Hello to one and all,
I am a new member and a total noob with minimal soldering skills who would like to build a headamp / preamp, preferably with 2*6SN7, 2*300B, 1 or 2*274B, as well as XLR input / output.
Is it gonna be very difficult?
What is the complete list of components out there that I need to buy? (finest quality possible)
Also any schematics available?
Cheers everyone!
I am a new member and a total noob with minimal soldering skills who would like to build a headamp / preamp, preferably with 2*6SN7, 2*300B, 1 or 2*274B, as well as XLR input / output.
Is it gonna be very difficult?
What is the complete list of components out there that I need to buy? (finest quality possible)
Also any schematics available?
Cheers everyone!
'' a total noob with minimal soldering skills''
This phrase, and cost-no-object headphone tube amp with 300B tubes DO NOT mix well.....
Please, take no offense, but you are a longgggg way from making that a reality without great hardship.
Get "Morgan Jones - Building valve amplifiers Vol. 4", read it from front to back, and then decide what you really need \ and or\ are capable of.
Your post is kind of like... - "I have never driven a car but I want to build a BMW M3, what parts do i need, and does anyone have a build sheet?"
Again, no offense, but you really need at least a basic knowledge of elektro theory and quite a few tools to make that happen. Maybe look up Elekit kits, they have some very nice amps with 300B and a headphone output. Or Tubelabs Simple SE, I have a few and they are tough to beat for value.
Hope that helps and gives you a direction to head in.....
Cheers
This phrase, and cost-no-object headphone tube amp with 300B tubes DO NOT mix well.....
Please, take no offense, but you are a longgggg way from making that a reality without great hardship.
Get "Morgan Jones - Building valve amplifiers Vol. 4", read it from front to back, and then decide what you really need \ and or\ are capable of.
Your post is kind of like... - "I have never driven a car but I want to build a BMW M3, what parts do i need, and does anyone have a build sheet?"
Again, no offense, but you really need at least a basic knowledge of elektro theory and quite a few tools to make that happen. Maybe look up Elekit kits, they have some very nice amps with 300B and a headphone output. Or Tubelabs Simple SE, I have a few and they are tough to beat for value.
Hope that helps and gives you a direction to head in.....
Cheers
300B and Headphones do not go together well, if the 300B filaments are not DC powered.
Without proper design electrically, magnetically, parts spacing and orientation, wiring placements, and reduction of ground loops . . .
an amplifier and headphones do not go together well.
This forum solves problems with bad designs and bad build details of good designs, but often that requires major changes to fix them.
Start with something proven.
Without proper design electrically, magnetically, parts spacing and orientation, wiring placements, and reduction of ground loops . . .
an amplifier and headphones do not go together well.
This forum solves problems with bad designs and bad build details of good designs, but often that requires major changes to fix them.
Start with something proven.
I'm going to give you an alternate path that I've recommended to others, and have seen work really well:
[1] Choose a simple first design that doesn't cost 3 arms and 4 legs. A design that if you f-it-up by simple ignorance of tube pin numbering, or capacitor polarity ... will only cost you a bit of money to recover from. You get experience. You get to see something come to fruition; you get to sharpen your chops for the much bigger amp that you will do next.
[2] Read a bunch, while doing [1] ... especially the recommendations that McTavish gave, as well as a bunch of old timers here (that will soon be chiming in). Everything is to be gained, and really nothing lost. Even your invested time isn't lost. It is traded for much heightened knowledge.
[3] Revise your dreams as your reading progresses. Who knows, maybe you'll come all the way around to a 300 B project with 6SN7's and all that. Maybe it'll advance further, with 805s or maybe amorphous custom-wound output transformers. Maybe you'll learn a great deal about the beauty and delight of XLR-balanced to unbalanced transformers. Who knows!
Then [4]Gin up the big amp. Get all the stuff. Get a nice chassis. Learn about star grounding. Learn about going with a bit more amplification, and if it is for a 'head amp', why you might really need it. And global negative feedback, and why it really can be a game changer. Which requires more open-loop amplification. And so on.
Best of LUCK! too. I recommend heartily taking the above points of advice and going about this project strategically. NASA didn't do The Moon Shot first. Had to figure out what the heck was going to go wrong in scaling, metallurgy, in computers, control systems, cryogenics, insulation and damping. Needed Mercury, Gemini and Apollo 1 thru 8 to develop both the confidence and recovery systems to get it done. All that. No all-in-one-go.
Just saying,
GoatGuy
[1] Choose a simple first design that doesn't cost 3 arms and 4 legs. A design that if you f-it-up by simple ignorance of tube pin numbering, or capacitor polarity ... will only cost you a bit of money to recover from. You get experience. You get to see something come to fruition; you get to sharpen your chops for the much bigger amp that you will do next.
[2] Read a bunch, while doing [1] ... especially the recommendations that McTavish gave, as well as a bunch of old timers here (that will soon be chiming in). Everything is to be gained, and really nothing lost. Even your invested time isn't lost. It is traded for much heightened knowledge.
[3] Revise your dreams as your reading progresses. Who knows, maybe you'll come all the way around to a 300 B project with 6SN7's and all that. Maybe it'll advance further, with 805s or maybe amorphous custom-wound output transformers. Maybe you'll learn a great deal about the beauty and delight of XLR-balanced to unbalanced transformers. Who knows!
Then [4]Gin up the big amp. Get all the stuff. Get a nice chassis. Learn about star grounding. Learn about going with a bit more amplification, and if it is for a 'head amp', why you might really need it. And global negative feedback, and why it really can be a game changer. Which requires more open-loop amplification. And so on.
Best of LUCK! too. I recommend heartily taking the above points of advice and going about this project strategically. NASA didn't do The Moon Shot first. Had to figure out what the heck was going to go wrong in scaling, metallurgy, in computers, control systems, cryogenics, insulation and damping. Needed Mercury, Gemini and Apollo 1 thru 8 to develop both the confidence and recovery systems to get it done. All that. No all-in-one-go.
Just saying,
GoatGuy
What's your whole system and what do you want it to be? Where exactly does a "preamp/headamp" fit in? Are you going to have a main amplifier for loudspeakers, and is this a preamp with a headphone socket that also feeds the main amp? Or what? And is the "XLR" reference because the amp has a balanced input?
Depending on your source you may not even need a preamp, for example if it's a good quality DAC with a decent level of output. And some have a headphone output anyway. Adding a preamp would just compromise the signal for no good reason. And if it's a head amp, why not use a proper design for a head amp - plenty about.
Some clarification needed!
Depending on your source you may not even need a preamp, for example if it's a good quality DAC with a decent level of output. And some have a headphone output anyway. Adding a preamp would just compromise the signal for no good reason. And if it's a head amp, why not use a proper design for a head amp - plenty about.
Some clarification needed!
Consider starting with a kit that comes with all the parts and detailed assembly instructions - for example Bottlehead or Elekit (no affiliation with either, but I've built a lot of BH stuff). And maybe do so some soldering practice before tackling the final product. If part of the attraction of the DIY approach is building something yourself and learning a bit about tube circuits, a kit is much preferable to having someone else build for you.
My own headphone system is based on two Bottlehead kits - their 300B preamp and their 300B power amp - which I've since modded, rebuilt and tweaked in various ways to suit my taste. But I started by using the amps stock and connecting my Audeze LCD-4 phones via an XLR to speaker posts adaptor. I was very pleased with the results. And if you run into trouble soldering the kit, there's almost instantaneous help available on the Bottlehead forum. The forum is also a great resource for learning the basics (and even a lot of the not-so-basics) of SET amp circuits.
Just my 2 cents.
cheers, Derek
My own headphone system is based on two Bottlehead kits - their 300B preamp and their 300B power amp - which I've since modded, rebuilt and tweaked in various ways to suit my taste. But I started by using the amps stock and connecting my Audeze LCD-4 phones via an XLR to speaker posts adaptor. I was very pleased with the results. And if you run into trouble soldering the kit, there's almost instantaneous help available on the Bottlehead forum. The forum is also a great resource for learning the basics (and even a lot of the not-so-basics) of SET amp circuits.
Just my 2 cents.
cheers, Derek
Have a look here: Headphone Amplifier Kits Archives | Bottlehead
Start with this, move up if you don't like it. IMO 300B is not the best tube. 6AS7\6080 makes more sense.
Start with this, move up if you don't like it. IMO 300B is not the best tube. 6AS7\6080 makes more sense.
As much as I love a good 300B, it is not the right choice for a headphone amp - as many here have pointed out. Building a headphone amp with a 300B is about like asking to build a golf cart with a 2.5 liter V6 engine. It could work, but isn't the smart choice.
The 300B became very popular because it's a good output tube that has enough power for most speaker systems used in a living room. It's a great all-rounder. But there are better tubes if you don't need 5 watts. For headphones you need a tiny fraction of that power.
Good luck with the build, there are plenty of good ideas already in this thread.
The 300B became very popular because it's a good output tube that has enough power for most speaker systems used in a living room. It's a great all-rounder. But there are better tubes if you don't need 5 watts. For headphones you need a tiny fraction of that power.
Good luck with the build, there are plenty of good ideas already in this thread.
One could argue that the best possible headphone amplifier is an amplifier that you already like, with an appropriate resistive voltage divider to a headphone jack. If the headphones are spec'd for a particular source resistance, incorporate that. For most amplifiers, load them lightly. Not rocket surgery.
All good fortune,
Chris
All good fortune,
Chris
For the OP's info - most headphone amps use 6AS7/6080 due to the low 280ohm plate resistance that makes it easier for OTL style to be done cheaper. There are others that offer that (in lower voltages) but the other alternative is simply put the money into an output transformer specifically designed for headphones.. Pretty sure you'll spend the same $$$ on either OT or OTL path once past the basic simple designs.
I would like use 2a3s for headphones, but that's probably not going to add much more for the exponential price increase over my multi-tube output stage. However I would probably design something like a mini-transformer'd 2a3 for headphones with the money disappearing into the custom output transformer.
Take it from me - a 'beginner' tackling their first 'advanced' OTL design almost from scratch. It's taken me 7 months (and 2 years overall) in my free time to get to this point and I'm currently just finalising the custom power supply transformers etc ready to order. Once it's built - the work isn't finished. Then comes the tuning and replacing parts by experimentation to what sounds good.
However it sounds like the OP has decided that the better option is to get a local experienced guy to design/build one - to me that will get you the end product quicker, safer and cheaper (allowing money to be spent where it should).
True. At line level you can simply run a set of capacitors to block any DC, then use an attenuator/pot. That works well if the headphones are designed for near line level. I listen to my intended cap configurations in this way.
Only issue I found is that a buffer provides the high impedance that the CD player is expecting so it sounds better. You get the sound of the CD player.. but that's missing a little warmth (even with a SS class A output stage on CD player). Tube buffer may be all that's required depending on the headphone..
As you say it's not rocket science.
What I meant to convey is that an amplifier capable of driving speakers (that you already have, use and like) is better capable of driving a headphone that some overloaded-into-a-near-short attempt at fudging a square peg into a round hole. Vacuum valve "headphone amplifiers" are a sign of the coming apocalypse. Rapturous foolishness and first world silliness.
All good fortune,
Chris
All good fortune,
Chris
Hehe very true.
A tube headphone amp is akin to sitting in the smok^H^H^H^Hvaping jacket after a good meal in the dark, only lit by the flickering flames of the (fashionable) wood burning fire whilst swiping on the iPad listening to vinyl presses of modern music..
This is about the worst possible way to go about designing or specifying an engineered item. You haven't defined the outcome parameters, but you've defined the input parameters.
Stop name-dropping components that are trendy, start defining exactly what you want this thing to do.
What are the sources you intend to use - turntable? DAC? FM receiver?
What are the headphones you intend to use - what impedance, what driver technology etc?
What are the input requirements for the power amplifier this pre-amp will be connected to? Its input impedance, its expected input voltage etc
Do you need a volume control on the preamp? Or just in the headphone section? Or none at all?
Yes, and possibly dangerous and outrageously expensive. Especially if you don't define what it will need to do.
Hard to know given the complete lack of any detail in your request.
LMGTFY - Let Me Google That For You
Ask 10 world class Chefs to:
Please consider what 7 spices they use most often.
Then, tell us the brands you prefer for each of those 7 spices.
Now, ask a similar question to 10 amplifier cost-no-object designers or builders.
Start with a single time-tested and widely-accepted amplifier circuit.
Then, ask what brand they recommend for the major parts (output transformer, coupling caps, output tubes, input tubes, etc.).
Now repeat the questions with a group of cost conscious designers or builders.
What if you like the output transformer choice of one designer, and the coupling caps choice of another designer.
Will they have positive synergy; or will they be detrimental to each other's sound characteristics?
Please consider what 7 spices they use most often.
Then, tell us the brands you prefer for each of those 7 spices.
Now, ask a similar question to 10 amplifier cost-no-object designers or builders.
Start with a single time-tested and widely-accepted amplifier circuit.
Then, ask what brand they recommend for the major parts (output transformer, coupling caps, output tubes, input tubes, etc.).
Now repeat the questions with a group of cost conscious designers or builders.
What if you like the output transformer choice of one designer, and the coupling caps choice of another designer.
Will they have positive synergy; or will they be detrimental to each other's sound characteristics?
Last edited: