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Oh nice! I really want to pick up some of those Modushop cases, but shipping is KILLER coming from over there! A 1U case sounds like a great idea, you can even rackmount it if you wanted. I think I'm going to settle for building my own out of wood.
Truepath! Now you got me jealous :p I have the Sympatico boards and transformers all hooked up, have not had anything to hook them too to test with though. Sold my old speakers and now I'm building my own bookshelf speakers...so only headphones for me at the moment.
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Brian,
I was one of the few that got in one the 1st round of Buffalo32s. In the 'seconds' frieze there wasn't much time to consider 'options'. I 'got in' on ordering only a DAC board. Wondering if 'group price option' for including both power supplies could be retroactively added due to ordering panic. Your consideration on this would be appreciated.
Thanks: Chuck alias VC1xVC2
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Rank: Advanced Member
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Russ, Brian, How important is the output impedance of the power supply feeding VD on the new 32S? :) Also, I'll be feeding my power amp directly from my Buffalo but I'm planning to install a pair of input transformers for balanced to single ended conversion on the amp's inputs. To optimize the performance of the transformers I'll have to drop the amp's input impedance from about 35k to 10k. Would you think this'll be a sub-optimal for IVY II or Counterpoints? Edited by user Wednesday, May 6, 2009 5:03:03 AM(UTC)
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Rank: Administration
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Hi Shaman,
Output impedance is a component of load regulation and load regulation will be important to overall performance. Now it is true that much of the VD work is at high frequency where the decoupling caps will do a lot of the heavy lifting, but this is not the whole story. :) There are components of the load which are in the audio band.
What you want is a good balance between noise and load regulation. LCDPS is good (and very cost effective) balance. A JSR would also be a good choice.
You also have to look at ramp up time. For that reason I cannot recommend the Teddy reg unless it has changed since I last looked.
In any case the local regulators will dominate the performance digital supplies. You would have to have terrible PS to really make thing bad. I mean awfully bad.
So bottom line is, don't fret too much over it. It's going to sound awesome. Just don't pick something with a slow start up.
Cheers!
Russ
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Thanks Russ! Well I guess that puts the SuperTeddyReg out of the picture (at least for VD). I was aware of ths slow startup time but it shouldn't be an issue with the extra accelerator circuit that can be istalled as an option. On the other hand, lack of load regulation and high output impedance are always there which is a minus. I'll go the ALWSR or even Sigma11 way for VD then, and probably I/V as well. I already have LCDPS/LCBPS at hand so I'll make some comparisons and see how it goes. If there is not much of an improvement I'll just stick to the "stock" power supplies and keep the rest for future projects. :) Edited by user Wednesday, May 6, 2009 11:40:14 PM(UTC)
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I've built the vref mod on breadboard; first time doing anything on breadboard so it was fun to say the least :) I've swapped a few different resistors and am now sitting a 3.46 with it not hooked up to the buffalo, I suspect it'll drop a bit once it's loaded so I'm thinking this is good?
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Rank: Member
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Regarding the power supplies themselves, has anyone tried to use "balanced" transformer connection? For example: 15-0-GND, we can wired it as: 7.5-0-7.5 and ground the 0 lead of the transformers (sort of like center-tapped connection). This way, all common mode noise before the power supply will be canceled.
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Rank: Member
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Location: Boston
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Hi Russ and Brian, While waiting for the Placid regulators, I'm experimenting with the positive regulators on the LCDPS and LCBPS. This is from reading the discussion on LM317 and LM337 regulators here: http://www.diyaudio.com/...hlight=&pagenumber=1The basic findings are the LM317 is distinctly inferior to the LM337 in output impedance linearity over frequency, and audible affects. To that end I'm trying the Linear LT3080 positive adjustable regulator: http://cds.linear.com/docs/Datasheet/3080fa.pdfOne problem with the 3080 is the very high value of setting resistor, and the resulting start up time if paralleled with any reasonable amount of capacitance. Can you comment please what you think would be a maximum start up time for the Vd supply for the Buffalo32. Thanks, Tom
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Rank: Member
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I´m using the lt 1085 with good results
best
Leif
Norway
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Rank: Advanced Member
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Shaman wrote:Thanks Russ!
Well I guess that puts the SuperTeddyReg out of the picture (at least for VD).
I was aware of ths slow startup time but it shouldn't be an issue with the extra accelerator circuit that can be istalled as an option.
On the other hand, lack of load regulation and high output impedance are always there which is a minus.
I'll go the ALWSR or even Sigma11 way for VD then, and probably I/V as well.
I already have LCDPS/LCBPS at hand so I'll make some comparisons and see how it goes.
If there is not much of an improvement I'll just stick to the "stock" power supplies and keep the rest for future projects. :) I've tried Teddy regs for both VA and VD (fast start up mod added) and did not like the sound in either position , the magic the Buffalo32s is capable of was lost imo Also be very careful if using ALW super regs, they are very finicky whats used on the output regarding cap type and value
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