Min Tube(12au7) Headphone Amplifier

[tiger0691]

Mini Tube(12au7) Headphone Amplifier

It would be first tube amp for me.
My aim is to use it as preamplifier.

 

[dheerajin]

If possible, please tell us about the source from which you obtained the circuit and build method.

Cheers

Dheeraj

 

[tiger0691]

If possible, please tell us about the source from which you obtained the circuit and build method.

Cheers

Dheeraj

If you want, I can send circuit(pdf file) to you

 

[tiger0691]

 

[tiger0691]

PCB for the headphone amp
Size : 6.5X0.9 inches

I got 2 No. one for Dheeraj

 

[saheb11123]

Did You fabricate these or buy from somewhere?
I think this would be a great group buy..if the costing we to be shared.




Regards

 

[tiger0691]

Did You fabricate these or buy from somewhere?
I think this would be a great group buy..if the costing we to be shared.




Regards

It was designed by my friend.
I am a Korean. So is he.
Things came by international courier.

If you want I can try to ask my friend but it may cost around Rs. 3500
- PCB + full parts + tube (except power supply, 24V DC)
- International courier
Give me a confirmation till toady evening.

 

[tiger0691]

Tube 12Au7
Maid in Russia

 

[saheb11123]

I was only asking for the pcb. This is way above my budget (still student sadly.)


Thanks for replying.


Regards

 

[suraj]

You can still make 12au7 amps for very low cost.200-300 rupees worth of parts,a decent tube-for 12au7 BEL or 18$ a pair shuguangs and you have a nice amp.

Here's mine.The RogGom 12au7 amp.
A few months ago, I had asked a fellow FM who offered me a pair of Bel tubes,but I could not make time to collect them. Perhaps he may send them to you.
Max you are looking at spending anything between rupees 500(yes you can do it )-2000,depending on how much time and effort you put in. Though you still have to make the pcb,hunt quality parts for cheap, get a good smps,build,debug,rebuild.

Or you could simply bite OP's offer. It looks very nicely made. Clean layout and a nice tube,which makes it cost 3500. Plus throw in shipping.

Like the song goes,its about the chase.not the catch.and be glad you are a student!

 

[tiger0691]

Other Parts.

 

[tiger0691]

Yesterday I completed 21V Power supply for this amp.
Now it is time for Headphone amp.
I am going to start after office work:sad:
Though today is sunday, I am working

 

[saheb11123]

A few months ago, I had asked a fellow FM who offered me a pair of Bel tubes,but I could not make time to collect them. Perhaps he may send them to you.
Max you are looking at spending anything between rupees 500(yes you can do it )-2000,depending on how much time and effort you put in. Though you still have to make the pcb,hunt quality parts for cheap, get a good smps,build,debug,rebuild.

Or you could simply bite OP's offer. It looks very nicely made. Clean layout and a nice tube,which makes it cost 3500. Plus throw in shipping.

Like the song goes,its about the chase.not the catch.and be glad you are a student!

Spending 3.5k for me is nearly impossible. I can hunt down and get the something made first with local components, then one by one I upgrade them into good quality, but that takes some time for me. 500-600 yes I can afford but above that becomes a strain in my pants.
A few days ago a very nice FM was doing a giveaway of some tubes, only problem was he was opposed to shipping. Anyway if the tubes can be sourced then other passive's are no issue.

Thanks for the reply.




PS :

Great build tiger0691 , nice and clean please share listening impressions.

 

[suraj]

Spending 3.5k for me is nearly impossible. I can hunt down and get the something made first with local components, then one by one I upgrade them into good quality, but that takes some time for me. 500-600 yes I can afford but above that becomes a strain in my pants.
A few days ago a very nice FM was doing a giveaway of some tubes, only problem was he was opposed to shipping. Anyway if the tubes can be sourced then other passive's are no issue.

.

500 is possible. 200 ish for a quality smps,100 rupees for the discretes and rest for the tube is how I made it,to gift.

Though,I blew my first smps and changed the PCB twice and have gone through 4 MOSFETs and equal number or regulators. Then there was the issue of buzz,which is solved 95?.
So,the 500 is theoretical. .

Shipping tubes is an issue. I spent 450 Rupees on shipping alone,but they made it to me safely because the kind FM who sent them packaged them very well.

You are in Kolkata I take it? The electronics market should have some source for valves. Places which sell parts for old radios and TVs may have the valves you need. Ask around. You can find used ones for as low as 100rs.

Or,buy shuguangs for 18$,two tubes on ebay.split it with another member.
Or pester the person giving away his things for one tube,which is the easiest thing to do. Cover the tube in bubble wrap,then put it in a little hard plastic box,cover it with foam,put it in another big box. That's how I got and sent my tubes. Maybe you could ship the packaging to the FM and pay for shipping it back. Or, search on the forums for members dropping hints of wanting to offload their parts and message them. One FM from Bangalore was.

@tiger0691,sorry for hijacking your thread.

 

[saheb11123]

I think maybe anymore conversation on this can be made via pm.

 

[tiger0691]

Soldering started

Voltage to the heater(tube) should be 6.3V
But Now it shows 21V
Any how soldering is done.

Tuning is remained.
- voltage to tube (heater) : 6.3V
- voltage to OP Amp : 14V

 

[aks07]

Voltage to the heater(tube) should be 6.3V
But Now it shows 21V

Bye bye 12Au7

 

[saheb11123]

Did you connect the tube?
What happened?

 

[tiger0691]

Did you connect the tube?
What happened?

Not yet

Voltage setting should be done before putting Tube and OP Amp.
After adjusting heater voltage 6.3 V, I am going to connect tube.
I feel, a variable resistor (50K) is not working.
Tonight I am going to change it.

Do you find anything wrong?

 

[tiger0691]

Assembling is done.

Heater Voltage : 6.28V
- there was some problem with 50k vary ohm
OP Amp : 14V
- it was easy to adjust

After putting Tube (30 min.)
and OP Amp inserting.....

No Blasting! No fireworks!

Sound comes..........
It is the first tube sound which I made for me.

30 min. after sound became settled
It is good!
Sound separation is much better.
Clarity is remarkable.
Bass became powerful.
Good enough!


There is little white noise but it can be cared when I make casing.