Output Coupling Capacitors

@Doc, gotta love it!  $5k for caps..... I have read much about the Duelunds, and I am sure they are the best you can buy, but....really???!!$5k?  I gotta start winding my own!

Love the new kit, almost ready to pull the trigger on one!

Here are some vintage Mallory 100uF 250V, it takes a bit for the page to load then scroll a ways down:

http://www.vt4c.com/shop/program/main.php?cat_id=2&group_id=1&hit_cat=
 
Although that link says, "Paper Tube Electrolysis Capacitor,"  I feel sure they meant to say Electrolytic.  Most old electrolytic capacitors are leaky.  And I don't mean physically.  The electrolyte is drying up and they are not as good as they were when made.

Maybe these Mallory caps are different?

On second thought these caps might have been used for electrolysis after all.
 
My Axons arrived today.  Not very scientific but I downloaded the jpg of the underside view and zoomed it up via Preview.  Best I could do was about 5.75"; close enough.  Holding one of the caps to my monitor it appears that they'll fit just fine.  They'll fit better without that terminal strip adjacent to the 6AS7. 

Doc B. said:
I ordered some of the Axons yesterday, and I'll let you guys know how we end up fitting them in. We also put C4Ss with BIG heatsinks on the 6080, so it may be a bit of a tight fit in our prototype.
Click to expand...
 
You could hop on over to Radio Shack and buy an extra 5 lug terminal strip, then add it to the 2nd bolt on the 6080.  Then the big honkin caps can fit between those two strips, with the caps tied between the outside terminals on the two strips.  I would jumper from the cathode pins of the 6080 (3 and 6) to the outside terminals of your added T-strip, then the wiring for the headphone outputs can be retained. 

You will, undoubtedly, have to bend the leads of the caps around their bodies a bit to get them to fit, but it should work fine. 
 
And what would be the value/rating of that?  Will you be including a TSHA with the kit?

Also, can I ask how many terminal strips will be in this amp -- not including the extra one PB just mentioned?

-- Jim
 
The power supply capacitors in the kit are the 220uf 250v caps found in the extended Foreplay III.  These are TSUP series Panasonics. 

There will be four terminal strips included with the kit: two 5-lug strips, and two 6-lug strips.

Although the quality of the last cap in the supply is quite important as PJ mentions, the value is also quite critical.  If it gets sized down much at all, the ripple becomes audible.  Of course, the ESR of film caps tends to be nice and low, so some experimentation will probably be needed to find a comfortable balance.

Incidentally, there is probably just enough room to squeeze a giant Solen cap between the 6-lug terminal strips that flank the power transformer.  I may need to trade in my ugly prototype for a fresh kit when the plates arrive...
 
Thanks, Paul.  I forgot to ask if there will be one or two of these PSU caps.  I'm assuming you're using dual supplies so as to balance the transformer secondaries on the PT-3, so I'm therefore assuming two big psu caps.

-- Jim

 
I may need to trade in my ugly prototype for a fresh kit when the plates arrive...
Click to expand...

You may have to take a number. We doubled the initial chassis plate order and just ten days after introducing the kit we have only ten kits left from  the first run.

We got the Dayton film caps in yesterday and gave them an initial listen. While they sound clearer and cleaner it makes me realize that the stock lytics are pretty good. I think the C4S upgrade makes a bigger improvement than the cap upgrade. We will be figuring out an upgrade for the final cap next. The chassis is getting very crowded with all this upgrade experimentation...
 
Oops, make that only seven kits left from the first run. At this rate those will probably all sell this weekend. We will start a second run as soon as those sell, which probably means a lag of at least a couple weeks between runs. So if you're thinking about ordering a kit, today would be a good day to do it.
 
I like your idea.  I've been toying with various ideas for securing those caps to the top plate; the glue gun idea didn't last long.  Strictly based on that photo I've been toying with not using either of those two terminal strips and going point-to-point but using strips as supports for those caps makes for a pretty elegant solution.

Caucasian Blackplate said:
You could hop on over to Radio Shack and buy an extra 5 lug terminal strip, then add it to the 2nd bolt on the 6080.  Then the big honkin caps can fit between those two strips, with the caps tied between the outside terminals on the two strips.  I would jumper from the cathode pins of the 6080 (3 and 6) to the outside terminals of your added T-strip, then the wiring for the headphone outputs can be retained.  
Click to expand...

You will, undoubtedly, have to bend the leads of the caps around their bodies a bit to get them to fit, but it should work fine.  
Click to expand...

Here are some rough dimensions if anyone's considering these caps:

Each lead is 2 3/8" long.  The body's 2 5/8" long and 1 3/4" tall.
 
jrebman said:
Thanks, Paul.  I forgot to ask if there will be one or two of these PSU caps.  I'm assuming you're using dual supplies so as to balance the transformer secondaries on the PT-3, so I'm therefore assuming two big psu caps.

-- Jim
Click to expand...

Jim, I looked at the picture of the Crack belly and there are 3 caps in the power supply.  One has to be for the heaters, the other two are for the high voltage. 
 
The three caps are all power supply caps for the B+.  It took a CRCRC to really get the Crack nice and quiet.

On the layout, I would suggest sticking pretty close to what is there in stock form, as the upgrades that are coming down the pipeline will be somewhat harder to install without some terminals on the T-strips available.
 
The newest:

http://www.cde.com/catalogs/944U.pdf

The littlest one is 100uF and less than 2" tall. For about $300 you can replace the last PSU and the output caps. Plus the cost of a second chassis box to mount them...

Here's the big guys:

http://www.cde.com/catalogs/947C.pdf

CDE makes more kinds; these are just what's at Mouser.
 
Ok, I goofed big time when I asked:

Thanks, Paul.  I forgot to ask if there will be one or two of these PSU caps.  I'm
assuming you're using dual supplies so as to balance the transformer secondaries...

Afterreading this again I realized how stupid that was.  Of course you're not using dual supplies as there is only one output tube ;-)

Ok, putting on my dunce cap and going to sit in the corner for a while :-).

I got a 6080 the other day and just love the look of it as it resembles a giant 6sn7.  Just never saw a tube quite with a form-factor like this.  I was expecting a big ST type like the 6AS7s I had a while ago.

-- Jim
 
Dude, you were right the first time. The output tube is a dual power triode, and a dual-mono power supply would be perfectly reasonable. Just not at the $199 price point ...
 
From the Crack "belly Shot" the PSU looks to be C-R-C-R-C, amd AC filaments for the two valves.  I'll SWAG those WW power resistors are around 270 ohms @ 5W ?

Would bypassing the two  100 uF output caps with something like 2.2uF @ 250V film, or "Green Kommie Kaps" be a useful upgrade?

Looks like I got the next to the  next to last one of the first run!  yahoux!!!!

/ed B in NC
 
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