Hi Erwin,

I had better check the CCS2 here. I have made a replacement for you. If you e-mail me your postal address I will air mail it tomorrow so you do not have to wait for me to check the faulty one.

Regards
Paul

Hi Erwin,

I am not sure what is wrong with the CCS2. Can you send it to me so I can investigate what has failed? My address is on my website. I will cover any postage costs and replace the CCS2 if faulty.

Details of how you are using it in the circuit would be helpful.  The input voltage and output voltage during operation are important parameters to ensure that over dissipation does not occur.

Also it pays to check for shorts and solder bridges very carefully, preferably with a magnifying glass. I recently built myself an automatic car battery charger on strip board, which, when switched on zapped two indicator leds. Close inspection revealed a very fine copper trace was left where I had supposedly removed an area of copper. This was enough to connect the two leds across the power supply with no current limiting resistor to save them.

The CCS2 was originally designed for use with a 12 volt input on the old Monica 2. With
24 volt input it will be running rather hot and could fail due to over dissipation.

For experimenters in general,
I have had a brief look through some of the Monica threads and notice that many modifications are being implemented. Some of the modifications relate to power supply voltage and current changes. Changes like this should never be done without first checking the ratings of all parts in the circuits under power. The CCS2 power transistor dissipation should be limited to 600mw. You can calculate this by using the formula Vin - Vout (in volts) x set current (in amps) = Dissipation (in watts).

My advice is if you are running at 52ma as applied to the TDA1545 dac diode bias chain
you should limit the input voltage to 17 volts. If you are using the mod that drives only
one diode to provide the Iref then limit the input voltage to 12 volts. This will give
you safe operation.

I soak test all my products for two days to try and avoid any failures from weak components and because of this failures are rare, however they do happen occasionally, so if any of you get further problems let me know and I will deal with them as quickly as possible.

Regards
Paul

Hi Jonas,

I have not had time to set up either M2 or M3 yet as I have been very busy. This means I am not up to date on all then mods that keep happening to M.

Hi Paul,

Now that you have a computer at home there will be no rest for us all.

One day ....... I will send you a pair of high voltage shunt regs for your SET power amp. This will either confirm or challenge the SET religion.

Regards
Paul

Hi Jonas,

It's all a question of degree and how far are you prepared to go to improve your system performance.

I first began using multiple power supplies in the 1980's after having heard the resulting improvements to my system. Since then everything that needs a voltage supply in my system has it's own power supply right back to the power transformer windings.

I have tried all the power supply options over the years and I have to say that I am not a big fan of choke supplies or switchers.  I have been honing the performance of my regulators since the 1980's, and they are currently my best effort, at a reasonable cost, to approaching the ideal power supply. I can do better but few would be prepared to pay for this added level of performance. You will not believe the amount of R&D that has gone into these regulators since I first began this journey. My journey began with an enquiring mind and I am pleased to see many of you display this on the forum thread. Keep looking and learning and helping each other and you will reap some profound rewards with your music.

Regards
Paul

Hi Jonas,

It is as well to remember that you are not just dealing with a steady state current draw in some areas of the circuitry. Also real world realisations of circuit functions are less than ideal.

A constant current source will only draw a constant current if it is an ideal current source showing infinite impedance at all frequencies of operation.  A regulator or battery will only be a perfect power source if it displays zero impedance at all frequencies of operation.

The real world is different from perfection and we are all searching for the "Holy Grail" to improve things in our music replay. There are many solutions offered to perfection but the majority do not come close to the required performance because the required performance has often not been analysed properly.

Enthusiasts on this thread have already found out, by careful sleuthing and consideration of the issues, that there are penalties for failing to approach the ideal performance of a current source. The same applies to a regulator. The closer you approach the ideal regulator performance the better the results will be.

Look at what is happening in your Monica signal circuits. There are high speed clocking signals mixed with analogue processing. This implies that you need to consider a wide bandwidth when assessing load current transients in the power supplies.

Does the regulator/battery react quickly enough to prevent a supply rail voltage fluctuation occuring during a load transient without overshoot or ringing. For this you need to consider the slew rate, transient response and settling time of the regulator/battery. Are these parameters fast enough to deal with Monica's clocking transients. How well do they control the rail voltage in operation.

If you use sloppy power supplies you will get sloppy results.

Regards
Paul H

Hi Folks,

Thanks for posting the pic Yeo. It will give people an idea of size. Most of the workings are surface mount on the flip side of the board.

The regulator in the photo was customised for use as an ultra quiet 1.2 volt precision reference for a development project. The regulators that I will be shipping to Yeo will have parts sized for higher power usage. I will be preparing application notes for Yeo to post on his site. All sales enquiries for use with DIY Paradise projects should be directed to Yeo. I will be providing technical assistance with the application and customisation of this regulator via Yeo's site.

Paul H

Hello Jonas,

Your question is valid as some regulators do not like driving low impedance capacitor banks.  I have used the PR3 topology driving a bank of 16 Panasonic FC 8200mf 16v caps, which is around a milliohm at 100 KHz, without stability problems. The output mosfet gate source voltage is clamped with a zener to limit the maximum current through the device. The regulator output voltage runs up slowly over a few seconds, reducing charging current surges considerably, so it can cope with charging such punishing loads. The capacitor bank looks like a dead short to the regulator on switch-on. Once the capacitor bank is charged the stress period is over. The regulator is also protected against reverse bias if the input voltage collapses.

Regards
Paul

Hello Toni,

Only with an impedance of absolutly zero ohms, at all frequencies, at the load terminals would you not be able to hear the effects of additional components or cables on the power rails. Whilst it is currently not possible to acheive zero ohms, over a wide bandwidth, the closer you approach this ideal the better the sonic results. People have different preferances in their systems as you and your friend find with the Optima and the Shunt regs. It is usual that the differences are relatively small at this level of performance and more a question of differing taste.


This last year I have had a lot of enquiries for a power supply for use with the Altmann BYOB amplifier, so I have prepared power supplies for this function. Due to the issues of cost and thermal management I chose my best series regulator topology for the job . The Red Top makes a good supply which is why Charles recomends it and any alternative supply has to at least compare favourably with the Red Top or it would be a wasted exersise. Not everyone wants to or is allowed to have a battery in the lounge so a good mains driven power supply is a useful alternative. I am just preparing the new PR3G Series regulator module for DIY enthusiasts. This can be used for amplifiers using single positive voltage power rails. Examples include Charlise, Altman BYOB amplifier, Trends, etc. The output impedance is comparable to the Red Top battery but over a wider bandwidth. The available current from then PR3G is 3 amps continuous and up to 10 amps transient and it can be used with a reasonably small heatsink rated at around 2 degrees C per watt. I can customise the module for much higher current capacity by replacing the output mosfet with a heavy duty isotop package that is bolted directly to a suitable heatsink.

The PR3G is a pure linear regulator and is very quiet with error amplifier devices specified for noise at 0.5 nanovolt root hz with a noise corner of 1 Hz. You can use it for vitually any function by customising the various parts. I have used this regulator topology to supply 10 amps continuously for a bank of four 6AS7 heaters in a Circlotron power amp, a moving coil cartridge head amp where noise is crytical, a power supply for the origin live DC motor used to upgrade record decks, Valve HT regulators at up to 450 volts. The list of different applications is large. I will also be preparing a negative voltage regulator board (NR3G) in the new year using the same topology but mirrored for negative supplies. I have used this negative regulator topology for operational amplifier or  power amplifier supply rails paired with the PR3 to give a dual rail supply and it was also used to give the negative grid bias to the bank of 6AS7 valves in the Circlotron amplifier.

Toni, if you would like to try the PR3G regulator module against the Red Top battery I will send you one free of charge. It will be very interesting for other enthusiasts to have such a test completed by an independant enthusiast as it will cost £70 when set up for Charlise. With the addition of a transformer and a heatsink for the module it will cost substantially less than a Red Top battery and charger.

E-mail me at [email protected] if you want a module to try a PR3G.

Regards
Paul

Hi all,

I see you are having some fun with the fet buffer mod to Monica.

There are several mechanisms at work here. I suspect that one problem is the tuned Ariel circuit that the fet and following components and interconnects can form. This can leave the fet stage open to RFI inter-modulation between the incoming RFI and the output signal. The resistor connected to the fet source acts as a RFI filter by using the drain capacitance of the source follower CCS to shunt the RFI to ground thus reducing the audio band inter-modulation products at the source terminal.

Paul N has found information on another aspect relating to impedance and parasitic oscillation, which can occur under certain circumstances. This would vary depending on the signal level and signal frequency giving the impression that certain instruments or voices were sounding weird and others not. Hence your concern regarding the Piano Paul.

Looks like you are getting good results with all your experiments. Keep up the good work. Hands on is the best way to learn.

Regards
paul