Why 7805 is better than LM1085?

[Fred Dieckmann]

Yes!

Fred

[fdegrove]

Sorry to wake you.Here it's almost five a clock...

"The maximum capacitance after the reg is pretty much defined by the datasheet of the manufacturer.Going over it will invariably bring instability and to top it all of it will render the regulator useless.It just won't do its job."

The datasheets I got state a maximum Fred.
I'll stand by that.I've seen al too many a reg fall on its' face overdoing it.

Yes!

And so could I.
My only problem with it is that I would not claim that to be a cure all unless you design with that in mind from the bottom up.

Cheers,

[Fred Dieckmann]

There is a real siimple solution for this.....

Post a schematic of what you consider to be a good and adequate supply. I will be happy to build it and compare it to what I consider to be a gratuitously tweaked supply.

Fred

[SY]

I'll be happy to. Send me the circuit you want powered, along with your specs for voltage and current. I'll design and build a supply for it. We'll evaluate the results using a procedure where neither you nor I know which is your supply and which is mine- assuming, of course, that both supplies show nothing but DC and have noise below, say, -100 dB. We'll post the results here.

Your place or mine for the evaluation? I probably have a better wine cellar, so I'd suggest the latter.

[fdegrove]

Hi fellows,

Who's putting who to the challenge here?

Cheers,

[fdegrove]

Your point about not verifying observations is key; it does indeed lead to a lot of chasing of one's own tail. I noticed people on other threads exulting over how much their sound improved when going from a fast silicon rectifier (very low Z) to a tube rectifier (very high Z). Or even worse, a mercury vapor tube, a horrific source of HF noise (I last used 866s in my high-power 8005-based transmitter and the PS alone screwed up every TV set in the house).

Remind me to address this please.

I urge you to post in the tube section as well so I don't feel like I have all the the "splaining" to do to paraphrase Jocko.

Sigh,

[SY]

fdegrove, I've posted a few things over at the tube section. The rectifier discussion didn't/doesn't interest me much. There are easier, cheaper, and more efficient ways to generate a stable DC rail, so I'm not real motivated.

No "challenge" intended, BTW, I just wanted to make the point that a power supply is part of an overall design. There are a lot of tools available to accomplish tasks in electronic devices, and how one chooses the tool is best influenced by understanding what you're actually trying to do in some box of gain with phono jacks and a power cord. Saying "submit a power supply design" is equivalent to saying, "design a cog."

And I'm always delighted to open a nice bottle when I have some excellent music playing, so...

[patwen]

Anybody in his right mind would be absolutely delighted with the concentrated knowledge and experience he got for free.

Not this guy. He just started a new thread, complaining that on the other one they gave him so many different answers, and pleaded if someone now please give him the RIGHT answer.

janneman>

Please don't be offended. We are all discussing here, right? For some answers which from my limited experience, I cannot agree on, I expressed my opinions. Taking other's comments without self-thinking is, IMHO. counter productive.

Please don't take that as anything negative, as my opinions could well be wrong. But at least I am trying, testing, listening and try to learn and share as I go along, so please don't shoot.

Anyway, I will post the circuit diagram up when I am back in town in a few days, so we could have something more solid to discuss our opinions on.

Many thanks for all the inputs.

[Fred Dieckmann]

And thats all we can ask of anyone. Don't apologize to anybody for that. As I have said hearing something for yourself is always better then hearing about something from someone else.

Go for it,
Fred

[fdegrove]

Hello,

I just wanted to make the point that a power supply is part of an overall design. There are a lot of tools available to accomplish tasks in electronic devices, and how one chooses the tool is best influenced by understanding what you're actually trying to do in some box of gain with phono jacks and a power cord. Saying "submit a power supply design" is equivalent to saying, "design a cog."

Absolutely.
Let's also agree that still a fair amount of engineers will dismiss the idea that for a given circuit reg X doesn't sound the same as reg Y.

And after all this IS what we're discussing.
No measuring rig can acurately display what we hear.
OTH,there is far more that can be measured then most seem to believe.

"Normally, capacitor values on the order of 100mF are used in the output of many regulators to ensure good transient response with heavy load current changes. Output capacitance can be increased without limit and larger values of output capacitor further improve stability and transient response of the LT1083 regulators"

That shows that the LT is a well designed regulator.
Saying you can do this with any off the shelf reg is where I would firmly disagree.

See you,

P.S. SY,can't help but wonder what delicacies you have sitting in your whine cellar....