Electrical Engineer's (or those who know amps), amp help please. (1 Viewer)

[Saurav]

For resistors, ALWAYS get a wattage rating that's equal to or larger than what was originally on the board. Never go with a smaller wattage than the original part. Think about it this way - the original part was able to handle 0.5W. Let's say it had enough current going through it that it was actually dissipating 0.5W. Now you put in a resistor that can only handle 0.25W, but the rest of the circuit is the same, so it's getting the same amount of current as before. So you're putting 0.5W through a resistor that's only capable of handling 0.25W. It will blow up.

On a resistor, the wattage rating tells you how much it can handle from the rest of the circuit, not how much it sends out to the rest of the circuit (speaking in a very non-technical way). So, a 1W resistor can take everything that a 0.5W resistor can, but not vice versa.

I would recommend getting a new amp, or send this one in to a professional repair station. There could be components damaged that won't show up as visible burn marks, and you don't have the test equipment to determine which pieces need to be replaced.

Hope that helps.

 

[Mary M S]

makes perfect sense seen written out like that. I think his off top-of-head worry was that a larger capacity resistor (name alone belies that ..if we had thought longer about it) would allow too much w out to other components. Additionally we spoke about the fire hazard if something had shorted internally to fry it initially, over whether or not it would be wise to let more wattage pass than designed for.

It will blow up as it did....and quite dramatically thank you!

He has prob. several things he would need, - voltage testers ect. But no time .. Nor time for finding the information regarding areas he has not worked in prior. If I bring him the information however ...he always applies it correctly, and when he used to have time for research, has always exceeded the abilities of paid professionals in most arenas. He can be....highly capable.

Knowledge is everything.

(he'd kill me for discussing his puff of smoke moment, he was very embarrassed (in front of me)

Thanks for the reply!

 

[Kyle Richardson]

We promise not to tell
If you decide to have this repaired contact me and I can get you in touch with somebody that can repair it at a reasonable price of $50 plus shipping each way. He is not affiliated with me, but just somebody I know and I know he does a great job.

 

[Mary M S]

Kyle, thank you. May take you up on that within next near weeks or months (my crazy schd).
I can drive myself insane with these path-choices dilemmas.
Have been extremely unhappy (the guys like it…it go boom) with my sub which I just pulled up stats on, it’s a cube, I’m pretty sure the Def Tech Pro200 (at min Pro100) which was more pricey than I had recalled (think I pd 450 new).
Factoring purchase price; it might be worth repairing for current use and future pass down to son. Its lower FR is listed at 18Hz or 19 Hz respectively , - but if it is doing that with any authority I’ll eat my hat.
Therefore my dilemma. I wanted to understand everything I’m capable of regarding SW and real room performance (Vs manuf. specs) and go back to learning something about room response, nulls. peaks nodes (or is it modes?) etc, but did not think I would ‘break’ the current one and felt I had time leisurely to learn the next couple years.
In a quick tour through HTF I became interested in checking into IB? type setup (prob. a great setup for our room) or something ready-to-go (I see the Everest is yours and greatly appreciate your reply!). Problem here…your unit is monster for our laughably small area and may not physically fit. (have to go behind the display for anything of that size) regardless of best location. And I really need to understand how my miniature room acoustics will effect the purchase of a subwoofer. I can already see that if I want ‘flat to x’ and ‘lower distortion’ (it was NEVER quantity due to our room size, well (maybe) we did fry it. But it really should not take much to fill/overwhelm the space. Rather an issue of quality, I found the Def Tech boomy. . There is just that tee-tiny problem of enormous enclosure sizes unless looking into something like an IB setup. (more work I will guess, - than we have time for.) To get the smooth FR I would ‘like’ to hear in a small box appears impossible. (the guys all went "cool" when they heard the port whoosh, I shudder, I should feel it not hear it!)
Right now I have:
Plan A: Quick fix: buy the Outlaws LFM-1 (I am very confidant regarding giving a test drive to any purchase from that company, which makes it a no-issue decision, as regards quality Vs price). Then take all the time I need to finally ship-to-fix the Def Tech unit and pass it on to a second system. Spend two years learning what I need to know (or longer in my case ) before purchasing anything with more FR.
Plan B: Make a knee-jerk higher end purchase without understanding everything I need to. (bad choice)
Plan C: After husband stated last night: “I really don’t have time to get into tracking the problem down” let him know Plan A and B and miraculously (many-many times in our past), he suddenly finds time for research and presto! Object in question is suddenly fixed!
by the by: first noticed your name in an extremely long thread regarding subw shootouts that was VERY entertaining.

 

[Saurav]

I'm not doubting the your husband's capabilities A voltmeter will be able to tell you if a resistor is bad. But if you've fried transistors or chips or anything like that, it becomes pretty difficult to troubleshoot those - figuring out which component is bad, where to get a replacement part, and so on. You can try, of course, it'll be a challenge, but it may be more frustration than fun. And if it comes down to replacing every component until you find the one that's bad, it may be cheaper, and definitely quicker, to buy a new amp. Just food for thought.
Good luck with whatever you do. And tell your husband he shouldn't feel bad about this, we've all made mistakes and still make them. In the long run, it's good to have some non-lethal fireworks sometimes - you don't get hurt, but it scares you enough that you're always careful from that point on

 

[Kyle Richardson]

Saurav is right, unless it is a hobby or he has a lot of spare time it probably wont be worth it to try to fix himself.

Quick fix: buy the Outlaws LFM-1 (I am very confidant regarding giving a test drive to any purchase from that company, which makes it a no-issue decision, as regards quality Vs price

A good choice from a good company and I'm sure you would be happy with it and not want to return it.
Plan C is funny. Let me guess, you've been married quite a few years?
I've also got to hand it to you for using the search function and bringing up a topic that is over 2 years old