Stereo 70 Caps/Cap Boards

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Stereo 70 Caps/Cap Boards

Postby Shannon Parks » Thu Feb 03, 2005 6:26 pm

Hi Gents,

Are the SDS cap boards available from anyone anymore? It seems to be the best option (that I know of) for those wanting to use modern snap mount caps - it's a good design. Anyhow, I'm not planning on doing my own cap board and just wanted to see what options are out there for folks. I guess I will recommend new manufacture twist lock replacements. Ned and AES have them.

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SDS cap boards

Postby Thermion » Thu Feb 03, 2005 8:19 pm

I think that Ned sells these at Triode Electronics. Thats where I got the cap boards for my MKIIIs.

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Postby TerrySmith » Thu Feb 03, 2005 9:07 pm

AES sells the twist-lock cap in the stock 30-20-20-20, or a 80-40-30-20 @525v for the same price. I have the latter in my '70, the 40 section first, then 80-30-20. Either fits and looks nice.
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Postby EWBrown » Fri Feb 04, 2005 7:25 am

Ned has the SDS boards listed at Triode Electronics, but they were out of stock as of the last time I checked.

I have used both the ST-70 driver and cap boards in a couple of ST70 retoration / clone projects (including the "stainless steel behemoth")

The latest restoration (basically a ground-up rebuild) I used the VTA-70 driver board from tubes4hifi.com. This one uses three 12AT7s, no 7199s or EF86s to deal with...


/ed B in NH
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Postby mesherm » Fri Feb 04, 2005 10:38 am

As Terry did, I also used the 80/40/30/20 in both of my ST70 types. I also used Roy Mottram's VTA driver board. It works well because all the driver filter caps are onboard so one only needs to supply the first 2 filter stages.
I had diode rectification so I used the 80+choke+40/30/20. I also added a Ruby 500v 47mfd cap to each side under the chassis. I used 2 of the surge resistors that Shannon uses on the ST35 in parallel on the PT primary for soft start and to drop extra B+ voltage due to the diodes. I modified the bias circuit to yield -65v maximum. I can now use 6L6s as well as EL34s. The VTA driver board, like the ST35 board has individual bias adjustments for each power tube.
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Postby EWBrown » Fri Apr 01, 2005 1:40 pm

I recently bought one of these ST70 cap boards,

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... eName=WDVW

THey fit under the chassis, and the mounting holes and spacers are located so that it can use one of the OPT's mounting screws to secure it.
Very nice construction, and it has the diode and caps to replace the original biasing rectifier and caps. THese are $69 plus shipping, and have a lOT more capacitance than the original or replacement can caps.It also has the two 0.02 uF caps for the filament CTs.

/ed B in NH
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Good Ol' Ned....

Postby Shannon Parks » Mon Apr 04, 2005 5:58 pm

I see Triode Electronics has the SDS Cap boards in stock again. Whew!

I also saw that Ned is now carrying the 'one piece' 9-pin PCB ceramic socket. This is good news. I just bought a bag of 'em several months ago from Handmade, so it is good we have these options. I highly recommend them over the 'two piece' socket.

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Blue Glow

Postby EWBrown » Tue Apr 05, 2005 1:19 pm

One neat trick that can be done with these sockets on the ST70 or DIY35 board, is to poke a blue LED up thru the "centering" holes on the board, some of the light will pass thru the tube socket center hole, and give those tubes an eerie blue glow. Doesn't have to be blue, any color will work, but blue just looks "coolest"...

Give it that "nuclear" (or is that nucular?) look...

/ed B in NH
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Re: Blue Glow

Postby Shannon Parks » Wed Apr 06, 2005 6:46 am

EWBrown wrote:One neat trick that can be done with these sockets on the ST70 or DIY35 board, is to poke a blue LED up thru the "centering" holes on the board, some of the light will pass thru the tube socket center hole, and give those tubes an eerie blue glow. Doesn't have to be blue, any color will work, but blue just looks "coolest"...

Give it that "nuclear" (or is that nucular?) look...

/ed B in NH


Ed,

Do you think we could just strap it and a resistor across the filament line?

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Postby EWBrown » Wed Apr 06, 2005 12:23 pm

The blue (as wel as white and "true" green)" LEDs don't like to be back-biased, they would need DC, so a small FWB would be needed. Or one can use the 5V CT winding, if pressent and not otherwised used, to feed them. Two diodes and a cap for rectification, The current is 10-20 mA for these LEDs, at about 3.6VDC. The big "Luxeon Star" 1 watt LEDs consume 350 mA, I use the 5VAC CT winding, two diodes and a 1600 uF cap, and feed the LED thru a 1 to 3 ohm resistor, if needed, to limit the current. They typically run 3.3-3.6VDC at 350 mA, about 1.25 watts into a single LED. They are BRIGHT! and good for under-chassis "effect" lighting.

(4/7/05 update)
Oh, yeah, how about those old Lionel electric trains, that had the little "smoke pills" to make the locomotive look like it was "steaming", gotta add that to the "effects"... Pimp My Amp, or "Monster Amp", or how about "Ampzilla"... Yellow_Light_Colorz_PDT_05

/ed
Last edited by EWBrown on Thu Apr 07, 2005 7:01 am, edited 1 time in total.
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Postby MarkC » Wed Apr 06, 2005 9:18 pm

Hey!...I'd like to get in on this!....Do you guys know where I can get some mini never-stop chrome wheels, low-pro tires and hydraulics for my chassis??? Yellow_Light_Colorz_PDT_05
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Re: Stereo 70 Caps/Cap Boards

Postby Uncle Ned » Thu Apr 07, 2005 12:49 am

separks wrote:Hi Gents,Are the SDS cap boards available from anyone anymore? It seems to be the best option (that I know of) for those wanting to use modern snap mount caps - it's a good design. Anyhow, I'm not planning on doing my own cap board and just wanted to see what options are out there for folks. Shannon


I have blank boards in stock, still waiting for some bits to complete the kit version.
http://store.yahoo.com/triodeel/sdsst70blank.html
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Postby Uncle Ned » Thu Apr 07, 2005 1:10 am

MarkC wrote:Hey!...I'd like to get in on this!....Do you guys know where I can get some mini never-stop chrome wheels, low-pro tires and hydraulics for my chassis??? Yellow_Light_Colorz_PDT_05



That's odd. I was participating in some bar blarney tonight and an otherwise dignified discussion about John Paul II degenerated into a argument over what would happen if the new pope put his popemobile on "Pimp My Ride". The spinning mag wheels (wheel covers? How hillbilly!) , hydraulic low-rider suspension and an electric Laz-e-Boy were some of the suggestions bandied about. Man, we got more sick brained Irish & Swedes around here than you'd expect to see in a Polish neighborhood...
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Postby EWBrown » Thu Apr 07, 2005 6:01 am

In addition to the PMR mods, the new popemobile should have a killer audio system, preferrably of "hollow state" technology..

Or let Jesse James and his Monster Garage crew turn it into a crazy off-roader Baja racer. With a dynamotor powered ST70 based power amp...

/ed Yellow_Light_Colorz_PDT_11 Yellow_Light_Colorz_PDT_07
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