# wanna start amp modifying



## cold21blooded (Apr 15, 2011)

I wanna start modifying amps just to try.. I have very good soldering skills i've been doing it for years and good knowledge of circuits.. I just need a starting point like what caps are switched out and things like that.. Anyone wanna help me out


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## wheelieking71 (Dec 20, 2006)

changing out caps, and modifying are two different things. if you want to upgrade parts, thats great. but, i suggest, you strictly follow the values of those components very closely. i really dont know anything about how an amp works (i got a clue, but thats about it). i do however know that untill you fully understand exactly how a circuit works, and why, and what effects changes will make, you are better off to just leave it alone. change parts all you want, just dont change part values, and you will be fine. although, that is not modifying. its upgrading.


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## cold21blooded (Apr 15, 2011)

wheelieking71 said:


> changing out caps, and modifying are two different things. if you want to upgrade parts, thats great. but, i suggest, you strictly follow the values of those components very closely. i really dont know anything about how an amp works (i got a clue, but thats about it). i do however know that untill you fully understand exactly how a circuit works, and why, and what effects changes will make, you are better off to just leave it alone. change parts all you want, just dont change part values, and you will be fine. although, that is not modifying. its upgrading.


Yeah I guess I wanna upgrade then.. I got a good idea on how basic amps work.. I built a couple back in high school.. But yes upgrading is what I want to do.. Does it make a great difference in sound just by swapping out a couple caps and resistors.. Like is it worth doing

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## mattchan2000 (Nov 7, 2008)

I've done on a few amp by changing its Alu Cap (same value) to better one such as Nichicon Muse, Rubicon ZA series etc. I would say that U can't really hear the differences vs changing cap on a line driver,EQ or processor unit but I believe that with quality cap in your amp it will run with much more stable current supply and thus may prolong your amp service life.
I'm tempt to change out the opamp in the amp but have yet to try due to ( I'm not semiconductor expert)


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## Brian_smith06 (Jan 31, 2008)

Trying soldering in some brown dog adapters and playing with different opamps. That would be a good start


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## ATOMICTECH62 (Jan 24, 2009)

You have to ask your self if its really worth it.If you want to ever sell the the thing you will never recoup the time and money you put in it.Also removing parts from a lot of boards is very hard without damaging the traces.You can upgrade resistors to 1% metal film,all caps in the signal path to film foil type or poly metalized,power supply caps can be upgraded (many choices),op amps (many choices).You can rewind the transformer to reach its optimal output into certain loads as long as you dont send to much voltage to other parts on the board.Upgrade the mosfets in the power supply.
You can also change the built in crossover frequencies to different values.
I have even put bigger power transformers in a few amps.
You will have to do some math and alldatasheet.com is a must to check for component voltage,current,power dissipation,pinouts etc...
Practice on a few cheaper amps first.


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## cold21blooded (Apr 15, 2011)

ATOMICTECH62 said:


> You have to ask your self if its really worth it.If you want to ever sell the the thing you will never recoup the time and money you put in it.Also removing parts from a lot of boards is very hard without damaging the traces.You can upgrade resistors to 1% metal film,all caps in the signal path to film foil type or poly metalized,power supply caps can be upgraded (many choices),op amps (many choices).You can rewind the transformer to reach its optimal output into certain loads as long as you dont send to much voltage to other parts on the board.Upgrade the mosfets in the power supply.
> You can also change the built in crossover frequencies to different values.
> I have even put bigger power transformers in a few amps.
> You will have to do some math and alldatasheet.com is a must to check for component voltage,current,power dissipation,pinouts etc...
> Practice on a few cheaper amps first.


Thanks for the response.. yeah my friend gave my a cheapo autotek amp I was gonna mess around with.. where is the easiest place to find the schematic for amps

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## ATOMICTECH62 (Jan 24, 2009)

You can search the net or call the manufacturer.Unless you are an authorized repair center for any major brand they are almost impossible to find.Since most amps are made in China or Korea the only ones that exist are probably in their file cabinets.
I hate to sound so negative but my personal experience with this matter has not been good.
I have contacted some company's looking for name badges,bottom plates,end plates etc... only to have them have them say "we dont sell those items" and hang up on me.
Trying to get the ZED AUDIO house Ic's are impossible


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## spooney (Nov 5, 2010)

I don't personally feel like there is a lot to gain in trying to modify an amp. Don't get me wrong I'm all about being a do it yourselfer and I love repairing amps but trying to drastically alter the amp from its original state just seems like a waste of time and money in my opinion. I've heard some minor improvement in certain amps by upgrading caps but certainly not anything you would notice if you hadn't already heard the amp without the upgrades. I think people trick themselves into thinking the op-amps they changed made some kind of real difference in the sound but in reality there is no real change. I'm all about making an amp more reliable whenever possible though but most decent quality amps are already built with that in mind. When used as intended you shouldn't have too many issues. I guess in short what I am trying to say is that if an amp doesn't do what you want in its "factory" state buy a different amp that does. It will be less headache in the long run


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## sirvent_95 (Feb 14, 2011)

spooney said:


> I don't personally feel like there is a lot to gain in trying to modify an amp. Don't get me wrong I'm all about being a do it yourselfer and I love repairing amps but trying to drastically alter the amp from its original state just seems like a waste of time and money in my opinion. I've heard some minor improvement in certain amps by upgrading caps but certainly not anything you would notice if you hadn't already heard the amp without the upgrades. I think people trick themselves into thinking the op-amps they changed made some kind of real difference in the sound but in reality there is no real change. I'm all about making an amp more reliable whenever possible though but most decent quality amps are already built with that in mind. When used as intended you shouldn't have too many issues. I guess in short what I am trying to say is that if an amp doesn't do what you want in its "factory" state buy a different amp that does. It will be less headache in the long run


I agree with this. The only 'mods' I ever perform is when the amp needs replacement parts as a result of a failure and I might use a better quality part. For instance a Nichicon capacitor instead of whatever the parts store keeps on their shelf. I don't think it makes sense to try to change certain parts of a circuit when the entire circuit is designed to work together correctly with the parts originally installed.


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## SQ_Bronco (Jul 31, 2005)

sirvent_95 said:


> I agree with this. The only 'mods' I ever perform is when the amp needs replacement parts as a result of a failure and I might use a better quality part. For instance a Nichicon capacitor instead of whatever the parts store keeps on their shelf. I don't think it makes sense to try to change certain parts of a circuit when the entire circuit is designed to work together correctly with the parts originally installed.


Things that make sense to me are on the order of: replace caps (a must after 10+ years), add functionality (vimex terminal blocks in place of old PPI plugs, etc), add balanced inputs (very easy nowadays with things like the INA2134, etc, and probably the most cost-effective mod), replace cheap RCA's with good RCA's, etc. Modern mosfets are vastly superior to ones available 10+ years ago, so you can gain lots of power by upgrading those, but you have to really understand the amplifier topology to realize significant gains, and that will probably be more expensive and less effective than buying a new amp.


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