[chuckwheat]

Would this be insane to try? I'm curious to make a simple little one to learn about how they work along the way, and see if it sounds anything decent on the hd650s. Anyone have any ideas? I don't know a thing about tubes or amps in general when it comes to circuits XD

 

[HiGHFLYiN9]

Nope, people do it every day. See DIYAudio.com. It doesn't get much more simple than the Bottlehead Crack, or this nice design http://headwize.com/?page_id=427
 
Both will work well with the 650s 
 
Please read this before you get started: http://www.diyaudio.com/forums/tubes-valves/30172-safety-practices-general-ultra-high-voltage.html

 

[macm75]

Something to entertain is to go kit on first go.  It's pretty much guarenteed success.  Scratch has more potential of less desireable sound particularly on first effort.  The last thing I'd want to do is dissuade someone from building from scratch - but it can be frustrating and patience is a requirement depending on complexity.
If you go scratch, check out headwize - think super cheap for low risk and forget about the rediculous "best".  Personally I have not had great success with OTL amps and, for me, things started to sound much better and less finicky with transformer coupled amps.  
It does not get any simpler than http://www.audiodesignguide.com/NewHeadphoneAmp/index.html - my amp is slightly more complicated (http://diy.ecpaudio.com/2008/03/SSS.html) but I have not looked back in years.  You don't have to use these tubes, Lundahls are on the expensive side, and an alps pot is "perfect".  Check out Edcor - super cheap, sound very good, and can be upgraded to Lundahl, Electra-print, Sowter, on and on, at any time.  I don't see an impedance match to HD650's but maybe they can easily make a 5K:300 ohm, 5W, GXSE series for you - a friend of mine used them and they are very fine.  So not as good as my Lundahl 1660's but I can listen to them all day with no complaints.
For tubes, look for high mu (25-80) and low plate impedance (1-2K ohm).  Triodes like 417a (5842) and 6C45Pi and pentodes wired in triode mode like 7788 (E810F), 6688 (E180F), D3a, C3g, or E55L.  At a min, read the Norman Crowhurst Audio Classroom papers.
Build it on a peice of plywood - one channel first.  If you like the results move on to second channel.  If you like the amp, then build an enclosure (the hard work).  Don't forget to use free CAT5 strands of solid wire.
For power supply, I don't care what folks who have not tried this think - stack switched mode power supplies (SMPS) in series.  I use 48V, 390ma, Cisco supplies from ebay.  $5-$8 each - you need 4 for the amp I referenced.  Takes 30min to wire up and it's dead quiet, super low imdedance, fast/detailed sound.
Finaly, never take a measurement with your hands in the amp.  Turn amp off, clip meter leads where you wish, remove hands from leads, turn amp on, read meter.  Of course if you use a conventional power supply with big caps make sure they auto discharge with bleeder resistors.
Go for it!

 

[AudioCats]

Bottlehead kits come with good step-by-step assembly instruction (usually in PDF format on a CD), suitable from someone new to building tube amps.
 
 
 
 
macm75, great idea on using cisco supplies in series, I might give it a try in my up coming "space warmer" headphone amp project.

 

[chuckwheat]

  Nope, people do it every day. See DIYAudio.com. It doesn't get much more simple than the Bottlehead Crack, or this nice design http://headwize.com/?page_id=427
 
Both will work well with the 650s 
 
Please read this before you get started: http://www.diyaudio.com/forums/tubes-valves/30172-safety-practices-general-ultra-high-voltage.html

 
 

  Something to entertain is to go kit on first go.  It's pretty much guarenteed success.  Scratch has more potential of less desireable sound particularly on first effort.  The last thing I'd want to do is dissuade someone from building from scratch - but it can be frustrating and patience is a requirement depending on complexity.
If you go scratch, check out headwize - think super cheap for low risk and forget about the rediculous "best".  Personally I have not had great success with OTL amps and, for me, things started to sound much better and less finicky with transformer coupled amps.  
It does not get any simpler than http://www.audiodesignguide.com/NewHeadphoneAmp/index.html - my amp is slightly more complicated (http://diy.ecpaudio.com/2008/03/SSS.html) but I have not looked back in years.  You don't have to use these tubes, Lundahls are on the expensive side, and an alps pot is "perfect".  Check out Edcor - super cheap, sound very good, and can be upgraded to Lundahl, Electra-print, Sowter, on and on, at any time.  I don't see an impedance match to HD650's but maybe they can easily make a 5K:300 ohm, 5W, GXSE series for you - a friend of mine used them and they are very fine.  So not as good as my Lundahl 1660's but I can listen to them all day with no complaints.
For tubes, look for high mu (25-80) and low plate impedance (1-2K ohm).  Triodes like 417a (5842) and 6C45Pi and pentodes wired in triode mode like 7788 (E810F), 6688 (E180F), D3a, C3g, or E55L.  At a min, read the Norman Crowhurst Audio Classroom papers.
Build it on a peice of plywood - one channel first.  If you like the results move on to second channel.  If you like the amp, then build an enclosure (the hard work).  Don't forget to use free CAT5 strands of solid wire.
For power supply, I don't care what folks who have not tried this think - stack switched mode power supplies (SMPS) in series.  I use 48V, 390ma, Cisco supplies from ebay.  $5-$8 each - you need 4 for the amp I referenced.  Takes 30min to wire up and it's dead quiet, super low imdedance, fast/detailed sound.
Finaly, never take a measurement with your hands in the amp.  Turn amp off, clip meter leads where you wish, remove hands from leads, turn amp on, read meter.  Of course if you use a conventional power supply with big caps make sure they auto discharge with bleeder resistors.
Go for it!

 
 

  Bottlehead kits come with good step-by-step assembly instruction (usually in PDF format on a CD), suitable from someone new to building tube amps.
 
 
 
 
macm75, great idea on using cisco supplies in series, I might give it a try in my up coming "space warmer" headphone amp project.

 
 
Thanks for your advice guys, but I was thinking something more like... not a kit. I would probably love to build a Crack, but I don't have much money XD.

 

[Mr Rick]

   
 
 
 
 
 
Thanks for your advice guys, but I was thinking something more like... not a kit. I would probably love to build a Crack, but I don't have much money XD.

Can you tell a resistor from a capacitor? How about a diode from an inductor?  Can you read a schematic? Can you solder?  If not, you have a lot of studying to do before you can design your own tube amp.

 

[macm75]

  Can you tell a resistor from a capacitor? How about a diode from an inductor?  Can you read a schematic? Can you solder?  If not, you have a lot of studying to do before you can design your own tube amp.

I think the topic concerns scratch from a pre-defined design.

 

[Mr Rick]

  I think the topic concerns scratch from a pre-defined design.

 
The OP seems not to be interested in building a kit. So, he would have to build from a schematic. Hence my questions. 
 
A schematic will tell him what parts to use, in general. But, not the layout of the components in the circuit or the location of those parts on a chassis.
 
On anything other then a complete kit with detailed instructions including layout, some design will still be necessary.

 

[chuckwheat]

  Can you tell a resistor from a capacitor? How about a diode from an inductor?  Can you read a schematic? Can you solder?  If not, you have a lot of studying to do before you can design your own tube amp.

 
yup, yus, mmmhmm, yar

   
The OP seems not to be interested in building a kit. So, he would have to build from a schematic. Hence my questions. 
 
A schematic will tell him what parts to use, in general. But, not the layout of the components in the circuit or the location of those parts on a chassis.
 
On anything other then a complete kit with detailed instructions including layout, some design will still be necessary.

Yeah, :/ sorry if that was worded badly.
I'm feeling like having some fun experimental project...

 

[HiGHFLYiN9]

Why not this one: http://headwize.com/?page_id=427

 

[DutchGFX]

I just designed and built my own amp for the first time. I built a bottlehead crack before hand.

I am planning on finishing it tonight because I had a few issues that took a while to solve since they were rare issues, but I'm currently working on learning how to make circuit boards so I can build more.

It wasn't that hard to design everything honestly, my amp is pretty simple using a 6SN7 and 2A3's. I used power supply designs from other people which made it easier.

 

[macm75]

  Why not this one: http://headwize.com/?page_id=427

I built that one years ago.  Good friend of mine built another at the same time.  I'm sure others had great success but It turned me off to OTL.  It sounded really good when I luckily acquired a very rare Telefunkin 6080 but it did not have a lotta life in it and I eventually had some issues with the tube.  All the old american 6080's, and I had a box at my disposal, sounded fine but not as natural/easy/detailed.  The output caps are also an issue - could not live with 'lytics, tried oil, then did a combo oil/film/silver mica and started to enjoy it.  
After that I built a simple transformer coupled amp, probably just luck, but it sounded rediculously good - end of story since.

 

[HiGHFLYiN9]

  I built that one years ago.  Good friend of mine built another at the same time.  I'm sure others had great success but It turned me off to OTL.  It sounded really good when I luckily acquired a very rare Telefunkin 6080 but it did not have a lotta life in it and I eventually had some issues with the tube.  All the old american 6080's, and I had a box at my disposal, sounded fine but not as natural/easy/detailed.  The output caps are also an issue - could not live with 'lytics, tried oil, then did a combo oil/film/silver mica and started to enjoy it.  
After that I built a simple transformer coupled amp, probably just luck, but it sounded rediculously good - end of story since.

 
Sure, always wise to get the electrolytic caps out of the signal if you have the money to do so. You could also incorporate CCS to bump up the sound quality. The OTLs tend to get along well with high impedance cans like Beyers with 250ohms and Sennheiser with 300ohms, but xformer coupled outputs will always be better for lower impedance or more power hungry cans.  

 

[wakibaki]

A tube amp is very attractive in some ways, but it's hard to get off the ground. You need transformers, tubes, it's dangerous, expensive.
 
You can experiment with solid state amplifiers for virtually zero cost. You can scrounge PSUs and high power transistors from scrap, although many components are cheaply available internationally. You can run from batteries. You can run speakers direct, no output transformer. You're unlikely to hurt yourself, other than maybe a burn.
 
Depletion MOSFETs behave very like tubes, but are even easier to apply. You could learn something playing with them.
 
Learn to work LTSpice. You can simulate tube amps if you have txfrmr and tube models. It's a good way to figure the best way to spend your money.

 

[Maverickmonk]

 
The OP seems not to be interested in building a kit. So, he would have to build from a schematic. Hence my questions. 
 
A schematic will tell him what parts to use, in general. But, not the layout of the components in the circuit or the location of those parts on a chassis.
 
On anything other then a complete kit with detailed instructions including layout, some design will still be necessary.

 


The AMB amps aren't kits by any stretch but are very, very well supported.