Search found 1607 matches
- Tue May 21, 2024 4:53 am
- Forum: Technical Discussion
- Topic: OT Primary Question
- Replies: 6
- Views: 189
Re: OT Primary Question
PP or SE?
- Tue May 21, 2024 4:49 am
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 34
- Views: 906
Re: A SSS Build
I had the same problem in one amp, when inside the box.. chassis and power transformer were extremelly hot.. while outside on the table, chassis and PT temp was just moderate, nothing to worry about... Then i discover that there is no sufficient air circulation in the cabinet, and tubes were heating...
- Tue May 21, 2024 4:44 am
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 34
- Views: 906
Re: A SSS Build
I only have one fuse, 3 amp slow on input power. In Operate 118vac wall voltage 320-0-322 vac secondary. 320vac leg is also feeding bias circuit. B+ 414vdc Bias -360vdc at 5mA PT's biased to 27mA with -49 volts. if this is in operation all looks ok.. temperature is ok also little bit hot, 45 deg C ...
- Mon May 20, 2024 5:51 pm
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 34
- Views: 906
Re: A SSS Build
Usually power transformer is last thing to fail..almost impossible in good wound transformer.. Also fuses should be burned before the transformer..
- Mon May 20, 2024 5:50 pm
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 34
- Views: 906
Re: A SSS Build
Hmm it is strange thing.. Does PT has normal voltages in operation? Pls retest IN OPERATION all the voltages, and write here.. If they are normal, and current consumption is normal.. And transformer is hot.. then is undersized for this application..
- Mon May 20, 2024 9:31 am
- Forum: Technical Discussion
- Topic: Common Mode Filtering - A slightly impractical approach to reducing heater induced noise
- Replies: 9
- Views: 244
Re: Common Mode Filtering - A slightly impractical approach to reducing heater induced noise
otherwise, making only V1 DC supply for heaters is simple.and cheap(7812) and fixing all of the problems.. V1 matters only, sometimes V2
- Mon May 20, 2024 9:30 am
- Forum: Technical Discussion
- Topic: Common Mode Filtering - A slightly impractical approach to reducing heater induced noise
- Replies: 9
- Views: 244
Re: Common Mode Filtering - A slightly impractical approach to reducing heater induced noise
the problem in the power transforner should be overtaken by making electrostatic shield between secondary and heater winding, which need to be located at the top (last winding), and gnd this winding
- Sun May 19, 2024 9:36 am
- Forum: Trainwreck Discussion
- Topic: On Stability
- Replies: 3
- Views: 192
Re: On Stability
Lead dress is causing oscillations in higher gain... oscillations are positive feedback, and cable connected to sensitive grids is acting like an antenna.. Whatever this cable picks up, it is getting amplified. grid is multiple turn of small wire so it is real antenna.. In guitar amp there are many ...
- Thu May 16, 2024 4:59 am
- Forum: Fender Discussion
- Topic: 1976 Fender Vibrolux refresh help
- Replies: 15
- Views: 488
Re: 1976 Fender Vibrolux refresh help
for the added fuse, check what is this and why is there
- Thu May 16, 2024 4:56 am
- Forum: Fender Discussion
- Topic: 1976 Fender Vibrolux refresh help
- Replies: 15
- Views: 488
Re: 1976 Fender Vibrolux refresh help
all electrolytic capacitors needs replacement.. another critical point are film capacitors after the PI to the output tubes, they need to be replaced too.. all those moves are preventive and cheap..all elcos are too old and can fail anytime in the future. on other positions film caps should be measu...
- Mon May 13, 2024 5:06 pm
- Forum: Technical Discussion
- Topic: Can I Parallel 2 Mosfets in VVR?
- Replies: 31
- Views: 789
Re: Can I Parallel 2 Mosfets in VVR?
connecting mosfets in parallel can easily lead to a silicone pop-corn
- Fri May 10, 2024 7:25 pm
- Forum: Garage Talk
- Topic: Congrats Amplified Nation!
- Replies: 10
- Views: 1069
Re: Congrats Amplified Nation!
Im just reading feedbacks on FB Tube Guitar Amplifiers group..not looking good..reliability problems?
https://www.facebook.com/groups/724815140961013/
posts down
https://www.facebook.com/groups/724815140961013/
posts down
- Fri May 10, 2024 11:13 am
- Forum: Dumble Discussion
- Topic: Couple of #183 derivatives
- Replies: 70
- Views: 11765
Re: Couple of #183 derivatives
Well you've got at least one dud there. Have you considered using thermistors for a soft start instead of a standby switch? not really , because you need to hold high voltage at least 20-30 seconds and if not.. all of the Ub line caps will be on max voltage .. You need something like 500k. So or Au...
- Fri May 10, 2024 11:02 am
- Forum: Dumble Discussion
- Topic: Couple of #183 derivatives
- Replies: 70
- Views: 11765
Re: Couple of #183 derivatives
Yes, and the voltage drops are there too in the same time.. on variac if i lower the input voltage, then in one moment is ok situation, but on nominal looks like is going to the white smoke.
Chasing the ghost
- Fri May 10, 2024 6:38 am
- Forum: Dumble Discussion
- Topic: Couple of #183 derivatives
- Replies: 70
- Views: 11765