  999 out of 1000 amps will be completely utterly totally fine.

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  • 3 months later...
Posted

Bit of an update on @aechmea's sub. Almost all of the electrolytic caps in the sub are high in ESR, with most not even registering on the ESR meter. I have replaced all the "through hole" caps, but the processor board is nearly all SMD caps.

 

powersupply.jpg.7069b386c3ce7bd1495d1fe7ffebe3bd.jpgamp-module.jpg.ddf4e8529686e880b7caca0eaa75b02d.jpgDD15ProcessorCaps.thumb.jpg.012b0292ff85ff6e65646f049c5511ee.jpg

 

As well as being high in ESR, many of the SMD caps have corroded solder joints due to electrolyte leakage. In at least one case so far, this has completely removed one of the solder pads.

 

corodedcaps.jpg.f395a2b362e3760a3e1863213f918337.jpgC31-C35.jpg.dc2d0b17cc1471beb6e91236e2c3f0a2.jpgC64.jpg.33896d6d28b8f12afa13bccf0cebd84d.jpg

 

Waiting on the SMDs to arrive and then see how it goes..

 

But something to be aware of for anyone chasing one of these (or similar) subs..

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Posted

Considering the cost (~$4500 each at the time but now double that new) these haven't lasted nearly long enough.

Posted
1 hour ago, aechmea said:

Considering the cost (~$4500 each at the time but now double that new) these haven't lasted nearly long enough.

 

You may want to check the other "working " unit for the same issue if they are both the same age

  • Like 1
Posted
11 hours ago, Addicted to music said:

 

You may want to check the other "working " unit for the same issue if they are both the same age

Yes, good point.

 

The other failed early and had the block of electronics replaced entirely.  However that was a while ago now.

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  • 1 month later...
Posted

The aftermath.  Just about every cap was cactus.

 

Sub bought in 2006 and spent entire life in smoke free, pet-free air conditioned environment.  Only ever used at half rat-power.  Seems to be an premature death to me.

 

The tenacity and skill of Bob to get this working again amazes me.

 

20231017_100427.thumb.jpg.2dd94632ae1f99cd4d4e519fb89b6aec.jpg

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Posted
On 29/08/2023 at 8:53 PM, Addicted to music said:

 

You may want to check the other "working " unit for the same issue if they are both the same age

 

I looked up my records.  The other sub was bought in 2010 and had the electronics slab completely replaced in 2013 so is a bit younger.  But maybe it has started its downward slide.

 

Do all subs go like this or is it just this brand or this model?  Dunno.

Posted
2 hours ago, aechmea said:

 

I looked up my records.  The other sub was bought in 2010 and had the electronics slab completely replaced in 2013 so is a bit younger.  But maybe it has started its downward slide.

 

Do all subs go like this or is it just this brand or this model?  Dunno.


 

it’s just the quality components they used,  just because it’s made in Germany or EU doesn’t mean quality, usually the accountant takes over…. Hats off to @bob_m_54 in getting it up and running.

  • Like 1
Posted

My SVS subwoofer amp first failed at around 3 years while it was thankfully still under warranty, second time was just now at 10 years.

 

I'm thinking that our Perth power supply is the problem, regularly shows 253V on the inverter

Posted
20 hours ago, turnthetable said:

I'm thinking that our Perth power supply is the problem, regularly shows 253V on the inverter

apparently this is within the standard...from a random interweb search:

https://electricalconnection.com.au/when-voltage-varies/#:~:text=The new Standard stipulates a nominal 230V%2C and,a reasonable voltage for any remaining 240V appliances.

 

from this site:

"A new power quality Standard, AS61000.3.100, has recently been released that details requirements additional to the existing systems Standard.

The new Standard stipulates a nominal 230V, and the allowable voltage to the customer’s point of supply is, as mentioned, +10% to –6%. However, the preferred operating range is +6% to –2%."

 

And 253V is 10% over 230V.

 

Without having thought about it a lot, it's likely capacitors in the power supply that are close to their DC voltage limit after rectification at AC 230V that are at risk of failing at 253V.

Most components fail from too much current = heat..turn the wick down and there's less heat.

 

Of course manufacturers try to reduce their costs with lesser specced components - which may push boundaries under over voltage conditions 😞

 

Mike

  • 4 weeks later...
Posted
On 29/08/2023 at 4:17 PM, bob_m_54 said:

As well as being high in ESR, many of the SMD caps have corroded solder joints due to electrolyte leakage. In at least one case so far, this has completely removed one of the solder pads.

 

@bob_m_54 I'm curious as to how you went about fixing the missing solder pads - exercise in patience no doubt.

 

Posted
4 minutes ago, lasseo said:

 

@bob_m_54 I'm curious as to how you went about fixing the missing solder pads - exercise in patience no doubt.

 

First up I tried the copper foil glued down method on the completely missing pad, but due to the size of the pads, it wasn't really practical (about 1.5mm X 2.5mm), especially trying to include the trace to extend over the open circuit section. So instead, I soldered fine enameled wire along the cap leads underneath the carrier, to extend them. Then I soldered the extended leads to the PCB traces. I then used a small amount superglue to attach the cap carrier to the board.

 

For the pads that were partially corroded, I cleaned them up and retinned them, and did the same with the leads, soldering them to the traces, extending past the open circuit where the trace met the pad.

 

Where there was enough of the pad left to secure the cap, with extended leads, I didn't bother with the superglue.

 

I should have taken some pics of the different stages of the repair process, but it was getting a bit tedious LOL.

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