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  1. try with normal 1N4148 diodes and see what you get

    try with normal 1N4148 diodes and see what you get
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    1mA is normal in 6l6 type tubes,in el34s is more...

    1mA is normal in 6l6 type tubes,in el34s is more like 5,the screens start to draw more when overdriving the power amp,in triode mode its different,they tend to be stressed more,especially with high...
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    DC resistance is often different between the 2...

    DC resistance is often different between the 2 windings,but you should check inductance and for potential short windings.
    Try reversing the taps to see if it's the OT Or something in the bias...
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    That is the waveform of a single tube,the other...

    That is the waveform of a single tube,the other is not conducting at all
  5. with gain on 2 and master on 5/6 the amp is...

    with gain on 2 and master on 5/6 the amp is clean,if its too dark just add bright cap on the 1M before the gain pot,for less gain put a 100k in parallel of gain pot.
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    http://www.valvewizard.co.uk/Common_Gain_Stage.pdf...

    http://www.valvewizard.co.uk/Common_Gain_Stage.pdf
    this amp is 4 stages plus CF so very high gain,whatever tube you use.
    I have seen in a similar model they used a first stage cathode with...
  7. https://youtu.be/GAEdc1l-t6g

    https://youtu.be/GAEdc1l-t6g
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    which amp?

    which amp?
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    if it has a dsp inside,its easy that in case of...

    if it has a dsp inside,its easy that in case of low voltage the regulator feeding it cuts out,i imagine,maybe it was designed too optimistic.
  10. Clipping is clipping, whatever the device you use...

    Clipping is clipping, whatever the device you use .
    Pedals today sound ok because the distorted sound is filtered with several low pass.
    But,there are things you can't easily replicate,like grid...
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    then why people go buying a high powered amp if...

    then why people go buying a high powered amp if its too loud?
    he could have gone 5e3 or another tweed model.
    You can go MV,pre or post PI.
    Or a simple scaling in the PI bias resistor.
    I guess...
  12. IC caps...if one fails it can easily lead to...

    IC caps...if one fails it can easily lead to feedback.
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    You can, just respect polarity,and since they are...

    You can, just respect polarity,and since they are floating and maybe you don't use the main cable,just give a ground reference to chassis to avoid noise.
  14. filter caps

    filter caps
  15. What was the noise,was it a specific frequency?...

    What was the noise,was it a specific frequency?
    This circuit is a bit different from what you find in most amps,when you are in standby,the B+ is not zero Volts and the bias is -80V,around that,so...
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    This is the new disposable series,I don't think...

    This is the new disposable series,I don't think it's possible to repair if smd parts are burnt,no scheme.
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    the last one,i did it myself with a GTO,i used a...

    the last one,i did it myself with a GTO,i used a normal 12V/2A external brick to the jack on the box,internally connection direct to the heaters in parallel and to the HV boost converter,It works...
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    I would try elevating the heater center tap. One...

    I would try elevating the heater center tap.
    One trick that was used in the old single ended radios,was the output transformer,that had the primary with a tap around 90%,to which the plate went...
  19. lets say that the 2 grid resistors burned out...

    lets say that the 2 grid resistors burned out first,just because they are very low wattage and maybe there is some hot trace underneath or the screen resistors,if they break you dont have any...
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    my way,i use some teflon grease on the nut(which...

    my way,i use some teflon grease on the nut(which has to be cut and sanded perfectly),on the string tree,on top of the saddles and remove the sharp angle on the 6 holes in the plate.
    There are...
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    Galeazzo Frudua videos on YT

    Galeazzo Frudua videos on YT
  22. The only way is to apply a high dc voltage on one...

    The only way is to apply a high dc voltage on one side,and measure on the other,it should be less than a volt.
    You can just install it in place and measure in circuit with no power tubes,if on pin 5...
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    i suggest to change all filter caps anyway,they...

    i suggest to change all filter caps anyway,they were not so good back then and they are already old,plus you don't want to change them one at a time in a pcb board made like that.
    Shotgun method,its...
  24. what i find very stupid in these low cost...

    what i find very stupid in these low cost amps,but in general in all the modern production where engineers think they are going to simplify the whole "tubes" experience for everybody,by introducing...
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    these amps are made to be disposable,i mean,if...

    these amps are made to be disposable,i mean,if there is a problem the official service guys toss the board and sub a new one.
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    i have a tonecat reverb somewhere,it has both...

    i have a tonecat reverb somewhere,it has both el84 and el34,and reverb circuit,if youre interested i can find it.
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    to work on those boards,you need to solder and...

    to work on those boards,you need to solder and desolder in the fastest way possible,that means you need enough power,especially on ground planes,i use 48W minimum,today you can find even a bargain...
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    bias voltage,thats all

    bias voltage,thats all
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