Hey... it's not a push pull, it is stereo - so one KT66 for each channel. The KT66s are triode strapped and simple cathode follower outputs. As for the need, most headphone amps either use parallel small triodes or an output tube of some sort. I figured whatever sound gain you would get from the small triodes is null once you have to parallel two or more sections to get the output drive. So, I just went for looks as well as sound quality. Plus, I already had the transformer and it was big enough to drive them. I also wanted to keep my circuit very simple, unlike most I've seen at headwize and other places.
Parts salvaged from the PC supply is wire, lots of free wire, a few PS electrolytics and yes I kept the case switch and AC receptacle. It also had a primitive noise filter on the AC line which I left in place. If I had it to do over, I'd use a larger chassis! I didn't realize at the time how large my output caps where going to be! I should have, I just didn't "turn on the brain" first.
As for the back, it doesn't look nearly as nice as the front, there are all the holes for mounting the supply in the pc and the large fan hole. I simply cut a piece of thin aluminum and filled that in and placed the RCAs on it. Nothing fancy, not impressive, but then again, I don't plan on looking at the back!
Sound quality is amazing, very cool to unplug phones from my CD/iPod/computer and then add the headphone amp in between... same source, but so much better sound out of the headphones!
Parts salvaged from the PC supply is wire, lots of free wire, a few PS electrolytics and yes I kept the case switch and AC receptacle. It also had a primitive noise filter on the AC line which I left in place. If I had it to do over, I'd use a larger chassis! I didn't realize at the time how large my output caps where going to be! I should have, I just didn't "turn on the brain" first.
As for the back, it doesn't look nearly as nice as the front, there are all the holes for mounting the supply in the pc and the large fan hole. I simply cut a piece of thin aluminum and filled that in and placed the RCAs on it. Nothing fancy, not impressive, but then again, I don't plan on looking at the back!
Sound quality is amazing, very cool to unplug phones from my CD/iPod/computer and then add the headphone amp in between... same source, but so much better sound out of the headphones!
Here's a pic of my latest creation
It's a single-ended triode amplifier using a 6336A driven by two stages of 5687.
The surround is made from 2.5" x 0.5' mahogany baseboard box jointed and treated with four coats of Danish oil.
Top plate is the undamaged underside of a lid from my Mother-in-Law's old 1956 Ferguson console, that had been rotting in her garage for the last thirty-five years. Said top plate is made of 0.75" plywood faced with walnut veneer and french polished.
Knob and radio apparatus license plate are from the same console.
Transformer and choke set are Hammond, sprayed with dark metallic green auto paint.
It sounds rather nice too.
Steve
It's a single-ended triode amplifier using a 6336A driven by two stages of 5687.
The surround is made from 2.5" x 0.5' mahogany baseboard box jointed and treated with four coats of Danish oil.
Top plate is the undamaged underside of a lid from my Mother-in-Law's old 1956 Ferguson console, that had been rotting in her garage for the last thirty-five years. Said top plate is made of 0.75" plywood faced with walnut veneer and french polished.
Knob and radio apparatus license plate are from the same console.
Transformer and choke set are Hammond, sprayed with dark metallic green auto paint.
It sounds rather nice too.
Steve
Attachments
My 6080 parafeed amp with 12at7 driver:
The chassis with the two plate chokes of the 6080.
The amp with the 12b4 preamp (on the lower shelf).
This amp sounds surprisingly excellent for a voltage regulator tube! The amp has total of 8 transformers, one power, one PSU choke, two plate chokes for the 6080 and two plate chokes for the 12at7 and two OPTs. The OPTs are mains toroidal transformer from Talema.
The chassis with the two plate chokes of the 6080.
The amp with the 12b4 preamp (on the lower shelf).
This amp sounds surprisingly excellent for a voltage regulator tube! The amp has total of 8 transformers, one power, one PSU choke, two plate chokes for the 6080 and two plate chokes for the 12at7 and two OPTs. The OPTs are mains toroidal transformer from Talema.
ErikdeBest said:
Erik,
The plate chokes are wound by a company here in the Philippines on Z11 cores (quite difficult to get better cores here on small quantities). It is measured at 300H at 60ma load.
I have not scoped the toroidal outputs, but I think it has very good frequency response, it sounds as good or a bit better than my SE KT88 that has FR of 28-18K.
Hi Alex
Thanks for the reply! 300H is a lot of inductance for the 6080 (one could also argue, ala Pass: too much inductance is not enough) as it has got a low plate resistance.
There is another thread going on about the use mains toroidals used as OPT, and Shoog reports obtaining good response from 10Hz up to 70kHz!
Erik
Thanks for the reply! 300H is a lot of inductance for the 6080 (one could also argue, ala Pass: too much inductance is not enough) as it has got a low plate resistance.
There is another thread going on about the use mains toroidals used as OPT, and Shoog reports obtaining good response from 10Hz up to 70kHz!
Erik
Nice work, Mabuhay ka Alex!alexg said:My 6080 parafeed amp with 12at7 driver:
The chassis with the two plate chokes of the 6080.
The amp with the 12b4 preamp (on the lower shelf).
This amp sounds surprisingly excellent for a voltage regulator tube! The amp has total of 8 transformers, one power, one PSU choke, two plate chokes for the 6080 and two plate chokes for the 12at7 and two OPTs. The OPTs are mains toroidal transformer from Talema.
My new J.E. Labs 300B
This my first Hifi build, base on the J.E. Labs 300B discover on Derek Walton web site, great help from Derek for a newbie like me, thank Derek.
The power TX are Angela Universal and the OT are the Hammond 1627 SEA with the Hammond choke 193J. I spend about two weeks to build the transformers cover with MAKORE wood, very curly wood.
I'm very happy with the "magic" of the 300B tubes, very musical. I'm building a pair of Mileva speakers to match those low power mono block amps.
This my first Hifi build, base on the J.E. Labs 300B discover on Derek Walton web site, great help from Derek for a newbie like me, thank Derek.
The power TX are Angela Universal and the OT are the Hammond 1627 SEA with the Hammond choke 193J. I spend about two weeks to build the transformers cover with MAKORE wood, very curly wood.
I'm very happy with the "magic" of the 300B tubes, very musical. I'm building a pair of Mileva speakers to match those low power mono block amps.
Attachments
