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Velodyne ULD-15 Demise....


Limberpine
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I picked up a used ULD-15 from an estate sale for a song, then had it reformed and it was working beautifully for 3 months, then it struck, the dreaded popping that indicates either the servo or the amp is bad, which from what I understand both are nearly impossible to fix due to the lack of parts to fix them. 

 

I could put a plate amp in the side of the box and call it good or I could go with something else. Looking for recommendations. 

 

I'm running this with Tube pre, phono and power amps on my 1978 Klipsch La Scalas.

 

Thoughts and reccomendations are much appreciated. I'd like to not spend an arm and a leg and I think I'd like to stay with a 15" if I can. 

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18 hours ago, Limberpine said:

had it reformed and it was working beautifully for 3 months, then it struck, the dreaded popping that indicates either the servo or the amp is bad

 

I presume you meant re-foamed. If the cone is off center and the voice coil rubs the magnet or pole piece during play, that can possibly cause a popping noise. I would first check for that.

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1 hour ago, Khornukopia said:

 

I presume you meant re-foamed. If the cone is off center and the voice coil rubs the magnet or pole piece during play, that can possibly cause a popping noise. I would first check for that.

Yes, I did mean re-foamed. I will check that. 

 

Thanks! 

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8 hours ago, Khornukopia said:

I would take a paper cup that fits over the dust cap where it joins the woofer cone, and gently press down and release, to feel if the voice coil rubs. Unplug the power cord, so the servo circuit doesn't resist you.

Okay, so I did that and if you push it down fairly far, you can hear some rubbing. But it seems like I have to push it down to the point where it is almost fully stretching out the surround. Just lightly pushing it up and down I don't hear any rubbing.

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29 minutes ago, Limberpine said:

Okay, so I did that and if you push it down fairly far, you can hear some rubbing.

 

Watch the subwoofer cone while playing some music and see if that is suspect. Any contact during play will usually make a popping noise. Next step in the process of elimination, you can bypass the built in amp and wire connect any other amp directly to the sub driver. 

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1 minute ago, Khornukopia said:

 

Watch the subwoofer cone while playing some music and see if that is suspect. Any contact during play will usually make a popping noise. Next step in the process of elimination, you can bypass the built in amp and wire connect any other amp directly to the sub driver. 

Will do.

 

The amp isn't built in though and I'm told to bypass it on this sub, it takes some doing. 

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6 hours ago, Khornukopia said:

I have not read this yet, Vintage Velodyne ULD-15 Subwoofer Problem! | Audiokarma Home Audio Stereo Discussion Forums  but maybe there is some info that can help you.

 

It appears as though he posted the in this thread over a week ago:

 

"Reviving a bit of an old thread here, but I'm having some intermittent popping like in the video. Called a local company and they said it would be $100 just to check it out, but if it needs to be fixed, that parts are hard to come by and it just might be done. Essentially slim chance of fixing it. I bought this out of an estate sale for $165 and had the surround re-done for $30, so I'm not too deep in cost into it, but I think it sound amazing in my system, plus the box is nice as well!

With that being said, should it be capuut, has anybody re-purposed the box into another sub? Or should I just give up on the idea of reusing the box with different woofer and components? Just looking for some advice on what's tenable before I go even further. It seems like these were rather good units for how low they go and their ability to produce nice bass. I've looked into possibly building a Tuba folded sub or even a Decware, but wanted to gathers other thoughts on what I might want to do should I have to get rid of the whole Velodyne system."

Thanks!

 
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6 hours ago, Limberpine said:

Will do.

 

The amp isn't built in though and I'm told to bypass it on this sub, it takes some doing. 

I had a Velodyne FSR-15? servo controlled sub but the amp was built in and went out, I installed a BASH 300 plate amp and it worked / sounded better (to me) than the original. Have to cut the servo wire lead off the cone but wasn't that difficult.

 

https://www.parts-express.com/Bash-300S-300W-Digital-Subwoofer-Amplifier-300-750?utm_group={group}&msclkid=fd2577c1a5701cfb78bb178afd09eeec&utm_source=bing&utm_medium=cpc&utm_campaign=Shopping - All Products&utm_term=4583245519259239&utm_content=All Products

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3 hours ago, jjptkd said:

It appears as though he posted ...

 

"Reviving a bit of an old thread here, but I'm having some intermittent popping like in the video.

 

Well then @Limberpine, if your popping noise is similar to the sound in the video on that other thread, I suspect that the voice coil is rubbing. I have heard that noise from woofers that are mis-aligned, or from woofers that have bottomed out and deformed or partly melted the voice coil. 

 

I would still connect the sub driver to another amp and test it for diagnostic purposes, to isolate and verify the problem before buying any new parts.

 

Be aware that the video clip used on that other thread has some deep bass that could drive some amps into clipping and cause severe distortion.

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4 hours ago, jjptkd said:

I had a Velodyne FSR-15? servo controlled sub but the amp was built in and went out, I installed a BASH 300 plate amp and it worked / sounded better (to me) than the original. Have to cut the servo wire lead off the cone but wasn't that difficult.

 

https://www.parts-express.com/Bash-300S-300W-Digital-Subwoofer-Amplifier-300-750?utm_group={group}&msclkid=fd2577c1a5701cfb78bb178afd09eeec&utm_source=bing&utm_medium=cpc&utm_campaign=Shopping - All Products&utm_term=4583245519259239&utm_content=All Products

In this case are you still using the servo? Or bypassing it all together? 

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37 minutes ago, Khornukopia said:

 

Well then @Limberpine, if your popping noise is similar to the sound in the video on that other thread, I suspect that the voice coil is rubbing. I have heard that noise from woofers that are mis-aligned, or from woofers that have bottomed out and deformed or partly melted the voice coil. 

 

I would still connect the sub driver to another amp and test it for diagnostic purposes, to isolate and verify the problem before buying any new parts.

 

Be aware that the video clip used on that other thread has some deep bass that could drive some amps into clipping and cause severe distortion.

So, could I connect it to another amp that has and XLR hookup? Or how does one connect it to another amp? It was my understanding that because of the servo you can't use other amps with it, without somehow bypassing the servo. 

 

Thanks for all of your help so far! 

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I am not familiar with the wiring for your sub, but you want to connect wires from an outboard solid state amp directly to the subwoofer driver (remove driver from the cabinet if needed? ). Unplug the servo circuit wires. For testing purposes, don't worry about the crossover, just play some music, turn it up to listen if the subwoofer makes the same popping sound.  

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47 minutes ago, Limberpine said:

In this case are you still using the servo? Or bypassing it all together? 

The servo tech from what I remember was basically in the the amplifier itself, there was a small microchip looking thing glued to the middle of the cone with wires running to circuit on the amp board. My amp was toast so I just cut the wires off the chip and left the chip stuck to the cone.

 

For testing purposes you would not need to disconnect the chip (assuming it's the same as what was in my sub) just disconnect the woofer inputs from the amp and run wire directly to a separate amp, probably have to be a different input than the stock inputs 

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Ahhhh! We did do that with the guy from the Speaker shop. He just ran alligator clips right to the speaker posts and played music through it without the Velodyne Amp attached and it played for 5 min with no popping. I will do the same, but for longer and see if there is any popping.

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2 hours ago, Khornukopia said:

I usually enjoy fixing things for the fun of it, but if the cost becomes more than the total value, I consider alternatives like this bargain, Klipsch R-12SW Sale - Page 2 - Subwoofers - The Klipsch Audio Community 

 

 

Agreed. The box itself just fits into my room so well doubling as a table, so I may try to find a way to just have a new woofer and amp put into the box and go that route, which bet would be around $250-300, but I could also buy the Klipsch one from Costco this weekend and return it if I dont like it. 

 

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1 hour ago, Limberpine said:

Ahhhh! We did do that with the guy from the Speaker shop. He just ran alligator clips right to the speaker posts and played music through it without the Velodyne Amp attached and it played for 5 min with no popping. I will do the same, but for longer and see if there is any popping.

 

1 hour ago, Limberpine said:

Agreed. The box itself just fits into my room so well doubling as a table, so I may try to find a way to just have a new woofer and amp put into the box ...

 

 

If the woofer driver passes the test, then @jjptkd's suggestion for a Bash amp and also the servo wire disconnect will work good for you.

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4 hours ago, jjptkd said:

The servo tech from what I remember was basically in the the amplifier itself, there was a small microchip looking thing glued to the middle of the cone with wires running to circuit on the amp board. My amp was toast so I just cut the wires off the chip and left the chip stuck to the cone.

 

For testing purposes you would not need to disconnect the chip (assuming it's the same as what was in my sub) just disconnect the woofer inputs from the amp and run wire directly to a separate amp, probably have to be a different input than the stock inputs 

Okay, so you just put a plate amp in the box and bypassed the servo to which you are happy with the sound with the original woofer? 

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