Sophia Electric™ 300B Single Ended Amplifier

Mark II

Reviewed by Enjoy The


We've never heard the (Avantgarde) Trio horn speakers better as with Your (300B) amp!!! We've tried many amps (including) a well known 16'000,-$ mono-block amps. None of them had the transparent, airy and the same time musical presentation as your Sophia Electric™ 300B Single Ended amp. This is by far the lowest noise 300B single ended amp we've ever heard on our 110 db Trio mit bass-horn!

Great Work!



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Since its introduction last year, Sophia Electric™ 300B single ended amplifier has been well received for its sonic beauty as well as artistic chassis design. Continue its tradition, the new mark II model is being made in the U.S.A. All mark I models can be converted into the new version with no fear of being out of date. Every Sophia Electric™ 300b amp is design and built with upgrade potentials.

Construction Quality:

9 watts per channel and a Single ended no Negative feedback design. Chassis is made of premium Japanese mirror stainless steel. Fitted with highest quality 24K gold plate nameplate, knobs and tube socket rings. The gold plate items were further coated with a layer of protective coating for durability. A visual design firm was commissioned to come up with this Patent protected four column feet chassis, using Titanium and Nickel coatings.

Point to point wiring with high quality wires. All capacitors and resistors are name brand audiophile grade made in Germany, Japan and the United States. Carefully selected parts for each function for the best sound. No guarantee it will last forever (nothing will), but 20 years later it will still be good looking and maintain its great sound.

The Circuit design:

There are many different ways to design a 300b amp, the following are some of the most popular ways:

SRPP design is to use the upper half (one triode) to provide the lower half of a 6SL7 tube for more favorable linear performance operating. The sound is extended in frequency. This SRPP arrangement is superior than using a plate resistor to do the same function. However, the 1-2 ma current the 6SL7 operates at is far from needed for a 300B. The lower current driver arrangement results very dry sounding.

The choice of using One 6SN7 (two triodes inside) to serve as input and drive tube to drive 300b would have more romantic sounding than SRPP (slightly more current than SRPP). Many internet DIY discussions seem favor this arrangement over the SRPP 6SL7. The popularity of these arrangements in many ways is due to the cost considerations and simplicity. Namely less tubes are needed (one 6SN7 or one 6SL7 per channel).

In the current market, there are a lot of commercial 300b amplifiers either use SRPP 6SL7(12at7) or 6SN7 mu follower drive 300b. They all sound fine for its price range, however, neither designs have enough current drive capability to drive 300b tube to the maximum potential. Here is some tech discussions of driver selections regarding current issues.

Sophia Electric's engineers like the SRPP for input stage for more frequency extension, and add one El-34 in triode connection per channel for current needed to drive 300B. El-34 is famous for its sweet, extended sound. Triode connection has very linear performance. We use a lot of current in the drive stage further enhanced the sonic performance.

The final design of this amplifier sounded shockingly dynamic, super sweet and liquid. There are more bass kicks than a typical Push and pull amplifier, there are more drive capability than most people ever thought possible for a 9watts x 2 amp. Click here to see user listening report.

There are two versions available:

Integrated version: This is not a cheap stereotype integrated, rather it is designed to be “one box solution” of the best sound possible for a 300b amp. Weight of 90 pounds, fully loaded with audiophile parts.

SRPP 6SL7 input triode connection El-34 as driver tube. Out put stage is single ended 300B. Four big Oil capacitors are being used for power supply and Allen Bradley carbon resistors are being used in the signal path, metal film resistor for power supply.. Two 5Z3PA or 5U4 rectifier tubes are being used, Capacitor-Choke-Capacitor (CLC) power supply. Two sets of inputs (RCA), stereo volume control. Many music-lover users like this version for maximum simplicity as well as first class sound.

Power amplifier version use two chokes for dual mono CLC power supply. 6SN7 input El-34 as driver. This is designed for maximum flexibility for any one who has a high end pre-amp already.

One year parts and labor. One year on Sophia Electric brand tubes, 6 month on third party tubes.

1. Integrated: $4995 with Sophia Electric™ 300B mesh plate tubes.

2. Power amplifier version: $4995 with Sophia 300B mesh plate tubes.

1. Power cable: 5 feet long. $175 each.

2. Speaker cable: 8 feet pair $300, 10 feet pair $350.

3. Inter-connection cable: 3 feet pair $400, 6 feet pair $600.

4. Acrylic tube cage: $199.99.

5. Sophia Electric™ 274B tube, $150 each, $300 per pair.(only mark II can use 274B).

6. NOS 6SN7, 6SL7 upgrades, Call 703-204-1429 speak to Richard.

7. Custom built to the way you like, call us.

Where to buy:
This version of amplifier is available through selected dealers in the US and in several European countries. More dealers and international distributors will be added.

In case there is no dealer in your area, you can buy it from us directly (phone 703-204-1429). We prefer you buy from a local dealer rather than over the Internet, as you can receive services locally. Email us where you are for dealer referral.

We take credit card, Paypal, checks/Money Order for US address. International buyer should pay by wire transfer or Money Order instead.

Via FedEx, UPS and US postal international express.

Copyright@2002-2003 Sophia Electric, Inc. All rights reserved.