Creating a differential signal from a single-ended signal for bridged amps

[Peter Daniel]

Originally posted by Pedja
For the adequate compensation and % of the $€£(...), I may offer you one such solution.

I think the solution here is not that challenging as I would have to hire a paid consultant.

But, I may be interested in discussing with you licensing your active I/V stage as I like it a lot. I'm also planning on developing my own version of parallel TDA1541 DAC and this circuit of yours fits there well.

[Steve Eddy]

Originally posted by Peter Daniel
I'm presently using S&B 102 TVC and as good as they are, there are certain limitations, like softening of highs in some systems/on certain material. Also dynamics are not always comparable to an active preamp. How would it be to combine transformer with an active line driver, like AD815 for instance (or discreet buffer)? I think there is even an example like that in application notes.

That approach has worked very well for me.

I posted this almost a year ago:

http://www.diyaudio.com/forums/showt...145#post264145

se

[Pedja]

You have mail, Peter.

But hey... what with this differential signal?! I've just had the idea. Anyone else interested?

Pedja

[Peter Daniel]

We surely are

[analog_sa]

I'm presently using S&B 102 TVC and as good as they are, there are certain limitations, like softening of highs in some systems/on certain material. Also dynamics are not always comparable to an active preamp.

Absolutely true. Keep in mind fixed ratio transformers for some reason sound a lot better than the S&B. And are much cheaper.
I have used Lundahl LL1660 for phase-splitting or step-down duties and can assure you it sounds way better than the S&B.

For line input splitting Lundahl make a very tiny (AD815 size? ) and very cheap transformer - LL1544. I have a set and if you let me know the configuration (input buffer? max input voltage?) will gladly hook them up to a couple of your favourite opamps and let you know how it sounds.

[Peter Daniel]

I would prefer no input bufers if possible. How about using it with AD815. I might order those Lundhals as well.

I have two pairs of LL1570, but I guess those are good for output only?

[Steve Eddy]

Originally posted by analog_sa
Absolutely true. Keep in mind fixed ratio transformers for some reason sound a lot better than the S&B. And are much cheaper.

Yeah. The thing about the TVCs is it's like having 24 or however many different transformers. A given transformer tends to work best with a specific source/load impedance. A TVC will typically see just one source/load impedance for all of its positions which means that most of its positions will have a less than optimum loading.

se

[carlosfm]

Originally posted by Peter Daniel
I'm presently using S&B 102 TVC and as good as they are, there are certain limitations, like softening of highs in some systems/on certain material. Also dynamics are not always comparable to an active preamp.

Not good for me, thanks.

[markp]

Really good transformers are big dollar items and come with their own set of problems. The DVR134/5 does a nice job with little extra parts and you may find after all the work on a discrete circuit that it was a learning experience with the same results. You dual FET circuit is an option but who wants more caps in the signal path?

[planet10]

Originally posted by Peter Daniel
I'm considering here a simple circuit to add to the LM4780 board and convert it into bridged amp, as many people asked about it. Transformer, apart form the size restrictions, will not always fit in everybody's budget.

Originally posted by Steve Eddy
Quite so. Unless you go with one of the cheapie $10 jobs.

This one is fairly respectable... a couple Joes have compared it favorably with much higher priced transformers.

http://www.edcorusa.com/transformers...wsm10k-10k.htm

dave