Exactly because the 1930/5171 are so fast I was afraid about oscillation.
One very efficient way to get low ESR in the output caps is to use 100 nF 1206 ceramic caps. There are some that can stand 63 V, at least in theory. I have had one of them explode at 48 V...
Spoerle is an idea, but then they only ship to businesses, so I'd have to talk somebody into ordering for me.
Don't know Heho. Got an URL? Are they reliable? Some others may ship you counterfeit junk.
Greetings,
Eric
One very efficient way to get low ESR in the output caps is to use 100 nF 1206 ceramic caps. There are some that can stand 63 V, at least in theory. I have had one of them explode at 48 V...
Spoerle is an idea, but then they only ship to businesses, so I'd have to talk somebody into ordering for me.
Don't know Heho. Got an URL? Are they reliable? Some others may ship you counterfeit junk.
Greetings,
Eric
Oscillation is no problem. To my opinion the ceramic caps sounds worse than the MKPs
The URL from heho is:
http://www.heho-elektronik.de
The URL from heho is:
http://www.heho-elektronik.de
Technically right. As decoupling caps for digital parts I'm using 100nF 0603 X7R ceramic caps. They have half the inductivity as the large 1206 caps. And 0603 are much cheaper than 1206.
WIMA has also some different opinion to ceramics.
You can obtain the superior performace of the ceramics only, if you are using a proper (I mean really proper!) layout. 95% of any layout seems not designed in a good (decoupling) way. Look to the return parth to nearly any PCB what I mean. If you take not care of the return path, you can use a film capacitor as well without any performance degration.
Again: sonically I prefer MKPs to ceramics, not only in the signal path also as (analog) decoupling caps
WIMA has also some different opinion to ceramics.
You can obtain the superior performace of the ceramics only, if you are using a proper (I mean really proper!) layout. 95% of any layout seems not designed in a good (decoupling) way. Look to the return parth to nearly any PCB what I mean. If you take not care of the return path, you can use a film capacitor as well without any performance degration.
Again: sonically I prefer MKPs to ceramics, not only in the signal path also as (analog) decoupling caps
Re: Re: discrete voltage regulator
Charles, Bocka, Jocko,
Good design, I have been using variations of this for years.
Charles you are right on WRT CFP FB loop. There is a loop
however small. And so it goes, you can do a 3 stage CFP
and get lower OP Z, more OLG and worse HF performance.
You could also replace 33R with current source, same effect
more OLG, worse HF performance. Seems simple works
best.
I've tried em all in follower mode and in shunt mode, 1, 2
and 3 stage versions.
Interesting experiment, once I built these for clients DAC
in shunt mode and left a shorting link for the CFP tranny
to turn it into simple 1 transistor follower. He didn't know
anything about electronics, just that it sounded different with
the link shorted (EF). Always preferred simple 1 tranny (EF)
config. So you are not alone Charles!
Terry
Charles Hansen said:
Charles, Bocka, Jocko,
Good design, I have been using variations of this for years.
Charles you are right on WRT CFP FB loop. There is a loop
however small. And so it goes, you can do a 3 stage CFP
and get lower OP Z, more OLG and worse HF performance.
You could also replace 33R with current source, same effect
more OLG, worse HF performance. Seems simple works
best.
I've tried em all in follower mode and in shunt mode, 1, 2
and 3 stage versions.
Interesting experiment, once I built these for clients DAC
in shunt mode and left a shorting link for the CFP tranny
to turn it into simple 1 transistor follower. He didn't know
anything about electronics, just that it sounded different with
the link shorted (EF). Always preferred simple 1 tranny (EF)
config. So you are not alone Charles!
Terry
Bocka,
You said you tried a Mosfet as a pass element and you did not like it, what mosfet did you use, and did you try it in a CFP mode?
Terry and Charles,
I have found the same result as you have. I find feedback regulators and CFP configured as the pass element might sound a tad more dynamic during initial listening but you soon realise they lack musicality, smear transients and are flat in comparison.
Have any of you found that loading the regulator at it's output helps the sound?
Regards,
Jam
You said you tried a Mosfet as a pass element and you did not like it, what mosfet did you use, and did you try it in a CFP mode?
Terry and Charles,
I have found the same result as you have. I find feedback regulators and CFP configured as the pass element might sound a tad more dynamic during initial listening but you soon realise they lack musicality, smear transients and are flat in comparison.
Have any of you found that loading the regulator at it's output helps the sound?
Regards,
Jam
Jam:
>you soon realise they (feedback regulators and CFP configured as the pass element) lack musicality, smear transients and are flat in comparison.<
Many feedback regulators and CFP configurations are problematic in a multitude of ways, but at least in my findings and opinion, some are not very problematic at all (although nothing is perfect). The outcome depends on the individual circuit (including the PCB layout and physical construction), what sort of load it is being asked to drive, and if we are to include subjective criteria, the remainder of the audio system, and the tastes of the individual listener(s).
OTOH, undoubtedly you should go with configurations that don't give you any problems (measureable or subjective) and you are personally happy with.
>Have any of you found that loading the regulator at it's output helps the sound?<
Auxiliary loads should be considered in combination with the behaviour of the circuit that the regulator is driving. In other words, I would look at the total load.
hth, jonathan carr
>you soon realise they (feedback regulators and CFP configured as the pass element) lack musicality, smear transients and are flat in comparison.<
Many feedback regulators and CFP configurations are problematic in a multitude of ways, but at least in my findings and opinion, some are not very problematic at all (although nothing is perfect). The outcome depends on the individual circuit (including the PCB layout and physical construction), what sort of load it is being asked to drive, and if we are to include subjective criteria, the remainder of the audio system, and the tastes of the individual listener(s).
OTOH, undoubtedly you should go with configurations that don't give you any problems (measureable or subjective) and you are personally happy with.
>Have any of you found that loading the regulator at it's output helps the sound?<
Auxiliary loads should be considered in combination with the behaviour of the circuit that the regulator is driving. In other words, I would look at the total load.
hth, jonathan carr
Hi Jonathan,
Where have you been hiding?
I might be generalizing but I is a lot harder to get a feedback regulator right. In my experiments I have built several feedback regulators and some have been very good but seem to always go back to the pass element referenced with a zener. The zener is usually bypassed with a small film cap and fed with a current diode.
Maybe one day I will find a feedback regulator that I am happy with. I have to admit that I fave a fondness for shunt regulators but they can be pretty complex.
Regards,
Jam
Where have you been hiding?
I might be generalizing but I is a lot harder to get a feedback regulator right. In my experiments I have built several feedback regulators and some have been very good but seem to always go back to the pass element referenced with a zener. The zener is usually bypassed with a small film cap and fed with a current diode.
Maybe one day I will find a feedback regulator that I am happy with. I have to admit that I fave a fondness for shunt regulators but they can be pretty complex.
Regards,
Jam
I'd used an IRF9530 for the positive regulator as pass element in CFP mode. The measurement behaviour is bad.
And it depends on the following amp someone is using. BTW it should have been said that the regulator requires 0,6V over the 33 ohms resistors. This regulator needs at least 20ma (better 30-40ma) of output current. Loading of the output in this way might not be an option it's necessary under some circumstances. My pre - where I'm using this regulator - requires about 120ma so I've no problems with it.
To my opinion higher driving currents in the first transisor sounds better.
I've used a (power-) shunt regulator before (and it sounds best) but the behaviour of my pre was more than a heating than an amp...
It's a differential bjt stage first followed by a VAS stage and shunt transistor. Vref is obtained by a LED and 6.2V zener. And it dissipates a lot of power. It's not (thermically) stable for no or very low output currents (it will burn, because it needs a well defined output current range), it's not a design you can simply modify or adapt to other circuits, because you must change nearly everything. That's why I do not post it here.
Re: Re: Re: discrete voltage regulator
Hello Jan,
Thank you! Just in case there is any confusion, there are two Charles Hansens in audio right now. One Charles Hansen lives in Maryland and contributes many articles to AudioXpress. I am the Charles Hansen that lives in Colorado and designs for Ayre Acoustics, Inc.
Best regards,
(the real!) Charles Hansen
janneman said:
Hello Jan,
Thank you! Just in case there is any confusion, there are two Charles Hansens in audio right now. One Charles Hansen lives in Maryland and contributes many articles to AudioXpress. I am the Charles Hansen that lives in Colorado and designs for Ayre Acoustics, Inc.
Best regards,
(the real!) Charles Hansen
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