2 x ADA8000, both with broken supplys ,.. should I ??? :-)

[Mister Mahler]

Thanks for the Membership !!!

I have been offered 2 x ADA8000 dirt cheap, both with broken supply, and I consider the offer, simply for replacing the hole supply unit with a new DIY one.

I would however be very thanksfull for your opinion, if there is a big risc that the rest of the unit is damaged as well ?

Thanks for any help !!!!

 

[shabtek]

If used in 120vac land  the power transformer usually burns open.

If thats the case you could feed it proper dc rails to regulators

 

[Mister Mahler]

Thanks for the answer, I am in DK, Europe, we got 240 volts,..

The seller originally had 3 units, the 2 are broken, they did "run hot", or something,...

I would consider to get them, and take the risc, if "in general" its just the supply that dies, without taking the rest down also

(price for the two units around 50 bucks)

 

[Tubetec]

I have an ada8000 noticed the regulators ran very hot on them ,transformer is under speced too I believe.
What I did was ripped out the mic pre's and wired direct to the A/D chips ,I removed the input board completely ,so now it all runs cool and no preamps in there ,so no stress on the components any longer ,+17dbu is required for 0dbfs . Hard to guess exactly what the damage is in them ,I have heard of a few people needing to replace the transformer though

 

[Tubetec]

As far as I can remember there's four rails 15 volts +/- ,5 volts for digital and 48volts phantom

 

[Mister Mahler]

Ok, guess its not worth the chance, I give it a few more days, put it up on GS + KVR also, and if there is still no opinions on the ods that rest of the circuitry is damaged, i will just drop it,..

Thanks again

 

[cyrano]

I've repaired two of those with a complete PSU failure. Both were 230 VAC units. None had any damage to the other parts, just failed regulators.

And I've modded several to prevent this from happening.

There's about 86 VDC on the poor LM317 that regulates the phantom supply. And the rest is equally over voltage. It's all heat damage, especially in tightly racked gear.

My guess is that it's a cheap way to make sure these units even work on something like 90 VAC in 120VAC countries.

The transformer is of good quality and a little weird, in that is asymmetrical on the primary. There's a 110 and a 120 VAC winding. In series, they provide for 230 VAC input. In 110 VAC countries, you can fix the heat problem a bit by cutting the wires and using the 120V in stead of the 110 V.

In 230 VAC countries, just put a well isolated power resistance in series with the primary winding...

 

[Mister Mahler]

Tanks Cyrano !!!

Very  good info, and good  news as well, I will see iff  I can  work something out with the seller

Found a diagram  also,  and got a working unit to compare  with