I am interested in building a tube headphone preamp/amp for a friend. He currently uses a Topping A90. Can anyone suggest any that would be likely to impress his ears? I don't want to bother making something that won't compete with what he already has. He has never experienced tube amps. I have some experience with them regarding guitar amplifiers and I'd like to build something for him.
A kit would be ideal, but not a deal breaker.
I might also be willing to just buy one and not build it (although building it would be cool to keep down the cost and make the gift more special).
Thanks for any help you can offer. Feel free to ask questions to help narrow things down more. I can try to get any answers that could help.
Edit:
35 ohm headphones would be the main use and focus of this
A kit would be ideal, but not a deal breaker.
I might also be willing to just buy one and not build it (although building it would be cool to keep down the cost and make the gift more special).
Thanks for any help you can offer. Feel free to ask questions to help narrow things down more. I can try to get any answers that could help.
Edit:
35 ohm headphones would be the main use and focus of this
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Whammy is well regarded and well documented.
Sapphire by RJM is also great and very well supported by Richard.
Both are DIY kits and you stuff the PCB yourself.
Sapphire by RJM is also great and very well supported by Richard.
Both are DIY kits and you stuff the PCB yourself.
Thanks for the input. I believe I will make the whammy and possibly send it to my friend for him to give it a listen and I thought also about making the ACA+ as well just for fun and for him to compare with his current gear, but my main focus is to find a Tube based amp to give him a taste of what he is missing having never experienced tube amplification and how it colours the sound differently.
My main issue is that I don't know what would be good. I know I could make a starving student ii headphone amp but I am not sure that would even compete with his Topping A90. He might enjoy trying it as his first tube amp but I might want to go more impressive. I feel like I need to but maybe I'm wrong. Should I just build one of those?
Hopefully some folks with much more knowledge and experience than I, can help ask the questions and give suggestions to lead me to some options that would make the most sense. There's not really any right or wrong but there should be some amps that would be better suited for the purpose and I'd like to find some of them. Thanks!
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Do you use headphones yourself?
If you do, you can try it before you pass it as a gift.
The main thing is that any gift will be well appreciated, so you shouldn't worry too much.
An easy way to go about with tubes is to get a PCB kit from the net and stuff it with some good quality components.
This is one of those I 've build and use frequently.
5670/ 6n3 6080/ 6n5p Stereo Tube Headphone Amplifier Heisang Amp Circuit PCB for sale online | eBay
It's a simple OTL design that's pretty good for its cost.
Power supply and filaments are well laid out and there is zero hum.
It has an SRPP input stage with a cathode follower.
Has the option of feedback resistors. I use it without at the moment.
Capacitors play an important role in OTL designs and if your friend has low impedance cans, better go big.
I went all the way and used around 1300uF per channel there.
If you do, you can try it before you pass it as a gift.
The main thing is that any gift will be well appreciated, so you shouldn't worry too much.
An easy way to go about with tubes is to get a PCB kit from the net and stuff it with some good quality components.
This is one of those I 've build and use frequently.
5670/ 6n3 6080/ 6n5p Stereo Tube Headphone Amplifier Heisang Amp Circuit PCB for sale online | eBay
It's a simple OTL design that's pretty good for its cost.
Power supply and filaments are well laid out and there is zero hum.
It has an SRPP input stage with a cathode follower.
Has the option of feedback resistors. I use it without at the moment.
Capacitors play an important role in OTL designs and if your friend has low impedance cans, better go big.
I went all the way and used around 1300uF per channel there.
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Yes, I have headphones and use them some. I would certainly test it before sending it. I have a couple pairs of Sennheisers. Here is some more background information: ACA for audiophile friend as a gift?.
I'm sure it would be appreciated but I would like for it to compete with the quality of what he is using and not be something that doesn't get much use.
That kit seems like a decent option. Thanks so much for the suggestion. I like EL34 tubes in guitar amplifiers. I'm not familiar with these other ones but that doesn't mean anything.
So you have had good luck with these kits and the components are decent? Tubes well-packaged so as not to be damaged in shipping and of ok quality? Are there much in the way of instructions with it or a resource elsewhere to help with the build?
What kind of approximate cost to do the cap upgrade you mention?
I just started doing this research and the OTL is something I just came across when looking at the Zana Deux and am learning about. I like that this design is like that. Thanks again!
Let me tell you something ...
For a few years now, I've been building headphone amplifiers with electronic tubes. I spent a lot of money to reach a certain quality.
Then I realized that I can get the same things using semiconductors, at a much lower cost and with features that are stored over time. The electronic tube is a consumable component and this aspect comes with other technical problems.
Yes, lamp montages have their charm, they attract amateur builders, I am aware of that.
In addition, coming from the past, it creates the classic feeling of something pure, etc ... Sellers know this and there are delightful stories in the description of some products. $$$$$$$ 😀
Try to build one, not buy. There are many projects on the forum.
What I wrote above is just a purely personal opinion and should not be taken too seriously. 🙄
For a few years now, I've been building headphone amplifiers with electronic tubes. I spent a lot of money to reach a certain quality.
Then I realized that I can get the same things using semiconductors, at a much lower cost and with features that are stored over time. The electronic tube is a consumable component and this aspect comes with other technical problems.
Yes, lamp montages have their charm, they attract amateur builders, I am aware of that.
In addition, coming from the past, it creates the classic feeling of something pure, etc ... Sellers know this and there are delightful stories in the description of some products. $$$$$$$ 😀
Try to build one, not buy. There are many projects on the forum.
What I wrote above is just a purely personal opinion and should not be taken too seriously. 🙄
OTL. There be dragons down that path.. with big pointy teeth.
I've spent the last .. year I think.. researching specifically OTL low impedance (30ohm) headphone amps.
You will find that it's easy todo voltage (valves and transformers) or do current (digital and mosfet).. OTL is like taking those problems from both and multiplying them. Doing voltage AND current (low impedance) .. as I say there be dragons 😀
Don't ignore the power supply with OTL. It will take a good 60-70% of your time, effort and budget.
Oh and for $199 I strongly doubt you'll get PSVane tubes - so check they supply the tubes too..
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I'm starting to think my friend probably has a solution for him that is more than adequate and I probably won't be able to pick the tube circuit that would melt his ears in the right way, that would take too much luck. I don't really know the questions to ask to try to find out what colouration of sound he might prefer nor do I know which tube amp design would work for that bias. It's all a crapshoot.
Maybe I'll just make the easiest ones (whammy and starving student) instead of wasting too much time and send them to him to evaluate and see how that goes. Appreciate the reply!
Lol...you have me scared a bit...a healthy kind though!
Makes sense that it wouldn't have tubes for that price.
I got it as a PCB kit, but i sourced all the components myself.
The kit comes with mediocre components to keep costs down.
Schematic was sent to me by the seller.
Tubes were not included. I bought them separately.
The capacitors I used were not costly.
Good quality Nichicons and BC/Phillips caps can be found at reasonalble prices.
However, they need to be bypassed with some good quality, smaller value, film/PIO/Mica or whatever your preference.
The real cost of the kit is in the iron you'll need and of course the enclosure.
All tubes require a lot of iron. I built it with two separate torroidals. One for the B+ and the filaments of the signal tubes and another one separate CT tranformer for the 3A filaments of the output CF tube.
As others have said, tubes are really nice and can sound absolutely lovely.
But they are bulky, heavy, produce heat, can get expensive and need space.
And imagine this kit is with solid state rectification and OTL.
If you go with tube rectification and/or output transformers, then multiply the above.
Tube rectification is nice though...
This particular kit is a good intro into tubes. It'll sound different than his solid state. This I can warranty.
Whether your friend will like it, that's another story. It depends on so many factors.
For example, If he listens to modern electronic music, I doubt it.
Tubes do better with older stuff like Blues/Jazz/Funk/Classical and pre-80s stuff in general.
Anyway, if you want to save yourself time and trouble just build the Whammy. Or something equivalent. Use good quality components and it will sound very good.
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I think this is good advice. Thanks. He listens to a little of everything so I think he could appreciate it for certain genres as you mention.
My experience with tube amplification is with guitar amps and you want that colour and distortion for the sound in the power section but that's specifically for the frequency of guitar. With headphone amplification I could see you not wanting it to do the same thing necessarily, so I get how a solid state could be "better" in a way for more types of music and consistency. It could be so much up to the taste of the person, I mean.
I think i'm going to build a whammy and a starving student and compare them for myself and maybe send them on to him for him to play with, hear and experience. Maybe I will get the bug and want to make another tube amp after that for him, depending on how he reacts. I feel like I certainly would be interested in making my own guitar tube amp and maybe I could get into tinkering and making more amps.
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Whammy with the right parts will sound great.
I suspect that it will blow the mass produced unit of your friend out of the water. Starving student could do the same with the right music.
One trick to drop in some 'valve flavor' (other than going hybrid) into a solid state circuit, is to use components that add some of that kind of harmonics.
For example, you could use carbon composition (current production preferrably) resistors in the signal path and when possible, bypass larger film/foil caps with smaller value Paper in Oil types. Or for small value caps in the signal path, use good quality PIO straight. I use certain Soviet era PIO that I like. Use non-metallised types (pure foil) if you can for film types, preferabbly polysterene and if your pocket/capacitance/space allows it, go for Silver Mica instead. They will usually blow all film types in the single path, including polystyrene.
So, both carbon resistors and some nice PIO caps will add some nice body, depth and smoothness to solid state amps. And I know that some folks hate carbon composition because they measure really badly for noise, but for audio they are fine.
And I say that only after building identical designs with good metal film (Dale CMF) first and with fresh carbon composition afterwards.*
My ears almost always settled for the carbon composition version.
*I followed a simple procedure.
Recorded digitally the signal of the same music tracks through each and then time edited them to exactly match both.
I also matched them within 0.1dB in gain and finally played them with foobar2000 using the 'ABX comparator plugin' where you can switch between tracks on-the-fly.
Ayone can apply this compulsive method to test the audible effects of any component of course.
Just take your time, grab a beer, record and then listen.
Trust your own ears cause that's what you'll use to enjoy your music eventually.
I suspect that it will blow the mass produced unit of your friend out of the water. Starving student could do the same with the right music.
One trick to drop in some 'valve flavor' (other than going hybrid) into a solid state circuit, is to use components that add some of that kind of harmonics.
For example, you could use carbon composition (current production preferrably) resistors in the signal path and when possible, bypass larger film/foil caps with smaller value Paper in Oil types. Or for small value caps in the signal path, use good quality PIO straight. I use certain Soviet era PIO that I like. Use non-metallised types (pure foil) if you can for film types, preferabbly polysterene and if your pocket/capacitance/space allows it, go for Silver Mica instead. They will usually blow all film types in the single path, including polystyrene.
So, both carbon resistors and some nice PIO caps will add some nice body, depth and smoothness to solid state amps. And I know that some folks hate carbon composition because they measure really badly for noise, but for audio they are fine.
And I say that only after building identical designs with good metal film (Dale CMF) first and with fresh carbon composition afterwards.*
My ears almost always settled for the carbon composition version.
*I followed a simple procedure.
Recorded digitally the signal of the same music tracks through each and then time edited them to exactly match both.
I also matched them within 0.1dB in gain and finally played them with foobar2000 using the 'ABX comparator plugin' where you can switch between tracks on-the-fly.
Ayone can apply this compulsive method to test the audible effects of any component of course.
Just take your time, grab a beer, record and then listen.
Trust your own ears cause that's what you'll use to enjoy your music eventually.
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Frankly, the A90 has absolutely superb specs. Topping A90 Headphone Amplifier Review | Audio Science Review (ASR) Forum
So you're not going to build anything "better". So definitely aim for something with a nice euphonic character, something clearly different. Forget about the whammy which is just one more iteration of the buffer in a an opamp feedback loop style of amps and just go for the starving student.
edit: if you want a more serious tube amps, I'd avoid anything OTL for low impedance headphones. Unless you're driving really inefficient headphones, this little parafeed is pretty decent. And in the US, you have access to cheap transformers (edcor).
So you're not going to build anything "better". So definitely aim for something with a nice euphonic character, something clearly different. Forget about the whammy which is just one more iteration of the buffer in a an opamp feedback loop style of amps and just go for the starving student.
edit: if you want a more serious tube amps, I'd avoid anything OTL for low impedance headphones. Unless you're driving really inefficient headphones, this little parafeed is pretty decent. And in the US, you have access to cheap transformers (edcor).
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Measurements aside, 'better' in terms of how it sounds to oneself will always remain entirely subjective.
Difficult to predict unless you listen first.
And I think the Whammy can be a really good starting point.
The starving student must also be great for starters!
Easy to build with its switch type PSU.
But I really like the sound and convienience of opamps too.
I have something similar to the Whammy (a Lehmann Cube Linear) that I've build several of with different parts each time and i think it sounds very good for its cost and with components matched to taste.
OTL I 've build a couple, one is an iteration of the Aren van Waarde project (itself based on an older Rudy van Stratum schematic).
A couple of double triodes, with a 6922 for the input stage and a 6AS7G as a CF.
Simple as it can be. Power supply is also kept pretty simple.
Unregulated, solid state but with regulated DC filaments.
The other is similar but with an SRPP stage and all filaments are AC.
I actually prefer this one.
I use it with my 50Ohm HD599 and i don't feel I am missing something.
Of course there must be designs out there that might sound better, but the low impedance cans can work fine with the OTL amp as long as you use large capacitance (470uF bypassed with smaller caps of choice).
Followed by a lowish resistance (2kOhm or so) to ground in order to avoid high DC offset building up and discharging when you plug your low Z cans.
I had this problem cause I was using a higher value resistor and got the tip from PRR regarding DC leakage calculation (thanks!).
Difficult to predict unless you listen first.
And I think the Whammy can be a really good starting point.
The starving student must also be great for starters!
Easy to build with its switch type PSU.
But I really like the sound and convienience of opamps too.
I have something similar to the Whammy (a Lehmann Cube Linear) that I've build several of with different parts each time and i think it sounds very good for its cost and with components matched to taste.
OTL I 've build a couple, one is an iteration of the Aren van Waarde project (itself based on an older Rudy van Stratum schematic).
A couple of double triodes, with a 6922 for the input stage and a 6AS7G as a CF.
Simple as it can be. Power supply is also kept pretty simple.
Unregulated, solid state but with regulated DC filaments.
The other is similar but with an SRPP stage and all filaments are AC.
I actually prefer this one.
I use it with my 50Ohm HD599 and i don't feel I am missing something.
Of course there must be designs out there that might sound better, but the low impedance cans can work fine with the OTL amp as long as you use large capacitance (470uF bypassed with smaller caps of choice).
Followed by a lowish resistance (2kOhm or so) to ground in order to avoid high DC offset building up and discharging when you plug your low Z cans.
I had this problem cause I was using a higher value resistor and got the tip from PRR regarding DC leakage calculation (thanks!).
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The main problem with OTL is output impedance. With a single 6as7, you cannot get a low enough output impedance for low impedance headphones, unless their impedance is very flat vs frequency or you're using a boatload of feedback. Second problem is available current output, if your headphones aren't very efficient.
See for example for your hd599: HD599 | DIY-Audio-Heaven , scroll down to the "output resistance" graph. That's pretty much what happens with a Van Waarde (I've built a pair of these too or similar enought). Not to say it sounds bad btw, but not everyone will like that bass boost. I kinda like the Van Waarde with the hd650 though, for which the effect is more subtle.
See for example for your hd599: HD599 | DIY-Audio-Heaven , scroll down to the "output resistance" graph. That's pretty much what happens with a Van Waarde (I've built a pair of these too or similar enought). Not to say it sounds bad btw, but not everyone will like that bass boost. I kinda like the Van Waarde with the hd650 though, for which the effect is more subtle.
*Puffs cheeks*
Low impedance and OTL is a challenge. However you're correct - to get 32ohm you need very very load impedance output from the amp and hefty amounts of current (looking at it from a valve world where milliamps are few and far between).
There are ways (adding solid state followers), feedback, parallel tubes, etc etc that all add to reducing impedance. In the end you'll find that low impedance OTL = current = current demand from HV PSUs where most valve PSUs and transformers don't output the current needed without further complications either by selecting rectification that doesn't drop 60% of current. Only made worse by class a idling for example.
I think the worst power efficiency is actually OTL, Class A push-pull, low impedance, linear power supply with full bridge rectification...
It's almost better finding the amp you like and then adding solid state to boost current from a low voltage supply.
Like I said, there be dragons down this path.
OTL 6SN7 + 6AS7 .. yes.. but I'd not call that a low output impedance. Those low plate resistance regulator tubes.. like AS7, MIG tubes etc all love heater current..
IIRC Chord's solid state offering uses 6 solid state output chips to lower the impedance, quote chord for their Mojo:
I saw that the A50 was quoted as 4ohms output impedance which seems incorrect to me. EDIT: another site says <0.1ohm, so 100mOhm or less..
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