Another great newbie question: I have this wacky idea of doing some sort of mod to the internal grounding of my Rotel amp, with the notion that it might improve sound quality (ie. lower distortion) - perhaps soldering extra wires or something? Are there any ideas floating about that might help acheive this? This is what my amp looks like inside:
http://www3.sympatico.ca/stilyagi/rotelra820A.jpg
http://www3.sympatico.ca/stilyagi/rotelra820A.jpg
No offence, but how on earth did you manage to move parts around in that?
Everything apart from the transformer is fixed on to a large PCB, which is fixed at the front and back by the RCA sockets and the control pots and switches.
What might be a better idea for you here seen as how this amp looks like it would take a quite a lot searching and component swapping to make much (if any) of an improvement, would be to spend a few dollars and go an order the parts to build youself a gainclone. It's dead easy and will cost less than the price of a good night out for most of the parts (if you want theree are even PCB's I could send you the layouts for to build one).
Everything apart from the transformer is fixed on to a large PCB, which is fixed at the front and back by the RCA sockets and the control pots and switches.
What might be a better idea for you here seen as how this amp looks like it would take a quite a lot searching and component swapping to make much (if any) of an improvement, would be to spend a few dollars and go an order the parts to build youself a gainclone. It's dead easy and will cost less than the price of a good night out for most of the parts (if you want theree are even PCB's I could send you the layouts for to build one).
bigparsnip:
> No offence, but how on earth did you manage to move parts around in that?
> Everything apart from the transformer is fixed on to a large PCB, which is fixed at the front and back by the > RCA sockets and the control pots and switches.
I think you misunderstood. When I said I "moved parts" to improve the sound, I didn't mean from one location in the amp to another. I just meant "moving the part". For example, so far, I've done all the 6 emitter resistors and the 4 little black "thingies" in between them, and also the large black 3-legged "thingy" behind the lg. right cap. Its just a matter of taking a pencil (or my finger) and pushing the part -ever so slightly-, in one direction or the other (6 possible directions at the least). Usually not enough to see a difference, but just enough to feel a difference. I think the secret is knowing when to stop. After I had acheived an intensely musical sound during my second effort, I was still not 100% happy, and fooled around a bit more with one of the emitter resistors. Then I kinda lost "the magic", and couldn't really get it back, no matter which way I bent the resistor. Since nothing was working, I finally got the idea of moving it from the bottom, rather than just the top. And after moving just one of the legs a certain way, no more than a mm, the change just blew me away. It was far and away better than I had ever heard it, and now I'm afraid to do any further experimenting on the parts. But imagine what I could do if I knew how to improve the grounding...
Seriously, there is no doubt in my mind that I could do a million things to improve (or at least "change") the sound of this amp. Moving parts is not the only thing I've done to prove that to be the case. I don't know why people think you can't make a significant improvement if its not an expensive high end amp, and only low-end budget audiophile gear (thats at least 12-20 years old...). In my mind, the opposite would seem to hold true. If its not a super-fantastic amp to begin with, then that means you have a lot of room for improvement!
> What might be a better idea for you here seen as how this amp looks like it would take a quite a lot searching > and component swapping to make much (if any) of an improvement, would be to spend a few dollars and go > an order the parts to build youself a gainclone. It's dead easy and will cost less than the price of a good night > out for most of the parts (if you want theree are even PCB's I could send you the layouts for to build one).
Thanks, but I'm not quite up to the task of soldering and desoldering parts on the PCB; doing solder work on the PCB is to me a big undertaking (as you noted, it has to be unfixed at the front and back), and I'm only approaching modding the amp -delicately-; nothing too invasive. I just recently got it (for my wife's system), I'm really fond of it and think its probably much better built (if not designed as well) than anything today selling at its original price. So I don't want to mess it all up (yet).
sam9:
I was just thinking of something minor, such as adding a wire from the amp's casing to the ground screw on the electrical outlet (since the amp only has a cheap two-bladed plug). I've kinda done this before already, where I've changed the 2-prong electrical cord one of my 'practice amps' to a 3-prong industrial-type cord, using solid-core house wiring fitted to a heavy duty 3-prong plug (which btw much improved the sound and never caused any electrical problems over the course of 3 or 4 years, despite moving the amp around quite a bit). But if you think I need a schematic and good knowledge of grounding theory before I attempt to do anyting to alter the grounding system, then okay, I'll take the hint that I'm probably better off leaving that part of it alone.
> No offence, but how on earth did you manage to move parts around in that?
> Everything apart from the transformer is fixed on to a large PCB, which is fixed at the front and back by the > RCA sockets and the control pots and switches.
I think you misunderstood. When I said I "moved parts" to improve the sound, I didn't mean from one location in the amp to another. I just meant "moving the part". For example, so far, I've done all the 6 emitter resistors and the 4 little black "thingies" in between them, and also the large black 3-legged "thingy" behind the lg. right cap. Its just a matter of taking a pencil (or my finger) and pushing the part -ever so slightly-, in one direction or the other (6 possible directions at the least). Usually not enough to see a difference, but just enough to feel a difference. I think the secret is knowing when to stop. After I had acheived an intensely musical sound during my second effort, I was still not 100% happy, and fooled around a bit more with one of the emitter resistors. Then I kinda lost "the magic", and couldn't really get it back, no matter which way I bent the resistor. Since nothing was working, I finally got the idea of moving it from the bottom, rather than just the top. And after moving just one of the legs a certain way, no more than a mm, the change just blew me away. It was far and away better than I had ever heard it, and now I'm afraid to do any further experimenting on the parts. But imagine what I could do if I knew how to improve the grounding...
Seriously, there is no doubt in my mind that I could do a million things to improve (or at least "change") the sound of this amp. Moving parts is not the only thing I've done to prove that to be the case. I don't know why people think you can't make a significant improvement if its not an expensive high end amp, and only low-end budget audiophile gear (thats at least 12-20 years old...). In my mind, the opposite would seem to hold true. If its not a super-fantastic amp to begin with, then that means you have a lot of room for improvement!
> What might be a better idea for you here seen as how this amp looks like it would take a quite a lot searching > and component swapping to make much (if any) of an improvement, would be to spend a few dollars and go > an order the parts to build youself a gainclone. It's dead easy and will cost less than the price of a good night > out for most of the parts (if you want theree are even PCB's I could send you the layouts for to build one).
Thanks, but I'm not quite up to the task of soldering and desoldering parts on the PCB; doing solder work on the PCB is to me a big undertaking (as you noted, it has to be unfixed at the front and back), and I'm only approaching modding the amp -delicately-; nothing too invasive. I just recently got it (for my wife's system), I'm really fond of it and think its probably much better built (if not designed as well) than anything today selling at its original price. So I don't want to mess it all up (yet).
sam9:
I was just thinking of something minor, such as adding a wire from the amp's casing to the ground screw on the electrical outlet (since the amp only has a cheap two-bladed plug). I've kinda done this before already, where I've changed the 2-prong electrical cord one of my 'practice amps' to a 3-prong industrial-type cord, using solid-core house wiring fitted to a heavy duty 3-prong plug (which btw much improved the sound and never caused any electrical problems over the course of 3 or 4 years, despite moving the amp around quite a bit). But if you think I need a schematic and good knowledge of grounding theory before I attempt to do anyting to alter the grounding system, then okay, I'll take the hint that I'm probably better off leaving that part of it alone.
Cybergent said:Moving (i.e. bending) parts
Huh
Welcome to the world of Voodoo.
Yeah, I know, I know... I expected that. I've been around the block, and fully realize that "techies" / engineers live with these huge mental wedges in the form of rigid doctrines developed by formal or informal "education". Which dictates that if they can't measure it, it don't exist (not that I'm saying it can't be measured, I won't even pretend to know what drives the effect. I only know for certain it causes an effect - so great, even my non-audiophile wife hears the effect of the accumulated differences). That unfortunately is why we have so many crappy sounding amplifiers on the market, that are no better with music than sound effects.
But I also know there are pioneering engineers who the more mediocre "doctrinaire engineers" scoff at. Criticising their ideas as "voodoo", because the engineers are not smart enough to understand the principles behind the effects the pioneers use (sometimes, neither are the pioneers!). So "the wedge" causes them to conclude they don't exist. Engineers like Yves Bernard Andre and Ivor Tiefenbrun have been lambasted with the "voodoo" tag by such other engineers, and when I listen to their products, they are usually sonically superior to most of the competition. So (even though I'm no engineer), I don't mind at all being in the same camp as true audio pioneers. Of course, if it weren't for mediocre engineers, who would never even think of experimenting with what they consider "voodoo" or "snake oil", we would never have acheived the thrilling "you are there" sound of home theatre systems, with their 600 sound processors and 65 speakers around the room... That's progress all right..
(The name "fotzepolitic" btw, is the title of a song. Other than that, I cant say whether it does have a particular meaning).
I´m aware of the fact, that not everything can be measured.
And a 100 years ago all technologies of today would have been regarded as miracles.
But bending the leads of an emitter resistor?
Sorry, but that is nothing but voodoo to me. Well, if you bend it often enough, it will break off. That would certainly have an effect.
BTW...
Your nickname is the German word for a very naughty description of the most female part (cu..-word) combined with the word politics. Just in case you like to know....
And a 100 years ago all technologies of today would have been regarded as miracles.
But bending the leads of an emitter resistor?
Sorry, but that is nothing but voodoo to me. Well, if you bend it often enough, it will break off. That would certainly have an effect.
BTW...
Your nickname is the German word for a very naughty description of the most female part (cu..-word) combined with the word politics. Just in case you like to know....
bigparsnip:
> Well, we'll have to see if Peter has anything to say here, as I doubt if many of the ears round here would be > sensitive enought to tall how a component has been 'poked', but if it sounds better to you I guess it can't be a > bad thing no
The amp now sounds much better to anyone who's heard it before all the careful pokin' and proddin'. Only they don't know why. And I no longer have any complaints about the sound as I did when I first got it. But I don't believe in any "golden ear" mythology. I don't think the problem is most people can't hear these differences (or that they're imagined), I think the greater problem is most people don't bother to try. Especially audo enthusiasts that are dictated to by their intellectual prejudices. I think if someone has a genuine interest in quality audio, they'll at least give it a try out of curiousity - and that's easy to do. All you have to do is take the cover off your amp (or CD player, or anything audio with circuity). Listen to it for a few minutes to familiarize yourself with its sound quality (because it will sound different than you're used to with the cover off). Then push (bend) every part you can find on the PCB, to a **significant** degree. Particularly things with long legs, like emitter resistors...
(Just don't move the position of the amp after you've taken the cover off, because my voodoo audio theory says this itself will alter the sound, and may taint the comparison test a bit).
Then you have another listen. I predict that you will have a hard time denying the fact that your beautiful amp has just taken a huge beating in sound quality, and you'll have learned something new about amplifiers - how easily you can screw up that wonderful sound you always took for granted... Of course, you'd really have nothing to worry about, because most people here would claim there could never be a difference, right?! Even if everyone around you who hears it after the intense poking session says "Hey man, what happened to your amp? Why does it suck so badly all of a sudden?", that shouldn't matter. Because you won't be hearing any "voodoo differences"... ;-)
Cybergent:
> Sorry, but that is nothing but voodoo to me. Well, if you bend it often enough, it will break off. That would
> certainly have an effect.
Yes, I could see where that would. That's why I only bend things very slightly, and I'm careful not the stress the metal legs too much with repeated bending at the same joint.
> BTW... Your nickname is the German word for a very naughty description of the most female part (cu..-word) > combined with the word politics. Just in case you like to know....
Thanks for informing me of this... now it all makes sense! It was after all a woman who invented the word (Elizabeth Frasier of The Cocteau Twins). And she's a Scot. They're kinda feisty like that...
> Well, we'll have to see if Peter has anything to say here, as I doubt if many of the ears round here would be > sensitive enought to tall how a component has been 'poked', but if it sounds better to you I guess it can't be a > bad thing no
The amp now sounds much better to anyone who's heard it before all the careful pokin' and proddin'. Only they don't know why. And I no longer have any complaints about the sound as I did when I first got it. But I don't believe in any "golden ear" mythology. I don't think the problem is most people can't hear these differences (or that they're imagined), I think the greater problem is most people don't bother to try. Especially audo enthusiasts that are dictated to by their intellectual prejudices. I think if someone has a genuine interest in quality audio, they'll at least give it a try out of curiousity - and that's easy to do. All you have to do is take the cover off your amp (or CD player, or anything audio with circuity). Listen to it for a few minutes to familiarize yourself with its sound quality (because it will sound different than you're used to with the cover off). Then push (bend) every part you can find on the PCB, to a **significant** degree. Particularly things with long legs, like emitter resistors...
(Just don't move the position of the amp after you've taken the cover off, because my voodoo audio theory says this itself will alter the sound, and may taint the comparison test a bit).
Then you have another listen. I predict that you will have a hard time denying the fact that your beautiful amp has just taken a huge beating in sound quality, and you'll have learned something new about amplifiers - how easily you can screw up that wonderful sound you always took for granted... Of course, you'd really have nothing to worry about, because most people here would claim there could never be a difference, right?! Even if everyone around you who hears it after the intense poking session says "Hey man, what happened to your amp? Why does it suck so badly all of a sudden?", that shouldn't matter. Because you won't be hearing any "voodoo differences"... ;-)
Cybergent:
> Sorry, but that is nothing but voodoo to me. Well, if you bend it often enough, it will break off. That would
> certainly have an effect.
Yes, I could see where that would. That's why I only bend things very slightly, and I'm careful not the stress the metal legs too much with repeated bending at the same joint.
> BTW... Your nickname is the German word for a very naughty description of the most female part (cu..-word) > combined with the word politics. Just in case you like to know....
Thanks for informing me of this... now it all makes sense! It was after all a woman who invented the word (Elizabeth Frasier of The Cocteau Twins). And she's a Scot. They're kinda feisty like that...
Can grounding be upgraded?......YES !!!
Back to your original question...........
There are a whole bunch of simple and little mods that can transform an amplifier like yours.
We all know that this is a relatively low priced entry level amplifier - these kinds of amplifiers usually have very good specs actually, but fall down sonically due to production line physical construction shortcuts (and ignorance???) that can compromise the sonics of the circuit design.
There are physical mods to do first, and then component mods also if you want to go that far.
The first thing to do is to shift the speaker returns away from pcb pins etc and directly to the earth common between the two main psu filter caps - you may need to drill a suitable sized hole between the caps
While you are at it, beef up the connection between the two main filter caps by fitting a strip of copper or fat wire.
Shift the center tap of the transformer to this position also.
You may like to experiment with swapping the polarity of the secondaries and also the 240V AC input polarity - usual 240V precautions apply of course.
I have been meaning to fit polarity reversing switches for primary and secondary winding for years but never gotten around to it, but a/b comparison show sonic differences.
If your amp runs Zobel networks, fit these directly across the speaker output terminals and not on the pcb.
If you are prepared to omit the front panel A/B speaker system switching, run the speaker actives direct from the pcb to the output terminals/zobel networks - non tin-plated solid core wire like building wire strands can sound nicer than the originals wires used.
Ceramic bodied WW emitter resistors add a particular sound character, and carbon and metal film of suitable power rating (you may need 2 or more instead of each original) add different sonic characters that you may prefer.
Capacitors also add sonic characters, especially ceramic capacitors of different ceramic formulations.
Signal electrolytics matter too - NP elecros cause lower distortion, and there is a whole range of polarised electros available for tweaking - low esr smps electos are usually nicer sounding.
Whilst you are doing this reworking the solder matters too - I much prefer Multicore Savbit 2% copper solder.
This is just a start for you - if you want more tips or fine pointers on some of this just ask.
Eric.
I have observed the effect also, more especially by moving the small electrolytics to vertical.fotzepolitic said:
Back to your original question...........
There are a whole bunch of simple and little mods that can transform an amplifier like yours.
We all know that this is a relatively low priced entry level amplifier - these kinds of amplifiers usually have very good specs actually, but fall down sonically due to production line physical construction shortcuts (and ignorance???) that can compromise the sonics of the circuit design.
There are physical mods to do first, and then component mods also if you want to go that far.
The first thing to do is to shift the speaker returns away from pcb pins etc and directly to the earth common between the two main psu filter caps - you may need to drill a suitable sized hole between the caps
While you are at it, beef up the connection between the two main filter caps by fitting a strip of copper or fat wire.
Shift the center tap of the transformer to this position also.
You may like to experiment with swapping the polarity of the secondaries and also the 240V AC input polarity - usual 240V precautions apply of course.
I have been meaning to fit polarity reversing switches for primary and secondary winding for years but never gotten around to it, but a/b comparison show sonic differences.
If your amp runs Zobel networks, fit these directly across the speaker output terminals and not on the pcb.
If you are prepared to omit the front panel A/B speaker system switching, run the speaker actives direct from the pcb to the output terminals/zobel networks - non tin-plated solid core wire like building wire strands can sound nicer than the originals wires used.
Ceramic bodied WW emitter resistors add a particular sound character, and carbon and metal film of suitable power rating (you may need 2 or more instead of each original) add different sonic characters that you may prefer.
Capacitors also add sonic characters, especially ceramic capacitors of different ceramic formulations.
Signal electrolytics matter too - NP elecros cause lower distortion, and there is a whole range of polarised electros available for tweaking - low esr smps electos are usually nicer sounding.
Whilst you are doing this reworking the solder matters too - I much prefer Multicore Savbit 2% copper solder.
This is just a start for you - if you want more tips or fine pointers on some of this just ask.
Eric.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.