Search found 1604 matches
- Mon May 20, 2024 5:51 pm
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 30
- Views: 789
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: 30
- Views: 789
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: 7
- Views: 187
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: 7
- Views: 187
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: 172
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: 14
- Views: 448
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: 14
- Views: 448
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: 778
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: 1058
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: 11696
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: 11696
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: 11696
- Fri May 10, 2024 6:29 am
- Forum: Dumble Discussion
- Topic: Couple of #183 derivatives
- Replies: 70
- Views: 11696
Re: Couple of #183 derivatives
Here is something what happened after in the amp.. failure on 450V elcos in the preamp section (they were new Kemet - Long life - ex Rifa) ? Very strange, i didnt measure wall voltage before.. maybe little bit over 230? Looks like caps took surge voltage during cold start (power and standby switch p...
- Fri May 10, 2024 4:53 am
- Forum: Dumble Discussion
- Topic: Couple of #183 derivatives
- Replies: 70
- Views: 11696
Re: Couple of #183 derivatives
For the past weekend we had some festival dedicated to vinyl and tubes, where was amp played.. i took nude and rude version without box.. Very nice experience.. maybe little bit too fatty/creamy sound with 1x12" Alnico Cream.. room and people damped the heights so better in the start to have more mi...
- Fri May 10, 2024 4:45 am
- Forum: Garage Talk
- Topic: Psycho-fonics - Blind testing
- Replies: 2
- Views: 100
Re: Psycho-fonics - Blind testing
I wonder if anyone can actually call out a tube by hearing it. not possible.. also there is wide range of manufacturing types and shapes..but you can hear the differences.. and NOS are at least 30% better than modern tubes.. Altough i have good luck with 12AX7 JJ, often they are good enough-till-gr...