Keantoken's CFP cap multiplier

Sorry for out of topic...

I changed the output caps and rail bypass caps on my Marantz SA11S1 and now it sounds very neautral and very smooth at high frequencies. My scope shows that the rails are very clean for high frequencies, BUT, I found 120Hz ripples at around 3mv p-p. I don't think the Marantz HDAM modules have any PSSR so no wonder the player does not sound as smooth or details as other high end CD players at lower frequencies!

Unfortunately I can't fit a CCS-shunt reg there because the heat within the chassis will quickly build up.

Which is the best series regulator circuit available? I have tried the Jung Supereg but at the time I did not have sufficient build experience to build it right, I guess. But then somebody reported that the phase margin is really low with that one. Any recommendations? my requirement is that the input is about +/-15V? output is about +/-11V.

Thanks in advance.
Regards,
Bill
 

keantoken

Member
2006-08-10 12:32 am
Texas
I have not found any high-performance series reg designs online except the Jung regs. There are discrete direct pin replacements for 7805-type regulators that can be bought, but they are hard for me to find on google.

I've done tons of sims with high-performance discrete series regulators, and I believe one could achieve better performance in a Jung-type regulator using discrete components rather than opamps, but that is an arena for another thread.

A full shunt reg might not work, but I think it's possible to hang a shunt reg off of a chip reg, for lower power and good performance.

However most of this is experimental, I haven't heard of anyone else using these techniques.

Do the boards use their own regulators, and if so, what type? Knowing this would make it easier to recommend a design with better specs, so as to avoid accidentally downgrading.

- keantoken
 
Thanks, jh. I will do some searches on that one.

I forgot to mention, one requirement is that the regulator must allow high capacitance at the load. In the original Marantz circuit, 6 x 470uF for each rail at the load (after the regulator, of course), which is huge. The Jung regulator would not like that.

Keantoken,

The Marantz uses a very simple series regulator at that place. I have the schematic but due to copyright reason I can't post it.
 
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klewis

Member
2007-09-05 10:51 pm
Sorry for out of topic...

I changed the output caps and rail bypass caps on my Marantz SA11S1 and now it sounds very neautral and very smooth at high frequencies. My scope shows that the rails are very clean for high frequencies, BUT, I found 120Hz ripples at around 3mv p-p. I don't think the Marantz HDAM modules have any PSSR so no wonder the player does not sound as smooth or details as other high end CD players at lower frequencies!

Unfortunately I can't fit a CCS-shunt reg there because the heat within the chassis will quickly build up.

Which is the best series regulator circuit available? I have tried the Jung Supereg but at the time I did not have sufficient build experience to build it right, I guess. But then somebody reported that the phase margin is really low with that one. Any recommendations? my requirement is that the input is about +/-15V? output is about +/-11V.

Thanks in advance.
Regards,
Bill

Bill,

The LME49600 application sheet has schematics for a regulator design cooked by Bob Pease and Mark (Audioman 54) I believe they presented a paper on the design. I've built it, it works well, and can share express pcb files if you desire. Mark references the paper in the thread National Opamp Inflation http://www.diyaudio.com/forums/solid-state/132471-national-opamp-inflation.html see post #5,#63 and #68. Somewhere I've seen a reference to the paper they presented, but, can't find it...

Ken
 

iko

diyAudio Moderator Emeritus
2008-05-29 2:41 am
Toronto
Bill, there's a very simple circuit which you'll be amazed by what a difference it can make. The resistor values will have to be changed to your liking. This is not a regulator.
 

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stormsonic

Member
2008-08-31 4:08 pm
some more options
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another one, Vout can be adjusted
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or HERE , everything on left side from C12 can be omitted

or mini shunt (more LEDs=higher Vout)
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if you want shunt reg and don't want to dissipate heat, you can use clever idea from Wenzel Finesse Voltage regulator to build your own clean-up shunt reg: FINESSE REG.
Or Maxim's design idea: NOISE CANCELATION

all above regs are from different authors, pick up your poison :D

But be aware, with high output Z regulators, big capacitance with low-ESR, ESR can dominate over regulator into audio band. Capacitor sound :p
 

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this might not be popular, but for your purposes here, I would recommend just using a linear technologies IC linear reg with simple surrounding circuit. such as the LT1764A or LT1963A. the ICs really are superb, the guys at linear really know what they are on about and the datasheets and app notes are very comprehensive. I have been using the 1763A and 1185 with very good results so far in a simple follower i'm working on and use their 176X series small LDOs in my portable sabre

low drop out V, low noise and low heat. not quite up there with a discrete shunt, but leagues ahead of any other ICs i've used before. also if you can use one of the fixed Vout versions (wont suit u here, too low V) they have a sense/force kelvin connection, but this is the same pin that is the adj pin in the adjustable versions.

just make sure to use a nice polymer cap in parallel with te datasheets ceramic at the output. or you could use film.
 
Thank you very much for your responses. I am changing my ISP at the moment and have not had access to the internet for a few days.

I hope I am not stealing too much out of Iko’s thread. This thread needs to be awaken from time to time. For those who are after the ultimate, no-compromise regulator, the Iko reg is one of the best options. I understood I could get better responses here than starting a new thread, but am conscious that I won’t be going too far down.

Most recommended regulators here look fine to me. However, many increase the output impedance. They may behave well in simulations or in “class A” circuit with a constant load. I am not sure how they would behave with “class AB” load with signals of transient / dynamic nature. The Iko reg, Salas reg and Jung reg are reportedly superior in sound quality probably due to their diminishing low output impedance right to high frequencies.

If I had the electronic circuit knowledge, I would probably take Keantoken’s advice and start a new thread on a discrete June reg. My knowledge is too poor for that and I won’t have the time anyway.

The TeddyPardonSuperReg has C-multipliers at the output which increase the output impedance. Iko’s circuit is two C-multipliers in serious. If I were to try the TeddySuperReg, it would be easier to try the Iko’s C-multiplier before the Marantz reg.

Stormsonic’s middle schematic is the closest to the Marantz regulator circuit I have been thinking about replacing or enhancing.

You may be interested in reading this:

I bought my Marantz SA11S1 based on the recommendation from a trusted friend. He had the Marantz, Mark Levinson and Audio Research CD players, out of which he liked the Marantz the most. With a reference level system running, my SA11 is obviously the “cheapest” component in the audio chain at just above $3000 retail. So I have been looking for a better CD player to match the level of performance of my system. I built everything (and designed the active loudspeakers) in my audio chain except the CD player which I could not build.

The stocked SA11 has the typical Marantz house sound. I replaced all the filter caps from Elna Silmic / Cerefine to Rubycon ZL and replaced the output caps from Silmic to Vishay MKP. The Marantz house sound is gone and it sounds a lot more neutral – it no longer sounds like any Marantz though.

A week ago I compared side by side my lightly modified SA11 to the EMM Labs CDSA ($15000) and dCS Puccini ($25000). I also invited the ex-president of the Sydney Audio club, JM, to join me in the audition of the CDSA. We were comparing oranges to apples. The CDSA and Puccini gave a much more detailed and rich sound but also more colourations at the same time. At the end, I did not know which one to choose. On many sound tracks the CDSA and Puccini are more attractive, on others they lost to the SA11. On drums, organ music and sopranos the SA11 killed the CDSA and Puccini. JM put it this way: The CDSA sounds like the best of HiFi. The SA11 sounds closer to the music.

So there you go. Perhaps I don’t need to stretch my wallet to get an expensive CD player. The thing that looks “promising” is that I have measured a few mV ripples on the rails on the Marantz, which means it has a scope to be improved upon. Perhaps if I can get the rails as flat as the Iko reg (which is a thin flat line) it would throw the expensive CDSA / Puccini into the water?

Andrew, no, I can not fit the Iko reg outside the Marantz box.

For now, it seems it is worthwhile to build a C-multiplier and put it in front of the Marantz reg and see how it sounds. I happen to have a pair of D44H and D45H in my part pin.

Any more advices are welcome.

Regards,
Bill
 

iko

diyAudio Moderator Emeritus
2008-05-29 2:41 am
Toronto
Don't worry too much about OT. I think we're fine and we talked about filters and gyrators in the past.

The cap multiplier won't give you low Zout if that's what you're looking for, but then... to get that you already know what kind of heat you need to dissipate with a shunt. It will, however, give you surprising line regulation (filtering). Perhaps you may not need to get such low output impedance for that load, and it's something that you can literally put together in a few minutes. This double cap multiplier beat the pants off the finnese and variations, and it's what I use in my low noise measurements preamp. Because the preamp schematic had such poor psrr I really needed this filter and got as low as about 0.4nV/rtHz preamp self-noise.

Sometimes a simple solution is enough. However, maybe a v1 Salas shunt is still doable with less idle current to avoid the heat issue? Then you get low output impedance too.

At least you have options :D
 
Because the preamp schematic had such poor psrr I really needed this filter and got as low as about 0.4nV/rtHz preamp self-noise.

0.4nV/rtHz at idle or when there is a dynamic load? I hope it is the later.

Anyway, given that the Marantz has such large capacitance in the load on board I guess higher impedance may be OK. I would add the Gyrator before the Marantz series regulator, in contrast to what TeddyPardon does to the output of the regulator.
 

iko

diyAudio Moderator Emeritus
2008-05-29 2:41 am
Toronto
This is a low noise preamp that I built to make low noise measurements with, and the idea is that you can't measure low noise if the preamp itself has self-noise. There are others who have built such preamps with even lower noise, but for me it is an achievent even so.

Bill, it's a simple circuit which you can do without a pcb, to test. If not good enough, chuck it and go to the next level. Or if you have doubts, definitely try something else.

Filter before the regulator, and then measure at the load. But remember to measure with very short ground lead on the scope probe.
 
Even the C-multiplier can be improved upon with a few components. In this case the output impedance is decreased, and bass response increases by a very large margin. Using a complimentary Darlington/CFP arrangement, the drive needed at the input is very small, in which case we can increase the bias resistors, increasing the RC time constant.

Using the CFP improves output impedance. It may improve HF impedance as well but it depends on the slave transistor, and the PNP version of the D44H11 has worse HF specs I believe which is why HF impedance is worse in this case. In this case you could probably avoid clunky low-voltage amp type devices and use old CRT flyback BJT's (cut out of monitors/TV's) which are fast with low Cob even if they have lower gain, and should be bulky enough for your application.

There is stigma surrounding the CFP because of its reputation for oscillating in amplifiers. I don't expect a big ordeal, but I haven't seen many do this so I can't be sure. The first thing I would try would be a base stopper on the power transistor.

- keantoken
 

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Another thing to consider with the CFP-multiplier is that if the load current drops below the quiescent of the master (Q3) the slave (Q2) will turn off. This is usually not an issue, especially if electrolytics are used in bypass, but if it is a problem you can use a bias resistor to draw several mA at all times.

Quiescent here is 4.6mA. For a 12V output, 1.2k will provide 10mA bias, good enough for me.

- keantoken