Mcandmars ramblings \ build thread...

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Offline mcandmar

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Reply #75 on: January 24, 2015, 11:01:10 AM
Interesting, they say with most audio equipment you are listening to the power supply, i suppose the same is also true for electrostatic speakers.  They sound like an interesting pair of speakers, i thought you were using a full Blumenstein setup?

I am still deeply impressed with these capacitors. I also picked up a pair of Jupiter paper/wax .1uf 600v caps for a steal recently so they should make for an interesting comparison.  I am a little concerned about the chassis heat despite the fact they have the same temperature rating as the Mundorfs of 70c.  More as it happens..


M.McCandless


Offline Grainger49

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Reply #76 on: January 24, 2015, 02:50:36 PM
The Servo-Static I was an interesting speaker.  It was electrostatic from 100 Hz up.  It had the first commercial subwoofer with motional feedback.  It came with a three way crossover/servo sub amplifier.  It took two more power amps to run them.



Offline mcandmar

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Reply #77 on: January 24, 2015, 03:37:04 PM
Motional feedback is an interesting concept i had never heard of before, complex looking circuitry mind you!

M.McCandless


Offline Grainger49

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Reply #78 on: January 25, 2015, 02:17:21 AM
It is old.  Many, maybe most, of the subs marketed for high end audio today use some feedback from the cone to the amp to correct its motion.  It is so widely used that it is hardly mentioned.

The SS-1 came out in 1969.



Offline mcandmar

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Reply #79 on: March 06, 2015, 11:39:07 AM
Fancy Caps: Jupiter HT Paper BeesWax .1uf 600v

HT are the "High Temperature" range suitable for valve amps. I have heard of potential issues with these failing due to heat, but they are rated for 70c which happens to be the same as the Mundorf Silver Oil range i am using in the output stage.  They do have to endure 30-40c inside the S.E.X. amp so time will tell how well they last.

Manufacturers blurb:
Quote
A unique blend of the old sound with refinements of the new. New high temp (HT) series replaces the original beeswax/paper design (3rd generation design). Jupiter Condenser HT line of capacitors feature a reinforced beeswax paper dielectric and (with further improved impregnation techniques) is now cased in a non-drip/melt casing and can withstand higher operating temperatures. Perfect for DIY and OEM use where natural sound is demanded.

The "new look" to Jupiter Condenser Co. capacitors, is true to form following function. Not just a new style, the outer casing is still true to natural materials yet offers improved environmental characteristics. A paper tube impregnated with phenolic resin assures excellent moisture resistance along with a resin end fill to lock moisture out. The casing material will not melt or drip even at higher temperatures.

For productions, a computer controlled wax vacuum impregnation system was engineered and built by Jupiter Condenser, and section processing is based on techniques developed by Western Electric and RCA. This is capable of deep vacuum and high pressure, providing consistent impregnation with more gas and moisture removal. New proprietary measures of strengthening dielectric properties have been developed and employed which yield higher insulation resistance and allow greater operating temperatures. Wax and paper construction yields a very well mechanically damped capacitor, free from electrostatic and mechanical ringing.
Specifications:

    Tolerance ±5% standard
    Rated voltage 600Vdc - Tested at 1200VDC at two stages of production
    Pure silver leadouts 20 AWG (0.812mm dia.)
    Max temperature +70°C
    Beeswax impregnated Paper dielectric
    Aluminum Foil electrode material

Normally i wouldn't have considered a "premium" capacitor such as these but i managed to pick up these two for less than half their retail price, an offer too good to pass up. They are clearly superior to the FT-3's so a side by side comparison is a bit pointless, vs the Gudeman oils however there is less of a difference.   The two are very similar but i would have to say the Gudemans have a larger, bigger sound to me.  i.e. more dynamic, and energetic sounding.  The Jupiters are a little bit more restrained, but have better tone/detail and a clearer high end.  I have switched between the two twice at this stage and still cant make up my mind which to keep in there.  Gudemans are more fun, but i suspect the Jupiters are technically more correct if that makes sense.

Are they worth the premium price new?   They are listed for @£22 or $33 each so if that doesn't scare you off then i can highly recommend them.  They are also tiny at 14x25mm!

M.McCandless


Offline kgoss

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Reply #80 on: March 06, 2015, 12:28:57 PM
I have had Jupiter HT caps in my S.E.X. amp for years with no problems.  My amp runs almost every day for several hours at a time - 8 hours today. I have had no problems in that time so I dont think you will have heat related problems either. I have a pair of 0.1uF caps in the interstage or coupling position and a pair of 2.0 uF output caps since I have the Magnequest full nickle output transformers installed on my 2.0 version of the amp. I like the Jupitor caps so much I have never wanted to replace them.  Although the new copper foil caps are tempting me...

Ken Goss


Offline Paul Joppa

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Reply #81 on: March 06, 2015, 08:54:56 PM
The original Jupiter caps, in the v2.0 SEX amp (without the ventilation holes in the top plate) has some incidents of melting wax and internal short circuits. I don't think we've heard of any such problems with the new, higher temp versions. Nevertheless, being a conservative engineer, I recommend parts rated 85 degrees C or more. I like my safety margins.

That said, the Jupiters I've heard sound pretty darn good.

Paul Joppa


Offline mcandmar

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Reply #82 on: March 07, 2015, 04:27:23 AM
That's good to know, thanks folks.   I also have a pair of 2uf HT's that i was going to install into the S.E.X but decided to keep those for my speaker preamp instead.

Its funny how premium grade capacitors like Mundorfs and Jupiters always seemed a little excessive to me until i actually tried them, now they seem great value :)

M.McCandless


Offline feeench

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Reply #83 on: March 09, 2015, 06:58:34 PM
Reporting in...

I placed two 1/4 watt 100R resistors from C1 to C3 and C2 to C3, I could hear a hum before with my HD650's on the 4ohm taps... It's gone now, for me. :)



Offline mcandmar

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Reply #84 on: March 10, 2015, 06:03:02 AM
Result!, thanks for reporting back :)

M.McCandless


Offline sbelyo

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Reply #85 on: March 24, 2015, 08:58:19 AM
I would like to install  the resistors from C1 to C3 and C2 to C3 during the initial build.  Right now I'm at the input wiring part.  What step would you install them, and would there be any notes like attach but don't solder just yet?



Offline mcandmar

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Reply #86 on: March 24, 2015, 09:19:12 AM
Page 21, the paragraph
Quote
( ) Using the end stripped back 5/8”, insert the black
wire into the bottom hole of terminal C1, from the back
side of the strip. Insert the red wire into the bottom hole
of C2. Solder C1L and C2L.

Just before soldering those two wires i would add in the resistors to C1L, C2L, and C3L, BUT i highly recommend you build the amp completely stock first because if you do have any issues those will only complicate matters and make it harder to troubleshoot.  They may also give you different readings for the resistance and voltage checks from what is in the manual.

M.McCandless


Offline sbelyo

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Reply #87 on: March 24, 2015, 10:23:27 AM
good point...  Normally I always build a bottlehead kit in stock form first.  It's just that it looks like it's hard to add them in afterwards.  I've already passed that step I think so I guess They'll go in later if need be
« Last Edit: March 24, 2015, 10:25:41 AM by sbelyo »



Offline i luvmusic 2

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Reply #88 on: April 04, 2015, 04:14:02 AM
What is the equivalent of the C3X from Hammond(Patrsconnexion)?

Thanks!



Offline Paul Birkeland

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Reply #89 on: April 04, 2015, 07:15:31 AM
What is the equivalent of the C3X from Hammond(Patrsconnexion)?

Thanks!

157H is pretty close. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man