SS vs. Tube Rectification (and chokes)?

[Sherman]

Hi,

...The trouble with using multiple caps in //, even from the same manufacturers and with the same nominal electrical data, is that they are all slightly different.
This won't be much of an issue if only a few are used but can potentially lead to odd resonances when alot of them are put in //.

Cheers,

Frank,
The largest value ASC I could lay my hands on is 100uF. Using PSU Designer II I "built" a PSU like this;
PTX-->Rect-->50uF-->5H Choke-->100uF-->on to the amp

Using a 350V PTX and that arrangement PSUD says 407+ VDC (I'm looking for 400 so that's good) and shows no ringing or other problems.

However a total of 150uF per channel seems low to me and that's why I asked about paralleling caps. But since PSUD seems to indicate it will work I'll probably give it a try "as designed" with just 150uF.

 

[Sch3mat1c]

An extra wire and/or solder joint is irrelevant, and none of the components mentioned so far aren't likely to fail in the circumstances you're going to use them in.

Yep. Come on... the tube might look like a 100 ohm resistor -- if it fails shorted! Heck, not even that; the OPT has more resistance. You'll have some respect for *real* currents building a project like I'm working on, an induction heater. Resonant currents of 200A at 100 to 200VAC in the 30 to 60kHz range. With a Q of even 80 in the coil, that's still 500W idle consumption! With a class C amplifier running maybe 33% duty cycle, that's 15A right away. Here, a few inches of the 1/4" tubing can matter.

Tim

 

[Sherman]

...You'll have some respect for *real* currents building a project like I'm working on, an induction heater. Resonant currents of 200A at 100 to 200VAC in the 30 to 60kHz range. With a Q of even 80 in the coil, that's still 500W idle consumption! With a class C amplifier running maybe 33% duty cycle, that's 15A right away. Here, a few inches of the 1/4" tubing can matter.

Tim

Holy cow! I'm not sure I'd want to be in the same room as that beast! On the other hand it would do a better job of heating my house than the average amp.

 

[Sch3mat1c]

Holy cow! I'm not sure I'd want to be in the same room as that beast! On the other hand it would do a better job of heating my house than the average amp.

Hehe. Not with me in control anyway (Unless you like the sacrifical smell of smoked solid state )

Tim

 

[Sherman]

Re: A LA CARTE........

... I'd replace the 6N1P and use a ECC88 of decent pedigree, ommit the cathode bypass on that one too.
...
Cheers,

I happen to have in my parts collection a pair of 6922 valves from Sovtek. Would there be any benefit from replacing the 6N1P with a 6922?

 

[fdegrove]

Hi,

Would there be any benefit from replacing the 6N1P with a 6922?

Since you already have them, why not give it a try?

Cheers,

 

[Sherman]

Hi,



Since you already have them, why not give it a try?

Cheers,

Will do. I had completely forgotten those tubes were in there. It is nice to get a surprise like that when poking through the shelves. (If only I could find a nice pair of OPTs in there somewhere! Oh well, a couple of "free" valves isn't bad.)

 

[jamato8]

I have found that in almost all cases that the 6N1P is a better sounding tube than the rest of the 6DJ8 types, including some very highly thought of ones. It does draw twic the filament current so that must be considered. But of all the 6DJ8 types I prefer the inexpensive 6BZ7, which came before the 6DJ8 and costs around 2 to 3 dollars.

John

 

[Sherman]

...of all the 6DJ8 types I prefer the inexpensive 6BZ7, which came before the 6DJ8 and costs around 2 to 3 dollars.

John

John,
You are the second person to tell me that! It is interesting to me how some older designs (I guess they are all older designs now ) are still the best. Like the 300B I suppose.

I think I'll give the 6922 valves I already have a shot and then consider either going to the 6N1P or a 6DJ8 type (or both). These tubes are not so expensive that I couldn't try a few.