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Kevin O'Connor's "The Ultimate Tone Vol. 6" started shipping a few weeks ago, so it's starting to trickle in here in the states. I've spent a few hours with it, and I thought some of you might like to know what's in it.
It's another TUT like the other TUTs. Once again, O'Connor spends his time on architecture, without alot of equations. Any attempt to apply his concepts would put the onus on you to do your due dilligence on power ratings, component selection, turn-on and turn-off conditions, etc. The previous volumes, along with his more basic books, if needed, should prepare you for this. He refers to previous volumes a bit, but it's readable as a first O'Connor book if you have enough background.
One purpose of the series is to get O'Connor's ideas disclosed in public to avoid liability, given the trend for large amp companies to files for and receive patents on silly, old, or unpatentable ideas. You'll find that when he presents an architecture, he shows implementations with tubes, BJTs, MOSFETs, op-amps, etc. to cover the bases, along with the obvious variations of the architecture. These options are generally discussed from simplest to most refined/complicated, and the preferred implementation isn't always identified. It's more of a tool kit.
O'Connor vacillates between an historical perspective of amp "icons", with a special emphasis on the RCA manual -> Fender -> Marshall -> everybody else perspective, and some ideas that are so far out there that it takes you ten pages to catch up. TUT6 is another mixed bag. Let's look at what you get.
1. DC Power Scaling - O'Connor's Power Scaling attempts to duplicate output stage distortion at low volume by reducing various supply voltages and compensating with bias adjustments. It's been a while since TUT4 outlined several approaches for Power Scaling, which were reflected in his first Power Scaling kits. He's evolved the concept a bit, reflected in his new "DC" power scaling kits. Chapter 1 give you another 78 pages of power scaling madness, and yes, you finally get schematics for the kits (you'd think you'd get them with the kits, but you don't). You're still going to need to know what you're doing to host them in a given amp.
2. Class-G Valve Amplifiers - Why not use several B+ supplies and switch between them for large and small amplitude output? Maybe because it's too complicated? But what if you did? How would you do it? What benefits and problems would you face? You get 11 pages on the architecture.
3. Z-B-X - How about push-pull with one tube running class B? Again, O'Connor's way out in left field, but it's fun... no flyback means you can crank up the supply, and you wind up with lots of extra output power. 40 pages.
4. Dumble - 18 pages of discussion on what's different in an Dumble pre-amp.
5. The 400 - How do you build a 400 Watt tube amp? What tubes? what supply voltage? What transformers? 26 pages for bass amp designers and guitar amplifiers who've gone a bit over the edge.
6. Mains Control - More discussion of the AC your amp runs on, how to remove DC, automate range selection, reduce inrush current, switch it with MOSFETs, fuse it, etc. 54 pages.
7. Sustain - TUT4 talked of sag, and developed a soft current-limiting circuit to variably duplicate the effect of a tube rectifier. The result is increased sustain, and O'Connor calls his sag circuits sustain circuits to differentiate them from Maven Peal's work. In this re-visit, the circuits look much more like log compressors, strangely located at the power tubes, like a primative tremolo, with many variations. 18 pages.
8. High Gain - O'Connor starts with "Do you really need more gain? No. Do you need more saturation? No. Do you need tose extra tubes? No. But...". He goes on for 69 pages, reviewing high-gain pre-amps throughout history, with 14 initial pages of discussion, followed by 55 pages of schematics and comments on 31 pre-amps from various manufacturers. There's some neat discussion on the need for cathode followers before tone circuits, the first stage, and some of the more novel successful high-gain architectures, with emphasis on architecture and commonality, and not too much discussion of "doing this sounds like this". Stage gain and frequency response are generally covered, with some discussion of the merits of various approaches sprinkled through the review.
So is it worth it? It depends who you are. Beginners won't get much out of it. If you're into power scaling, another 78 pages probably make it worth the price. The "high-gain" stuff is pretty cool, and the chapters that fall into the "circuits you'll definitely never use" catagory are at least entertaining. There's a schematic on almost every page, and if you read 1500 pages of the TUT series, just studying the schematics will definitely improve your chops and expand your options.
It's another TUT like the other TUTs. Once again, O'Connor spends his time on architecture, without alot of equations. Any attempt to apply his concepts would put the onus on you to do your due dilligence on power ratings, component selection, turn-on and turn-off conditions, etc. The previous volumes, along with his more basic books, if needed, should prepare you for this. He refers to previous volumes a bit, but it's readable as a first O'Connor book if you have enough background.
One purpose of the series is to get O'Connor's ideas disclosed in public to avoid liability, given the trend for large amp companies to files for and receive patents on silly, old, or unpatentable ideas. You'll find that when he presents an architecture, he shows implementations with tubes, BJTs, MOSFETs, op-amps, etc. to cover the bases, along with the obvious variations of the architecture. These options are generally discussed from simplest to most refined/complicated, and the preferred implementation isn't always identified. It's more of a tool kit.
O'Connor vacillates between an historical perspective of amp "icons", with a special emphasis on the RCA manual -> Fender -> Marshall -> everybody else perspective, and some ideas that are so far out there that it takes you ten pages to catch up. TUT6 is another mixed bag. Let's look at what you get.
1. DC Power Scaling - O'Connor's Power Scaling attempts to duplicate output stage distortion at low volume by reducing various supply voltages and compensating with bias adjustments. It's been a while since TUT4 outlined several approaches for Power Scaling, which were reflected in his first Power Scaling kits. He's evolved the concept a bit, reflected in his new "DC" power scaling kits. Chapter 1 give you another 78 pages of power scaling madness, and yes, you finally get schematics for the kits (you'd think you'd get them with the kits, but you don't). You're still going to need to know what you're doing to host them in a given amp.
2. Class-G Valve Amplifiers - Why not use several B+ supplies and switch between them for large and small amplitude output? Maybe because it's too complicated? But what if you did? How would you do it? What benefits and problems would you face? You get 11 pages on the architecture.
3. Z-B-X - How about push-pull with one tube running class B? Again, O'Connor's way out in left field, but it's fun... no flyback means you can crank up the supply, and you wind up with lots of extra output power. 40 pages.
4. Dumble - 18 pages of discussion on what's different in an Dumble pre-amp.
5. The 400 - How do you build a 400 Watt tube amp? What tubes? what supply voltage? What transformers? 26 pages for bass amp designers and guitar amplifiers who've gone a bit over the edge.
6. Mains Control - More discussion of the AC your amp runs on, how to remove DC, automate range selection, reduce inrush current, switch it with MOSFETs, fuse it, etc. 54 pages.
7. Sustain - TUT4 talked of sag, and developed a soft current-limiting circuit to variably duplicate the effect of a tube rectifier. The result is increased sustain, and O'Connor calls his sag circuits sustain circuits to differentiate them from Maven Peal's work. In this re-visit, the circuits look much more like log compressors, strangely located at the power tubes, like a primative tremolo, with many variations. 18 pages.
8. High Gain - O'Connor starts with "Do you really need more gain? No. Do you need more saturation? No. Do you need tose extra tubes? No. But...". He goes on for 69 pages, reviewing high-gain pre-amps throughout history, with 14 initial pages of discussion, followed by 55 pages of schematics and comments on 31 pre-amps from various manufacturers. There's some neat discussion on the need for cathode followers before tone circuits, the first stage, and some of the more novel successful high-gain architectures, with emphasis on architecture and commonality, and not too much discussion of "doing this sounds like this". Stage gain and frequency response are generally covered, with some discussion of the merits of various approaches sprinkled through the review.
So is it worth it? It depends who you are. Beginners won't get much out of it. If you're into power scaling, another 78 pages probably make it worth the price. The "high-gain" stuff is pretty cool, and the chapters that fall into the "circuits you'll definitely never use" catagory are at least entertaining. There's a schematic on almost every page, and if you read 1500 pages of the TUT series, just studying the schematics will definitely improve your chops and expand your options.
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