While building (or designing an amp) in general what components would be the most important, and whats one (in general) would be mid importance, to low...
Since Im a 100% total newb, I have only a hunch. But just to see the format Im hoping to see in the responses I will start.
1) Layout and wiring technique, OPT quality, coupling capacitors, power supply and filtering, heater wiring and heater power supply, resistor and capacitor selection, biasing all of the tubes
Expand as required, and feel free to give your reasons or explanation...
Since Im a 100% total newb, I have only a hunch. But just to see the format Im hoping to see in the responses I will start.
1) Layout and wiring technique, OPT quality, coupling capacitors, power supply and filtering, heater wiring and heater power supply, resistor and capacitor selection, biasing all of the tubes
Expand as required, and feel free to give your reasons or explanation...
Power supply, yes, tick, must be quiet, and reasonably well regulated, choke input with another L-C section after that.
Might seem out of order, however the next priority were it mine, is interfacing the gain stage to to the grid of the output tube. Tubelab's Power Drive floats the boat here, the low impedance of a direct coupled MOSFET source follower nukes all the issues with Miller effect (grid capacitance), enabling wide bandwidth. And CCS loading the (triode) gain tube tube maximises gain and linearity. Just my $0.02 worth 🙂
Might seem out of order, however the next priority were it mine, is interfacing the gain stage to to the grid of the output tube. Tubelab's Power Drive floats the boat here, the low impedance of a direct coupled MOSFET source follower nukes all the issues with Miller effect (grid capacitance), enabling wide bandwidth. And CCS loading the (triode) gain tube tube maximises gain and linearity. Just my $0.02 worth 🙂
1. The tubes used. Preference to DHTs whenever they can be used. Also be aware of using older pre WW2 tubes before miniaturisation of tubes into 9 pin sockets. Use only true triodes or if this isn't possible, pentodes in triode.
2. Capacitors. DC Link caps for last cap in PSU and all cathode bypasses. Coupling caps are personal but I'd make a case for Russian teflon caps.
3. 2 stage design.
4. Plate chokes on the input tubes in preference to solid state active loads.
5. Just enough amplification and not more than is needed.
2. Capacitors. DC Link caps for last cap in PSU and all cathode bypasses. Coupling caps are personal but I'd make a case for Russian teflon caps.
3. 2 stage design.
4. Plate chokes on the input tubes in preference to solid state active loads.
5. Just enough amplification and not more than is needed.
1. Have fun building it.
2. Remember HV safety measures.
3. Decide if you wish pursuing good sound or just having fun building it.
4. Study your tubes well. Some can be prone to easier oscillations than others.
2. Remember HV safety measures.
3. Decide if you wish pursuing good sound or just having fun building it.
4. Study your tubes well. Some can be prone to easier oscillations than others.
Absolutely perfect! Interstage transformers instead of plate chokes are another option...
You might as well just forget about this question as a practical approach for designing an amp. An amp is a system that depends on the designer having a set of goals for the amp, first. Then comes the budgeting for parts and hope you have all the funds necessary to build it with no compromises. But you have to keep in mind it's a system and there are no parts of secondary importance. One missing/dead/off-value plate resistor that costs $.25 will render the amp quiet or unlistenable just as much as a $.25 cathode resistor could, too, or a poorly chosen OPT primary impedance, or a design with no FB.... It was obviuosly a "newb" question. Every part has its part... and only if you know what you are doing can you fudge the quality of one part and then compensate with another to achieve the design goals.
Take your dream budget build. Cut that budget in half. Now tell us what your priorities are lol...
Its a difficult question to pose, and it requires the person who replys to have some insight as to the general idea of its intent. Obviously everything matters. Thats a given, but paying $300 for a capacitor when even a $50 capacitor does more than enough gives $250 more towards great iron.. So, I repose the question again, given half of your dream budget, what gets priorities?
. . Hmmm... I'll have to write that down. Such designer wisdom is rare in these boards. I thought you said you were a newb.
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You either build a smaller amp that has good parts, or you reject the boutique BS and build the amp that puts out your design goals for sound quality and power.
As someone who built their first amp not long ago.
- start simple and get a good baseline and reasonable parts. Capacitor input is OK, have something which works and is stable even if full of electrolitics.
- I'd go with RC coupling, the miflex kpcu is cheap, fuss free and other parts will be the bottleneck long before the coupling will.
- once the inevitable upgrade bug hits, do the PSU, chokes, poly caps, I like clarityCap TC
- don't go for expensive parts unless the rest of the system is up to scratch, dac and transport are key.
- don't be hard on yourself on mistakes, it's part of the learning process but safety first.
- parafeed is a nice way to start and gets close to really good for cheap but in the end gaped SE is better.
- once the bootcamp is done you'll know what's your cup of tea. For me it's spud PX4 for headphone use with custom japanese nanocrystalline iron, no resistors in the signal path.
- start simple and get a good baseline and reasonable parts. Capacitor input is OK, have something which works and is stable even if full of electrolitics.
- I'd go with RC coupling, the miflex kpcu is cheap, fuss free and other parts will be the bottleneck long before the coupling will.
- once the inevitable upgrade bug hits, do the PSU, chokes, poly caps, I like clarityCap TC
- don't go for expensive parts unless the rest of the system is up to scratch, dac and transport are key.
- don't be hard on yourself on mistakes, it's part of the learning process but safety first.
- parafeed is a nice way to start and gets close to really good for cheap but in the end gaped SE is better.
- once the bootcamp is done you'll know what's your cup of tea. For me it's spud PX4 for headphone use with custom japanese nanocrystalline iron, no resistors in the signal path.
I'd say speakers. I'm prone to worry much more about my speakers than the $.47 coupling cap in my amps. There are often a lot of sacrifices necessary to gain efficiency suitable to SETs. Second is iron, unless you use a Solid State subwoofer and cheat the laws of physics completely. But as always, ymmv.
When you design an amp, or anything else for that matter, you need to start with a requirements analysis. What are your requirements?
Suppose I'm an amateur and I want to design my own house and I ask you: what components are most important? As a competent designer, I would hope you turn around and ask me: what are your requirements? How else would you know if energy efficiency is more important to me than a barrier-free floorplan?
Suppose I'm an amateur and I want to design my own house and I ask you: what components are most important? As a competent designer, I would hope you turn around and ask me: what are your requirements? How else would you know if energy efficiency is more important to me than a barrier-free floorplan?
I would vote for 50AE + pblix + dgta.
Also, don't spend over $5 for a coupling capacitor. Consider a second, higher voltage, B+ supply for the driver to allow RC coupling while maintaining low distortion into a lower mu output valve. The difference between a mu of 5 and a mu of 8 is significant.
All good fortune,
Chris
Also, don't spend over $5 for a coupling capacitor. Consider a second, higher voltage, B+ supply for the driver to allow RC coupling while maintaining low distortion into a lower mu output valve. The difference between a mu of 5 and a mu of 8 is significant.
All good fortune,
Chris
I can see your point all to well here. I sidestep this issue by making my amps in 2 separate parts - the output section and the driver section. Each has its own power supply and chassis. I can use resistor loading or a plate choke on the driver stage - I have that freedom. If I build in one chassis it would be a plate choke, since I like to have a decent amount of current through the driver stage, like 7mA or more, and I'd just use one PSU.
I hear, all the time, from people whose opinions I value, that they *like* the sound of simple amplifiers with choke loaded plates (including my building partner itishifi.com). Given that a quality plate choke is both difficult and expensive, you have to ask yourself where this comes from. In Iain's case at least, it's not coming from a preference for bandlimiting or distortion. (His personal system is Klipsch Jubilees and such. 108dB SPL/1W/1M).
Mu of 5 output triodes are a challenge to drive linearly from the same B+ supply that the output valves get, if RC coupling is to be used. This is all background for the OP, to get a handle on some design issues.
Then why use mu of 5 output valves? (2A3, 300B, 845, trioded 4E27, etc?) Because the output transformer's distortion varies with driving impedance. Research this, and all good fortune,
Chris
Mu of 5 output triodes are a challenge to drive linearly from the same B+ supply that the output valves get, if RC coupling is to be used. This is all background for the OP, to get a handle on some design issues.
Then why use mu of 5 output valves? (2A3, 300B, 845, trioded 4E27, etc?) Because the output transformer's distortion varies with driving impedance. Research this, and all good fortune,
Chris
Reminds me of the time one of my friends was served a very tasty snack, a breaded and deep fried thing. He absolutely loved it. The host wouldn't tell him what it was. Later I told him it was cow brains. He almost threw up.
If people were given a bunch of sealed black boxes to audition and like or dislike, they would be much happier and way ahead financially. The problem begins when they open the box and see what's inside.
Since Im a 100% total newb
Do not consider designing your first one. Pick one you like and get in touch with the designer regarding output transformers. After you have an idea of quality of OPT that matches your budget, quality of other components will fall into line. Staying in contact with someone who is experienced with the design you like will avoid numerous mistakes in all the things you list in your original post. After you have built and debugged one you will have enough appreciation of important details (such as grounding) to consider designing something simple. If you do not gain the build/debug experience first you are setting yourself up for some slow, frustrating and expensive trial and error learning, and you will still lack the necessary background to even ask the most important questions as you try to figure out what you did wrong.
I have used this approach to build two pairs of what I consider to be top quality amps, 845 SET and Williamson monoblocks. Both were quickly debugged and have state of the art tube sound. Don't get too far beyond your existing skills and experience as you advance in this hobby.
Do not consider designing your first one. Pick one you like and get in touch with the designer regarding output transformers. After you have an idea of quality of OPT that matches your budget, quality of other components will fall into line. Staying in contact with someone who is experienced with the design you like will avoid numerous mistakes in all the things you list in your original post. After you have built and debugged one you will have enough appreciation of important details (such as grounding) to consider designing something simple. If you do not gain the build/debug experience first you are setting yourself up for some slow, frustrating and expensive trial and error learning, and you will still lack the necessary background to even ask the most important questions as you try to figure out what you did wrong.
I have used this approach to build two pairs of what I consider to be top quality amps, 845 SET and Williamson monoblocks. Both were quickly debugged and have state of the art tube sound. Don't get too far beyond your existing skills and experience as you advance in this hobby.