Allnic OTL/OCL Phono vs Allnic DHT

Here are some additional resources that may be useful-

From the Allnic H-10,000 OTL/OCL manual:

“Some circuit experts might be concerned about DC potential in the music signal in an OTL/OCL design.  However, the chance of this problem occurring can be essentially and reliably 100% mitigated. To do this, Allnic uses a “floating power supply circuit”, a design that deals with the issue by not creating any DC potential in the first place, or such a small potential that it is harmless.”

My personal experience with these units:  the H-10,000 requires less user attention for tube maintenance, more stable circuit and more robust to different environments.  

For the more advanced Allnic circuits I recommend this read:

https://www.kevalinaudio.com/circuit-balance-review-recommendations

For Manuals:

https://www.kevalinaudio.com/copy-of-current-legacy-allnic-manuals

For Reviews:

https://www.kevalinaudio.com/allnicreviewcurrentlist

“Some circuit experts might be concerned about DC potential in the music signal in an OTL/OCL design.  However, the chance of this problem occurring can be essentially and reliably 100% mitigated. To do this, Allnic uses a “floating power supply circuit”, a design that deals with the issue by not creating any DC potential in the first place, or such a small potential that it is harmless.”

That's an interesting turn of phrase ("floating power supply circuit").  Usually you would design the unit so as to have as little DC offset as practicable at the output, then cancel (or greatly reduce) that small DC offset with a servo circuit. Perhaps Atma-sphere can comment on whether the Allnic circuit might be unique. I think Allnic may be saying they treat the power supply as in a circlotron, a la the Atma-sphere products. Semantics.

To do this, Allnic uses a “floating power supply circuit”, a design that deals with the issue by not creating any DC potential in the first place, or such a small potential that it is harmless.”

@kevalinaudio We have two patents concerning a method of using a Circlotron circuit for this purpose as @lewm  suggested. It indeed is

a “floating power supply circuit”, a design that deals with the issue by not creating any DC potential in the first place, or such a small potential that it is harmless.”

During warmup, the Circlotron circuit can produce small DC offsets less than 1 Volt. Once warmed up the DC Offset is typically less than a milliVolt. Its plug and play since no adjustment is required. 

However its pretty obvious such a circuit is not used here. 

On reading the documents at the links you provided, it appears an SEPP circuit is used. The SEPP is a push-pull circuit of the 'totem pole' variety not unlike what you see in Futterman OTLs. They are often used in headphone power amps. 

Was wondering how or even if the floating PS as used by Atmasphere in the circlotron could be implemented in a SE output.

Regardless of the design wizardry Allnic employed in the OTL/OCL phonostage, I find it to be noticeably quieter than the DHT — and far easier to live with in terms of maintenance, operation, and day-to-day running. Cartridge loading flexibility is effortless, and the noise floor is effectively nonexistent.

With the older DHT 8000, I often battled microphonics and an occasional quirk where the soundstage would lean subtly to one side. Achieving a rock-solid, dead-centre image could be frustrating, requiring constant fussing with tubes and fine adjustments. The H10,000 OTL series has been the complete opposite: it simply warms up and is ready to make music, no drama, no fiddling.

What really stands out is the leap in performance: transparency, microdetail retrieval, tonal accuracy, soundstage precision, and dynamic range all surpass the DHT 8000 — which I had always regarded as an exceptionally musical phono stage in its own right. The H10,000 series feels several levels higher on the ladder.

Bass is no longer a touch overripe; instead, it extends deeper with greater control. Vocals have gained refinement without losing body and presence, while the highs are sweeter, more polished, and free of any edge — delivering a presentation that’s both revealing and inviting.