My First Tube Preamp

[fantom_mayonaise]

Sir Ryu : Wala po sya nung shield strands. 3 conductors lang sya. Papalitan ko din sya this weekend ng single conductors. Siguro i-tape ko na lang sa gilid ng chassis yung individual wires para di magdikit.

Sir Efren : I did use teflon tape on my DIY interconnects. Pwede na po siguro 5mm separation sa lahat ng adjacent signal paths dun sa board, ano po?  

[efren]

 : I did use teflon tape on my DIY interconnects. Pwede na po siguro 5mm separation sa lahat ng adjacent signal paths dun sa board, ano po? 

how did you use the Teflon "tape" what i mean is the insulating material itself is made of Teflon:

my DIY interconnects made of Teflon, the ground shield & center conductor is made of silver, this came from an aircraft instrument panel no longer in service.


as signal paths in the circuit

[fantom_mayonaise]

pinang-bind lang po yung teflon tape sa braided wires. 2 layers sya.

That teflon tube is interesting. May local source po kaya sya dito sa atin.

[efren]

alam ko sa mga stores selling high end audio meron nyan, si sir Jojo may alam din yata kung saan nakakakuha nyan. binigyan lang ako ng brother ko, palit tube amp na EL84

another good alternative is Belden coax cable RG-58 use in transcievers, get the stranded center conductor type.

[JojoD818]

teflon tubings are available online, medyo nakakainis lang bumili kasi per roll at siyempre may shipping....

[johnravacio]

The current PCB




Assembled Preamp Chassis






Another round of modifications and this should be done. 

1. Remove the relay and replace with toggle switch
2. Separate switch for the heater, still dependent on the main power switch
3. Replace pcb-mount neon bulbs with chassis mount neon bulbs. Handa na yung butas sa front panel
4. Optional Selector switch for cathode bias : Diode Bias, Different LEDs Bias, Battery Bias 
5. Optional Ulit : Light an LED under the tube.

@fantom_mayonaise good work! I was wondering what was the black one between the two green capacitors? Is that a relay? If yes, can I know what its doing on the circuit? and lastly the part number of the relay you've used?

Thanks!
John

[fantom_mayonaise]

Sir johnravacio : That relay was meant as bypass for the preamp. It connects the input directly to the output when powered off.  I've since removed it on subsequent rebuilds. While it provided a 'soft start' upon turn-off, it caused major thump on power off.

I put it there for A/B testing purposes comparing the sound with and without tube preamp. It served its purpose, I found that that layout sucked heehehe

 

[maldihtah13]

Pashare naman ng diagram. And san galing trafo nyo?

[fantom_mayonaise]

You can find the diagram on one of Sir Tony's threads here

http://www.wiredstate.com/forum/viewtopic.php?f=11&t=24713


Sa kanya din galing yung transformer and choke. Actually yung buong kit pwera lang tubes and case. Di ko ginamit yung kasamang casing ng kit nya.

[johnravacio]

Sir johnravacio : That relay was meant as bypass for the preamp. It connects the input directly to the output when powered off.  I've since removed it on subsequent rebuilds. While it provided a 'soft start' upon turn-off, it caused major thump on power off.

I put it there for A/B testing purposes comparing the sound with and without tube preamp. It served its purpose, I found that that layout sucked heehehe

Alright got it and thanks for sharing your experience with it. Saves us time and effort as well 

[johnravacio]

Sir johnravacio : That relay was meant as bypass for the preamp. It connects the input directly to the output when powered off.  I've since removed it on subsequent rebuilds. While it provided a 'soft start' upon turn-off, it caused major thump on power off.

I put it there for A/B testing purposes comparing the sound with and without tube preamp. It served its purpose, I found that that layout sucked heehehe

Alright got it and thanks for sharing your experience with it. Saves us time and effort as well