[ScottRT]

Digikey comes up blank now on the 3A diodes previously part # 1N5821. They have some 5822 but they are only rated 20 volts.

I cant come up with anything in their search engine for 3A, 30V, axial, fast recovery, available in individual piece lot size.

Can anyone recommend a properly rated sub, preferably fast recovery and axial that will work?

Thanks....
Scott T.

[Bill Epstein]

http://digikey.com/scripts/DkSearch/dksus.dll

Expensive silicon carbide, the best

Michael Percy still has the cheaper Fairchild Stealth

[GBB]

When I check, I see that Digikey has them in stock from several different manufacturers:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=1N5821-E3%2F54GICT-ND

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=1N5821DICT-ND

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=1N5821RLGOSCT-ND

And the 1N5822 can be substituted since it's got a higher reverse breakdown rating.
---Gary

[ScottRT]

Thanks Gary. I can't for the life on me figure out why I could not get these to come up. I spent over an hour filtering diodes. I have bookmarked your links!

Gratefully,

Scott T.

[tubesforever]

Scott, I plan to do this modification down the road. 

From what I have learned in researching HexFreds for power supplies, it is not the speed of recovery that is important but rather having a soft recovery.  For that reason an more expensive SFRED does not necessarily sound better than the Fairchild Hexfred.

I am pretty sure M Percy has what you need.  You might ask him what his take is on this subject.  Knowing him, he would have whatever is best for power supply needs.

The ultra expensive SFRED's are suppose to sound really great.  I understand these are pricey but effective.  I was hoping to hear back from Bill Epstein about his C2 with the Fairchilds.  He has his C2 on a slow simmer while he finishes some speakers.  I think he said the Fairchilds run about 1.50 each.  I will need 24 to do my two amps and Clarinet/Cornet 2.  I could order 4 extra if you want to try them.  Let me know.

Uh ohhhh   I think I am volunteering for a group purchase thing again.   I had better watch out.  The last one consumed about 18 hours time! 

[Bill Epstein]

Hey Tubes, the speakers are done, driver holes drilled, stuffed, wired, etc.,  except for the last coat of finish but the humidity is holding me back. Got to get a pair of ceramic caps for C100 and 101 then I'll be back to the Cornet. You may be the one to let us know about the diodes, first.

[ronpod]

Does a soft recovery mean that the diode does not have a ring out that must be filtered by the PS cap? (And the harmonics may escape deeper into the audio circuit?) Snappy recovery diodes appear to have a ringing characteristic that would not be wanted anywhere close to early stage audio. Does C106, C209, C210, and C211 in the Cornet have trouble filtering this type of signal from the tube heaters?

ronpod

[tubesforever]

Ronpod,

I hope that others with more knowledge than I have will step in here.  From what I understand, back in the day designers could sometimes specify Zener diodes to create the DC heater current and the DC bias current in an amplifier.  However the Zeners are known to produce ripples and the ripples mean noise.

When the Fairchild Hexfreds came out they were all the rage.  Now you could achieve a quieter noise floor.  The key was combining the better DC conversion of the hexfred with a soft recovery feature.  That made for less ripples and improved sonics.  Perhaps ringing can be as bad as the ripples, however it would depend on where they hit in the audio frequency. 

The thing with the Shottke diodes that JH recommends is that they are also an improvement over the Zener diodes.  I am fairly certain they are a huge improvement over a Zener diode.   My Clarinet and Cornet 2 are so quiet that you think you have the wrong input selected on the preamp.....  All the way until the needle hits the grooves. 

If the Fairchild Hexfreds are better I will be able to hear it on my system. 

I have not gotten to this yet because I have some turntable projects that have to be completed on a tight time frame.  These are labors of love.

The Fairchild hexfreds project might slip right into fall or winter before I get a chance to try them.

Cheers!

Ringing and Ripples....these are all bad things for audio.