Dual La2a - [silent:arts] version

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Postby bernbrue » Thu Dec 20, 2007 4:45 pm

[silent:arts] wrote: to fit it in a 2U case, modifie the sockets of V104 / 204 (while you are there do V102 / 202 too).


Hi Volker,
for the tube sockets, what exactly do I have to do with them? Removing upper or lower part to reduce their height?
I've got these sockets:
Image

regards
Bernd
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Postby [silent:arts] » Thu Dec 20, 2007 4:55 pm

just remove the upper part (dremel works well):

Image
Last edited by [silent:arts] on Fri Feb 11, 2011 7:30 am, edited 1 time in total.
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Postby bernbrue » Thu Dec 20, 2007 5:30 pm

Ah, I see, I thought I had to remove the upper part of the ceramic socket, so the upper parts of the pins have to be removed. Thx Volker.
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Postby [silent:arts] » Thu Dec 20, 2007 5:39 pm

:D yes, only the upper part parts of the pins :D
gave me the 3 mm I needed (when using 5mm spacers - and is case dependent)
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Postby ChuckD » Sat Jan 05, 2008 10:07 am

Why did you go with the Solen 10uF caps instead of the TC72 Mallory?
Did you get a chance to compare the two?

Starting my BOM. HEy if anyone is interested I have finished sourcing the parts# for the Caps in North America. (Mouser and PartsConnexion)

Still can't believe we can get by with 1/4W resistors!


I'll post it up if there are any Folks beside me building one over here.

-ChuckD
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Postby [silent:arts] » Sat Jan 05, 2008 10:30 am

ChuckD wrote:Why did you go with the Solen 10uF caps instead of the TC72 Mallory?
Did you get a chance to compare the two?

:-( no, haven't compared them. the easy answer is: I just used components I had arround, or where I knew I can buy them :lol:
I have no idea if there is any source for the Mallory in europe.

oh, and the 1/4W resistors work fine in my unit :wink:
(but remember the four 2W resistors)
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Postby ChuckD » Sat Jan 05, 2008 7:30 pm

Volker,

I have 4 older Mallory Caps (silver cans) that someone gave to me for free. Send me you address and I will mail you 2 of them! I will use the other two on mine. I measured them with my Fluke MM and 2 came out as ~13uF and the other 2 came out as ~12uF so I will pair them up that way.

Not sure if they are good. They are new old stock but they were free ... so.

I will throw them in the post for you.

-ChuckD
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Postby [silent:arts] » Sat Jan 05, 2008 11:04 pm

hey Chuck,

if you don't need them - many thanks :D
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Postby bernbrue » Sat Jan 12, 2008 1:36 pm

Volker,
there are two resistors (R125,225) to be determined. They seem to be related to the GR meter. Assuming, I´ll take a Sifam VU, what are there values? What did you take there? Thx a lot.
Cheers
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Postby [silent:arts] » Sat Jan 12, 2008 2:32 pm

Bernd,
this is the resistor Urei provided with each T4b.
rumors are they are always 33K (mine were both 33k).
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Postby ChuckD » Mon Jan 14, 2008 6:28 pm

I was about to ask the same question!

I'll go with 33K I guess.

-Chuck
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Postby ChuckD » Thu Jan 17, 2008 12:10 am

Hey Volker,

Why do we need 2x6.3 supplies? Can't I just run all the heaters together?

-Chuck
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Postby [silent:arts] » Thu Jan 17, 2008 7:31 am

of course you can run the heaters all together (6.3V 4A)
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Postby ChuckD » Thu Jan 17, 2008 7:06 pm

The transformer I picked out is

250-0-250 / 6.3 @ 3A / 12.6 @ 2A

Hopefully the 6.3 @ 3A will be enough to heat up all the tubes?

The 12.6 will be the source for the 5VDC circuit. The LM7805 input range is 5-18V for a fixed 5VDC output, so it should work fine.

Found it here :
http://www.toroid-transformer.com/
For $23.00 USD which is very cheap.

I already bought from this guy and he is really great to deal with. The quality is very high.

-Chuck
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Postby [silent:arts] » Thu Jan 17, 2008 8:21 pm

ChuckD wrote:Hopefully the 6.3 @ 3A will be enough to heat up all the tubes?


12AX7A Ih = 0.3, 12BH7A Ih = 0.6, 6AQ5-A Ih = 0.45
all together this is 3.3A :?
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