Behringer ADA-8000 owners: PLEASE READ!!!

[electric]

Just had an ada8000 tranny blow out on me today and I happened to stumble on this thread.

I honestly would rather NOT have phantom power on the unit after servicing it. (I was thinking about disabling mine before the unit broke).

Is there a cheaper transformer out there that could replace the stock behringer tranny if you arent concerned about a secondary for phantom power?

I am not familiar enough with transformers to properly sort through all the various types at a site like Digikey.

In the case there is not a cheap replacement does anybody know the part# of the behringer replacement xformer and where the cheapest place to source is?

Regards,
Electric

 

[drtester]

Hey Guys,

Came across this thread just tonight... I've done a few different mods to ADA8000s, including fixing the gain jumping.

The transformer is the bad part, as everyone here has mentioned.  But there's something else that hasn't been discussed: the sucker appears to be close (if not in) to saturation under _normal conditions_!

Have a look at the winding that provides the 5V regulator input.  You'll see a rather nasty waveform.  The normal "AC" voltage you see from this winding is round 12v in-circuit, but pull the plug off the circuit board, and measure it again.. MUCH higher!  I think the windings were for much lighter-duty.

Definitely, a better transformer would fix this, although a better solution would be an external DC power supply.

 

[wingsurfer]

OK - looks like I'm not the only one with a dead transformer. The problem is I just replaced it (+ couple of regs) with a behringer replacement and its just fried. Stupid me didnt check any voltages in the 2 minutes it worked. So now I've wasted hard earned cash on a transformer that's only good as a paper weight. This was a broken unity I picked up on ebay, so maybe it serves me right, but I was hoping it would be an easy fix.
So anyway, a couple of questions..

1. As I'm not 100% convinced it was wired correctly in the first place (one reg had been bodge-soldered in place). What are the colours/colors of the primary? I'm in the UK and need to run on 240V, so have assumed that the primary is red - black. and the blue is the centre/center tap for 110V - is that right? As I now have 2 transformers with no primary continuity - its hard to tell!

2. I'm loathed to buy a second transformer, as reading this forum is seems they are rubbish anyway. So I'll probably go down the external PSU route. what are the secondary windings / ratings. I'm not too bothered about phantom power.

Thanks for your help!

Cheers
Mike

 

[JLegnon]

Does anyone have pictures of Keiths mod for the ADA8000 power supply ? 

 

[rawl747]

I too have recently suffered a blown transformer in my ada8000.  The primary reads open.  I read in this thread that in the US using the 120 Volt selection, only 1/2 the primary winding is used.  This begs the question of whether the other half of the primary (which it sound like is center tapped) should still be intact. 

If I understand this previous post correctly, the primary must come out to the fuse "switch" base and when the fuse holder is inserted in the 240 Volt position, the center taps are connected to each other creating one winding for the 240 Volt primary winding and the two ends of the complete primary winding are connected to the mains.  When the 120 Volt mode is selected, only 1/2 of the total primary winding is used leaving the other half unused and therefore still intact.

Does this make sense or have I been inhaling too much PCB cleaner?

I hate to replace the transformer or buy a new one of these if the fix could be this easy.

 

[gemini86]

if they're using a dual primary, they should both be wired parallel for 110 operation, check this though. If they were dumb enough to just use one winding, then hooking up the other remaining winding will eventually result in the same failure.

 

[s2udio]

If they were dumb enough to just use one winding,

Indeed they were ?!

I hate to replace the transformer or buy a new one of these if the fix could be this easy.

Buy one ...no other easy fix,
It is an easy job,easy fix
Then contemplate keiths mod.

 

[rawl747]

Well folks, I am very happy to report that this fix did indeed work as I expected!  I moved the red wire from the 240 Volt side of the fuse holder base to the power switch in place of the black wire that originally went to the transformer from the power switch and voila, I was back in business.  Now, I didn't leave it on very long because I need to see if there is a bad cap causing an overload.  The other possible cause may have been a surge from an extremely bad thunder storm that occurred about the time the unit died.  So, it may not have been a bad component that blew the transformer at all.

So, the engineering of my fix is sound despite some comments here: 

The Blue wire which goes to the 120 Volt pin of the fuse holder base goes to the center tap of the transformer primary winding.  The red wire must go to one far end and the black wire to the other far end of the transformer primary winding.  Normally, Putting the fuse holder in the 120 Volt position connects the mains to the 1/2 of the primary winding between the black and the blue wires which energizes just that 1/2 leaving the balance of the primary winding between the blue wire and the red wire unused.  Putting the fuse holder in the 240 Volt position connects the mains to the red wire and black wire of the primary which energizes the entire primary winding. 

When I got continuity between the red and the blue wires even though I had none between the blue and black wires, I knew I was on to a fix.  The 1/2 of the primary winding between the blue wire and the black wire may now be open but there is nothing wrong with the other 1/2 between the red wire and the blue wire.  Glad I live in the good old US of A where the standard power coming out of the wall is 120 Volts.

Now to Keith's Mod...

Rawl

Fired it up and pretty green lights!  Pressed the Phantom Power switch and got a pretty red light.  Merry Christmas.   

 

[s2udio]

The same thing will happen to that half of the winding......so see it as a temp fix.

 

[Rochey]

I have one of these that I purchased from another forum member.
My plan is simple, but it'd be nice to have it verified by some other members!
±15V Torroidal transformer and a separate 5V Transformer.

It looks like the ±15 requirements are low, but the 5V and 3.3V really need some juice.

 

[rawl747]

I agree that the same thing will happen with the other half of the winding if I don't take appropriate action.  This unit did run almost continuously for several years before a very severe T-Storm took it out but no reason to tempt fate twice. 

Keith's mod seems to be the best insurance and I will implement that before I run the unit again.

Meanwhile, for those in the US or other locales where the voltage is 120V there may be an alternative to replacing the transformer.  If you read continuity between the blue and the red wires of your transformers primary you should be able to do as I did.  I wasn't looking forward to purchasing a replacement from Europe!

Cheers,
Rawl 

 

[Autophase]

Hi guys,
I'm going to get one of these in the next few weeks purely because i need a basic 8 analogue out from ADAT (i will not be using the pres, or the input at all for that matter) and for the money this looks fit for purpose.

I'll be hooking it up to the ADAT on my RME HDSPE AIO, so I would assume clocking it to the RME will give a better performance? (feel free to comment)

1:With this in mind are there any mods may (if any) i need to make to improve performance, again i'm only using the output of this unit, so nothing related to the Pre's is needed.
2: what should i look out for on a second hand unit, or should i just buy a new one (the price difference is nominal) and of course geting a new one would ensure i get a later revision.

 

[fznuk]

I recently went and made a new ADA8000 thread without thinking of posting it here as i thought i wouldn't get a reply:

http://www.groupdiy.com/index.php?topic=48287.0

There are some great repair ideas and mods on here but im still wondering if anyone had used a seperate DC power supply that is a switchmode?

I have a boxful of these...and loads of PC SMPS PSU's..... Im not bothered about phantom power (but handy if the option is there...not essential though)

OR is it best to find the transformers and just get the AC voltages needed? - add the better filtering?

What are the 'prefered' AC voltages to run into the unit?

My Transformer isnt blown yet but i expect one of the Regs have shorted since when i replaced the internal fuse it became real hot real quick...and someone mentioned on here that this could be the case?

Sifting through some electronics i have here would be preferable than buying in new.

Cheers 

 

[Andy Peters]

I recently went and made a new ADA8000 thread without thinking of posting it here as i thought i wouldn't get a reply:

http://www.groupdiy.com/index.php?topic=48287.0

There are some great repair ideas and mods on here but im still wondering if anyone had used a seperate DC power supply that is a switchmode?

I have a boxful of these...and loads of PC SMPS PSU's..... Im not bothered about phantom power (but handy if the option is there...not essential though)

A power supply designed for a personal computer may not be the quietest thing on the planet.

OR is it best to find the transformers and just get the AC voltages needed? - add the better filtering?

The ADA8000 has a standard linear-regulator-based AC-to-DC power supply. From the mains and a transformer and rectifiers, it generates a bipolar "analog" supply (I think +/- 15V but it could be +/- 12V or whatever) and a +5V supply for the digital stuff (PLL. clocking), which may or may not be shared with the converters.

The problem with the ADA8000 is that the transformer secondary voltage is kinda high, and as such the regulators tend to run real hot, and the heatsinking is inadequate.

What are the 'prefered' AC voltages to run into the unit?

Whatever is used as the local mains supply, of course.

-a

 

[Sredna]

What are the 'prefered' AC voltages to run into the unit?

The power transformer got three secondaries: dual 15V (CT), 5V and 48V.

As mentioned before in this thread the AC voltages are way too high and therefore causing burned regulators and windings.

If you want to use separate transformers a 2x15V (or18V) and a 6V one (or 9V) would do.
The 48V for phantom power you can get from the 2x18V plus two capacitors or a voltage doubler/tripler.

 

[fznuk]

Fantastic responses guys...thank you

And when i wrote what AC input voltages....I meant recommended outputs.... sorry! (but for reference im in the UK so on 240). And this was answered...thank you

I am going to have a dig around my old circuit boards, box of power supplies etc to see what i can find.....I also have another Behringer unit to repair..a DDX digital mixer....but this one seems a little more complicated...or at least put more time in and build the PSU Dummy load (seems the power connectors are a little hard to get hold of ;( )

I will sometime this week have a bash at the ADA8000 as i would like it working again

 

[fznuk]

Well guys... I went to have a look at finding a suitable transformer but then stumbled upon a random website mentioning the mod for the opamps and that he was going to mod his faulty ADA8000 since the power supply had burnt out. BUT he pointed out that it was down to a shorted ceramic cap (103 - .01ufd) on the 60V AC input from the transformer.

Low and behold on checking this cap, it was indeed shorted!! - I replaced it and so now no more transformer heating!

I must have caught this transformer blowing in time...and probably a good job it blew the rear fuse!

I dont know how much damage the transformer has had and wondering if i should insert a thermal cut-out now just in case?

But all in all, its working and the transformer is cool.

 

[tubestation]

Hello !!!
Thank you very much for the  maybe  livesaving Information.Everybody should  be carefull with the B"..... Stuff!!!!  I had a few naerly burning Units in my Place .The Headphoneamps are also a Source for a Studioburn.These  Ada 8.. Are so cheap that a Transformer change ,Outsourced in a Solid Case ,isn t a Big Deal.I Don t want to be Seen as a paranoid,but behause of These "Timebombs" I Banned  all B...... Out of the Studio.A Good Friend fixes 19" and he has a Mountain  of Burned B .....  lying around..for the 5v rail i Would use a switching powersupply with Some extra C Filtering ,if you already have One,for the Rest  go konventional.
Greatings from Berlin. Lothar
.

 

[s2udio]

The Headphoneamps are also a Source for a Studioburn.

The B...headphone amps are very reliable...........WTF are you doing to them ?
Invest in air conditioning,or dont stack so much stuff in your racks  ;D
Sorry ...just your post seems very misinformational,and pointless.

 

[smallbutfine]

hm, i just have to second s2udio...
I always considered especially the B. headphone amps to be on the reliable und useful side of units that behringer did. There is nothing wrong with them. (If we talk about the same thing....the older ones, don't know it they are still in production)
No point in Behringer bashing against everything they ever did......

Best regards,
Martin.