Tweaking time again, and I'm experimenting with covering various electronic components on the PCB with "Fun-Tak" aka "Blu-Tak" aka "adhesive putty". I'm thinking of blanketing every component on the PCB with fun-tak, except for the output transistors. This would include the various fuses, the two large filter caps, emitter resistors, transistors, ceramic disc caps, tiny caps, etc. (Just to be clear, the putty would form a complete seal over the part). The amp is the Rotel 820A (for a pic, see link), and as its actually my better half's amp, my concern is whether covering the parts might affect long-term longevity or reliability, due to a possible increase in heat from not being open and exposed to the air. Are there perhaps some parts on the PCB that shouldn't be covered for this reason or for safety reasons; ie. fuse? FWIW, this is a Class A/B amp and in normal operation does not get very hot (although I expect its going to get a bit hotter once I overbias it....).
Rotel 820A:
http://www3.sympatico.ca/stilyagi/rotelra820A.jpg
p.s. Yes, I "know" this 'crazy tweak' has no effect on the sound, and anyone would be crazy to think otherwise, but I like placebo's... they taste so much sweeter than the regular pill!
Rotel 820A:
http://www3.sympatico.ca/stilyagi/rotelra820A.jpg
p.s. Yes, I "know" this 'crazy tweak' has no effect on the sound, and anyone would be crazy to think otherwise, but I like placebo's... they taste so much sweeter than the regular pill!
Why not just make a mold, buy some potting compound and turn it into a block of "jello from hell"?
You might be surprised with how dampening electronic devices affect the sound. I would be a little careful with simply splashing it all over the place. Use with care, or you might end up with a dulll, overdamped sounding amp. Also, to decide if a place should not be covered because of heat, simply run the amp hard and then pop the hood (after switching off) and put your finger on the components in question. Try to put some on your main capasitors and on critical vibrating chassi-panels 😉
You might end up with lots of high value resistors from point to point due to the resistance of the blu-tak itself. Measure the resistance of a blob of it about 1/8" apart on your highest ohm scale to see if it conducts.
Mad_K said:Use with care, or you might end up with a dulll, overdamped sounding amp.
No, this is crazy talk.
Bill Fitzpatrick said:
No, this is crazy talk.
Depends on your goal. If you're trying to build a straight-wire-with-gain, yeah, it's rather meaningless to talk about overdamping. If you're trying to build an amp from microphonic parts and tune those to get a particular desired coloration, then it certainly IS possible to overdamp.
That said, real potting material is infinitely preferable to sticky stuff of uncertain dielectric and thermal properties.
SY said:If you're trying to build an amp from microphonic parts and tune those to get a particular desired coloration, then it certainly IS possible to overdamp.
I've stretched my imagination to the limit and can't figure out why someone would want to do that. I assume you have the answer and are going to share?
I've never understood it either, but I recognize that amp-as-signal-processer is a popular concept in segments of the audiophile community. I've never understood why anyone could find Adam Sandler the least bit funny, but I still recognize that some people do.
Maybe mrfeedback knows. He seems to be a fan of resonant panels on speaker enclosures.
What about it Eric?
What about it Eric?
SY said:
Depends on your goal. If you're trying to build a straight-wire-with-gain, yeah, it's rather meaningless to talk about overdamping. If you're trying to build an amp from microphonic parts and tune those to get a particular desired coloration, then it certainly IS possible to overdamp.
It's not just an amp, its a signal shaper too!

Some people like distortions but if you say their system is distorting reality they go off the handle!
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