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My DIY headphone tube amps - Page 3

post #31 of 42
Quote:
Originally Posted by Artsi View Post

It seems that i'm not going to get tired with this one in the near future. " src="http://files.head-fi.org/images/smilies/atsmile.gif">

 

Now look at this

RCA 6AS7G as a driver tube. Surprisingly it sounds amazingly good! Gain is much lower, but this amp is otherwise so sensitive, that i get easily enough power to my headphones.

 

Rare ECC230 tube is a driver tube too. " src="http://files.head-fi.org/images/smilies/dt880smile.png"> 

 

I have also octal to 6DJ8 and octal to 12AX7 adapters, so i can use many many different tubes with this one. Waiting impatiently 6BX7GT and 6BL7GT tubes to arrive soon. They have gains 10 and 15.

 



Just wondering how much did it cost you to build it? and will you sell it in the future XD. Looking awesome haha..
post #32 of 42
Quote:
Originally Posted by Artsi View Post
 

It's a little dubious to start thread about my DIY amp, since i'm not any pro with these electric things. Just have made couple working headphone tube amps before this. 

 

So here is photo of my contraption with 6080WC tubes.

And here is schematics for one channel.

 

 

 

As you can see it is simplified from some schematics from internet.

 

And what a mess it is inside.

 

Box is little too small for this kind of amp. Cast aluminium Hammond 1550J 275x175x63mm.

 

B+ supply is made with full wave bridge rectifier. After that is 1H 300mA choke and then two parallel 1000uF 250v capacitors. After that there is 1000uF's for each channel loaded with 68ohm resistors. Heaters have also DC with 22000uF capacitor. 

 

Volume potentiometer is ALPS 100k stereo LOG. Transformer is inMADout TA34M100.

 

Amp works perfectly with 6SN7's as powertubes too. Driver tubes run very low power, I think 470ohm resistors could be as low as 270ohm, but how much this could add amp output power, i do not know. Also from 6AS7's could take much more power with lower resistance resistors, but i have not needed more power. Total power consumption of amp is around 85w with 6SN7's and 6080's.

 

At least i'm very happy that this thing works without hum and measured frequency response is totally flat between 10-20000hz. Now i just need more tubes to roll.

 

 

I DO NOT SUGGEST BUILDING ANY TUBE AMP WITHOUT ANY EXPERIENCE OR UNDERSTANDING. Voltages inside these amps are pretty much lethal.

 

Edit: changed something to schematic. 6AS7 anode resistors from 270ohm to 150ohm.

Thanks a lot Artsi for sharing this built, I'm really interested to build one myself, I just need a clearer wiew of the PSU side as it will be my first PtP build.

 

I shall make a photo WIP of the build, as it may help others too.

post #33 of 42

Well I took a little time studying the schematic and photos of Artsi's build.

I came up with a complete schematic (amp section and Psus) but I'm still wondering about the res and cap in parallel with the two 1000uf 250v caps, I think the res is a bleeder but not sure about it's value, the poly cap seems to be a way to reduce ripple but no idea of it's value or real usefulness.

 

If you see anything odd please let me know.

 

http://i1342.photobucket.com/albums/o769/cowneko/6sn7_schematic_zps9f2wxjuq.png

 

http://i1342.photobucket.com/albums/o769/cowneko/built_legend_zpsyqkpoi2s.png

post #34 of 42
What brand power transformers do you use? It looks like Edcor, but I had terrible noise on the one transformer I got from them, so I use Hammond nke for my builds. Should I give Edcor another shot?
post #35 of 42
Quote:
Originally Posted by DutchGFX View Post

What brand power transformers do you use? It looks like Edcor, but I had terrible noise on the one transformer I got from them, so I use Hammond nke for my builds. Should I give Edcor another shot?

Seems like you're talking about the Tubelab SSE witch is present in my photobucket library, if that's the case, yes the OPT are Edcor (CXSE25-8-5K) the Power tranny is a Hammond 374BX (good transformer but tend to heat up quite a bit).

 

The Edcor are superb, no noise whatsoever, just great overall response, big bass. I can't recommend them enough in regards of their price/performance ratio. I don't know about their Power tranny performance, but they seem great.

For the Head amp I don't really know witch tranny to use yet, I'll have to know the overall load of the amp to choose a right one (the InMADout one seems overkill for the project, but I could be wrong)


Edited by cowneko - 1/2/16 at 3:39am
post #36 of 42
Quote:
Originally Posted by DutchGFX View Post

What brand power transformers do you use? It looks like Edcor, but I had terrible noise on the one transformer I got from them, so I use Hammond nke for my builds. Should I give Edcor another shot?

 

In my experience, Edcor's bad PTs run about 1 in 30.  The other 29 in that ratio are completely silent.  So, yeah - I would give them another chance.  I haven't had direct experience with Hammonds except for their chokes, but from someone who knows - the Hammond PT's are inherently more noisy than Edcor.  IOW, a perfect Hammond is not going to be as quiet as a perfect Edcor.

post #37 of 42
Quote:
Originally Posted by cowneko View Post

Seems like you're talking about the Tubelab SSE witch is present in my photobucket library, if that's the case, yes the OPT are Edcor (CXSE25-8-5K) the Power tranny is a Hammond 374BX (good transformer but tend to heat up quite a bit).

The Edcor are superb, no noise whatsoever, just great overall response, big bass. I can't recommend them enough in regards of their price/performance ratio. I don't know about their Power tranny performance, but they seem great.
For the Head amp I don't really know witch tranny to use yet, I'll have to know the overall load of the amp to choose a right one (the InMADout one seems overkill for the project, but I could be wrong)

Quote:
Originally Posted by tomb View Post

In my experience, Edcor's bad PTs run about 1 in 30.  The other 29 in that ratio are completely silent.  So, yeah - I would give them another chance.  I haven't had direct experience with Hammonds except for their chokes, but from someone who knows - the Hammond PT's are inherently more noisy than Edcor.  IOW, a perfect Hammond is not going to be as quiet as a perfect Edcor.

Im only on my third build, but I certainly am avoiding OPT's in the future since they cost an arm and a leg. However, if the edcors sound good I may give them a try. I used Electraprint OPT's before and they sound amazing, but they cost around $300 so that kind of sucked.

I was concerned with the power tranny. I have an escort that has really bad mechanical noise. I have used 2 Hammond's, both of which were silent. I have another Hammond coming for my next build, but maybe I'll try Edcor again.

How come noone uses Antek? I thought people preferred toroidal...
post #38 of 42
Quote:
Originally Posted by DutchGFX View Post



Im only on my third build, but I certainly am avoiding OPT's in the future since they cost an arm and a leg. However, if the edcors sound good I may give them a try. I used Electraprint OPT's before and they sound amazing, but they cost around $300 so that kind of sucked.

I was concerned with the power tranny. I have an escort that has really bad mechanical noise. I have used 2 Hammond's, both of which were silent. I have another Hammond coming for my next build, but maybe I'll try Edcor again.

How come noone uses Antek? I thought people preferred toroidal...

It really depends on the application. Toroid trannies have a far higher primary to secondaries capacitance, hence more noise than EI trannies, it's true for power transformer but even more for OPT trannies. For Power transformer you can deal with the noise by adding more filtering at psu stage, but for OPT, the toroids needs special winding technics to lower their capacitance. Good trannies for audio can be found from TOROIDY ( I know antek are making audio toroid too but they are harder to obtain in Europe), they make PP and SE trannies as well as power transformers and they are really good (and not that expensive if not chosing the boxed models).

 

The second reason for using EI transformers is the good old fashioned look ;)

 

I might use Toroid myself for the OTL amp.


Edited by cowneko - 1/2/16 at 6:47am
post #39 of 42
Quote:
Originally Posted by DutchGFX View Post
 
Quote:
Originally Posted by cowneko View Post

Seems like you're talking about the Tubelab SSE witch is present in my photobucket library, if that's the case, yes the OPT are Edcor (CXSE25-8-5K) the Power tranny is a Hammond 374BX (good transformer but tend to heat up quite a bit).

The Edcor are superb, no noise whatsoever, just great overall response, big bass. I can't recommend them enough in regards of their price/performance ratio. I don't know about their Power tranny performance, but they seem great.
For the Head amp I don't really know witch tranny to use yet, I'll have to know the overall load of the amp to choose a right one (the InMADout one seems overkill for the project, but I could be wrong)
 
Quote:
Originally Posted by tomb View Post

In my experience, Edcor's bad PTs run about 1 in 30.  The other 29 in that ratio are completely silent.  So, yeah - I would give them another chance.  I haven't had direct experience with Hammonds except for their chokes, but from someone who knows - the Hammond PT's are inherently more noisy than Edcor.  IOW, a perfect Hammond is not going to be as quiet as a perfect Edcor.

Im only on my third build, but I certainly am avoiding OPT's in the future since they cost an arm and a leg. However, if the edcors sound good I may give them a try. I used Electraprint OPT's before and they sound amazing, but they cost around $300 so that kind of sucked.

I was concerned with the power tranny. I have an escort that has really bad mechanical noise. I have used 2 Hammond's, both of which were silent. I have another Hammond coming for my next build, but maybe I'll try Edcor again.

How come noone uses Antek? I thought people preferred toroidal...


PT means Power Transformer.  Not sure which post you were addressing, but I was not referring to OPTs.


Edited by tomb - 1/2/16 at 7:39am
post #40 of 42
OPT - output transformers
post #41 of 42
Quote:
Originally Posted by Artsi View Post
 

It works \o/ ! 

:beerchug:

 

Newer 6BY5GA rectifier tube does not look that bad. It does have pretty strong glow. I also have older coke bottle model 6BY5G.

 

There is relay that disables speakers, if headphones are inserted. I have to be careful not to burn my headphones accidentally, this amp is capable to do that. Need to find a way to lower gain if headphones are inserted.

 

Frequency response seems to be flat between 10hz-20khz, so everything is working as expected and inMADout output transformers seem to be very good for the price.

This looks beautiful, nice work.

post #42 of 42
Quote:
Originally Posted by Artsi View Post
 

It's a little dubious to start thread about my DIY amp, since i'm not any pro with these electric things. Just have made couple working headphone tube amps before this. 

 

So here is photo of my contraption with 6080WC tubes.

And here is schematics for one channel.

 

 

 

As you can see it is simplified from some schematics from internet.

 

And what a mess it is inside.

 

Box is little too small for this kind of amp. Cast aluminium Hammond 1550J 275x175x63mm.

 

B+ supply is made with full wave bridge rectifier. After that is 1H 300mA choke and then two parallel 1000uF 250v capacitors. After that there is 1000uF's for each channel loaded with 68ohm resistors. Heaters have also DC with 22000uF capacitor. 

 

Volume potentiometer is ALPS 100k stereo LOG. Transformer is inMADout TA34M100.

 

Amp works perfectly with 6SN7's as powertubes too. Driver tubes run very low power, I think 470ohm resistors could be as low as 270ohm, but how much this could add amp output power, i do not know. Also from 6AS7's could take much more power with lower resistance resistors, but i have not needed more power. Total power consumption of amp is around 85w with 6SN7's and 6080's.

 

At least i'm very happy that this thing works without hum and measured frequency response is totally flat between 10-20000hz. Now i just need more tubes to roll.

 

 

I DO NOT SUGGEST BUILDING ANY TUBE AMP WITHOUT ANY EXPERIENCE OR UNDERSTANDING. Voltages inside these amps are pretty much lethal.

 

Edit: changed something to schematic. 6AS7 anode resistors from 270ohm to 150ohm.

 

 

Thanks for this!

 

Do you have a circuit board for this project? I would like implement this using a board. If you have this, please send me the project files.

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