Sophia Electric 845 Single Ended Mono-Block Amplifiers

Sophia Electric 845 Single Ended Mono-Block Amplifiers
Sophia Electric 845 Single Ended Mono-Block Amplifiers
Regular price
Sale price

Price: S.E.T. Princess 206 drives 845 single ended mono-block amplifier: USD $20,000 per pair.

Price: S.E.T. Princess 206 drives 845 push-pull custom-made mono-block amplifier: USD $36,000 per pair.

Every 845 or 211 vacuum tube amplifier has power, so what makes this 845 amplifier design stand out? It is the sonic beauty. This Sophia Electric™ 845 amp can match a 45 tube amp for purity and musicality, while putting out 22-25 watts of glorious single ended tube amplifier power. As experienced audiophiles know that 845 tube amps can have great mid and bass, but extended and smooth high frequency performance is not easy to achieve. This amp excels in the mids and highs unmatched by other big power tube amplifiers.

845 amplifier
This amp is unconventionally built for the best possible sound in mind. The design has the shortest signal path with all resistor and capacitor leads cut to less than ¼ inch long. So the conventional approach does not apply to this amp. There is little that conventional Tweaks can add to the performance of this amp (plus the 1000V inside the chassis argues against tweaking).

845 amplifier
There are 3 transformers and two chokes per channel. The power transformers provide 350 watts of power, yet in super small size. The secret is using very expensive Japanese iron material, so there is no hum, no vibration, and it generates much less heat for a powerful 845 Single ended amp. How is the sound? The amp has great dynamics, extension at both ends, and transparency. Most importantly: it is extremely musical with a rich tonality that nevertheless remains accurate. It makes other amps sound dead.

25 watts output from a single 845 tube per channel. Super linear, distortion-free sound, just like live-performance. When you listen, you believe.

User Experiences:

Now I want to tell you what I'm very excited about my newly purchase Sophia Electric 845 amplifiers. They are settling in. I have four days of listening on them. These amplifiers keep getting better and better as they burn in. They are like nothing I have ever heard before. I have heard what some people think are the best like Wavac's and Ongaku's ect. Sophia Electric 845 amps are so real sounding. They have uncanny detail that is presented with weight and authority. The sound stage is life-like. These Sophia Electric 845 amplifiers are truly amazing amplifiers. I had no idea it could get this good but you have made it happen for a seasoned audiophile. What can I say but thank you from the bottom of my heart! Now it's time to get back to enjoying music!

All the best to you both,


 Hello Richard and Sue,

As you may recall I bought a used Sophia Electric 845. I have been using it as the ‘tweeter’ amp (above 1200 hz) on my Dali Megalines (ribbon/cone hybrid) with very good results. The Sophia Electric 845 amp has been driving the ribbon and I have tried a few amps on the bass/MR cones: Canary reference Ones (pp 300B design) and more recently a pr of NAT Se3 Reference (PSE 845 design). I have been generally having very good sound but have not yet been completely satisfied with the Megalines and the mixing of amps through their active (solid state) crossover.

Two days ago, I tried something different - I put the Sophia on the lower (cone) section of the speakers and the NAT on the ribbons. The Megalines are rated at approx 90 db efficiency and run 3 ½ to 6 ohm impedance. Well after adjusting the balance between the amps I was stunned!!! The Sophias give up a little in the bass in terms of power and damping to the NAT (which are very good in the bass) but the overall sound was now absolutely exquisite! I’m still in a mild state of unbelief at how much more musical and realistic the Sophias sound when driving the cones (1200 Hz and below) than any of the other ‘super’ amps. I listened for 5 hrs straight yesterday and the sound just kept getting better (I think it took an hour of two for the Sophias to adjust to the new load and settle in). The entire sound field was incredibly transparent and open. The midrange was the best I’ve heard in my house – ever.

Anyway the Sophia 845 amps are staying in the premier position for driving the midrange from now on! I am still not convinced I am going to keep the Megalines – which still bothers me to have an active crossover, especially a solid state one. But having said that I have not heard any other speakers I prefer – I am going to audition another speaker system soon as the manufacturer lives in the next town over. I guess we’ll see.

If I do decide to keep the Megalines, I will almost certainly look to get a second pair of Sophia 845 amps. With that in mind I wanted to ask you how the newer 845 amps differ from mine?

Another question – I know some people have had new crossovers built for their Megalines using tubes instead of solid state. The crossover is not just filtering but also adding EQ in places and boosting the gain on the ribbons by several db. Would you be interested at all in possibly designing/building a custom tube based crossover for the Megalines? I am so impressed with your results on the Sophia 845 amps that I should think you could build a superior crossover circuit. Just a thought.

Thank you for this exceptional amplifier!


Roy of Fallbrook,California

 Hi Richard: Here are my experiences with the Sophia Electric 845 mono-blocks and some history.

As you know, I purchased the amps from Robin Wyatt in Feb 2005. They came configured with Sophia 274B rectifiers...2 solid plate, for the 845 tubes and 2 mesh plate Princess for the Princess 206 tubes. The 3A5 tubes were RCA and there were 2 pairs of 845 tubes. One Shuguang and one Chinese of unknown source. I have since changed to Sylvania JAN 3A5 tubes. 845 B and M tubes have been tried but I have returned to the A's.

I had previously been using a 300B amp. The Sophia’s were much more truthful. They had a richness of timbre that the 300B amp was just missing. You could at last tell what the instruments were made of. It was the Sophia’s that started my love of acoustic instruments as I realized that I could at last reproduce acoustic instruments really accurately. I formed the idea that if I could firstly reproduce a simple acoustic instrument, and then more complex ones, that all the other stuff that many Audiophiles talk about endlessly...punch, slam, bass, mids, highs, image would take care of itself. I now have a system that can reproduce a full grand piano REALISTICALLY. The 845 mono-blocks continue to be my connection with the instruments I am reproducing. They are by far the best amplifiers I have ever owned (and there have been many over the years) and I intend to keep them.

Recently a 20K front-end upgrade only strengthened by belief in these amplifiers.

Regards Geoff Clarke

 Dear Richard:

I want to take this opportunity to thank you for everything you have done for me. The 845 amps you have are the best amps I have ever heard BY FAR. They are more real sounding, with better highs, midrange, and lows. They sound more powerful than any amps I’ve ever heard, including some 400 and 600 W/ch amps I’ve auditioned in my system, and their resolving power is better, too, than anything else. Unprecedented and simple AMAZING!

Nobody will believe the words I have just written until they hear for themselves; then they won’t have to believe, they will know.

Best regards,

John Zermani

 Having lived with these amplifiers for several months now, I can say without hesitation that they are the finest 845 amps I have ever heard. They compare favorably to the best out there, and I have listened to the Cary, the Jadis and others of that quality. They overcome some of the traditional weaknesses of the 845 tube, particularly in top end extension, and they take control of the bass in a way the best solid state amplifiers do. Mated with quality ancillary equipment, the sound is dynamic and musical while making no concession to the euphony so often a characteristic of other amps in this class. In sum, excellentamps, well constructed and a bargain at this price.

Sophia Electric 845-05 mono-block Tube Amplifier Specification


26 watts output per channel single ended 845 direct heated triode tube amplifier with zero negative feedback.

OPT Transformers

Sophia Electric designed and in house made 845-05 output transformers. Potted with three layers of metal shielding.

Frequency Range:

12 Hz – 50 KHz

Input Sensitivity:

1.5V RMS for full power output

Input impedance:


Residual Noise/Hum:

1.2 mvac


-0.1% at 1 watts at 1KHz


68 pounds per mono-block unit x 2

AC Power versions:

1USA 845-05A
European 845-05B
China/Asia 845-05C
Japan 845-05J

Required break in time:

50-100 hours


One year parts and labor, Sophia electric brand tubes one year, Non-Sophia Electric tubes 6 month.

Above information is subject to change without further notice.

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