my first tube kit, i need help!! i have problem in 1 channel

knowledge base for the classic Dynaco ST70

Postby mati1979 » Sat May 09, 2009 8:20 am

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Postby TomMcNally » Sat May 09, 2009 8:37 am

I would suggest you determine which revision of the board you
have, then very carefully check your wiring. It sounds like
the new board has different filament wiring. Make sure you
have theat right, so your tubes heat up.
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Postby mati1979 » Sat May 09, 2009 9:00 am

Chad (from triodeelectronics say:)
What type of preamp tube are you using in the middle position of the tube driver board? If you are using a 12AU7 you need to put a jumper wire between pads J1 & J2 on the driver board. If you're using a 6DJ8, 6922, or 6CG7 in that position, then you don't need a jumper wire.
Best Regards,
Chad at Triodeelectronics.com


I have bought this kit:

DriverBoard : newEF86 (?)
Tubes : With Tubes 4 EL34 , 1 GZ34 , 2 EF86 and in a center board Ecc82
Transformers : Standard 120VAC
.
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Postby TomMcNally » Sat May 09, 2009 9:16 am

So you need the jumper ... did you try it ?
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Postby mati1979 » Sat May 09, 2009 9:19 am

mati1979 wrote: If you are using a 12AU7 you need to put a jumper wire between pads J1 & J2 on the driver board..


ECC82 = 12AU7 ? =:o
i have ECC82
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Postby TomMcNally » Sat May 09, 2009 9:21 am

mati1979 wrote:
mati1979 wrote: If you are using a 12AU7 you need to put a jumper wire between pads J1 & J2 on the driver board..


ECC82 = 12AU7 ? =:o
i have ECC82


Yes ... without the jumper, your tube filament is at 1/2 voltage.

Put the jumper in, it will light up - and hopefully your amp will work.

... tom
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Postby mati1979 » Sat May 09, 2009 9:31 am

TomMcNally wrote:
Yes ... without the jumper, your tube filament is at 1/2 voltage.

Put the jumper in, it will light up - and hopefully your amp will work.

... tom


Jumper = I need to solder a short wire between J1 and J2?
pic:

http://www.mirastelescopicas.com/dyn3.jpg

. :))
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Postby TomMcNally » Sat May 09, 2009 9:37 am

Yes - put that jumper in.
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Postby mati1979 » Sat May 09, 2009 9:52 am

im sorry for my high quantities asks :'(
this is ok ?

http://www.mirastelescopicas.com/solder.jpg


.
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Postby kheper » Sat May 09, 2009 9:58 am

mati1979 wrote:im sorry for my high quantities asks :'(
this is ok ?

http://www.mirastelescopicas.com/solder.jpg


.


Yes. Do as the instructions say. Solder a jumper between J1 and J2.
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Postby mati1979 » Sat May 09, 2009 10:07 am

ok thank you FRIENDS !

after I answer this question I am going to weld. :))

why i see in a maual board this :

Eyelet #4 & #5 to Pins 1 & 2 of the left power take-off socket (Note 1)
(i have soldered 2 and 7)
NOTE 1: These are the input tube filament connections. A stock ST-70 uses the front panel power take-off
sockets as a tie point for the input board tube filament wiring. Many amplifier modifications use these
socket holes for input jacks or other purposes. If the tube filament power is not present on these jacks or the
jacks themselves are not present, then the filament wiring can be run (as twisted pairs to reduce hum) from
the output tube filament connection (EL34: pins 2&7). The phase inverter position (V2) now has extra flexibility to use tubes with different pinouts, to use 12AU7, 12BH7, ECC99 solder a wire from J1 to J2 and make your filament connections to eyelets 24 & 25, to use 6CG7, 6922, 7308, or 6DJ8 do not jumper J1 and J2 and instead make your filament connections to J1 and J2 and ignore eyelets 24 and 25.
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Postby TomMcNally » Sat May 09, 2009 10:15 am

You don't have a power takeoff socket ... disregard that stuff.
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Postby mati1979 » Sat May 09, 2009 11:29 am

WORKK !!!

im very HAPPY ! (lol) (lol) (lol) (lol)

Thank you Friends !

(love)
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Postby mati1979 » Sat May 09, 2009 11:34 am

i have many pics :))

Image

Image
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Postby SDS-PAGE » Sat May 09, 2009 12:54 pm

Totally unrelated to the ST-70, that pattern on your wood floor is very interesting. I am sure it took a lot of work to get it put in like that. I DIY'ed the wood floors in my house and it was hard enough to piece together 5.5" wide engineered floor throughout the house.

Congrats on the amp. Not sure if those Solens are the best option for coupling caps sonically, but whatever works.

Min
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