[Paul Hynes]

Hello folks,

I have been asked to describe various power supply upgrades that I promote, and power supply products that I manufacture, by forum members. It would appear that, to conform to site regulations, this is the circle to do this on.

If any members have any questions they would like me to answer about my products and services please feel free to post here for the time being.

Paul
Paul Hynes Design

[Paul Hynes]

Hi Richidoo,

Referring to your questions on the Affordable££Audio circle.

The Altmann Attraction DAC 12 volt master supply feeds the analogue output stage directly. The DAC chip and clock control circuitry are powered from an L7805 three terminal surface mount regulator that takes its power feed from the 12 volt rail. The digital interface chip has a further regulation stage powered by an LM1117-3v3 LDO (low dropout) surface mount regulator that takes it's feed from the L7805 five volt rail.

The L7805 and the LM1117-3v3 are not designed for high performance wide bandwidth regulation and seriously restrict the performance of the excellent signal processing circuitry and clock circuits regardless of what you use to power the 12 volt supply section. Upgrading these two three terminal regulators with high performance wide bandwidth regulation, with a fast transient response and settling time, will keep the supply rails under much better control when high speed digital signals are propagating through the circuitry. This reduces interaction between the various digital chips and reduces any power supply induce jitter problems. The net result is a radical improvement in audio resolution adding to the already well regarded musicality of the attraction DAC.

The Z100A 100 watt shunt regulator module should work OK with the Pass F5 although you would have to implement EXTREME thermal management to apply it. There are two supply rails per amplifier and you would need 4 Z100A regulator modules and 4 CCS1A 50 watt current source modules all running at their limits. You would require six heatsinks rated at 0.25 degrees C per watt each. This would be rather large and add 600 watts of heat to your listening room. I would be disinclined to go this way unless I lived within the Arctic Circle. A good solution here would be to use a high performance series regulator with a heavy duty power mosfet output stage. This would be much more thermally efficient and cost considerably less than the shunt reg option. I have a circuit I could adapt for this to give you a really good performance with the F5 if you wish to pursue regulation of this amplifier.

Out of interest I designed a similar circuit to the F5 topology in the 1980's when working for Omniphonics Research Limited. The input stage was fabricated out of complementary bipolar transistors with complementary current source biasing. The output stage was a pair of Hitachi complementary mosfets with the output taken from the Drains like the F5 output stage. It did not use such a high bias as the F5 but it did sound very promising for audio use. Unfortunately the company had other priorities at the time and the project fell by the wayside.

Paul

[Paul Hynes]

Hello Eugene and Denjo,

Your questions on Affordable$$Audio circle have been partially answered in my previous post above. It is within the capabilities of competent diy enthusiasts to implement the on-board reg upgrade. If you want some more details about this Eugene, can you e-mail me.

I will let you know about the difference between the two power supplies (SR1 and SR3) once I have prepared a pair for trial.

Thanks Denjo, I will get on with the reg upgrade.

Paul

[richidoo]

As always, your thorough and friendly responses are very encouranging to inexperienced diy'ers like me.  Thanks so much, Paul.  Looking forward to trying these out.  I will be building the F5 unregulated at first to get a feel for it on my own speaker. I might regulate the supply later if the supposed 100uV noise is too much. Thanks!
Rich

[ngchaisoon]

Hi Paul,

Using seven of your SR1 power supplies for my CD transport/DAC brought me to audio nirvana.

A very happy customer.
Ng

[Paul Hynes]

Hello Chai Soon,

I was thinking about e-mailing you recently to see how you got on with the multiple power supply system you were building. A very impressive project. I am pleased it has been so successful for you.

Many people would think that such a system of power supplies would be well over the top. Actually, powering each circuit stage with it's own high performance low noise power supply stops any power supply modulation between the circuit stages via supply output or via ground current returns. My system has been powered this way since 1986. The difference between using this power supply distribution method and using one common power supply is not subtle. Combined with careful organisation of signal circuitry and signal grounding the results achieve rock stable stereo imaging under all dynamic levels and the all important low level information is clearly audible even when the music gets very busy.

Paul

[Adamay]

I'd be grateful if somebody could report on what sort of an improvement the Paul Hynes linear power supply makes over an Optima battery for powering the Altmann Attraction dac.  Thanks in advance.

[ferenc_k]

It is extremely difficult to make a difference between the PH PS and the battery. I prefer the PH PS a bit more as it has a bit more air and just a little bit easier to follow the melody and rythm. But my system is quite unusual, so your opinion can be different. I think it is a vey good news how close the PH PS is to the battery as the battery is working very well with the Altmann goodies. I am looking forward the modification of the Attraction DAC mentioned by Paul above and using the PH PS with a Konnekt audio interface and other pro audio interfaces too. can be a good match.

[Paul Hynes]

Hi Folks,

I have been running the SR1-12 v SR3-12 trial with the Altman DAC for a few weeks now. To try and keep the two supplies on a level playing field I built them together and placed them in my soak test bay for a week to give a little run in time on them. They are now both operating side by side in my system. Each evening I keep swapping between the two to see how burn-in affects any audible changes in performance.

A little back ground about the technical differences would be helpful.

The SR1 is a shunt-regulated design that uses a precision current source and a very wide bandwidth error amplifier chip. The error amplifier chip’s typical spec shows a slew rate of 5,000 volts per microsecond, a rise time of less than one nanosecond, a settling time of around 10 nanoseconds, a gain bandwidth product of 1 GHz and a noise spec of 2 nanovolts root Hz rising slowly below 100 Hz. The output impedance of the regulator is sub 1 milliohm out to 200 KHz. The power transformer is rated at 18VA.

The SR3 is my best series regulated discrete component design using error amplifier transistors with a bandwidth of 100MHz (extended by cascode operation) and a noise spec of 0.5 nanovolts root Hz with a noise corner of 1 Hz. The output impedance of the regulator is in the region of 2 milliohms from Dc to 100 KHz. The power transformer is rated at 60VA.

The SR1-12 is rated at 600ma (maximum). The SR3-12 is more efficient and is rated at 3 amps with a short-term transient capability of around 10 amps. I designed it for for use with small power amps like the Altmann BYOB, Trends T10 and Charlise but it is applicable to a wide range of equipment including analogue circuitry, digital circuitry, valve heaters, record deck motor supplies, etc. I use a high voltage version of the SR3 regulator topology in my valve phono stage. This is currently my quietest regulator topology.

There are audible differences between the two power supplies, as expected. Both supplies are much better than typical three terminal regulator based power supplies (I have a couple of different ones for comparison purposes).

The SR3 is the better power supply for this application. Subtle details can be heard more easily no doubt due to its lower noise floor. The fluid musical presentation with the SR3 is better than the SR1 and the best I have heard with the Altmann DAC. For those with limited budget the SR1-12 will perform well for the cost, but if the budget is of less concern I will be recommending the SR3-12 as a worthwhile improvement. I will certainly be using the SR3-12 in my system in future. I am currently setting up 5v and 3v3 versions ready to go all the way with the possible Altmann DAC power supply upgrades.

Regards
Paul

[brj]

Great info, Paul!  I really appreciate seeing that kind of detail about the hardware coupled with explanations about why the differences matter!

A question for you... you state:

The SR3 is the better power supply for this application.

This would seem to imply that the SR1 might be the better unit for other applications.  Can you comment on which applications might benefit more from the SR1 and why?

Thanks!

[dwk]

The SR3 is the better power supply for this application. Subtle details can be heard more easily no doubt due to its lower noise floor.

Very interesting. Would you attribute the better performance to a lower noise *floor* or a lower noise *corner*? One of the ideas that I've seen crop up recently is the idea that low frequency noise in clocks and DACs is more detrimental than might be expected. In this case, a noise corner at 1Hz would seem to be very low, and at least suggests the possibility that it's an important factor.

[BlkNotes]

Hello Paul;

      I now see the differences between the SR1 & SR3 but how do these electrical supplies compare to the battery option like the optima which are off the grid. Thanks

BN

[Eugene]

Hello Paul,
As satisfied user of your SR1-12 on my Altmann Dac you've made me very curious. I will send you a pm for the SR3.

Regards
Eugene

[satfrat]

As a present customer awaiting delivery of his SR3-12 power supply to be used on an Empirical Off-Ramp 3 USB reclocking transport, all I can say is I can't frakin' wait.

Cheers,
Robin

[richidoo]

slew rate of 5,000 volts per microsecond, a rise time of less than one nanosecond, a settling time of around 10 nanoseconds, a gain bandwidth product of 1 GHz and a noise spec of 2 nanovolts root Hz rising slowly below 100 Hz. The output impedance of the regulator is sub 1 milliohm out to 200 KHz. The power transformer is rated at 18VA.

bandwidth of 100MHz (extended by cascode operation) and a noise spec of 0.5 nanovolts root Hz with a noise corner of 1 Hz. The output impedance of the regulator is in the region of 2 milliohms from Dc to 100 KHz. The power transformer is rated at 60VA.

Yeah, but do you make a 'high performance' version? haha 

Thanks for testing with the DAC, Paul. I did not see pricing for the SR3 model on your website. How much is it?  I have BYOB and Attraction. Can one SR3 power them both?

Do you still recommend replacing the 3 pin regulators on the DAC even with SR3 replacing the battery?
Thanks
Rich

[Paul Hynes]

Hi brj,

Whether the SR1 would beat the SR3 in other applications remains to be seen. I do know that one of my friends has had a similar experience to my Altmann trial with the SR1-5 and a 5 volt regulator module that I gave him (with the same regulator topology as the SR3), when powering his Squeezebox.

Hi dwk,

The difference in noise performance between the two power supplies is significant. The error amp in the SR1 has a noise spec of 2 nanovolts root Hz wideband and 10 nanovolts root Hz at 10 Hz. The graph only goes to 10 Hz so I have no idea what the spec would be at 1 Hz. The error amp transistors in the SR3 spec at 0.5 nanovolts root Hz to the 1 Hz noise corner. Noise will be a significant error source in clock and dac circuits so it makes sense to minimise it and you would expect to hear an improvement sonically in doing so.

The SR3 regulator topology has fewer active devices between the reference node and the output node. It’s transient response and settling time is very good. So both power supplies are up to it in the speed stakes.

Hi BN,

I cannot give you a personal experience regarding the Optima Red Top battery, as I do not have one. My customers are reporting better performance with both the SR power supplies and I would certainly expect a difference sonically based on output impedance and bandwidth.

Hi Robin,

Calm down! LOL. You will have your power supply soon.

Hi Rich,

Actually Rich I do (not trying to play on your forum signature) make a higher performance version of these power supplies, on a custom basis, with Teflon circuit boards, Bulk Foil resistors and Black Gates. I can configure this regulator topology for high voltage use in valve HT supplies and I have supplied my flagship phono stage to several friends in the UK with 12 of these regulators in the chassis. Each valve stage had it’s own double regulated (to improve supply rejection) HT supply with separate power supplies right back to the transformer windings and all the heaters had their own power supply and regulator too. This phono stage haunts me and I will never forget the way it played the music. I will have to build one for myself when I can afford all the materials.

More tests will follow as time goes by and I am sure that customers will post their findings in this thread.

I am not sure if I should be stating prices on the thread so I will just say the SR3 is exactly 1.5 times the price of the SR1. For this you would certainly expect an improvement. One day, hopefully in the near future, I will finish updating the website with all the new products including the SR3.

The SR3 power supply can supply enough current to power the BYOB and the DAC however, to avoid ground current interaction, you should give them separate power supplies for the best performance. This may sound a little like a sales pitch but it is true. Customers would have nothing to lose by trying it anyway as my 56 day return if not satisfied guarantee covers them if they feel I am short changing them.

Regardless of what is providing the 12 volt power, changing the on board regulators gives a big improvement in performance as these on board regulators are seriously limiting the performance of the digital interface, the clock system and the DAC chip.

Regards
Paul

[richidoo]

Actually Rich I do (not trying to play on your forum signature)

Of course you do!! and I should know better than to tease you. I am saving up to do the DAC regulators. This is Industry Talk and Events circle, so I think it is OK to mention prices here.
Thanks!
Rich

[ferenc_k]

The SR3 runs really well on the BYOB, I really like it. It sounds a bit different than the battery, but you will not be disappointed for sure. I now got a Naim HDX hard disk and network player to be connected to the BYOB with a Zu Gede interconnect and this combination sounds really, really involving ( against all rules  ).

Sidenote: I feel the SR3 less sensitive on the mains cable than the SR1 was. It works very well with the ordinary mains cable I got with the HDX - the HDX is using a Naim Powerline at the moment.

I hope to try SR3 with my TCElectronics Konnekt 8 firewire audio interface too. I know it costs more than the Konnekt  but hey it is life and high-end audio!

[Paul Hynes]

Hi folks,

I have another update for you regarding the Altmann DAC on-board regulator replacement.

I wanted to be sure that I knew first hand what the best option was, regarding regulator type, for the 5 volt and 3.3 volt replacements, so I prepared a set of series regulators and a set of shunt regulators.

Just to recap, the 12 volt master power supply feeds the analogue output stage. It also supplies power to the 5 volt and 3.3 volt regulators feeding the DAC, clocks and the digital interface chip.

After fitting the series regulators I have to say I was not too impressed with the results. The all-important musicality was subdued and even after 7 days burn-in it has not returned to anywhere near its former glory. In fact the music just sounds a little flat.

I have just changed the series regulators to the shunt regulators and the musicality is back, but with across the board improvements over the standard on-board regulator performance. The image is more three dimensional and very stable in space. The revelation of subtlety within the musical performance is better and is not masked by large dynamic swings. Pace and rhythm is exemplary and timbre is more natural. The shunt regulators have had no burn-in time yet so I am looking forward to progressively better sound quality over the next month.

All in all an interesting result considering the SR3 series regulated power supply was better than the SR1 shunt regulated power supply when used as the 12 volt master power supply. It would suggest that ultra low noise level is not the prime requirement with the Altmann digital circuitry and that transient response and settling time are more important. This is born out be the difference in working bandwidth and speed, between the two regulator types, when asked to deal with high-speed digital circuits. Using the shunt regulators would also allow a shorter return loop for transient currents, which is also likely to be significant.

The shunt regulator modules I used are the ALTREG1A-3v3 and the ALTREG1A-5. These are the same circuit as the Z1A modules used in previous Altmann DAC regulator upgrades but with a smaller footprint to allow fitting on the spruce base next to the dac to give a tidy modification.

Regards
Paul

[Paul Hynes]

Hi Folks,

For those who have asked for a picture if the modded Altmann DAC :-



I will be pleased to answer any questions DAC owners have about this mod.

Regards
paul