Output transformer for sub-groups outputs

[Sonoman222]

Hi,

I'm french (excuse me for my english...) and I would like to get help because I'm lost ...

My console outputs are unbalanced, and I wish I could find a transformer balanced. There is a empty slot...

Which output transformer to choose?

Thanks 

 

[gyraf]

Do you have the circuit schematic?

This would be helpful in determining a suitable transformer.

Otherwise, I'd try with e.g. a LL5402, hot-glued and wire mounted to the PCB

Jakob E.

 

[Sonoman222]

Yes I have it, it's noted on the schematic "optional transformer" on the left.

http://www.mafiora.com/dynamix_3000_subgroup.pdf

 

[RuudNL]

The output is driven from 470 ohms + 10 uF.
A resistor in series with the primary winding of the transformer will increase distortion.
(Distortion will be lower when driven from a low impedance.)
Personally I would also increase the value of the 10 uF capacitor, of course depending on the transformer you are going to use.
I did not take a look at the datasheet of IC3, but I am afraid that this stage won't have very much 'drive'.
(Unable to drive a high level into a low impedance.)

 

[mjrippe]

Bottom right of parts list says "TRI Sauter 5503*", could that be the transformer part #?  No hits from Google.

 

[RuudNL]

Sauter = Sowter ? ? ? ? ?

 

[andre tchmil]

PM'd

 

[mjrippe]

Sauter = Sowter ? ? ? ? ?

Tried that, no match!

 

[jensenmann]

Not to discourage you, but this desk has other, more essential flaws, than unbalanced outputs.
If you´re determined enough to add a tranny then Gyraf´s way or adding a sub-PCB (perfboard) with your transformer of choice is the best route. I´d not try to hunt down the original iron. The desk has been made on a budged and so I suppose will the original transformers be. OTOH, if you´re looking for oldschool sound with artefacts, then why not....

 

[Sonoman222]

The output is driven from 470 ohms + 10 uF.
A resistor in series with the primary winding of the transformer will increase distortion.
(Distortion will be lower when driven from a low impedance.)
Personally I would also increase the value of the 10 uF capacitor, of course depending on the transformer you are going to use.
I did not take a look at the datasheet of IC3, but I am afraid that this stage won't have very much 'drive'.
(Unable to drive a high level into a low impedance.)

Ok thanks RuundNL

Bottom right of parts list says "TRI Sauter 5503*", could that be the transformer part #?  No hits from Google.

Yes no hits from Google, "TRI Sauter 5503" I don't know what it means...

Do you have the circuit schematic?

This would be helpful in determining a suitable transformer.

Otherwise, I'd try with e.g. a LL5402, hot-glued and wire mounted to the PCB

Jakob E.

I think the LL5402 is not appropriate  My problem is the following:

Outputs are unbalanced and I want to put a transformer to make balanced outputs

 

[dirkwright]

It might be better to build an outboard unbal. to bal converter. You could use a single 1646 chip from THAT Corp.

 

[Sonoman222]

It might be better to build an outboard unbal. to bal converter. You could use a single 1646 chip from THAT Corp.

Yes thanks I think I must do this

But LL1517 is good? http://www.lundahl.se/wp-content/uploads/2013/06/1517.pdf

 

[RuudNL]

Yes, good but not cheap...

 

[Sonoman222]