I have always wanted to make my own amp that was compareable to a macintosh amp for a fraction of the price but what exactly makes it better? Lets ignore the warm harmonics the tube produce to make a better sound for simplicity so not get into the tube/solid state which is better debate.
I know amps can be graded by their THD to give you a rough idea: For instance a shit sony or equivalent will have a THD of 0.8% while a harmon kardon in that power range will be around 0.08% and a Marantz will be around 0.03%. Not that this is the answer to good sound you can hear the difference in a sony and a better amp.
So to get the best sound: Is it just a matter of hand selecting all the parts so the values are as close to design spec as possible? This would make sense why a cheap amp would sound worse because they can just buy 5% components and use them all where as higher end starts with a lower tolerance and then will hand pick them. Also would matching parts: LR channel transistors that are very close also play a big part?
So if my understanding is correct you could take an amp that has a good circuit design (are almost all of them mathematically the best we can do since its really a simple circuit that's been improved over 100 years) and then hand selected the best/matched parts;IE buying 100 resistors and discarding 99% of them could you turn the cheap sony amp into a good one? Perhaps also over sizing filter caps/ over specing parts to run at less load etc.
Hi Beamin,
Congrats on starting a stimulating thread.
I can't answer your questions definitively but here are some comments and suggestions.
First, your point about solid state vs. tube electronics is insightful - this topic alone is likely to stimulate some debate - but if you are really in search of what makes a Macintosh amplifier sound "better" (your word, not mine), perhaps you should keep your inquiry open to examining both solid state and tube amplifiers.
Next, with respect to a "$#*!" Sony, I would say that it's a bit of a harsh comment on Sony. While Sony has over the years produced many relatively entry level (inexpensive) amplifiers, receivers, and other stereo equipment Sony was for a number of years pretty competitive in stereo equipment design. In the 1970s they had a model called the STR-7065 that rivaled the Marantz 2270 (generally a very well regarded receiver). The 7065 held it's own in parts, specs, and sound against the 2270 in the power amplifier section as well as in the pre-amplifier and tuner sections.
Marantz 2270
70 watts per channel RMS 20-20kHz into 8 Ohms
Harmonic Distortion 0.3%
IM Distortion 0.3%
Sony 7065
60 watts per channel RMS 20-20kHz into 8 Ohms
Harmonic Distortion 0.2%
IM Distortion 0.2%
Regardless, let's take your question about replacing the parts on a "$#*!" amplifier. Maybe as an experiment you could select whatever you consider to be a "$#*!" amplifier and replace the parts with better quality parts, ie, parts that perform similar functions but with better values, ie, better individual measurable performance at the component level. The idea would be to retain the same basic circuit but see if the circuit once enhanced with better parts delivers better performance. Now we are down to the question of “What is better performance?” Is better performance something that can be measured (Harmonic Distortion, etc.)? Or is better performance something that can be heard? Or both? Is there really a measurement for everything we can perceive with our hearing? Who knows?
Maybe you could give it a try and let us know what you determine with your measurements and listening.
Next we have the notion that the amplifier is just a "really a simple circuit that's been improved over 100 years". 100 years is a fairly long time (one human lifetime or more in most cases) and the last 100 years have been subject to considerable developments in knowledge and technology, with technology accelerating our understanding of what causes what. The point here is that now, after 100 years, perhaps there is more than one simple circuit design for amplifiers. Toward this end, a second experiment might include studying the designs (including the parts and their specs, and the overall circuits and circuit performance) for some of the popular and/or more well regarded amplifiers over say the last 50 years - perhaps since the 1970s or so. You could look at the solid state designs from Phase Linear, Crown, Marantz, and others to see if you notice any differences in the designs. Likewise, you could look at tube amplifiers from Macintosh, Audio Research, VTL, and others to see if you notice any difference in the designs. These would be more expensive to obtain and certainly more expensive to surgically adjust with different parts so this part of the experimental process might require more study than hands-on work, but I bet if you look across the spectrum of amplifiers you will find that in both solid state and tube amplifiers there are actually quite a few different designs. Perhaps they all came from the same amplifier tree 100 years ago and perhaps they all have a common goal of amplifying a relatively small signal from a pre-amplifier and forwarding the larger amplified signal to speakers but I think you will find considerable differences in design. Even the most ardent, “science is science and not audiofoolery” members of this forum would have to recognize that there are quite a few different designs in the world of amplifiers. Class A, Class B, Class AB, Class D and more – especially when you consider both solid state and tube, not to mention analog vs. digital.
If you listened, could you hear any differences between the various designs? This has become a key subject of the firestorm of a debate your post has kicked off. I'm not ready to go there just yet, but here are some other considerations.
When we say "so to get to the best sound" (again your words, not mine) are we talking about some type of test tone or tones fed into the amplifier with an objective of determining the best sound exiting the amplifier? Or are we talking about the best sound after real music has left the amplifier and passed through the speakers into a room in which the speakers reside? How much consideration are we giving to the complexities of harmonics and any other interactions among all the sounds that occur in real music? And are we giving any consideration to these signals as they entered the amplifier? From what preamplifier was the music delivered? And perhaps even more importantly, from what source was the signal delivered to the preamplifier? For example, if it started as a signal embedded in a record (ie, as complex music etched into vinyl), how were these signals captured (recorded) before the record was cut? Setting aside the microphone or microphones that were used to record the signal(s), or the acoustics of the performance that was recorded, or the performance of the tape recorder, or the skill of the sound technician that did the recording used to make the record, was the stylus that was used to retrieve the mono or stereo signals from the record part of a ceramic cartridge, or a magnetic cartridge, or a moving coil cartridge? And what tone arm with what mass, what anti-skate, and what alignment geometry on what turntable with what suspension was used to hold the cartridge and stylus with the proper force so that the signal or signals could be retrieved from the record?
I know, none of that is what you asked about. But at the end of the day, the amplifier is just one part of a larger chain - and it's somewhere in the middle to the back half of the chain. Most people here would say a power amplifier has relatively little impact on the overall sound - at least compared to the impact of the quality of the recording and the playback components which required acoustic and mechanical vibrations to be converted to electrical energy and compared to the impact of the quality of the back end components (the speakers) that convert electrical to mechanical and acoustic energy. The job of the amplifier is to amplify the signal, not add anything and not subtract or change anything. While in some important respects a power amplifier has among the easiest of the jobs in the chain it is important to remember that amplifying test tones might be somewhat easier than amplifying complex music filled with subtleties.
Next, speaking of the speakers - this is where amplifier design can and should vary, ie, with consideration given to the speakers that will be driven by the amplifier. For example, if the amplifier will be driving very efficient horn speakers (think Klipschorn), the amplifier might need relatively little power output - perhaps a couple or a few watts from perhaps a 45 or 2A3 Single Ended Triode tube amplifier. On the other hand, some inefficient speakers might need a couple or a few hundred watts from a pentode tube amplifier or a solid state amplifier. To design an amplifier to sound "good" we need to have some idea of the load - which means we need to have some idea of the speaker design.
The selection of the speakers can't be done in a vacuum (no pun intended) either because the speakers need to be placed properly with respect to room acoustics, ie, room shape, room size (how much air needs to be moved to achieve what Sound Pressure Level), and room surface treatments. There is a reason why symphony halls have the shapes and materials they have.
Now, back to the original question, what makes an amplifier sound the way it does? It comes down to the design including the execution of the design (ie, including the parts and the craftsmanship/quality control of the manufacturing process). Will the differences in the design and execution be measurable? With a part change here or there perhaps. Will the differences between fundamentally different designs be measurable? Probably, but it might depend on the measurement equipment and skill being applied. Will any of these differences be audible? Perhaps, but it might depend to some extent on all the other variables in the system from signal recording and retrieval (cartridge and tone arm) to especially the particular speakers and especially the particular room that acoustically mates with the speakers.
Net, net: Changing some parts in a given amplifier design and then measuring and listening might be a worthwhile experiment if this line of inquiry intrigues you. Likewise, if you have the opportunity, you might measure and listen to disparate amplifier designs and see what you determine, especially as those designs are embedded in various systems and rooms. My guess is that changing a few parts for similar but better values will be time consuming and tedious with minimal differences in overall amplifier output measurements and the differences if any will be very difficult to hear since by the time you take the amplifier apart and put it back together with different parts your mind will not be able to distinctly remember what it previously heard. Most A-B comparisons need to be instantaneous at the same volume levels in order to have a decent chance of revealing differences. On the other hand, putting fundamentally different amplifier designs into otherwise same systems and rooms will very possibly reveal some different overall sounds as well as some different amplifier measurements. Likewise, moving the same amplifier into different systems and rooms might also reveal some different overall sounds.
What causes what in sound systems is a complex issue and developing a vocabulary that accurately and effectively conveys all the possible combinations of design, measuring, and listening can add a layer of complexity and confusion that is more likely to stimulate debates than agreement unless people develop some common goals, in which case the debates can sometimes be methodically narrowed down so as to isolate some areas of agreement about what causes what.
Let us know what you determine if you make such measurement and listening tests.
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