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Comments please on this statement..Ahemmm..."Kill the hum...Kill the Music."

152.132.10.193

Posted on June 15, 2015 at 09:21:43
Iczerman
Audiophile

Posts: 147
Joined: July 23, 2000
In my particular case I exchanged 50uf ASC Blue Line 1200v as 1st Cap in a CRC pi filter with 12.5 uf Continental Capacitor and REALLY liked the sound..but at the cost of a little more hum. I don't want to add more inductance because I believe too much inductance literally "chokes" the sound.
I running 845's ac filaments-b+ is around 1030 volts.

Just looking for others opinions.

I have 3 orphaned ASC blue line caps that are looking for a good home...I think I can say that here because they are not for sale????

 

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RE: Comments please on this statement..Ahemmm..."Kill the hum...Kill the Music.", posted on June 15, 2015 at 10:02:17
BofService
Audiophile

Posts: 741
Location: Atlanta
Joined: February 28, 2003
Two, 3 or 4 of those 12.5 uf Continental Capacitors might sound just as good and also kill the hum.

 

+1, posted on June 15, 2015 at 10:51:20
Tre'
Industry Professional

Posts: 17260
Location: So. Cal.
Joined: February 9, 2002
There is no reason the music should be killed just because you properly filter the B+.

In some cases having too little inductance and capacitance in a power supply filter will cause the B+ voltage to soar and sag with the music, giving it a more dynamic sound.

Having a fast settling time means that the voltage drop (or rise) happens very fast. With Class A circuits the average current draw is constant.

The power supply only has to hold the voltage steady against the current draw change that follows the music signal. The longest 'time of change' would be 12.5ms. (1/4 wave of the lowest frequency of interest, 20Hz)

Take a look at what happens in the first 12.5ms when using the PSUD's step function (which by the way does not represent anything that happens in a Class A circuit).

Remember, following the first 1/4 wave of increased (or decreased, in the case of a 2 stage amp) current draw is a 1/4 wave of decreased current draw (getting us back to the idle current draw) followed by a 1/4 wave of decreased current draw and then 1/4 wave of increased current draw getting us back to idle again.

The longer the settling time the less the voltage sags (or soars) in that first 12.5ms. The shorter the settling time the more the voltage sags (or soars) in that first 12.5ms.

Some people like that sound but it has to be considered distortion.

Longer settling times equals greater voltage regulation and that leads to less distortion of the output signal.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: +1, posted on June 15, 2015 at 11:11:16
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
"Some people like that sound but it has to be considered distortion."

Frank VA has, uncompromisingly, said, "You like distortion, you have bad taste". JMO, some folks equate euphony with fidelity, which is NOT the case.


Eli D.

 

Kill the hum, listen to the music., posted on June 15, 2015 at 19:11:41
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
nt

 

too much inductance won't kill sound but too much capacitance might, posted on June 16, 2015 at 02:31:32
lovetube
Dealer

Posts: 3008
Location: Melbourne Australia
Joined: June 8, 2003
if it was me I choose to use more choke than more capacitors

 

The question you should ask..., posted on June 16, 2015 at 07:11:14
PakProtector
Audiophile

Posts: 12356
Joined: May 14, 2002
would be why do the 'hum-y' circuits seem to work better?
cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

I think you might be right..., posted on June 16, 2015 at 08:36:03
Iczerman
Audiophile

Posts: 147
Joined: July 23, 2000
So I'm going from 3H to 10H.

 

RE: too much inductance won't kill sound but too much capacitance might, posted on June 16, 2015 at 16:55:18
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
That's been my experience with SE amps in general. Tried cranking the capacitgance way up thinking it would be more quite and the sound suffered. Finally went back to getting rid of the hum by having a properly designed psu and good lead dress. Works like a charm. Duncan's psud2 is a great help.

 

Agreed... I use 8 henry chokes 300 ma with DCR 35~nT, posted on June 16, 2015 at 17:23:50
Cleantimestream
Audiophile

Posts: 7542
Location: Kentucky
Joined: June 30, 2005
!
The Mind has No Firewall~ U.S. Army War College.

 

RE: I think you might be right..., posted on June 17, 2015 at 07:54:44
Triode_Kingdom
Audiophile

Posts: 10011
Location: Central Texas
Joined: September 24, 2006
" I'm going from 3H to 10H."

You're risking significant response ripple in the filter with that value. Large values of C will be probably be required after that choke in order to smooth the response and output Z.

EDIT: So as not to be misunderstood, 10H is excellent for eliminating hum and noise, just be sure the overall design performs well in other respects as well. I use SPICE to analyze the output Z of all my supplies. That - plus PSUD - will tell you just about everything you need to know.

 

Boys and Girls, posted on June 17, 2015 at 09:39:31
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
So far, NO ONE in this thread has gotten it right. Its hilarious to me !!

Don't people listen ??

Stay with what you hear, 3 HY and 12.5 uF. What you HEAR is what counts, NOT theory.

Jeff Medwin

 

RE: Comments please on this statement..Ahemmm..."Kill the hum...Kill the Music.", posted on June 17, 2015 at 10:21:33
I guess you mean CLC . You will get far superior sound with a much lower value first cap . 12.5uF is too high . I tend to use CLCLC for SE with the first cap usually 1uF or less and the first choke value approaching critical inductance . Second choke/cap by ear using whatever is suitable from the parts bin . It's a scheme closer to choke input which may require for your amp a different HT transformer . I'd suggest trying this regardless , even it it means a slight change of operating point

Al

 

RE: too much inductance won't kill sound but too much capacitance might, posted on June 18, 2015 at 09:28:50
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
I disagree. "I" find, any choke over 2.2 HY, 10 Ohms, and 2 pounds in weight degrades the sonics of my SE amps. YMMV. Fine !! A larger choke in the Finals B+ filter has too much DCR , and too much stored energy, and it always ( since 1982 ) ruins the timing of the music to my ears.

Jeff Medwin

 

RE: too much inductance won't kill sound but too much capacitance might, posted on June 19, 2015 at 02:55:40
jazbo8
Audiophile

Posts: 70
Location: Europe
Joined: January 16, 2012
May be it's you that have too much stored energy ;-)

 

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