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Old 21st July 2013, 07:58 AM   #791
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Quote:
Originally Posted by 45 View Post
SE is not better by default. It's a myth! It always depends on so many things......
In practice almost every time PP is better...
I've tried SE and PP on numerous occasions, like most of us here. I never got the vocal quality of SE on any PP amp I ever built, and since I listen to singers of all kinds, that seals it for me.

But second to SE, the most important thing for me is eliminating all coupling caps and cathode bypass caps. I can do this in SE with 4P1L and 26 in filament bias, and interstage transformers. But cathode bypass caps can be eliminated in PP amps with various kinds of CCSs in the tail, so that helps and can bring a PP amp pretty close to a SET. I suspect one way to go is SE first stage and driver and an interstage/phase splitter into the finals. Something good like a Tango.
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Old 21st July 2013, 10:36 AM   #792
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Originally Posted by regal View Post
I understand what you are saying but if we are letting numbers make our decisions a hybrid with a P-P mosfet output is just very effective for headphones if you want p-p. And one can say the some thing that Mosfet P-P is better than tube P-P "almost every time" (going off numbers/measurements.)

There is something special about SET sound, I don't claim to know what it is but I like it. Since I already have a 5W hybrid P-P headphone amp that I paid $300 bucks for it makes little sense for me to invest time and $'s trying to beat it with all tubes. Now a 300B or 2A3 SET headphone amp costs $3k to $5k. Plenty incentive to DIY if I want that sound.

BTW, The DCR of the Tribute secondary is only 1 ohm, vs the Electraprint which was 12 ohms. That's a significant gain in power transfer with 32 ohm headphones.
I did a quick calculation and its a little tricky because i not know the primair dcr but i hope the current density primair-secondair is equal.
I also hope that each 8 Ohm winding has 1 Ohm dcr and not all together.
So i calculated 156 Ohm primair dcr and 0,25 for all sec. In this case your transformer has an efficiency of 94.1% (0,263dB).

If the all secondair windings are 1 Ohm together efficiency drops to 86.5% 0,63dB (not so good...)
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Old 25th July 2013, 10:02 AM   #793
regal is offline regal  United States
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Originally Posted by andyjevans View Post
I've tried SE and PP on numerous occasions, like most of us here. I never got the vocal quality of SE on any PP amp I ever built, and since I listen to singers of all kinds, that seals it for me.

.
Absolutely voices and strings, if I want P-P sound I have a 5W hybrid that anyone can buy off the shelf Lyr for 300 bucks, very little incentive to DIY.
I love the SET sound and it takes a big DHT project like this to get it with Hifiman orthos. Again I would not be pursuing this if power hungry Hifiman orthos weren't the best sounding headphones I've every owned.


Quote:
Originally Posted by esltransformer View Post
I did a quick calculation and its a little tricky because i not know the primair dcr but i hope the current density primair-secondair is equal.
I also hope that each 8 Ohm winding has 1 Ohm dcr and not all together.
So i calculated 156 Ohm primair dcr and 0,25 for all sec. In this case your transformer has an efficiency of 94.1% (0,263dB).

If the all secondair windings are 1 Ohm together efficiency drops to 86.5% 0,63dB (not so good...)
I am away from the house and need to check the primary. It was less than one ohm per secondary. But this is important data as the transformer efficiency really drives the final quality of a high powered DHT headphone amp.

Anyway you look at these Tributes are much more efficient than the electraprints I had. Also this is a core that is on the cutting edge so to speak, I lost the link but there is a new 300B tube supplier in Japan and to showcase their new very expensive tubes they chose transformers wound with this core lam. I forget the metallurgy but basically it starts as an amorphous but then I believe it ends up crystalline after annealing. Basically its nano-technology which wasn't part of my material engineering course 25 years ago With the brief testing I did with the 417A's the sound reminds me of nickel in a good way.


So for not a whole lot of money its very likely to DIY a 300B/2A3/PX4 headphone amp that should very well outperform an Eddie Current/Moth/Woo that costs thousands. I basically chose the 2A3 because NOS tubes are available, I could switch to modern 300B tubes if I come up short on power which is very possible with 77dB/mW headphones. Of course the issue with DIY is time, and I'm not into chassis work during the summer

And you guys are going to be disappointed that I plan on driving the DHT outputs with a good IDHT like the E182CC (gain=24). I just can't justify a three stage headphone SET and it really reduces complexity using a single IDHT driver. I am a huge proponent of simplicity when it comes to headphone amplifiers.

Where I am stuck in the design phase is CCS + capacitive coupling verses trying DC coupling. I am leaning more toward a Maidia powered DC coupled amp, again reduced complexity. But the Salas Shunt does so well with my SPUD that I haven't ruled that out if I could get my head around stacked supplies.
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Old 25th July 2013, 01:46 PM   #794
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The e182cc is an excellent tube and very hard to beat i think, excellent choice.
A e55l (in triode mode) would be nice too. The e55l is better the almost any dht.



Quote:
Originally Posted by regal View Post
Absolutely voices and strings, if I want P-P sound I have a 5W hybrid that anyone can buy off the shelf Lyr for 300 bucks, very little incentive to DIY.
I love the SET sound and it takes a big DHT project like this to get it with Hifiman orthos. Again I would not be pursuing this if power hungry Hifiman orthos weren't the best sounding headphones I've every owned.




I am away from the house and need to check the primary. It was less than one ohm per secondary. But this is important data as the transformer efficiency really drives the final quality of a high powered DHT headphone amp.

Anyway you look at these Tributes are much more efficient than the electraprints I had. Also this is a core that is on the cutting edge so to speak, I lost the link but there is a new 300B tube supplier in Japan and to showcase their new very expensive tubes they chose transformers wound with this core lam. I forget the metallurgy but basically it starts as an amorphous but then I believe it ends up crystalline after annealing. Basically its nano-technology which wasn't part of my material engineering course 25 years ago With the brief testing I did with the 417A's the sound reminds me of nickel in a good way.


So for not a whole lot of money its very likely to DIY a 300B/2A3/PX4 headphone amp that should very well outperform an Eddie Current/Moth/Woo that costs thousands. I basically chose the 2A3 because NOS tubes are available, I could switch to modern 300B tubes if I come up short on power which is very possible with 77dB/mW headphones. Of course the issue with DIY is time, and I'm not into chassis work during the summer

And you guys are going to be disappointed that I plan on driving the DHT outputs with a good IDHT like the E182CC (gain=24). I just can't justify a three stage headphone SET and it really reduces complexity using a single IDHT driver. I am a huge proponent of simplicity when it comes to headphone amplifiers.

Where I am stuck in the design phase is CCS + capacitive coupling verses trying DC coupling. I am leaning more toward a Maidia powered DC coupled amp, again reduced complexity. But the Salas Shunt does so well with my SPUD that I haven't ruled that out if I could get my head around stacked supplies.
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Old 6th August 2013, 01:43 PM   #795
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Arrived the Edcor's GXS5E-600-15K, looks great, attached pics & schematic
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Old 7th August 2013, 10:44 AM   #796
regal is offline regal  United States
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Quote:
Originally Posted by merlin el mago View Post
Arrived the Edcor's GXS5E-600-15K, looks great, attached pics & schematic


Did you not read one post in this thread 600 ohm primary has no business connected to a headphone. Those are preamp output transformers.
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Old 7th August 2013, 10:55 AM   #797
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It's 15K primary... 600 sec. most probably refers to his HD 600's impedance.
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Old 9th August 2013, 09:32 AM   #798
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I guess if the load HD600 have 300 ohms the primary will be 7K.
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Old 9th August 2013, 04:49 PM   #799
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Sorry typo 7K5
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Old 9th August 2013, 05:16 PM   #800
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Just make sure the DC current spec is fine with the 307A bias current and be careful to connect it properly. Cheap, practical solution.
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