[Audiodoc]

My EHHA is dead silent. One cannot tell whether it is powered on or off even at maximum volume.
I have crammed a tube heater delay circuit two toroids a low noise regulated supply to my tubes in series a temperature sensor based fan assembly and amb headphones protection circuit in my chassis of 20 x 30 cm.
Initially i had some hum which was coming from the main ground. Grounded the pot screw and put in a main ground isolator. That was it.

 

[Pars]

Looks really nice! Where did you source the case from? Also, where's the PRoN?

 

[bluebyte60]

After half a year, finally finished a tube amp. It's a Aikido Octal single end preamp. Happy to finish this project.

 

[FullCircle]

 

[HiGHFLYiN9]

Finally finished up an interesting build for an Aikido-based OTL headphone amp with enough drive for low impedance cans. The boards are available on ebay for just $30 - hvforless on eBay (no affiliation). They can be configured with 6BL7 or 6BX7, as well as 6SN7, and uses a standard 5AR4 rectifier.

 

[bluebyte60]

Finally finished up an interesting build for an Aikido-based OTL headphone amp with enough drive for low impedance cans. The boards are available on ebay for just $30 - hvforless on eBay (no affiliation). They can be configured with 6BL7 or 6BX7, as well as 6SN7, and uses a standard 5AR4 rectifier.

look nice!

 

[Whitigir]

Balanced out ? Very interesting...the schematic doesn’t show balanced out though ?

Finally finished up an interesting build for an Aikido-based OTL headphone amp with enough drive for low impedance cans. The boards are available on ebay for just $30 - hvforless on eBay (no affiliation). They can be configured with 6BL7 or 6BX7, as well as 6SN7, and uses a standard 5AR4 rectifier.

 

[HiGHFLYiN9]

It's single-ended. The 4 pin is just there for convenience.

 

[FallenAngel]

After half a year, finally finished a tube amp. It's a Aikido Octal single end preamp. Happy to finish this project.

Very nice!

 

[mwhouston]

Havent posted here for a long time and have had a few email changes in that time. All Telstra Australia email accounts fail eventually and they cant fix them so moved to gmail. All good.

A few new builds since Sanguine. Ill just leave links to my mian blog if you would like to take a look at some 6AS7 based headphone amps and a two stage 6H3N build. The 6H3N has tuned out to be an excellent tube and I’ve used the amp as both a HP amp and a stunning preamp in my all DIY system.

Links:
http://retro-thermionic.blogspot.com/2017/11/sanctum-simple-tube-headphone-amp.html

http://retro-thermionic.blogspot.com/2017/12/sanctorum-simple-headphone-amp-on.html

http://retro-thermionic.blogspot.com/2022/04/apparition-6h3n-triode-headphone-amp.html

 

[mt877]

A fun build. Oatley K272C-NEW with Burson V6 Vivid op-amp.

I gave my DIY amp a name which honors our Aussie friends... I present the "Koala Amp".

 

[Whitigir]

A fun build. Oatley K272C-NEW with Burson V6 Vivid op-amp.

I gave my DIY amp a name which honors our Aussie friends... I present the "Koala Amp".

Very nice! Tube based SE and OTL ?

 

[mt877]

Very nice! Tube based SE and OTL ?

Yep, tube hybrid. Is SE, coupling cap at the V6 Vivid L/R outputs. I included a 4.4mm socket for convenience to plug in some of my 4.4mm terminated head gear. Drives my DIY 500Ω flat head earbuds to perfection. I have some 600Ω transducers as well, but haven't built those earbuds yet. It will definitely drive the 600's very well too.

 

[Whitigir]

Yep, tube hybrid. Is SE, coupling cap at the V6 Vivid L/R outputs. I included a 4.4mm socket for convenience to plug in some of my 4.4mm terminated head gear. Drives my DIY 500Ω flat head earbuds to perfection. I have some 600Ω transducers as well, but haven't built those earbuds yet. It will definitely drive the 600's very well too.

I am interested, where can I source these stuff ? thank you

 

[mt877]

I am interested, where can I source these stuff ? thank you

Oatley Electronics K272C-NEW kit.
The kit ships from Australia and contains the board, Raytheon JAN6418 sub-miniature pentodes, NE5532P op-amp and loose components.
Look for the link of the product page for PDF notes, that will have some assembly tips and the schematic.

Burson Audio Supreme Sound Opamp V6 (Vivid Dual x 1)
Ok, you can tell from my pics that I didn't use the NE5532P Op-amp... went for the big gun Burson V6 Vivid.

SENRISE Aluminum Project Box, 43x78x140mm
From Amazon. If you go with the Burson V6, this box is a must. Many boxes I looked at didn't have the height clearance needed for the Burson V6 Op-amp.

APIELE 12mm Latching Push Button Switch SPST
From Amazon. Battery on/off switch on back panel. This switch has a ring LED, but I didn't use the LED and cut the LED wires off. It is a nice compact switch and looks nice.

BusBoard Prototype Systems Adhesive Standoffs
From Amazon. You don't see these in my picture. These standoffs are used to secure the board to the chassis.

18650 5000mAh Lith-ion Rechargeable Battery
From Amazon.

PNGKNYOCN 4.4mm Balanced Replacement Jack
From Amazon. This is really a replacement jack for a cable, but I used it as a bulkhead connector... got to use some ingenuity sometimes.

Some of the other parts I already had on hand. The USB C battery charger board and 18650 battery holder can be found on AliExpress.

For the volume pot I used a dual gang 50k audio taper (log) pot with a switch to turn on / off the amp.

Hope this helps you get started on this project.

Edit: Forgot some info. The Oatley kit doesn't come with an 8 pin DIP socket. They expect you to solder the Op-amp directly to the board. Make sure you have an 8 pin DIP socket. If you look at my picture, you see 2 green capacitors behind the op-amp, there are 3 caps, one is hidden behind the op-amp so you don't see it. Anyway to fit the Burson V6 you need to offset bend the leads of the center capacitor so that the cap is a little further toward the back of the board. If you don't do that there won't be enough space for the Burson to plug into the DIP socket.

Behind the capacitors you see a small board standing on edge. That is the 18vdc buck-boost board. If you mount that board flat, you won't be able to adjust the trim pot for the 18vdc because a capacitor will be in the way. I mounted the board on it's edge with the trim pot screw facing upward. Makes adjusting the 18vdc much easier.