Balanced out for SSL9k pres.. trafo, discrete or opamp?

[Svart]

which one would you choose?

 

[Svart]

nobody? damn. :shock:

I'm looking to balance the outputs of my ssl9k's as you might have guess and i was wondering what everyone would do. cost and time are somewhat of a factor but i am looking for something interesting to try. i might even do a few different things.

:thumb:

 

[Svart]

the 5534 is pretty stout however i haven't explored it in this application too much. mostly i just wanted some opinions.

:thumb:

 

[rafafredd]

I think along this lines.... If the thing is a transformerless input, and alreaddy have opamps in the signal path, keep the same rout and use one of the great opamp balanced driver schems around, like the Porter, Elberg, or Cohen.

Or just do like Keith does, and go for the simple one opamp solution SSM something from AD...

 

[Sammas]

yeah i think an input transformer would be the most benefical in terms of sonic character... I've almost finished stuffing a pair of 9k's including one of Keef's balancing boards... i never really considered anything else.

 

[drpat]

...

 

[Svart]

thanks for the opinions so far!

I was thinking about trying trafos just for curiosity's sake but the cost of a simple IC opamp output can't be beat. i think i will do two channels of each.

any suggestions on trafos?

 

[Neeno]

I've built 4 9k preamps and i've used Keith line balancer boards for the output...

The preamps sounds really transparent and clean... i think they aren't much different from the real thing...

Maybe a Lundahl can be the right choice... ?

 

[cuelist]

[quote author="Sammas"]yeah i think an input transformer would be the most benefical in terms of sonic character... [/quote]

If you're looking for 'character' rather than 'transparency' then I would suggest that the 9k with an input transformer is a very roundabout and less than optimal way to achieve that!

The elaborate circuitry that make up the 9k is needed because it needs to perform without a transformer. Direct coupling a low impedance, low level source results in very different design criteria than coupling through a transformer.

 

[Svart]

Cuelist, the reason for this is the need of balanced output. i'm not really looking for charachter. :thumb:

 

[cuelist]

[quote author="Svart"]Cuelist, the reason for this is the need of balanced output. i'm not really looking for charachter.[/quote]

Oh I know (I did read the original question), but they guy suggested an input transformer (off topic) and I questioned the sense in this.

Sorry if I added to the confusion!

 

[Svart]

hey no problem!

 

[soundguy]

[quote author="Svart"]Cuelist, the reason for this is the need of balanced output. i'm not really looking for charachter. :thumb:[/quote]


If you arent looking for character I cant see why you'd ever chose to use a transformer unless you need the isolation, which if you are using it in a recording studio, you probably dont. High quality dip opamp will cost probably under $6. A cheap transformer will cost many times that and a quality transformers some times that. If you arent turned off by a transformerless balanced output and dont want color, by all means use a quality dip and be done with it.

dave

 

[Kev]

what inputs are you likely to be driving with this output ?

min load impedance and max level required could be worth knowing before making a choice.

 

[Svart]

Kev and all: it will be driving sandstate opamps at line level, OPA2604 through elna stargets to be exact. this will be around 25ft very close to AC wiring, halogen lamps and CCFLs(lcd monitors).

Dave: i do understand that the trafos would likely be expensive. i was kinda hoping for someone to come up with a suprise trafo.. but you are right i don't need the isolation but i'm still interested in trafos. you never know what you might find that works wonders. I like the OPA627 for a variety of reasons i'll not go into here, but they are like 15-20$ a piece. audiofool territory for sure but i'll pick it against the 5534 anyday..

Color is not something i was looking for but i am absolutely not writing it off! so far the rest of the circuitry in the whole system is by far very smooth sounding which is what I prefer over today's raw, rather gritty sound you hear a lot of.

I know that many are of the mind to "just do this/that/the other" but i'm honestly looking for something interesting to do here. these preamps are so cheap to build and such a great basic pre that i might build another box of them with various modifications for all kinds of sound, maybe even input trafo? class A output(real, not forced..)

thanks for the input!

 

[rafafredd]

this will be around 25ft very close to AC wiring, halogen lamps and CCFLs(lcd monitors)

So, I would discart the "impedance balancing" trick.

I would go for the SSMs solution for a simple and effective answer.

 

[Sammas]

[quote author="cuelist"][quote author="Svart"]Cuelist, the reason for this is the need of balanced output. i'm not really looking for charachter.[/quote]

Oh I know (I did read the original question), but they guy suggested an input transformer (off topic) and I questioned the sense in this.

Sorry if I added to the confusion![/quote]


Yes i understand this, i was merely saying that one of the reasons to choose a transformer would be for sonic character but using an output transformer yeilds less sonic character then what an input transformer does...

This is why im more than happy to use keef's balancing cards :thumb:

 

[soundguy]

Ive always felt that the output transformer colors things a bit more then the input. guess it depends on the transformer selection, etc.

dave

 

[Sammas]

[quote author="soundguy"]Ive always felt that the output transformer colors things a bit more then the input. guess it depends on the transformer selection, etc.

dave[/quote]


indeed it probably varies with a lot of things.