My massive gamble - acuhorn R2R dac with switchable DHT tube output

[Nuforce]

I couldn't resist any longer, so I decided to take a gamble and try this very interesting looking dac from polish outfit acuhorn.

Very interesting design using a simple SET output with Soekris R2R board. Power supply very unusual.

I will be trying a new pair of WE300B and a pair of 45 Ken Rad to start.

Acuhorn R2R T

Founded in 2003, presented high sensitivity single driver speakers, with highly recommended Acuhorn Nero125. The best matched series of OTL tube amplifiers Acuhorn S2 and series of Mosfet single ended amplifiers Mono and Stereo. Next introduced the rare puristic design of one 'Big Tube' tube...

www.acuhorn.pl

 

[eskamobob1]

Any updates on impressions?

 

[Nuforce]

extremely pleased with the unit. I've been switching between NOS National Type 45 ST tubes and some WE300B replica and the sound is extremely natural, with a wide soundstage and very good instrument separation.

I believe the vicor power supply is playing a big part in the unit's performance, offering the Soekris R2R board a clear power supply, but also offering a very pure and stable DC filament source for the DHT tubes.

 

[Tuckers]

This is a very interesting DAC!

 

[DasguteOhr]

a soekris board with tube stage are great sounding dacs, like lampizator atlantic, i have a lot experience with that
in the end i change to SSB 01 Bufferstage the best of both worlds transistor and tubes.
clear buy recommendation from me

 

[Nuforce]

Just bought a pair is mint NOS 01A tubes to try on the 300B, 5v heater setting.

With 3 different heater settings I can roll pretty much all DHT tubes just like a Lampizator.

 

[Nuforce]

Currently using almost century old 112A triodes in the Acuhorn. I wasn't expecting much from these in comparison to my €1000 Emissions labs 45 Mesh Globes but they are just as gorgeous sounding.

Who says you need a Lampizator to roll the wide array of wonderful triodes out there !

 

[Golum]

Oldie goldie for peanuts

 

[Nuforce]

Oldie goldie for peanuts

Honestly I am totally shocked how good these tubes are. I paid $70 for the pair!? Totally silent in operation and oozing in timbre with my magnepan 20.1 ribbon tweeters and my atma-sphere MA-1 OTLs.

 

[Golum]

Honestly I am totally shocked how good these tubes are. I paid $70 for the pair!? Totally silent in operation and oozing in timbre with my magnepan 20.1 ribbon tweeters and my atma-sphere MA-1 OTLs.

 

[Tuckers]

How is the Acuhorn going? Long term impressions?

 

[Nuforce]

Hi

Still enjoying the Acuhorn and in fact I've had the owner rewire the unit for me using a mix of Mundorf silver/gold and Dueland pure silver. I've setttled on EML 45 mesh globes although as per another thread I've very recently discovered the joys of type46 tubes using the 45 heater setting and pin adapters.

Currently using it via coaxial into my new Hifi Rose RS130 transport. A wonderful device.

I still intend to try an officially used Lapmizator Pacific at some point, but very happy with the Acuhorn for now.

 

[spiritofmusic]

There are two Acuhorn tube dacs, yes? This one using 300Bs and a less expensive one using smaller tubes in the output stage?
Has anyone heard both to compare?

 

[Nuforce]

There are two Acuhorn tube dacs, yes? This one using 300Bs and a less expensive one using smaller tubes in the output stage?
Has anyone heard both to compare?

yes that's correct https://www.acuhorn.pl/acuhorn-R2RTS.htm

Mine is the R2R T which has a 5 Volt, 4 Volt or 2.5Volt heater switch like a Lampizator. There is also a balanced XS version which I thought was unnecessary so just bought the SE version.

Unlike Lampizator these designs don't use tube rectification. When I asked Acuhorn why, this was their response

"Because I use a super fast modern Vicor power supply module.
I have a constant voltage at the output.
No need rectifier tube in front of the module.
These modules act as an audiophile power conditioner.
If I would use a rectifier tube behind the module,
it would spoil the effect of the super stable sound image of the soundstage"

When I looked on Mouser I noticed those Vicor DC-DC modules are not cheap, and some of their versions are military grade, so the PSU section is super interestingly designed.