Show your headphone amplifier

I really wouldn´t know how to do a whole thread about assembling the kit. It´s just installing the proper components in the right place and soldering them in :)

And hoping it works :)

Anyway, I bought it from headnhifi.com for €70 plus €7 shipping. I was glad to find a supplier here in Germany. They also offer the O2 fully assembled for €110.
 
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DIY Pete Millett Starving Student, 12A*7 version running JAN 6829 tubes at the moment. It drives my T50RP mkIII's most excellently. Case is a pet urn (yes, as in to put their ashes into) I found on Amazon. :D

I believe Panasonic FC power caps, Nichicon Muse ES cathode bypass caps (100% of signal goes through these. Not seen in initial pics, I assembled with cheapies first) and Nichicon KW + Wima MKS2 for output filtering. MKS2 for the other box caps as well. All resistors are Vishay-Dale milspec metal films.

VWkOaVC.jpg


ELAs30T.jpg


BRHXg3C.jpg


LlWJV6W.jpg


WJyXnGg.jpg


q1E6C9f.jpg


WJyXnGg.jpg


And finally complete with the new tubes:

2HDXreQ.jpg


Cheers
Nathan
 
DIY Pete Millett Starving Student, 12A*7 version running JAN 6829 tubes at the moment. It drives my T50RP mkIII's most excellently. Case is a pet urn (yes, as in to put their ashes into) I found on Amazon. :D

I believe Panasonic FC power caps, Nichicon Muse ES cathode bypass caps (100% of signal goes through these. Not seen in initial pics, I assembled with cheapies first) and Nichicon KW + Wima MKS2 for output filtering. MKS2 for the other box caps as well. All resistors are Vishay-Dale milspec metal films.

VWkOaVC.jpg


ELAs30T.jpg


BRHXg3C.jpg


LlWJV6W.jpg


WJyXnGg.jpg


q1E6C9f.jpg


WJyXnGg.jpg


And finally complete with the new tubes:

2HDXreQ.jpg


Cheers
Nathan

Awesome :rockon:
 
DIY Pete Millett Starving Student, 12A*7 version running JAN 6829 tubes at the moment. It drives my T50RP mkIII's most excellently. Case is a pet urn (yes, as in to put their ashes into) I found on Amazon. :D

I believe Panasonic FC power caps, Nichicon Muse ES cathode bypass caps (100% of signal goes through these. Not seen in initial pics, I assembled with cheapies first) and Nichicon KW + Wima MKS2 for output filtering. MKS2 for the other box caps as well. All resistors are Vishay-Dale milspec metal films.

VWkOaVC.jpg


ELAs30T.jpg


BRHXg3C.jpg


LlWJV6W.jpg


WJyXnGg.jpg


q1E6C9f.jpg


WJyXnGg.jpg


And finally complete with the new tubes:

2HDXreQ.jpg


Cheers
Nathan

Looks great! Nice shielding on the inside of the box.
 
Looks great! Nice shielding on the inside of the box.

Thanks! The shielding is a pain to put in but it keeps it quiet and also acts as a sacrificial later when I need to remove the board. The board is hot snotted to the foil, so if I pull firmly on the back edge of the board I can remove it along with the foil under it, do whatever needs to be done to the board, re-foil and reglue. I tried to mount with screws but the top of the box is only 1/4" thick do there just wasn't enough purchase.

I got the foil idea from electric guitars and wooden stomp boxes.

Cheers,
Nathan
 
What's the story behind this M8

the RTR mechanism went kaput. i lacked the knowledge and discipline to restore it back to its intended form so I committed the unforgivable sin of using the amps for another purpose.

if you're here to shame me about gutting the akai, you'll need to get in line :-D
 
the RTR mechanism went kaput. i lacked the knowledge and discipline to restore it back to its intended form so I committed the unforgivable sin of using the amps for another purpose.

if you're here to shame me about gutting the akai, you'll need to get in line :-D

No I'm not trying to do that at all. That thing is huge yet cool at the same time. Its massive. It gets the job done tho but in an overkill kind of way. Like dropping a bomb on an ant hill. lol
 
No I'm not trying to do that at all. That thing is huge yet cool at the same time. Its massive. It gets the job done tho but in an overkill kind of way. Like dropping a bomb on an ant hill. lol
They make for a nice little single ended tube stereo amp also. If you have sensitive speakers they can get loud. Around 5 watts I think. Those little mono blocks can make for a nice basic guitar amp also. I have a single ended tube amp that is around 6 to 7 wpc and will drive some 84db speakers I have, just not loud. Others I have that are more sensitive 6 watts get pretty loud.
 
That bad boy looks like it weighs about 40lbs!
Close! User manual says 32lbs. The interface box adds a bit of weight, but not by much.
Hey I have one of those amps! Thanks for posting the diagram. Might have to try that. What make before break switch did you use?
Not sure off-hand who made the switch I used; I believe it's sold under the "Philmore" brand at my local electronics store (ex-Radio Shack franchisee). Whatever you use, make sure it doesn't have a 'center off' position, or you could potentially leave the tube amp unloaded, which is a Bad Idea™. Just about anything listed here or here should work, methinks.

Also, make sure the power resistors you use are non-inductive. Radio Shack used to sell 8 ohm 20W non-inductive power resistors, but since they're no longer around (for the most part), you'll have to check Mouser or another supplier to see what they have in that regard. Granted, the NTE-brand 8.2 ohm 25W power resistors I'm using in the headphone interface box I built didn't explicitly say "non-inductive" on the packaging, so maybe it isn't especially critical, but tube amps tend to prefer resistive loads, AFAIK.
-Adam
 
Close! User manual says 32lbs. The interface box adds a bit of weight, but not by much.

Not sure off-hand who made the switch I used; I believe it's sold under the "Philmore" brand at my local electronics store (ex-Radio Shack franchisee). Whatever you use, make sure it doesn't have a 'center off' position, or you could potentially leave the tube amp unloaded, which is a Bad Idea™. Just about anything listed here or here should work, methinks.

Also, make sure the power resistors you use are non-inductive. Radio Shack used to sell 8 ohm 20W non-inductive power resistors, but since they're no longer around (for the most part), you'll have to check Mouser or another supplier to see what they have in that regard. Granted, the NTE-brand 8.2 ohm 25W power resistors I'm using in the headphone interface box I built didn't explicitly say "non-inductive" on the packaging, so maybe it isn't especially critical, but tube amps tend to prefer resistive loads, AFAIK.
-Adam
Thanks! I do at leased know not to run my tube amps without a load attached. Thanks for the info about the resistors! I really do miss the shack when you need bits like these.
 
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