Legato 3 - Look ma! No caps!

[Sync]

Originally Posted by Russ White

We are also using new 2-ohm FETs.

Supertex TP0604 ?

[Russ White]

Originally Posted by Sync

Supertex TP0604 ?

Correct. The same transistor will work for Legato 1/2 but you need to install them backward on those boards as the pin-out is reversed.

That part has a number of advantages, first is that he Vth is very consistent and low! This gives better headroom and THD. Second the low Ron. It is a great workhorse for the CFP. Especially in parallel.

Cheers!
Russ

[needsp]

Hi Russ

Like the look of those so much I've just ordered some from Mouser!

I'd tip my hat again, but it might fall off

Thanks

Paul

You use pairs, rather than triples?

[Russ White]

Thanks, you are very kind.

Triples.

[barrows]

Cool news on the Legato 3. Any chance you might post the schematic sooner rather than later for those who might like to experiment with existing Legatos but who are not adept enough to figure it out themselves (like me).

[boudy]

I have a parts order on deck that's awaiting this information.

Originally Posted by barrows

Cool news on the Legato 3. Any chance you might post the schematic sooner rather than later for those who might like to experiment with existing Legatos but who are not adept enough to figure it out themselves (like me).

[labjr]

Originally Posted by barrows

Cool news on the Legato 3. Any chance you might post the schematic sooner rather than later for those who might like to experiment with existing Legatos but who are not adept enough to figure it out themselves (like me).

Yank out those Mundorf caps you just bought.

[barrows]

Should be interesting... but no cap should always be better. Of course, the trimmer in the circuit will add a little additional noise... Once everything is trimmed and stable, one could exchange the trimmers for TX-2575s!

[Russ White]

The pots in the L3 are very low value(and as such low noise), actually much lower than the CCS Rs. And in fact the way they are used any noise would be almost all common mode, and thus differentially negated. In fact you would be hard pressed to design a servo that would even come close to being this low noise.

[barrows]

Originally Posted by Russ White

The pots in the L3 are very low value(and as such low noise), actually much lower than the CCS Rs. And in fact the way they are used any noise would be almost all common mode, and thus differentially negated. In fact you would be hard pressed to design a servo that would even come close to being this low noise.

Thanks Russ, good to know. I am a little skeptical of servos, as they are just another feedback loop (yeah, I know, DC only, but not really!).
I look forward to trying the L3...