Legato or IVY III outputs for Buffalo II?

[Russ White]

Originally Posted by needsp

Hi Russ

One other thing I don't understand. Your reply implies that Legato sounds better at 15V. If R20 etc is adequately rated as you say, why not recommend 15V operation in the manual, rather than 12V?

Thanks

Paul

The manual is clear why. There is no other reason than heat. If your case is adequately ventilated use 15V. I don't assume all people have adequately ventilated cases.

The manual does assume people will maybe use the buffer, which adds even more heat. So I decided to guide people toward moderation.

I am running and have always run 15V with no issues for more than a year. My legato is performing as well as ever.

Cheers!
Russ

[ylingf]

Hi Russ,

I need a SE output, but really don't like to have an opamp in the path for balanced to SE conversion. Since I know my preamp's input impedance is 10K. Is it possible to load the negative output of the balanced output with a 10K resistor, and connect the positive output to the preamp?

Thanks,

Fred

[Russ White]

Hi Fred, It is possible to do, but you likely to get some nasty turn on and turn off thump unless you employ some sort relay or something.

You would be better off just forgetting the opamp is there and enjoy the good music.

You could also use a transformer or some other external BAL/SE conversion.

[qusp]

I knew the opamp would cause some comments (as did you no doubt ) its not an issue for me, as i'm running BAL, but I did wonder a bit about the choice TBH. people buying legato are most often doing so in order to use a no global FB discrete circuit; seems a bit counterproductive (regardless of sound) to ruin that in the last stage with an opamp for SE conversion

[Russ White]

Originally Posted by qusp

I knew the opamp would cause some comments (as did you no doubt ) its not an issue for me, as i'm running BAL, but I did wonder a bit about the choice TBH. people buying legato are most often doing so in order to use a no global FB discrete circuit; seems a bit counterproductive (regardless of sound) to ruin that in the last stage with an opamp for SE conversion

I don't see it that way at all. Here is why. There are two distinct processes involved here.

First we have a symmetrical I/V converter. It is fully discrete with no global NFB. It stands on its own.

Then we have an orthogonal but practical and extremely useful bal/se stage which you the builder can decide to use or not. It is completely optional. The DAC is a balanced DAC, not SE. This I/V stage is a balanced I/V stage.

All of that to say to do BAL/SE with discrete components right would take more space than I had on this PCB, and would not have yielded as good results as what is there right now.

Instead, I took the pragmatic approach and offered the builder options. Use the excellent on-board BAL/SE stage, or do something else with the balanced signal.

One great option would be the Ventus which is a discrete BAl/SE converter. But it is far too large and makes too much heat to put on something like the Legato PCB.

So I think the choice was the most logical I could make given the goals regarding form factor etc.

Cheers!
Russ

[NicMac]

Originally Posted by Russ White

One excellent option would be the Ventus which is a discrete BAl/SE converter. But it is far too large and makes too much heat to put on something like the Legato PCB.

Hi Russ,

Would the Ventus used as a BAL/SE converter work better with or without the buffer stage on the Legato? Would the connection need decoupling caps? Can the output DC offset of the Ventus be set (very) close to zero?
I'm considering to use of the Ventus with a dual-mono BII/Legato connected to (balanced) Hypex modules with by-passed buffer stage (input impedance 1k8R, not very tolerant to DC offset).
Last but not least - will the Ventus be re-stocked?

Thanks,
Nic

[BrianDonegan]

Originally Posted by NicMac

Would the Ventus used as a BAL/SE converter work better with or without the buffer stage on the Legato?

Either would be fine, without would be cooler and easier to power.

Would the connection need decoupling caps?

No.

Can the output DC offset of the Ventus be set (very) close to zero?

Yes.

Last but not least - will the Ventus be re-stocked?

It is getting a little tweaking attention, but will be available again very soon.

[NicMac]

Originally Posted by needsp

It sounds absolutely superb! Stunningly good! Unbelievably good! I don't say this lightly- it sounds better than the I/V stage I was using (which used a CFT, with a CCS above and below), and I've recently invested a lot of time and effort in that. Believe me it was no slouch sound-wise either- Legato had to be damn good to get my attention!

Hi Paul,
What are you using for BAL/SE conversion? I seem to recall that you are using a single ended power amp.
Cheers,
Nic

[NicMac]

Thanks Brian,
I will try this combination when the Ventus becomes available again.
I'm doing my best to understand why so many people hate op-amps
I seem to understand that the Ventus as added value can give me back a bit of the gain that I lost by bypassing the gain stage on the Hypex modules.
Cheers,
Nic

[needsp]

Originally Posted by NicMac

Hi Paul,
What are you using for BAL/SE conversion? I seem to recall that you are using a single ended power amp.
Cheers,
Nic

Hi Nic

Just the op amp stage provided

Paul