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Buffalo II - Assembly for the Electronically Bewildered.

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In the last days i was doing some experiments with voltage and current setting for Legato. The most dynamic sound is +-15V and 80-90mA, i reduced it to 14V and 70mA and sound became more relaxed. I will probably stay at 14V / 70mA. For me it is the best compromise between (little lazy and slow) 12V/60mA adviced by TPA and the "fast and dynamic" 15V/90mA ;)
 
That's interesting tomek - I'll tweak mine tomorrow.

Another question - is it OK to stack transformers? I'm trying to work out how best to accommodate another two plus Buff., legato etc.
 
Suffolk Tony said:
Thought I'd go ahead & order a BP HD Placid, Buffered Legato (still not quite sure if I need the buffered bit or not...) & a couple more transformers. I just need another set of Tridents now!

I don't know what it is with me & TP but as I placed my order for the Placid HD they went out of stock; must have grabbed the last one.

I'm wondering if the BP HD Placid will power both Legatos - it should do, shouldn't it?
Click to expand...

Tony,

Why would you need to run two Legato's at the same time? :confused:
 
There is one "tweak" for free. You can use both secondary of the small transformer to feed the Placid, instead of using only one secondary.

Here is a picture:

IMG_1920.jpg


Just connect orange with black and yellow with red.

In this way the transformer can deliver double current :)
 
tomek said:
There is one "tweak" for free. You can use both secondary of the small transformer to feed the Placid, instead of using only one secondary.


Just connect orange with black and yellow with red.

In this way the transformer can deliver double current :)
Click to expand...

Another tweak is to remove those bog standard rectifiers and us Schotkys or Q Speeds. There is less RF gunk ( I assume switching noise from the diodes) if you do this - I have scoped both and you can see the difference.

Regards
 
ron said:
Maybe try tweaking the output filter like done with Legato? I found those 15nf Wima filter caps to over soften the sound in both Legato and IVY
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Thanks, ron, that smells right. I've got some 15nF Relcaps or some 22nF Soviet polystyrenes that I can swap for C1-4. I suspect the polystyrenes are going to get me some more edge.

Martin, that's a good point about the rectifiers in the Placid circuit. They're not even paralleled with capacitors. I managed to get a BP HD Placid board, so I'll substitute some decent rectifiers.
 
Agreed. 22nf will most likely roll off HF too much, which was the accusation aimed at the 15nfs. I ended up with 1.5nf and I think legato 3 now has something like 2.2nf?
 
flashgo said:
Thanks, ron, that smells right. I've got some 15nF Relcaps or some 22nF Soviet polystyrenes that I can swap for C1-4. I suspect the polystyrenes are going to get me some more edge.

Martin, that's a good point about the rectifiers in the Placid circuit. They're not even paralleled with capacitors. I managed to get a BP HD Placid board, so I'll substitute some decent rectifiers.
Click to expand...

I ended going a bit more extreme, eliminating the rectifiers on the Placids and supplying DC from a PFM rectifier board using Q-Speed diodes and C-R-C-R-C filtering. I kept the R value fairly low. I'll do the same with the HD.

I did read a few articles on paralleling caps with the diodes and cponcesus seemed to be that it was far better to use low noise diodes, since if you get the cap value/resistance wrong you can actually get worse ringing than no cap at all.

Regards
 
Cheers, Martin, the thought of popping in an outboard cap bank had crossed my mind. At this point, I think I'm chasing the analog aspects of the DAC's sound, so this makes sense. Did you actually listen to the stock Placid BP vs. + outboard cap bank? Or was this one of those "for good measure" things? ;)

A few details:
Did you leave the little caps on the Placid board post rectifier bridge?
What values did you use for the C-R-C-R-C?

Thanks
 
sq225917 said:
Low impedance, low impedance, low impedance.... you know it makes sense. ;-)
Click to expand...

This, IME. Enough impedance can be...quite small ;)

And a 'no' to caps in parallel with diodes, too. But series RC across transformer secondaries before the bridge is with worth playing with, whatever you do/use. (100-470R + 47-100nF, ballparkish)
 
flashgo said:
Cheers, Martin, the thought of popping in an outboard cap bank had crossed my mind. At this point, I think I'm chasing the analog aspects of the DAC's sound, so this makes sense. Did you actually listen to the stock Placid BP vs. + outboard cap bank? Or was this one of those "for good measure" things? ;)

A few details:
Did you leave the little caps on the Placid board post rectifier bridge?
What values did you use for the C-R-C-R-C?

Thanks
Click to expand...


To be honest, I didn't listen to the stock Placid vs. the offboard reg/caps, but did look at the outputs (with a 100Mhz storage scope) running both prior to the Placid shunt as well as after it. In both cases the outboard reg regs had less HF noise. So to some extent it was a 'good measure' move,and it also allowed me to move the transformers and regs into a different case. The caps were 3300uF and the resistors 0.47ohm.

Regards
 
Suffolk Tony said:
Another question - is it OK to stack transformers? I'm trying to work out how best to accommodate another two plus Buff., legato etc.
Click to expand...

Hi Tony,

You can prpobably stack transformers without any negative effect, but i think that the best solution will be to put ALL transformers (without Legatos) in a separate case and connect the cases with a kind of "Burndy" cable, or just use some other cheaper but good connectors - Neutrik ?
 
Thanks Tomek, I was thinking that may be an option. I'm also considering, given that my enclosure is quite high, of adding a metal shelf above the existing transformers and fixing the new transformers to it, staggered from the ones below.

Having now ordered a HD BP Placid and a vs.3 Legato, I'm wondering how this will work when going dual-mono. I'll end up with an unbalanced setup. Mind you, I can't do anything in that direction until I can order some more Tridents. Still no indication of when these will be available.

Oh, and I upped the voltage on my existing BP Placid to 14V, and did as you suggested by running both transformer secondaries into the Placid for the Buffalo. Not a huge difference IMO but it does give a bit more depth to the sound.
 
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