I guess Zana Deux is a reminder for those that said 6C33C is too much for headphone use !!
Looks like a Class A OTL to me
I'm sure it will work just fine, probably sounds great, just a bit more than needed to do the job was all I was saying..
I have designed and built OTL amps with 6C33, not my best design and I much prefer DHTs these days.
I don't think I have much more to add to this discussion, so adios..
The reason why I overbuild is headroom.
A large amp has to work less sounds cleaner as it can drive more difficult loads.
Am I ever going to use or need 5W for a headphone amp ???
Not really, but for the different types of music i listen to sometimes is nice to have the extra power to move through some of the bass heavy passages as tube amps don't seem to like those specially when driving low impedance loads.
Therefore its just logical to overbuild to compensate for this weakness
A large amp has to work less sounds cleaner as it can drive more difficult loads.
Am I ever going to use or need 5W for a headphone amp ???
Not really, but for the different types of music i listen to sometimes is nice to have the extra power to move through some of the bass heavy passages as tube amps don't seem to like those specially when driving low impedance loads.
Therefore its just logical to overbuild to compensate for this weakness
I guess Zana Deux is a reminder for those that said 6C33C is too much for headphone use !!
Looks like a Class A OTL to me
Looks like a dangerous fashion.
I have a white cathode follower 6as7 OTL headphone amp that is just excellent. That said, the best sounding headamps I have for my modded, woody Alessandro MS-1s or Senn 600s use 5687 or 6cg7/6gu7 output tubes. This may be because I can use a good nos 6cg7/ 6sn7/ 7n7 for the input/ gain tube with 5687s etc... while the 6as7 amp requires a higher gain input tube which I have yet to find quite as magical. 6sn7s sound dead with the low mu 6as7/6080s IMO. With 6as7s I specifically use the Amperex 7062 which is my favorite from the 12AV7 types.
The Little Dot design leaves much to be desired. That amp runs way to hot and the sound quality is just ok .... not great.. If you are going to clone the amp use a much larger chassis and use high temp caps, plus beef up all the resistors. The balanced LD is known to be noisy and prone to buzzing.
If you want high power and balanced why dont you look at one of the Cavelli hybrid designs using a 12au7 etc.. front end at lower voltage... and a Class A mosfet output. Most of these are good for two watts or so single ended which is way beyond overkill for everything but low efficiency orthodynamics. If you want to go even further do a true high voltage front end using someting like a 6sn7.
Pictured below is a Cavelli design Stacker 2 hybrid (having two sets of tube sockets) using a high voltage 6/12sn7 or 6/12fq7 front end and mosfet output .... and a transformer coupled Sound Quest SQ-84 speaker amp/ headphone amp using PPT 6V6s .... which just happened to be in the picture. These are single ended but either one is much peferable to the LD for sound quality.
NOTE: I like using the nos 12sn7 because this is the same tube as the 6sn7 but much less expensive. The mostly unknown $5 6gu7 (a 6 volt 12bh7 with a 6cg7 pinout) is an excellent input or output tube for headphones.
http://i79.photobucket.com/albums/j124/6bx7gt/076.jpg
http://i79.photobucket.com/albums/j124/6bx7gt/075.jpg
Yes but unless you are part of the designer's inner circle, you cannot buy a Stacker II board set. And I've promised not to sell mine.
EHHA maybe?
Actually I have the latest Stacker II amp board, most of the group have disabled the E12 dc offset protection circuit. I don't recommend this, best thing is to use a series regulated HVPS otherwise mains swings wreck havoc with the dc servo in the buffer stage. I think I have the only StackerII in existance without dc offset issues, I asked the designer if it was OK to sell since I got it to work without resorting to Planars as I've moved on to OPT's as preferred to SS bufferes so mine is in the for sale section here. It is a good amp but I want to build an all DHT headamp.
At it again with a modified version, I added a baxandall tone stack PCB to the main PCB. It can be removed, just unscrew and the connector allows for them to be decoupled. The tubes will have the reflector shield like the last one.
Turned out that the first one also worked great as a Class A line preamp prior to the power amp, I decided to add a RIAA PCB to this one for make it a RIAA preamp with tone control.
The SRPP stages in the RIAA amp require elevated heaters so it also required an extra 12 volt DC supply PCB that will be referenced about 70-80 volts.
For the B+ supply, I decided to add a tube diode as a delayed pass device. I'm trying 12AL5's to see if they can handle it. I do the same trick in my power amps with the larger damper diodes.
I'm missing a few components, so I'm stuffing all PCBs as far as possible prior to making the next order.
Turned out that the first one also worked great as a Class A line preamp prior to the power amp, I decided to add a RIAA PCB to this one for make it a RIAA preamp with tone control.
The SRPP stages in the RIAA amp require elevated heaters so it also required an extra 12 volt DC supply PCB that will be referenced about 70-80 volts.
For the B+ supply, I decided to add a tube diode as a delayed pass device. I'm trying 12AL5's to see if they can handle it. I do the same trick in my power amps with the larger damper diodes.
I'm missing a few components, so I'm stuffing all PCBs as far as possible prior to making the next order.
Attachments
I design the PCB's, print them out in b&W and copy to clay paper. Its the toner transfer method, some PCB's turn out better than others. I have a few that the top graphics are a little weak. This is a pic of the PCB set for the preamp: consisting of the RIAA, tone control, headphone amp/preamp, main power supply; dual 12 vdc, 240vdc, and RIAA power supply for the elevated 12volt for the SRPP heaters. I learned from the last one that you can make simpler power supplies, but you can hear them!
I still have several components to scrounge for the last? order. THen its time to fire it up!
I still have several components to scrounge for the last? order. THen its time to fire it up!
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