High performance regulators for the Buffalo DAC and IVY

rklein · « **Reply #40 on:** 30 Aug 2010, 02:30 pm »

Hi multibit16:

I greatly appreciate you taking the time to share this info in regards to my question.

I posted this same question in The Lab Circle and Blair from Nightshade Audio came up with a different way to approach the regs connected to the output stage of the Buffalo II.

I certainly plan on ordering from Paul most if not all his regs and PS's as they relate to the Buffalo II. Thanks to you, Richidoo and Paul for being patient with me in regards to this future build project.

Thanks,

Randy

dboy · « **Reply #41 on:** 30 Aug 2010, 05:01 pm »

Ditto that - Thanks for sharing your experience there Multibit!

I have now ordered a full set from Paul, with PR3.

Do you (or anyone) find that 5.5v offers an advantage over 5v when using all Paul's regs? I understand Twisted Pair used an AVCC voltage slightly higher than 3.3v on their module (haven't got around to measuring it), but I am not sure if this is the main reason why they recommend 5.5v. I guess this depends on whether VD supplies anything other than the regs - which I am unclear on.

One other related question that has been playing on my mind - when we remove L6-8 from the Buffalo II board, are we removing the input to, or the output from, the onboard regs? If it is the output and VD only supplies the regs, then might it be a better option to supply the regs with 5-5.5v via wires direct from PR3 or Z1P and omit connecting to VD on the board completely?

Sorry if these are daft questions that I should already know the answers to!

Thanks,

Dave.

Paul Hynes · « **Reply #42 on:** 1 Sep 2010, 09:47 am »

Hi Folks,

I have been asked several times about using the PR3 regulator in place of the Z1P as a pre-regulator for the Buffalo II regulator set.

I have applied the same discount rate for the buffalo II kit with the PR3 replacing the Z1P.

The Buffalo II kit with the Z1P-05v5 is still £162 and insured carriage and packing for the kit in the UK is £8, in Europe is £12 and the rest of the world is £15.

The Buffalo II kit with the PR3-5v5 is £192 and insured carriage and packing for the kit in the UK is £10, in Europe is £14 and the rest of the world is £17.

Paypal payments are fine.

I hope this helps.

Regards
Paul

multibit16 · « **Reply #43 on:** 5 Sep 2010, 11:04 am »

Just a quick a lash up, I'll take more pics after regs for XO,VD and core have been updated

Currently trying Legato, I lowered output voltage of Z1A/Z1N from 15v to 12v5, mainly because of transformers used but also reduced voltage makes Legato run cooler although it should be fine at +/-15v if your case is well ventilated

multibit16 · « **Reply #44 on:** 18 Sep 2010, 11:29 pm »

Once the SMD inductors on the underside of the BII pcb are removed to disconnect the onboard regs (Core, VDD, XO) it seems the caps going to the input of the stock regs are disconnected too . It maybe worth trying adding input caps to the new regs to be fitted especially if the main supply source is not close to the regs, I'm going to try some caps with the inputs to the PH regs

Also thing to note, even though the input of the stock regs is disconnected their output is still connected to the circuit so it may be worth doing a small track cut to isolate them from the PH regs output

poseidonsvoice · « **Reply #45 on:** 19 Sep 2010, 04:02 am »

Quote from: multibit16 on 18 Sep 2010, 11:29 pm

Once the SMD inductors on the underside of the BII pcb are removed to disconnect the onboard regs (Core, VDD, XO) it seems the caps going to the input of the stock regs are disconnected too . It maybe worth trying adding input caps to the new regs to be fitted especially if the main supply source is not close to the regs, I'm going to try some caps with the inputs to the PH regs

Also thing to note, even though the input of the stock regs is disconnected their output is still connected to the circuit so it may be worth doing a small track cut to isolate them from the PH regs output

multibit,

I posed your question on the Buffalo II forum at diyaudio and Russ white has replied to it here.

Best,
Anand.

dboy · « **Reply #46 on:** 20 Nov 2010, 11:29 am »

Hi Paul,

My regs arrived today - thanks. I have a couple of quick questions and thought I would ask here in case the info is useful to other readers.

- Two of the Z1703v3 regs are marked Z1703v3HP. Which locations on the BuffII board are the "HP" ones (higher power?) intended for?

- The PR3 board I got is designated PR3i-5v5 rather than PR3GAP. No rectification or reservoir caps appear to be onboard and the supplied sheet suggests this board needs 12v DC rather than 9vAC. Can you confirm the cap value that you consider optimal for a simple diode bridge and cap external supply and also what tolerance/range is likely to be acceptable for the 12v DC input? Also, I heard elsewhere that several lower value caps in parallel can be preferrable to one big one - would you (or anyone else) suggest that here?

(It is no problem adding the extra components, I just like my instructions idiot-proof).

Thanks in advance,

Dave

Paul Hynes · « **Reply #47 on:** 22 Nov 2010, 12:59 pm »

Hi Dave,

The standard Z1703v3 regulatorss are used for the AVCC supplies and the Z1703v3HP (high power) regulators are used for the VDD_XO(3.3V) and DVCC (3.3V).

Sorry I have sent you the wrong PR3 module (DC version). I have mixed up your order with another order that will battery powered. I am making PR3 modules this week so I will send you the correct AC input version once the batch is finished. If you send the DC input voltage PR3 back I will refund your carriage costs. The AC input PR3i board uses two energy storage caps in parallel and the capacitance value depends on the voltage rating required. In this case it would be 2 x 4700 uf 16 volt.

Regards
Paul

dboy · « **Reply #48 on:** 22 Nov 2010, 02:35 pm »

Hi Paul,

Thanks for your reply. Does the AC input PR3 board contain extra circuitry besides the rectification diodes and 2 x 4700uF caps?

I ask because before getting your reply I was thinking in terms of dismantling the power section of a gainclone I made a few years ago and using the IXYS FRED bridge rectifier and 4 x Black Gate 1000uF Standard caps to supply the PR3. If I add an extra cap or caps to this arrangement to increase the uFs then does this seem likely to sound better than swapping boards with you? (I have a 6800uF Nichicon KG, 2 x 470uF BG FK & 2 x 220uF BG FK hanging around waiting for deployment, as well as 4 x 100uF BG N also on the redundant gainclone).

I am happy to send the board back for swapsies, but if a version of the supply described above seems likely to sound better then I am also very happy to go for that. Best sound quality is the goal and I am confident you will offer your opinion on that basis.

All the best,

Dave

Paul Hynes · « **Reply #49 on:** 22 Nov 2010, 05:24 pm »

Hi Dave,

The PR3 AC module uses Schottky barrier diodes and Panasonic FC caps for rectification and energy storage. I chose these to give a very good all round performance. I think you will appreciate that this sort of product is price sensitive to a degree and if I were to fit such items as Black Gates (if available) in the required sizes for energy storage and IXYS FREDs the cost would be somewhat higher. If people wish to customise my products I am OK with that although I would be very careful doing this with the small shunt regulators I have sent you for the Buffalo II. The Z series regulators have an extraordinarily wide bandwidth and speed. Changing the caps on this board without a wide bandwidth scope (250 MHz or better) to check for stability could lead to problems.

The PR3 is less critical as far as component options are concerned so I would advise you to keep the DC version of the regulator and fit your IXYS FREDs and Black Gates for rectification and energy storage, as this should give you some performance improvement, although without trying it with the components you have, I cannot say how much.

The dropout voltage of the PR3 DC module I sent to you is around 5 volts so make sure you have around 12 volts DC input under worst-case conditions. Remember to factor in any supply ripple on the raw DC supply as well as mains voltage droop at times of heavy load on the grid.

There is a cost difference between the PR3 AC and DC versions so I owe you a refund or a credit note for £15 allowing for the kit discount. I don’t mind which you choose.

Regards
Paul

dboy · « **Reply #50 on:** 23 Nov 2010, 11:28 am »

Thanks for your guidance here Paul.

I will not attempt to modify the smaller regs. To PR3i I will add a bridge rectifier and a rail of caps of various values to roughly approximate a total value of 9400uF, perhaps finishing with 2x100uF BG N in super E configuration closest to the board input. Unless you advise against it I may also experiment with 2x100uF BG N in super E at the VD input of the Buffalo board, but will perhaps wait until later for this (to allow listening comparison). Based on my understanding of your advice above I may also replace the 470uF cap on the PR3i board with one of my spare BG's (unless you say no). All of the above depends on me not having damaged my Buffalo board with my clumsy desoldering of AVCC a few weeks ago. I should know later today.

£15 is very generous. Although I am sure I will be a customer again I will take it as a refund please, as my spending on this hobby has been rather excessive lately... and there is still more I want to do.

Thanks again - your patience and generosity with your time makes it a real pleasure to do business with you.

Dave.

---I would also very greatly appreciate the comments of any other forum members regarding the proposal to try the Super E cap arrangement - is it worthwhile when it only represents a small proportion of the capacitance employed for the job? Any thoughts or experiences?

dboy · « **Reply #51 on:** 28 Nov 2010, 02:41 pm »

Please excuse me asking further questions!

Has anybody used Paul's regs on a Buffalo with Volumite? Is the current supplied by Z1703v3HP sufficient to power Volumite as well as DVCC or is another solution required? Russ advises using the DVCC supply for Volumite to avoid problems with either Buff or Volumite starting/powering down before the other (which I guess might leave volume uncontrolled).

I will ask on the TP site to try to find out the current draw of Volumite but thought I would ask here in case anyone has done this.

Thanks,

Dave

Paul Hynes · « **Reply #52 on:** 28 Nov 2010, 03:03 pm »

Hi Dave,

According to the datasheets of the Amtel micro-controller and the LDO regulator their joint operating current is less than a milliamp. This doesn’t take into account any load current drawn by the Buffalo but I would be surprised if this is significant. With this in mind I think you should be Ok powering from DVCC. If more current is required from the regulator, the regulator current setting resistor can be reduced if you are OK with removing and replacing a surface mount resistor. Get back to me if you require any help.

Regards
Paul

dboy · « **Reply #53 on:** 28 Nov 2010, 05:58 pm »

Hi Paul.

I'll try powering from DVCC then. We are advised to omit the LDO so I guess this makes things even more efficient. I'm definitely not OK with replacing SMD resistors since this is precisely how I fried my first Charlize - the source of my desoldering neurosis!

But so far so good with this Buffalo...

If I were to go a little silly with this would it be OK to replace the 470uF 16v cap on PR3i output with 2 x 470uF BG NX 6.3v in Super E. I know there is no real call to go to such extremes, but I think richidoo said it best above, about expressing a desire for perfection.

All the best,

Dave

Paul Hynes · « **Reply #54 on:** 28 Nov 2010, 07:03 pm »

Hi Dave,

I have run the PR3 topology regulators with Black Gate capacitors without problems so feel free to go a little silly and experiment.

Regards
Paul

dboy · « **Reply #55 on:** 28 Nov 2010, 07:28 pm »

Thanks very much Paul. I really do appreciate your reassurance on the above points.

Dave.

kpavey · « **Reply #56 on:** 18 May 2011, 02:19 am »

Greetings

Dboy - not wanting to teach you how to suck eggs, but if you are having desoldering issues, I recommend using a quality desoldering braid, (eg Goot), this makes things way easier.

Paul - I would like to exchange my Vd reg you sent me for an all in one reg with rectifiers, plus buy a few extras of the same. I will be in the UK in about 3wks time, and would plan to send to you then to reduce postage. (May even visit the Islay Isles if you want to catch up for some single malt!!! I digress...). Please PM me to discuss further. Cheers, Kendrick

NicMac · « **Reply #57 on:** 18 May 2011, 07:24 am »

I'm almost done with my (latest) dual mono Buffalo II build.
All PSU rails are separate (different secondaries) and have three levels of regulation: CRLRC or CRC filter, LM317/37 based pre-regulators and final regulation using shunt or series regulators from Paul.

poseidonsvoice · « **Reply #58 on:** 18 May 2011, 01:38 pm »

Quote from: NicMac on 18 May 2011, 07:24 am

I'm almost done with my (latest) dual mono Buffalo II build.
All PSU rails are separate (different secondaries) and have three levels of regulation: CRLRC or CRC filter, LM317/37 based pre-regulators and final regulation using shunt or series regulators from Paul.

Top notch my friend! What output stage did you use, looks like dual mono Legato II's?

Anand.

NicMac · « **Reply #59 on:** 18 May 2011, 02:55 pm »

In the picture the output stages are dual IVY III.
I also have the Legato's but I did not yet test them in the dual mono rig. The Legato run quite hot and I need to verify that my layout is able to dissipate the heat.
One very nice thing about the dual-mono configuration is that it can be used for A/B comparisons (in dual stereo mode) of different output stages or tweaks.