# Your amplifier can be modified for better SQ



## ChrisB (Jul 3, 2008)

Here is something that I once believed in, amplifier modifications for better sound quality. The only problem is any post modification improvements were subjective and more along the lines of being psychoacoustic. Why? Because human auditory memory is terrible. In fact, I first believed the modification was worth it because I paid money for something that I was led to believe would make an improvement and I somehow believed that I could hear a sonic improvement from something that was not in the car for close to a month. 

Unfortunately, I performed as scientific of an a/b experiment as I could between an unmodified amplifier and the modified one by performing level matching and reproducing a variety of source material on several different sets of home speakers. It didn't take me long to from being content with paying money for modifications to being completely disappointed and seeing them as a complete waste of money. Hindsight being 20/20, I should have known better because most of my questions regarding the overall sonic impact of the modifications were answered with "trust me, it will sound better" by the person performing the modifications. 

Oh well, live and learn!


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## Sarthos (Oct 29, 2010)

It is entirely dependent on what you have to begin with and how far you're willing to go. Also in what ways you're trying to help sound quality. Also the condition of the amp. If parts are getting worn on an amp, you might get some small gains with certain modifications. But there aren't really any cheap mods to get way better SQ out of an already good amp


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## mokedaddy (Feb 26, 2007)

My amp was modified for full power at 4 ohms instead of 2 ohms. It has the super sq!!!!


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## ChrisB (Jul 3, 2008)

Sarthos said:


> It is entirely dependent on what you have to begin with and how far you're willing to go. Also in what ways you're trying to help sound quality. Also the condition of the amp. If parts are getting worn on an amp, you might get some small gains with certain modifications. But there aren't really any cheap mods to get way better SQ out of an already good amp


Therein lies the problem. My amplifier was sent in for repair and I was told it could be made to sound even better. I shouldn't have fallen for the marketing pitch.

Here is the thread referencing the amplifier in question: http://www.diymobileaudio.com/forum...anced/59737-linear-power-mods-real-scoop.html


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## Sarthos (Oct 29, 2010)

It looks like the mods they did may have helped out with power output into higher impedances though, but not sound quality.


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## CBRworm (Sep 1, 2006)

Rarely do mods improve SQ, but sometimes signal path parts can be improved, or power supplies can be stiffened.


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## Chuck (Jan 15, 2009)

Truth most of the responses. Mods work, but I think more depends on your level of experience.

The overall effect is the similar to your first experiences with hifi. Once I got into the hifi world, I was able to hear a difference between Monster Cable HotWires or Powerflex cables and zip cord. I was able to tell the difference between standard RCA patch cords and better stuff from Vampire, Straight Wire, and Monster. 
What I couldn't hear was the crazy stuff like upgraded power cords, Tweek, and expensive connectors.


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## Troon (Mar 7, 2008)

Chuck said:


> The overall effect is the similar to your first experiences with hifi. Once I got into the hifi world, I was able to hear a difference between Monster Cable HotWires or Powerflex cables and zip cord. I was able to tell the difference between standard RCA patch cords and better stuff from Vampire, Straight Wire, and Monster.


In proper blind tests?

As the OP said, auditory memory is terrible, and the influence of expectation on perception is *huge*. If you think something's going to sound better, it will - particularly if you are aware of a price and/or reputation attached to the "better" item.

I've run PA systems for years, and had several experiences where I've been asked to make an adjustment that I believe to be unnecessary, not made any adjustment but given the impression that I may have done, to be told by the requestor that the sound is "much better now, thanks".

On the subject of PA systems, microphone cables carry tiny signals over long, often mechanically- and electrically-noisy environments. I've tried various cables, and there's no audible difference in properly-constructed and terminated cables until the things are starting to physically fail, then the differences are clear (crackles, pops, drop-outs etc).

For an amp's SQ (measured as distortion, noise, slew rate etc) to even feature in the list of significant effects on sound quality in a car audio environment, something must be badly wrong with that amp.


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## Chuck (Jan 15, 2009)

Troon said:


> In proper blind tests?
> 
> As the OP said, auditory memory is terrible, and the influence of expectation on perception is *huge*. If you think something's going to sound better, it will - particularly if you are aware of a price and/or reputation attached to the "better" item.


I can't think of a real way to properly A/B test cables without influencing the sq with breakout boxes/switches, or affecting the listener's sonic memory by making them wait during a cable swap, so no, I didn't do "proper blind tests". However in my case I approached the comparison with a healthy skepticism, thinking that "wire was wire". 

I never heard the difference in the audio store, because all the systems there were set up with oxygen isolated wire, but when I was given a roll of Superflex II to take home and try, the improvement was so dramatic on my DH220 and Infinity speakers I was amazed. Likewise, several years later when I picked up a set of 1.5 wires to put between my GFA555 (Wavetrace mod'd) and my DM602's, I noticed a much improved soundstage and clarity. 



Troon said:


> On the subject of PA systems, microphone cables carry tiny signals over long, often mechanically- and electrically-noisy environments. I've tried various cables, and there's no audible difference in properly-constructed and terminated cables until the things are starting to physically fail, then the differences are clear (crackles, pops, drop-outs etc).


That may be true, but the data you're carrying on those cables are usually single source to a dedicated channel in your board, yes? There is a slight difference between that and an amp channel receiving mixed audio from a patch cord in a 100+ degree environment with shock and vibration that easily rivals or exceeds that which you would find in a professional environment. 



Troon said:


> For an amp's SQ (measured as distortion, noise, slew rate etc) to even feature in the list of significant effects on sound quality in a car audio environment, something must be badly wrong with that amp.


Believe me I am no stranger to the snake oil that is represented by amp specs, especially advertised specs. If it isn't cheater claims, its what we used to call OIABM (Once In A Blue Moon) at our store. Either underrated to win competitions, or overrated based on what a precision-built in-company test unit provided under ideal conditions.

But back to the OP - a lot of mods are goofs, but there are some real things that can be done to upgrade sq. My GFA555 was tweaked by Wavetrace Technologies, and it sounds worlds different from a "stock" 555. The owner of Wavetrace was one of the few people that David Hafler considered qualified to upgrade the DH amps back in the early 80's. I think he's out of the business now, but he's a brilliant tech, and I learned a lot from him back in the day.


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