? re: trafo balanced out for Neotek modules

[blakbeltjonez]

i have some Neotek Series 1 modules that i'm going to rack up and i'd like to have a transformer balanced output with a little color in addition to the unbalanced (0 dBv?) direct output. so my questions are...

1) what transformer specs would i need to do this, and could i use
something similiar to the Profile/A*P*I trafo to get a hint of the A*P*I
vibe? i'm not looking for Jensen, Lundahl, etc cleanliness or price...

2) can i put an attenuator after the transformer to tame the level into my
audio interface if i really want to whack the transformer with a lot of
signal?


any insight would be greatly appreciated - thanks!

 

[blakbeltjonez]

[quote author="buttachunk"]do you have a schemo ?[/quote]

i had a service manual floating around somewhere, but can't find it at the moment..... if i remember right all the Series I/II/III pres are exactly the same aside from EQ and some other stuff - all unbalanced, 0 or +4 output (can't remember which)

 

[idylldon]

Neotek's are unbalanced +4.


Cheers,
--
Don

 

[SSLtech]

[quote author="idylldon"]Neotek's are unbalanced +4.[/quote]
Tape outputs and inputs are +4, Patchbay outs are zero.

The output is a 5534 or 5532 with not so much as a DC blocking cap to remove its offset.. Basically you're limited to what a 5534/5532 can drive, which is not a huge amount. API output transformers (or anything that you will ever hope to not fall over and die, stealing all of your low end) are driven by large transistors, not modest chips. Most output transformers will also not like the DC that the Neotek puts out.

The Neotek sounds okay because there's bugger-all inside it. It's also a primitive design and not very strong. Use it as-is or modify it heavily. You can sticka 600-600 transformer on the output, insert a blocking cap and have soe iron in there, but the overall result will be a design with significant potential weakesses...

My $0.02...

Keith

 

[blakbeltjonez]

[quote author="SSLtech"][quote author="idylldon"]Neotek's are unbalanced +4.[/quote]
Tape outputs and inputs are +4, Patchbay outs are zero.

The output is a 5534 or 5532 with not so much as a DC blocking cap to remove its offset.. Basically you're limited to what a 5534/5532 can drive, which is not a huge amount. API output transformers (or anything that you will ever hope to not fall over and die, stealing all of your low end) are driven by large transistors, not modest chips. Most output transformers will also not like the DC that the Neotek puts out.

The Neotek sounds okay because there's bugger-all inside it. It's also a primitive design and not very strong. Use it as-is or modify it heavily. You can sticka 600-600 transformer on the output, insert a blocking cap and have soe iron in there, but the overall result will be a design with significant potential weakesses...

My $0.02...

Keith[/quote]


it's currently got a OPA132 in the place of the TL072 that i pulled out (rest of the EQ and line amp is TL074). the IC power supply caps were beefed up and blocking caps were put in the path of the OPA132's to keep DC out of the faders back when the whole console was together and i redid half the input modules (it became a maintenance nightmare what with the solid buss wire through all the modules, the control room section developed a problem and the board was also loaded with solid core wiring and at that point i decided it would serve me better as modules since i originally got the console for $300 anyway) .


i like the as-is sound of the input module but i would like to have a balanced out for flexibility and if i can get some iron goodness along the way then so much the better.... maybe some kind of additional line driver to help the output from the OPA132 on the way to the tranny? this is all just a thought, otherwise i am fine just racking them as they are.


you're right, the Neotek guts are an exercise in minimalism..