Plate blue wire from OT

  • That´s right,and schield from a shielded Wire is ever connectet at one side,ever connected on the Input Side,where is Signal comming from!

    Yes I mean I did it the same on the 18 watts, the thing about this is that like you said I learnt from pictures, that was not good and you told me many times and you are right, always listening to the Senior experts, hehehe thanks a lot for the whole help received

    I am nearly done with the amp I checked all resistors already mounted on board checked 5 times so far all values are correct, used multimeter and I checked all caps directions orientations and values all seems correct.

  • O.k,thats good,but if you got trouble to working this Amp,get better solder Joints in eyelets,add some fresh solder from the upside with enough heat,

    them look like are glued,not really soldered ;)

    Glued ahahahah right I will do it again adding more solder I think I remove the tip too early

  • Hendrixianer

    Just a confirmation I am doing the channel 2, connecting pots (variable resistors) I am at the shielded wire.

    One wire goes to the board (signal) and shielding wire to ground same for the other wire that goes to VR7 signal but shielding wire to ground. this is clear.

    However on the other end on the SW2 switch you connect just the signal, so when removing insulation what do you do with the shielding wire , cut it off completely and connect just signal as shown on layout?

  • Hendrixianer and at MAD

    The Amp is finished. I checked many times caps orientation and that is definitely all good checked many times at least 10 resistors value if were positioned correctly and they are.

    I also ended up consuming all resistors and all capacitors and all items provided and I didn't have any extra spare or even the last 2 resistors were the one meant to be going on V4 and V5 which let me think I didn't put any wrong resistors value anywhere else since I would have find them at the end of the building or I would have missed parts used on the wrong spot.

    I want to put Amp on my idea is to do it this way

    1) Using a bulb current limiter turn on the amp without valves tubes for 1 min and check for anything unusually such smoke glooming parts then turn of the amp

    2) put the valves tube and turning amp on and check again obviously I will not touch the amp with hands I know that and I learnt to use wooden stick if really need to touch an amp element

  • Did it work? :/

    Hehehehe I'll put it on tomorrow, I am going to check everything one more time each component one by one and I will check if there is anything lose one by one all connections.

    after that i will turn it on, btw how do I know on this amp if the switch (power on Switch) is in on or off position.

    When I followed the instructions I put it on the orientation that they said to, however isn't clear if is in on or off position

  • Using a simple multimeter. If you don't have one you should buy one asap, it's a really useful and necessary tool. You don't need most of the fancy stuff out there, but a decent multimeter is an absolute must have.

    of course i have one, how would I have built the amp otherwise, all resistors were checked one by one with multimeter. I have everything that is needed to build an amp let me put is this way, I have successfully built 2 18 watts already and they both works perfectly, the reason why i succeeded is because I was able to follow instructions pictures and step by step very detailed instructions.

    where in Madamp is not exactly like this. Now You guys teach me a lot and this is the first time I build this amp using brain and that is why I asked questions that for you were too easy and non sense, but for me were not.

    Now i definitely know more :)

  • Hendrixianer and MAD

    Here you go phase one no tubes on

    Turned amp on no smoke not acre smell.


    It is connected using a bulb limiter, I now added the tubes, the switch power button turns on, when switched on, but the tubes do not gloom, I mean there is day light coming from window, but I should have seen them glooming? I didn't connect the speaker I don't wanna burn them out lol.

    Now it could be because of the bulb limiter limiting the current, but there is no short since the bulb remains off, I remember once when I built the first amp 18 watts there was a short at first try and the bulb on the current limiter turned on

    The connections to the boards and to power supply boards are all correct, all resistors capacitors everything, wiring included, seems ok checked 10 times or more.

    Only doubt is the power transformer, Maybe you can see it, the yellow wire might be connect to wrong lug? This is the same story, number one problem is my knowledge but...if the power transformer was well documented with no changes from what explained in photos and layout there would have been no issues even for a beginner like me.

    Now if the PT wires were wrong the power switch wouldn't have turned on red led light .

    Shall I try all without bulb limiter ?

    See photo I have removed on yellow wire the shrinking isolation tube for you to see better

    Are you able to understand if the above wiring on the PT are correct, you once explained but honestly it was not super easy for me and I admit my ignorance and not being handy so kindly if you could help I finished the amp and I would like it to make it work

    Side notes

    I also checked all soldering with wooden stick chop to make sure all connections are solid. I know the soldering quality and look isn't great on the way it appears but I can guarantee there are no lose connections

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