TRC920 Start Up Popping
- Thread starter skunkape
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Yep, mine does the same. I might be wrong on this, but I think it might have to do with the ground wire that is soldered to the cassette deck. I was going to have a look at mine, but haven't gotten around to it.
I think the popping is caused by the capacitors. It could very well be the age of them releasing the stored power 
Was hoping to hear an explanation from :superduper:
Was hoping to hear an explanation from :superduper:
baddboybill said:I think the popping is caused by the capacitors. It could very well be the age of them
:superduper: where are you?
Well my clairtone 7980 does the same thing....maybe we should rename this thread so :superduper: will look at it.MONOLITHIC said:Don't hold your breath... He has absolutely "0" interest in Lasonic products.
Mine also does it when I flip the switch from stereo to wide.
GOOD POINT!MONOLITHIC said:Don't hold your breath... He has absolutely "0" interest in Lasonic products.
I sent Norm a PM
Maybe we can get a little "Pitty" advise! 
Actually My 920 does not do this on start up and I tested it several times, but one thing I know is that I dont leave my Bbx's plugged in to power when not in use because of transformer humm...Lasonics seems to be notorious for this Humming 
Ok. I avoided this thread because lately, I'm not really "feeling" it. But also because there is no real solution to a POOR or BAD design.
Cheap boomboxes will do that. Especially higher-power cheap ones. Ever turn on a pocket radio -- you know, the ones with 1-1/2" speakers? Does that pop every time you turn it on. But since the volume is so low, it's not really offensive. But with a boombox that outputs wpc instead of milliwatts and 6 or 8" woofers -- that pop is much more noticeable.
Anyhow, high quality boomboxes include timing delay and soft start circuitry to prevent or minimize the pops. If the pop is caused by power transients from the switch action, then installing a small .01uf or so high-voltage capacitor across the switch contacts should help with that. But ideally, the turn on sequence should be source, preamp, then amp and power down sequence should be amp, preamp, source. Of course if you were designing boomboxes on the cheap, you overlook and omit these litle details. It's no coincidence that on quality boomboxes, the innards are jam packed with circuitry whereas on the big black boxes, there is one single small board. All that extra circuitry is not there simply because the manufacturer had money to throw away. Therefore, the pop, is probably normal for those models as they lack the circuitry to supress the pop. On models using IC amps with a mute or remote turn on feature, you can delay the turn on of the amp by cutting a series resistor into that circuit to delay the turn on of the amp. I say live with it. It's the nature of the primitive beast.
Cheap boomboxes will do that. Especially higher-power cheap ones. Ever turn on a pocket radio -- you know, the ones with 1-1/2" speakers? Does that pop every time you turn it on. But since the volume is so low, it's not really offensive. But with a boombox that outputs wpc instead of milliwatts and 6 or 8" woofers -- that pop is much more noticeable.
Anyhow, high quality boomboxes include timing delay and soft start circuitry to prevent or minimize the pops. If the pop is caused by power transients from the switch action, then installing a small .01uf or so high-voltage capacitor across the switch contacts should help with that. But ideally, the turn on sequence should be source, preamp, then amp and power down sequence should be amp, preamp, source. Of course if you were designing boomboxes on the cheap, you overlook and omit these litle details. It's no coincidence that on quality boomboxes, the innards are jam packed with circuitry whereas on the big black boxes, there is one single small board. All that extra circuitry is not there simply because the manufacturer had money to throw away. Therefore, the pop, is probably normal for those models as they lack the circuitry to supress the pop. On models using IC amps with a mute or remote turn on feature, you can delay the turn on of the amp by cutting a series resistor into that circuit to delay the turn on of the amp. I say live with it. It's the nature of the primitive beast.
Am I the only one that thinks Norm is like Yoda? Just start putting your predicates before your subjects and you're there. Thanks for the great explanation. And for the record, I think my 920 is without a pop, but I believe my C100F has an aggressive one when you turn it on. And maybe it's related to the pop, but I thought it was a 'neat' feature, but is the C100 supposed to have the red level lights go 100% and then taper down to 0 when you power up? Thought was is intentional, but maybe they're just showing the level of the 'pop'.
And if anyone needs any detailed pics on the circuit boards or inside of the C100, I have one just about as stripped down as possible with the boards out and all.
And if anyone needs any detailed pics on the circuit boards or inside of the C100, I have one just about as stripped down as possible with the boards out and all.
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