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Old 12th January 2016, 09:00 PM   #571
AlexanderTD is offline AlexanderTD  Ukraine
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I just finished trying various capacitors some more and my conclusion - all is good except replacement of decoupling caps. If powered by single Placid 2.1 - reducing caps from 100uF to 0.1uF actually makes it all worse, including dynamics, but the most obvious effect is the loss of lower bass - there's simply less of it so all mid-high details stand out and that's where impression of more transparency and detail is coming from. What you get is actually less smooth, more "shouty" and "pale". You get similar sound if using very small value electrolytics .So i think proper decoupling is important.. No oscillation in any case btw.

All this with Placid BP 2.1 so maybe it's different with Salas.
My test system was buffalo IIIse > Pass F5 > TroelsG. DTQWT speakers

As a side note: I also tried different electrolytes in decoupling positions, including elna silmic II, BlackGate-PK, Nichicon KZ of same value\voltage to see how esr/inductance/dissipation affect these positions - and despite all my audiphilic hopes - i found panasonic FM works the best. If most colorless/precise sound is the goal of course.
The only truly 100% worthy replacement i ever had with full Buffalo3 dac is getting Mundorf AG power caps in my Placids, but again - those have remarkable low ESR/ESL/tan...

francolargo: "loss" and "fidelity" are kind of opposite, don't you think? What i do believe is that when you hear more = more resolution and dynamics, you also hear more noise/distortions etc. of your system so you either "blur" it with some components, or continue to pursue ultimate purity of reproduction which allow you to hear full detail and dynamics while musical and enjoyable. The hardest way in audio imo. But I think Buffalo DAC is the product born from such a goal as is most TPA stuff...

Last edited by AlexanderTD; 12th January 2016 at 09:29 PM.
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Old 12th January 2016, 10:05 PM   #572
barrows is offline barrows
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Default I think...

Quote:
Originally Posted by AlexanderTD View Post
I just finished trying various capacitors some more and my conclusion - all is good except replacement of decoupling caps. If powered by single Placid 2.1 - reducing caps from 100uF to 0.1uF actually makes it all worse, including dynamics, but the most obvious effect is the loss of lower bass - there's simply less of it so all mid-high details stand out and that's where impression of more transparency and detail is coming from. What you get is actually less smooth, more "shouty" and "pale". You get similar sound if using very small value electrolytics .So i think proper decoupling is important.. No oscillation in any case btw.

All this with Placid BP 2.1 so maybe it's different with Salas.
My test system was buffalo IIIse > Pass F5 > TroelsG. DTQWT speakers

As a side note: I also tried different electrolytes in decoupling positions, including elna silmic II, BlackGate-PK, Nichicon KZ of same value\voltage to see how esr/inductance/dissipation affect these positions - and despite all my audiphilic hopes - i found panasonic FM works the best. If most colorless/precise sound is the goal of course.
The only truly 100% worthy replacement i ever had with full Buffalo3 dac is getting Mundorf AG power caps in my Placids, but again - those have remarkable low ESR/ESL/tan...

francolargo: "loss" and "fidelity" are kind of opposite, don't you think? What i do believe is that when you hear more = more resolution and dynamics, you also hear more noise/distortions etc. of your system so you either "blur" it with some components, or continue to pursue ultimate purity of reproduction which allow you to hear full detail and dynamics while musical and enjoyable. The hardest way in audio imo. But I think Buffalo DAC is the product born from such a goal as is most TPA stuff...
You might have misunderstood my findings? I reported that the Placid HD would become unstable (not the L-III) if one reduced the L-III decoupling caps to .1 µF, this is likely the cause of your sonic problems using .1 µF decoupling with the Placid HD. Russ has noted that the Placid HD is compensated such to expect higher value caps at the load.
On the other hand, when using Salas Shunts (BiB), the L-III decoupling needs to be reduced to .1µF as the Salas Shunts do not like to see lots of C on their outputs.
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Old 12th January 2016, 11:30 PM   #573
AlexanderTD is offline AlexanderTD  Ukraine
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Originally Posted by barrows View Post
You might have misunderstood my findings? I reported that the Placid HD would become unstable (not the L-III) if one reduced the L-III decoupling caps to .1 µF, this is likely the cause of your sonic problems using .1 µF decoupling with the Placid HD.
Yes, i understood that and checked Placids with the scope. I forgot to mention though that i never touched the 100uF decoupling close to the buffers because i believe they are a must, maybe that was enough to keep Placids stable.

Anyway - my point is that reducing most of decoupling caps to 0.1 with placid 2.1 didn't work well, even though i measured no problems. But other mods described earlier did make a difference, although smaller and i'm yet to decide on them

Last edited by AlexanderTD; 12th January 2016 at 11:41 PM.
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Old 12th January 2016, 11:46 PM   #574
francolargo is offline francolargo  United States
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Thanks, guys, for the additional clarifications... As I'm powering my boards with Placids, my plan is to parallel the panasonic decoupling caps with 1837s tacked underneath - the same as augmenting large electrolytics with smaller film caps in an amp power supply. Perhaps we should also state our respective shunt currents? Mine are 85-90 mA. I have both Placid HDBP versions 2.0 and 2.1 and appreciate the significant upgrade from the earlier to the current version!

My comments about distortion were principally directed toward those arising in loudspeakers and due to imperfect room acoustics - if that makes more sense...
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Old 13th January 2016, 02:11 PM   #575
AlexanderTD is offline AlexanderTD  Ukraine
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Originally Posted by francolargo View Post
As I'm powering my boards with Placids, my plan is to parallel the panasonic decoupling caps with 1837s tacked underneath - the same as augmenting large electrolytics with smaller film caps in an amp power supply.
I tried bypassing decoupling caps with 0.1 films - there was a similar slight change, but with no obvious shortcomings in bass/dynamics i mentioned earlier. But since i don't have a way to measure caps for resonances yet i decided not to mess with it for now.
But you can try it and see for yourself - it's the easiest mod possible, just solder films to electrolyte's legs from the other side to one channel and compare.
I'm shunting about 80mA +assymetric voltage output (30mV higher voltage on - line). Honestly - i didn't hear much change from shunting more/less past 50-60mA.. Did you?

Last edited by AlexanderTD; 13th January 2016 at 02:22 PM.
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Old 13th January 2016, 06:04 PM   #576
francolargo is offline francolargo  United States
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Quote:
Originally Posted by AlexanderTD View Post
I tried bypassing decoupling caps with 0.1 films - there was a similar slight change, but with no obvious shortcomings in bass/dynamics i mentioned earlier. But since i don't have a way to measure caps for resonances yet i decided not to mess with it for now.
Good thought... I just looked up the intrinsic MKP 1837 resonant frequency and it looks like +/- 6.5 MHz for 0.1 uf. I haven't found specific data for the Panasonic FM version, but general design guidelines suggest it is no higher than 1MHz and very broad. So I don't expect any trouble and my goal in adding the 1837s is simply to increase slew rate.

Question: When you were testing the 330 uf Panasonics, in which positions did you place them (C9-C16)? ...on one stereo pair I'm looking to eek out the very last drop of bass extension and damping, plus there is a bit of supply 'wiggle' from the Placid 2.0 on that Legato.

Quote:
I'm shunting about 80mA +assymetric voltage output (30mV higher voltage on - line). Honestly - i didn't hear much change from shunting more/less past 50-60mA.. Did you?
Until some other equipment upgrades are done, I'm running what i liked with the L2: +15v, -13.5v, and a little over 70mA shunted. On this new build I have silent, isolated active heat extraction over the three placids. So even shunting over 100 mA runs cooler than 70 mV with open-top convection. But with B2+L2 I didn't hear any benefit beyond ~70mA...

Photo: 12v 5" fluid bearing fans mounted over grounded screens - with 9v switching supply, start/stop relay and a bit of speed control...
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Old 13th January 2016, 10:43 PM   #577
AlexanderTD is offline AlexanderTD  Ukraine
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Quote:
Originally Posted by francolargo View Post
Question: When you were testing the 330 uf Panasonics, in which positions did you place them (C9-C16)? ...on one stereo pair I'm looking to eek out the very last drop of bass extension and damping, plus there is a bit of supply 'wiggle' from the Placid 2.0 on that Legato.
C9,C10,C13,C14... You think larger than 100uF decoupling caps could be beneficial? Recently i tried 220uF BG-PK at C15/C16 and had the impression that bass got a bit stronger and more "firm", i thought it just BG's coloration but could be from increased capacitance? There's another trick i found easy and somewhat audible - paralleling 2 identical electrolytes (adding similar one at at other side of PCB) like 100+100..

Last edited by AlexanderTD; 13th January 2016 at 10:52 PM.
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Old 13th January 2016, 11:10 PM   #578
francolargo is offline francolargo  United States
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Quote:
Originally Posted by AlexanderTD View Post
C9,C10,C13,C14... You think larger than 100uF decoupling caps could be beneficial? Recently i tried 220uF BG-PK at C15/C16 and had the impression that bass got a bit stronger and more "firm", i thought it just BG's coloration but could be from increased capacitance? There's another trick i found easy and somewhat audible - paralleling 2 identical electrolytes (adding similar one at at other side of PCB) like 100+100..
I have 220uf Panasonic FMs coming, with the idea of beefing up C9,10,13,14 on the bass board. On that one I also plan to test whether there is any audible benefit of 220 uf at C15&16, both with and without a MKP 1837 bypass. ...might use all of that 90mA shunt overhead after all?
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Old 14th January 2016, 01:43 AM   #579
Erlend Sæterdal is offline Erlend Sæterdal  Denmark
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Legato 3 - Look ma! No caps!
Trow away the Placids and buy Teddy Pardo or Belleson
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Old 14th January 2016, 09:12 AM   #580
AlexanderTD is offline AlexanderTD  Ukraine
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Quote:
Originally Posted by francolargo View Post
I have 220uf Panasonic FMs coming, with the idea of beefing up C9,10,13,14 on the bass board. On that one I also plan to test whether there is any audible benefit of 220 uf at C15&16, both with and without a MKP 1837 bypass. ...might use all of that 90mA shunt overhead after all?
I thought 100uF is a lot already, but - let us know if you got any improvements! I still have quick connects soldered so i can swap caps quickly - i'll try it too, not sure if i'll be able to hear a lot of difference, but we'll see

Quote:
Originally Posted by Erlend Sæterdal View Post
Trow away the Placids and buy Teddy Pardo or Belleson
Why's that? I can't find schematics on their sites...only some comparisons to the stuff Placids will likely eat for breakfast...
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