Hiwatt build voltage issues

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sluckey
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Re: Hiwatt build voltage issues

Post by sluckey »

meter set to measure dc volts
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playonit
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Re: Hiwatt build voltage issues

Post by playonit »

sluckey wrote: Sun Sep 17, 2017 4:12 pm meter set to measure dc volts
We have sound ..... As you suspected it was a missing Jumper on the 2.2k and 22k resistor.. I have traced the amp 5 times never caught it :oops: The layout when printed did not print the light gray underboard wire so I never seen or traced that all the times I went over it... The only issue now is a loud shrill sound that fades immediately after I take it off standby and a harsh gated sounding distortion when I pluck a string hard... I thought maybe a bad tube and switched out the pre-amp tubes but no change... I can't thank you enough for the help ... Thanks
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sluckey
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Re: Hiwatt build voltage issues

Post by sluckey »

The only issue now is a loud shrill sound that fades immediately after I take it off standby and a harsh gated sounding distortion when I pluck a string hard...
This may be a sign of improper phasing of the NFB loop. Disconnect the feedback wire from your speaker jack. Does the sound get better? If so, reconnect the feedback wire and swap the OT primary plate leads on pin 3 of the output tubes. That would be the red and blue OT wires on your layout.
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playonit
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Re: Hiwatt build voltage issues

Post by playonit »

sluckey wrote: Sun Sep 17, 2017 5:34 pm
The only issue now is a loud shrill sound that fades immediately after I take it off standby and a harsh gated sounding distortion when I pluck a string hard...
This may be a sign of improper phasing of the NFB loop. Disconnect the feedback wire from your speaker jack. Does the sound get better? If so, reconnect the feedback wire and swap the OT primary plate leads on pin 3 of the output tubes. That would be the red and blue OT wires on your layout.
Disconnected the feedback wire and lost the shrill noise that came after I took it off standby but still have the distortion when I pluck the strings hard. I will switch the Blue and Red wires from the OT when I get home from work Monday and see what happens.... Just have to keep plugging away until she's right.... :D
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Stevem
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Re: Hiwatt build voltage issues

Post by Stevem »

Swapping the red and blue OT primary's will stop the feedback squeal, but your distortion is another issue.
I have learned to not trust wiring diagrams, this is why it pays to read schematics !
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gldtp99
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Re: Hiwatt build voltage issues

Post by gldtp99 »

[/quote]

We have sound ..... As you suspected it was a missing Jumper on the 2.2k and 22k resistor.. I have traced the amp 5 times never caught it :oops: The layout when printed did not print the light gray underboard wire so I never seen or traced that all the times I went over it... The only issue now is a loud shrill sound that fades immediately after I take it off standby and a harsh gated sounding distortion when I pluck a string hard... I thought maybe a bad tube and switched out the pre-amp tubes but no change... I can't thank you enough for the help ... Thanks
[/quote]


Power Supply not wired correctly------- as I advised weeks ago on another forum.

Now you've got the amp "in phase" with NFB connected----- that's good.

Move on to finding/fixing the remaining issues and you'll be good to go.

You will learn a great deal by the time this project is finished.

Many of us learn by fixing our own builds that don't initially work out as we wish.

Keep with it----- you're doing well !!!
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