mods for Adcom GFP-750

As someone that makes their living by "modding" electronic components, i would COMPLETELY disagree with Sd's comments. Manufacturers build their products to meet specific specifications and price points. Keep in mind that adding one dollar to production costs equates to AT LEAST a 4 dollar increase in retail price and sometimes as much as 8 dollars. This means that they tend to use cheaper parts that will get the job done in order to keep the cost down as much as possible. As long as the unit will meet spec, survive the warranty period with minimal problems and draw in customers, that is pretty much all that they are worried about. Since most companies, especially those that produce "reasonably priced gear", think that wire is wire, resistors are resistors, caps are caps, etc... they use what they can get at the best prices with good reliability. On top of this, they tend to be conservative when it comes to really "fine tuning" the circuitry for best performance. Keeping the bias down reduces heat, power consumption, reduces production costs due to the need for less heat-sinking material, increases lifespan and reliability and helps them to easily surpass the warranty period. On top of that, they will tend to make use of larger amounts of negative feedback than what is really needed to get the job done. This is done because it makes the amp look better under test conditions and reduces distortion in terms of "paper specs". Since most of the people that are buying "affordable" gear are still quite "spec oriented", being able to print "pretty figures" is still quite important to manufacturers in terms of a marketing tool. They do this even though most all designers agree that negative feedback iin quantity is a BAD thing in terms of sonics. I could go on and on, but i think you get the point. Mods CAN be QUITE succesful if carefully thought out and well executed. If the basic circuitry was "as good as it gets", manufacturers would not be able to "upgrade" them and produce new models that DO perform better. "Tweaking" not only "fine tunes" the unit, it helps to advance the state of the art when done correctly. "Mass production" simply means "making as many units for the highest profit margin". It does not mean "quality" in most instances. Sean
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Don't get me wrong, many mods are FOOLISH at best. Some are not cost effective and in many cases, actually degrade the performance of the unit. There there are the "cosmetic" upgrades, such as swapping one brand of gold plated copper binding posts for another brand of similar design but shaped differently, etc.. While "old golden ear" might be able to hear the difference between well designed components like these, i sure can't. Internal wiring and its routing is another story though. Things like this can make not only an audible difference, but also sometimes quite measurable differences. Sean
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I do not like to bunch wires together ( especially power supply and signal wires ). Spread them out as much as possible. In terms of "re-wiring" something internally, keep in mind that this WILL alter it's tonal balance to a noticeable degree in most cases. This can be taken advantage of to some degree if you know what your doing and working with. As to specific recommendations of brand names, i won't / can't do that. There are just too many variables involved, especially the one called "personal preference". As to the various solders that i've worked with, Wonder is by far the easiest to work with. As to which one "sounds best", i don't know. I've read that Jenna labs did a test and they came away with the opinion that the Cardas sounded the best. As you might guess, that is what they use on all of their cables. I have used it many times before and found it slower to melt, slower to form and easier to make a bad connection with. I also like to take detailed notes when doing mods, as this way you can always "back-track" should you need to. There are some things that just don't work out the way that you think that they should. Being prepared for that will never hurt you. Sean
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I work with radio communications gear and most of my audio based "experimentation" has been on some specific power amps and mostly speakers and DIY cables. I'm currently "gutting" some preamps and will consider this to be a "learning experience" in this area. As such, i will say that there is no ONE thing in ANY design that is a cure all unless the product is really just underdesigned to begin with. From what i've found, "modding" or "tweaking" gear is kind of an accumulation of a bunch of small steps forward that add up to a long and pleasurable walk down music lane. Most of it is trial and error based and that's why it is important to be able to reverse your "mods". Even the experts run into "why doesn't this work right" type of situations. As to shielding, i would try that in your sources, especially digital. I have found that my DAC's are quite susceptible to RF based interference. Other than that, let US know what YOU find out.... : ) Sean
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