DBX 160a Power transformer

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Hey guys, just came across this post since I have the same problem with my dbx160a unit. I’ve just ordered the power transformer that was suggested by timtom, however to my embarrassment I have absolutely no experience in fixing up audio equippment.

Could you maybe advise me on how I actually do exchange the old power transformer with the ordered new power transformer? That would be an amazing help. Thank you very much.
 
I had a similar problem with my dbx286s channel strip, and fitted a toroid to solve the problem.

This is the one I used: https://cpc.farnell.com/multicomp/mcta015-18/15va-toroidal-2x18v/dp/FF01539

One thing to note -- ( and apologies if this is already obvious! ) --
If you do fit a bolt to mount the toroid, you must make sure it cannot come into contact with the metal top cover of the unit.
If the metal top cover and the bolt make electrical contact, the bolt and the case will create a single shorted turn through the toroid core ... Not a good idea!!

How close to the top of the case the new transformer comes will depend on the vertical dimension of that transformer -- which may vary between types.
In my case I did not fit the bolt - nor the top mounting washer - but used double sided tape to attach the transformer to the bottom of the case, and a suitably sized pieces of neoprene on top, to ensure that the case top held the transformer firmly, via the neoprene. No chance of a shorted turn.

Couple of other points -- that may not apply to the 160?.

While my 286s performs well, the 'bean counters' at dbx seem to be in control, when it comes to actual construction.....

There is no on/off switch or primary fuse in the AC connection socket. Fusing relies totally on a single thermal fuse fitted directly to the cheap (and noisy!) original mains transformer.... ( Which actually also runs quite hot as well).
When replacing my transformer, I added an internal inline fuse in series with the live connection to the input socket, for my own peace of mind
(Not actually shown in the attached photo - I added it later) .

The replacement transformer also runs quite a lot cooler, and is now virtually silent..

When it came to recommending a channel strip to a friend, I was hesitant to suggest the dbx 286s because of the shortcomings listed above, so I suggested he might like to try the SubZero RS100 instead.... A lot more features, and quite a lot cheaper than the 286s. (About £100 + tax)
Not a well known item it would appear, from a quick internet search? ...

Some details here: https://d1aeri3ty3izns.cloudfront.net/media/60/600722/download_600722.pdf

I suggested he buy from a well known dealer with a return policy - which he did.
He bought it here: SubZero RS100 Recording Channel Strip at Gear4music
I think it could be that this is an exclusive item to that company here in the UK, so I'm not sure how easy it is to find outside the UK?

It performs really quite well - and has a primary fuse also fitted to the AC input IEC socket ... and an on/off switch, (which is perhaps a bit less important? )
 

Attachments

  • dbx.toroid.jpg
    dbx.toroid.jpg
    286.2 KB
Last edited:
I had a similar problem with my dbx286s channel strip, and fitted a toroid to solve the problem.

This is the one I used: https://cpc.farnell.com/multicomp/mcta015-18/15va-toroidal-2x18v/dp/FF01539

One thing to note -- ( and apologies if this is already obvious! ) --
If you do fit a bolt to mount the toroid, you must make sure it cannot come into contact with the metal top cover of the unit.
If the metal top cover and the bolt make electrical contact, the bolt and the case will create a single shorted turn through the toroid core ... Not a good idea!!

How close to the top of the case the new transformer comes will depend on the vertical dimension of that transformer -- which may vary between types.
In my case I did not fit the bolt - nor the top mounting washer - but used double sided tape to attach the transformer to the bottom of the case, and a suitably sized pieces of neoprene on top, to ensure that the case top held the transformer firmly, via the neoprene. No chance of a shorted turn.

Couple of other points -- that may not apply to the 160?.

While my 286s performs well, the 'bean counters' at dbx seem to be in control, when it comes to actual construction.....

There is no on/off switch or primary fuse in the AC connection socket. Fusing relies totally on a single thermal fuse fitted directly to the cheap (and noisy!) original mains transformer.... ( Which actually also runs quite hot as well).
When replacing my transformer, I added an internal inline fuse in series with the live connection to the input socket, for my own peace of mind
(Not actually shown in the attached photo - I added it later) .

The replacement transformer also runs quite a lot cooler, and is now virtually silent..

When it came to recommending a channel strip to a friend, I was hesitant to suggest the dbx 286s because of the shortcomings listed above, so I suggested he might like to try the SubZero RS100 instead.... A lot more features, and quite a lot cheaper than the 286s. (About £100 + tax)
Not a well known item it would appear, from a quick internet search? ...

Some details here: https://d1aeri3ty3izns.cloudfront.net/media/60/600722/download_600722.pdf

I suggested he buy from a well known dealer with a return policy - which he did.
He bought it here: SubZero RS100 Recording Channel Strip at Gear4music
I think it could be that this is an exclusive item to that company here in the UK, so I'm not sure how easy it is to find outside the UK?

It performs really quite well - and has a primary fuse also fitted to the AC input IEC socket ... and an on/off switch, (which is perhaps a bit less important? )
Thank you very much for the tip with the bolt, I was not aware of that (completely new to all of this unfortunately). Are there any other points I need to keep in mind for repairing the power transformer with the toroid?
 
Are there any other points I need to keep in mind for repairing the power transformer with the toroid?

As you have some doubts on how to do this and as you are not experience in this kind of repair my best advise is to not do it by yourself. Get a friend or someone with electronics knowledge to help you out, then you are sure that it's done well and with safety and you can also learn with that more experienced person.
It's the best advise I can give
 
Thank you very much for the tip with the bolt, I was not aware of that (completely new to all of this unfortunately). Are there any other points I need to keep in mind for repairing the power transformer with the toroid?
Firstly - excellent advice from Whoops in the post above. If you're not experienced with this kind of electronic repair, then working on the most dangerous part of the unit is not a really a good place to start learning. Get the connections wrong, and it will either go bang - or kill you!

You will need to make sure you understand all the transformer winding terminations, and if the primary has a dual winding, ensure you identify the correct pair to be joined to allow the primary to be connected in series. Don't forget to insulate the linked - but unterminated - centre tap pair.
Again with the secondary windings, ensure that the centre tap connections are of the right polarity (the 0v of one winding is joined to the 18v terminal of the other, to provide the centre tapped connection).

If you are still confident in attempting this modification, then I would strongly advise adding an inline fuse in series with the primary winding to the transformer.
Use a 'slo blo' (delay) type, and try a 100mA first. If the magnetising current is too high, you may need to up that to 250mA if the lower value fuse blows on power up.

If any of this doesn't make any sense to you, then I think you should follow Whoops advice and seek professional help.
As I mentioned above, working on this part of the unit is potentially lethal if you have no experience with these kinds of modifications..
 
Firstly - excellent advice from Whoops in the post above. If you're not experienced with this kind of electronic repair, then working on the most dangerous part of the unit is not a really a good place to start learning. Get the connections wrong, and it will either go bang - or kill you!

You will need to make sure you understand all the transformer winding terminations, and if the primary has a dual winding, ensure you identify the correct pair to be joined to allow the primary to be connected in series. Don't forget to insulate the linked - but unterminated - centre tap pair.
Again with the secondary windings, ensure that the centre tap connections are of the right polarity (the 0v of one winding is joined to the 18v terminal of the other, to provide the centre tapped connection).

If you are still confident in attempting this modification, then I would strongly advise adding an inline fuse in series with the primary winding to the transformer.
Use a 'slo blo' (delay) type, and try a 100mA first. If the magnetising current is too high, you may need to up that to 250mA if the lower value fuse blows on power up.

If any of this doesn't make any sense to you, then I think you should follow Whoops advice and seek professional help.
As I mentioned above, working on this part of the unit is potentially lethal if you have no experience with these kinds of modifications..
Thank you very much! I will try to find someone who is experienced enough to handle the build in for me.

If you guys know anyone in the Berlin / Germany Area by any chance who could take care of these kind of mods for a fair price, I would be very thankful for any tips. Already bought the Ring Transformer that @timtom suggested. Best Regards!
 
I had a similar problem with my dbx286s channel strip, and fitted a toroid to solve the problem.

This is the one I used: https://cpc.farnell.com/multicomp/mcta015-18/15va-toroidal-2x18v/dp/FF01539

One thing to note -- ( and apologies if this is already obvious! ) --
If you do fit a bolt to mount the toroid, you must make sure it cannot come into contact with the metal top cover of the unit.
If the metal top cover and the bolt make electrical contact, the bolt and the case will create a single shorted turn through the toroid core ... Not a good idea!!

How close to the top of the case the new transformer comes will depend on the vertical dimension of that transformer -- which may vary between types.
In my case I did not fit the bolt - nor the top mounting washer - but used double sided tape to attach the transformer to the bottom of the case, and a suitably sized pieces of neoprene on top, to ensure that the case top held the transformer firmly, via the neoprene. No chance of a shorted turn.

Couple of other points -- that may not apply to the 160?.

While my 286s performs well, the 'bean counters' at dbx seem to be in control, when it comes to actual construction.....

There is no on/off switch or primary fuse in the AC connection socket. Fusing relies totally on a single thermal fuse fitted directly to the cheap (and noisy!) original mains transformer.... ( Which actually also runs quite hot as well).
When replacing my transformer, I added an internal inline fuse in series with the live connection to the input socket, for my own peace of mind
(Not actually shown in the attached photo - I added it later) .

The replacement transformer also runs quite a lot cooler, and is now virtually silent..

When it came to recommending a channel strip to a friend, I was hesitant to suggest the dbx 286s because of the shortcomings listed above, so I suggested he might like to try the SubZero RS100 instead.... A lot more features, and quite a lot cheaper than the 286s. (About £100 + tax)
Not a well known item it would appear, from a quick internet search? ...

Some details here: https://d1aeri3ty3izns.cloudfront.net/media/60/600722/download_600722.pdf

I suggested he buy from a well known dealer with a return policy - which he did.
He bought it here: SubZero RS100 Recording Channel Strip at Gear4music
I think it could be that this is an exclusive item to that company here in the UK, so I'm not sure how easy it is to find outside the UK?

It performs really quite well - and has a primary fuse also fitted to the AC input IEC socket ... and an on/off switch, (which is perhaps a bit less important? )
Sorry if I missed something out but has this transformer came with that foam padding for the top?
 
Sorry if I missed something out but has this transformer came with that foam padding for the top?
Toroidal transformers are normally supplied with a neoprene washer - similar to the one in my photo - in addition to the metal disc washer the mounting bolt passes through. (You can get them separately - OEM toroidal transformer Mounting for 20-100W Ø50mm | eBay )
In my case, using the mounting bolt would have meant it was possible for the bolt head to form a shorted turn with the case lid, so I decided to fix the transformer with double sided tape to the base of the case, and not fit the bolt.
I then added both the supplied neoprene washer - and a couple of extra layers of 4mm neoprene cut from a sheet - to ensure the transformer was held firmly in place, once the case top was re-fitted.
The unit runs much cooler - and doesn't hum any more!
 

Latest posts

Back
Top