Fried my UCD 180AD

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Dusting my preamp and something twitched... Maybe a contact wiggled in the XO, not entirely sure, but I now have a very nice producer of 13V DC on one channel.

Anyone blown (and hopefully, repaired) these before? I was under the impression that they were bulletproof having gotten half a decade of quality service from mine. I'm not terribly enthused with the prospect of having to upgrade both modules (cash is tight).
 
Maybe if the OP wants to try fixing it himself he could check for expected 15 or 12 volts at the op amp supply rails, and checking for offset on either side of the coupling caps could be informative, especially if they're the stock electrolytics, which could last a lifetime but maybe they dried out and should be upgraded anyway.

Checking for proper continuity along the input path, including the connectors and cables wouldn't hurt either, the later easily done by swapping with the working channel.

You can desolder the mosfets and check them with an ohmeter for a failed output stage if worst comes to worst but check the simple things first. You stated this occured while cleaning your pre, perhaps internally, so maybe that's the source of your fault. Have you checked to see if there's any offset or short at the pre? Also easily verified by swapping with a working channel.

I'm sure MOER can walk us through the rest if there's anything more harder.
 
Repairing UCD modules

We have a lot of experience with these. Due to the fact that we manufacture our own Class D amplifiers, we have access to quite a selection of low gate charge MOSFETs. Since the UCD modules were introduced there has been much advancement in MOSFET technology.

With UCD amplifiers the biggest pain is when the small epoxy coated board goes bad as one has to remove the epoxy and repair it....time consuming.

I have considered designing a drop in replacement for this board as all UCD modules use the same basic front end. I would do this if enough repairs came our way.

The dead time is adjusted on the mother board with either a trimmer or a fixed resistor.

All the parts on the mother board we keep in stock.

The over current limiters in these UCD modules are NO guarantee that they will protect into a shorted or very low Z load.


Steve Mantz
Zed Audio
805 526 5315
Zed Audio Corporation
 
Dusting my preamp and something twitched... Maybe a contact wiggled in the XO, not entirely sure, but I now have a very nice producer of 13V DC on one channel.

Anyone blown (and hopefully, repaired) these before? I was under the impression that they were bulletproof having gotten half a decade of quality service from mine. I'm not terribly enthused with the prospect of having to upgrade both modules (cash is tight).

For service you can always return the modules to Hypex. Please contact rma (at) hypex (dot) nl.

Repairs by third parties are not supported by Hypex.

In the case we cannot fix the older AD modules we offer you some discount if you buy a new HG modules. This is decided on a case to case basis.

Regards,

Jan-Peter
 
An improved current limiting circuit, making the modules able to work indefinitely into any load impedance, would prevent far more unpleasant things to happen than all that high-end stuff (buffers, fashion op-amps, exotic components).

I managed to add both instantaneous (no delay) current limiting (self oscillating) and long-term true-rms current limiting to my phase-shift oscillating circuit with just a LM319, a couple TL062 and another TL072 and a pair of NAND gates. TL062 used in a non-conventional way can make a poor-man four-quadrant multiplier with <10% error. These parts cost as much as an exotic op-amp, but there is substantial engineering work involved (unlike in replacing a standard part by a exotic one).
 
For service you can always return the modules to Hypex. Please contact rma (at) hypex (dot) nl.

Repairs by third parties are not supported by Hypex.

In the case we cannot fix the older AD modules we offer you some discount if you buy a new HG modules. This is decided on a case to case basis.

Regards,

Jan-Peter

Make sure you have plenty of time on hand. I returned a brand new faulty SMPS board to hypex almost 4 weeks ago and am still waiting.
No music for 4 weeks now.
Not a happy chap.
Perhaps what is even more worrying is there a reliability issue with the Ucd modules?

Ianmac
 
Repairs to all UCD modules

We are able to repair any model of UCD modules. Our turn around time is typically less than 48 hours. If you prefer to spend the freight sending it back to Europe for repair simply adds unnecessary expense.

Steve Mantz
Zed Audio
 
One of my UCD400 modules blew a couple of years ago (and took a speaker with it) and I posted back to Hypex. They repaired it at no cost and returned it in about a month. I don't know if this is typical but I was very impressed. Given the modules are so tiny the postage cost is minimal so I wouldn't worry about that.

Good luck

Simon
 
You've got it all wrong!

Moer has every right to offer repair services for UcD modules. It doesn't take a lot of IQ to realise that he couldn't possibly make a living repairing UcD modules. He isn't duplicating and selling UcD modules! Besides , he isn't doing anything illegal.
Hypex would love to offer their service to their customers but I'm sure they loose no sleep over a few faulty UcD modules repaired by Moer !

I'm sure it helps them as it conserves their 'down time' . They rather spend time making new UcD modules than repair faulty ones. They don't shirk their responsibility but if someone can do it , it should be a good thing for them. Remember that equipment costing thousands of dollars can fail........even the Shuttle at possibly over a billion dollars each has failed many times! And YOU paid for it partly ! Did you complain ?

Moer isn't publishing Hypex designs on the Net even if they have figured out the full circuit diagram. You should be thankful that someone close to home ( for US residents) can fix it .

You can always choose to send it to Hypex. Moer isn't 'forcing' you to accept their services.
If you wrote this after having several :drink: , it still isn't forgiveable.

And using words like "Vulture" to describe people on this forum isn't acceptable AT ALL !

We would be happy to see an apology from you to Moer.
 
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One of my UCD400 modules blew a couple of years ago (and took a speaker with it) and I posted back to Hypex. They repaired it at no cost and returned it in about a month. I don't know if this is typical but I was very impressed. Given the modules are so tiny the postage cost is minimal so I wouldn't worry about that.

Good luck

Simon

What about the speaker?

I'm a bit concerned about all these tales of failed UCD modules, as I'm considering getting some for use with my compression drivers, as the datasheet say they're low noise.
 
UCD module repairs

To the best of my knowledge UCD modules are reliable. Like all gear there are failures.

No we do not make a living repairing stuff, simply a service which we offer.

Yes we do have all parts in stock from small signal transistors, Schottky diodes, various low Qg MOSFETs from IR, Infineon and Fairchild as we use these parts in our own amplifier production. which is class D as well as class B amplifiers.

Regular passives are no issue as our amplifier production is exclusively SMD.

I was given the schematic of the Hypex drive board and as a matter of courtesy to Hypex I will not divulge this to anyone.


Steve Mantz
Zed Audio
 
I am using my UCD400's with the Hypex SMPS400's built as two mono block amps.
There is a protection link via a connection from the LS out +ve on the UCD to the SMPS DC error input.
According to the Hypex data sheets--" In the event of a critical failure occurring in the connected amplifier which may cause damage to the connected loudspeaker the SMPS needs to be switched off rapidly."

In my experience with the first pair of UCD400/SMPS400 I built this protection did work. The activation of the protection was due to a mains related problem with my upstream pre amp which caused a transient voltage on its output which must have overloaded the UCD.
To reset the SMPS it has to be disconnected from the mains supply and left to discharge for a few minutes the powered up again

I have no more info on the UCD or SMPS other than that received from the Hypex data sheets but I hope there is no need to connect protection relays when using the combined Hypex UCD/SMPS. I certainly have faith in the Hypex inbuilt protection.

I have my current UCD400's connected to a pair of rather, in my book, expensive speakers

I appreciate some of the earlier comment may be associated with UCD amps built using conventional power supplies.

Ianmac
 
Now I have my friends DS8.0 on my table. I believe it consists of roughly two UCD180 bridged.

Every now and then one pair of FETs stop modulating completely. Nothing on the gate. The output, of course, drops to zero.
It seems like every now and then output level just decreases to about 1/3 power, not sure what that is because it is hard to measure it on the right time.
I try to leave it on running of a lab PSU and into a 12ohm resistor at a few watts and every now and then I try to look at the scope screen :) But it can work fine for an hour at a time.

Varying voltage to power stage does not change anything it seems. Cold spray anywhere does also not seem to do anything.
What does the tiny black epoxy coated pcb do?
It seems to give out 2 out of phase square waves at about the input frequency???
I used 1Vpp at 20kHz as input. It is easier to compare 20k with 400k pulses than 20Hz with 400kHz PWM :)
 
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