Newbie Amp/Preamp descisions

[imjjc2]

I am currently trying to decide on an amp/preamp for my first build. I really like the idea of being able to tube swap to find preferences so I've been focusing in on hybrid/ full tube designs.
Ones I've found so far
NP-100v12: DIY 12AU7 (ECC82) Tube / IRF510 MOSFET Headphone Amplifier

4S Universal Preamplifier for 12A*7 Tubes

DIY ECC802S (12AU7 / ECC82) Vacuum Tube SRPP Preamplifier

NP-100v12: DIY 12AU7 (ECC82) Tube / IRF510 MOSFET Headphone Amplifier

Headphone Hybrid Tube Amp (SSMH): 4 Steps (with Pictures)

Right now I'm only driving Creative Aurvana Live! headphones but very soon I intend on getting some better ones.
As far as what I'm looking for other than tubes is something I could use to upgrade in the future as my current budget of $50-100 is nothing compared to some things on here.
My music preference is cinematic rock with a focus on vocals which is why from what I've read I believe that tubes would be a good fit.

Building ability, I don't have a ton of experience past building some smaller projects/ house wiring. However I am going to school for EE so I do have access to great help and tools.
If you could help set me on the right path or give me more ideas it would be greatly appreciated. I've spent the last couple days reading as much as I can, but I can tell I've only scratched the surface of this great DIY world.

I've also found it interesting how 90% of the designs/builds are from 04-10 is there any reason for that?

 

[Eli Duttman]

Any design that uses the 12AU7 family for voltage amplification is highly suspect. The 'U7 is non-linear.

Do you already own decent speakers and the SS power amplification to drive them? What sort of equipment is already on hand?

 

[imjjc2]

I own the type of headphones I said above and I'm currently using just my desktop motherboard to drive them, I'm trying to build a headphone amp/ preamp since I'm not too picky on the gain. And as far as tubes go these are the only popular designs I've found in my price point, But I'm happy to add any other hopefully superior designs to the mix.

 

[Eli Duttman]

Your budget rules anything other than a tube/SS hybrid out, as the cost of O/P transformers alone will easily consume all of the available cash.

The 32 Ω impedance of your "cans" presents certain problems. Of the designs you linked, only Pete Millett's, SSMH, is (IMO) worthy of your time. Pete is a very well established member on this "board" and his work, most definitely, can be trusted.

 

[stocktrader200]

Eli, you are right I couldn't get the 12AU7 to sound very good. The 12AX7 fed to a transistor buffer sounds wonderful. 6922 also is a very very good tube. Properly done SS / Tube Hybrid will take on the very best > 10K all tube amplifier.

 

[imjjc2]

From my limited research that was the one I was leaning toward, and hopefully a good first building block. If there's a preferred build version that someone could suggest I'd appreciate any knowledge. Otherwise I'll probably prepare to order parts later this weekend.

 

[Eli Duttman]

Before parting with any cash, try PMing Pete Millett. He just might provide some very useful hints.

 

[kodabmx]

I use this and love it, and as a bonus the 6N3P is about $1. You can use a 5670, too.

You can sub a 6DJ8 by using 100R cathode resistors, and a 200V B+
You can sub a 6CG7 by using 240R cathode resistors, and 300V B+.

You can also use a eliminate the positive feedback by doubling the cathode resistors, and returning the 18K to ground instead of the first cathode, and bypassing the first cathode with a 1000uF cap.

 

[silasmellor]

If you're starting from little experience you should stick to low voltage hybrid designs for your first build in my opinion. Since you like the idea of tweaking the sound you may also consider an opamp based headamp to let you play around. I will also recommend Pete milletts designs, some of them are great beginner projects. The butte amp is very easy and I believe you at be able to get am aching case from Pete. Not tube, but sweet sounding nonetheless, and quite cheap. The nutube headlamp can also be built reasonably cheap and he sells the natives himself. Also great sounding.

 

[pmillett]

It's too bad that the 19J6 has been depleted - I think it does work better than the 12AU7 in the Starving Student design.

But using efficient 32 ohm headphones, the 12AU7 is probably OK. You will rarely need more than 1V RMS out. It will sound like a tube amp for sure, with significant even-order harmonics, but that's the goal anyway

And it's simple, easy to wire point-to-point, and affordable.

Pete

 

[Lingwendil]

I am currently trying to decide on an amp/preamp for my first build. I really like the idea of being able to tube swap to find preferences so I've been focusing in on hybrid/ full tube designs.
Ones I've found so far
NP-100v12: DIY 12AU7 (ECC82) Tube / IRF510 MOSFET Headphone Amplifier

That particular arrangement (from the old Headwize forum) was my very first tube build. It can work very well, but not with a 12AU7 at 12 volts. Best thing you can do is use a 48-60 volt DC supply, a 6DJ8 or similar tube, and the LM317HVT and this amp will rock. It can even drive speakers pretty well if you increase the heatsinking and current through the output stage.

This is a very nice circuit if you build it at 60 volts and use a 6111 subminiature tube, or something similar like the Russian subminiature, 6n16b. I ran a 6111 version 12 hours a day for nearly ten years, biased hot enough to put 5 watts into some efficient speakers. Fond memories

4S Universal Preamplifier for 12A*7 Tubes

This can work, but I would stay with more linear tubes, like the 6SN7, 6SL7, 6CG7, 6n1p, 6n2p, 6DJ8. The 12AU7 is not a very linear tube, and the 12AX7 types take some real work to deliver the goods.

DIY ECC802S (12AU7 / ECC82) Vacuum Tube SRPP Preamplifier

SRPP used to be very trendy, but it's not much better than a basic grounded cathode unless you have some very specific needs, so I would save a tube by doing a single triode per channel.

A recommended circuit that is a bit "overengineered" but is pretty nice, is the Aikido amplifier. Kits are available. Tube count is high, though... The CCDA is very good, and uses less tubes. Easy and adaptable circuit, as kodabmx shows

GlassWare Line Stage & Headphone Amplifiers Kits and PCBs

Building ability, I don't have a ton of experience past building some smaller projects/ house wiring. However I am going to school for EE so I do have access to great help and tools.
If you could help set me on the right path or give me more ideas it would be greatly appreciated. I've spent the last couple days reading as much as I can, but I can tell I've only scratched the surface of this great DIY world.

Building is nicer with the right tools. Tubes are thankfully pretty simple, and so are most hybrid designs. I find that doing up a nice enclosure is 70% of the work in any electronics project.

Are you looking to do a PCB, or "point to point" type build? For what it's worth, I like PCBs for power supply circuitry, and like to go "point to point" with tag strips for the tubey bits.

I've also found it interesting how 90% of the designs/builds are from 04-10 is there any reason for that?

Tubes (especially hybrid designs) got really popular again around this time for... whatever reason. There were a ton of designs floating around, some good, some not so good. General rule of thumb is to avoid any low voltage (12 volt or so) design unless it uses special tubes meant for ultra low voltage, unless you're looking to build an effects box. 48 volt DC power bricks are $12-15 shipped on Amazon, and can work great for these types of builds. Just add a regulator for heater power (LM317, LM7806, etc) and it's easy to build up something nice.

Anything pmillet says is good advice, and his designs are solid, give his site a read