- watt meters - 3 Updates
- surface mount (guitar amp hisses) question - 3 Updates
| Trevor Wilson <trevor@rageaudio.com.au>: Jan 16 05:45AM +1100 On 15/01/2022 9:27 pm, Phil Allison wrote: >> horrible LCDs. Proper LED display. > ** You on drugs ? > the display is very clearly LCD - with an orange backlight. **Oops. [Smacks head]. Must be the drugs. |
| Trevor Wilson <trevor@rageaudio.com.au>: Jan 16 05:50AM +1100 On 15/01/2022 9:27 pm, Phil Allison wrote: >> horrible LCDs. Proper LED display. > ** You on drugs ? > the display is very clearly LCD - with an orange backlight. **Seriously, I kinda mixed them up with this one. I bought one of these initially: https://www.banggood.com/Geekcreit-3-in-1-AC-60-500V-100A-Voltmeter-Ammeter-HZ-Hertz-Frequency-Meter-22mm-Digital-Current-Voltage-Amp-Signal-Light-LED-Lamp-Indicator-with-CT-p-1548114.html?rmmds=myorder&cur_warehouse=CN&ID=229 But I preferred the LCD ones. Thanks for the correction. |
| Michael Trew <michael.trew@att.net>: Jan 15 09:39PM -0500 On 1/15/2022 0:50, danny burstein wrote: >> Thanks. I wanted confirmation that one of the inexpensive ones has been >> tested and approved. The $17 models might still be crap but if this is >> above that price point then that's what I needed to know. You're welcome. I'm happy with the $25 or so Kill-A-Watt for my purposes, testing appliances. > "lock" those readings and hold them if you > moved it off the outlet and then plugged it > in elsewhere. Mine, in the $25 ball-park range, immediately resets when unplugged. |
| legg <legg@nospam.magma.ca>: Jan 15 04:00PM -0500 >https://imgur.com/jIXc5Be None of the imgur links will display on my browsers, but surplus epoxy glue dots shouldn't be an issue, unless they are obviously flattened/distorted from actual use. Depopulated board positions likely still use full population adhesive dot location programming. The hiss might be self-oscillation - possibly visible on a scope. Check input / output signal filters, zobel network components on the output. Possibly sensitive to temperature. Could be problems with simple frequency comp components - intermittent cap or rc network component, or bad switch contents in the equalisation bypass (if present). Mechanical grounding connections for good components also suspect. RL |
| Three Jeeps <jjhudak4@gmail.com>: Jan 15 05:16PM -0800 On Friday, January 14, 2022 at 11:41:59 PM UTC-5, Mike S wrote: > board. > https://imgur.com/zBnbbjR > Do those red globs mean anything? I suggest that you carefully inspect solder joints and traces looking for crystalline (cold) joints or micro-cracks in the ckt board. Touch up any suspected joint with soldering iron, and fluxed solder. Also check wired connections in/out of the board. Random/variable hissing on the audio output can often be attributed to 'noisy' semiconductors, e.g. transistors, diodes. Output transistors are a likely suspect as they experience a fair amount of heat that can cause degradation. If you know how to use a scope you could inject and trace a signal and see where it acquires a lot of noise. Another approach is to change any transistor in the audio signal path (s). Good luck J |
| Phil Allison <pallison49@gmail.com>: Jan 15 05:28PM -0800 Three Jeeps wrote: ============== > Random/variable hissing on the audio output can often be attributed to 'noisy' semiconductors, e.g. transistors, diodes. ** Not diodes. > Output transistors are a likely suspect as they experience a fair amount of heat that can cause degradation. ** ROTFL - you are just making shit up !! > If you know how to use a scope you could inject and trace a signal and see where it acquires a lot of noise. ** Or just turn the vol pot down and see if that changes things. > Another approach is to change any transistor in the audio signal path (s). Piss off fool. ..... Phil |
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