Realizing that I have exploited all the possibilities out of my push-pull 2A3 amp, for my next project, I decided to go single-ended. I have serviced and built quite a few Kit Is for Steve while he was busy building his WE 91 clone. Although sonically quite different from each other, they are both fine sounding amps. My instinct sensed that I can combine the virtues I admired from those two amps using my favorite octal based twin triode, the venerable 6SN7. Since I need at - least 7-8 watts of clean power to enjoy my music, 300Bs were a natural choice.

Off I went, borrowing back-issues of MJ from the Angela archives, searching the internet and talking to friends. Funds are a bit tight this year but
sourcing transformers and parts that are beyond the realm of my "junk box" is not a problem; they are available from Steve (many thanks and also to the gentleman in Japan who bought my PP2A3, you actually helped fund this project) along with his liberal terms policy. Only to me folks, I am privileged!

My circuit choice narrowed down to the Reichert, Fi Primer 3008, and the Audio Note Conquest series. All these amps use the 6SN7 as an input/driver tube so no drastic alterations were necessary to try these circuits on my pair of chassis.

For two weeks, I listened in mono; one side Reichert, on the other, Fi Primer/AN Conquest (thus called because my choice of values for load resistors are somewhere between the two). I treasure my Acro 20/20 amp because it has that dark and austere sound quality that I find haunting. The Fi Primer/AN Conquest circuit had these qualities but added a hint of glare or sheen in the upper midrange which bothered me. Herb's amp was very smooth and full bodied in the mids but comparatively lacking the impact and dynamics of the latter. At this point I was itching to listen in stereo, so a decision had to be made...... DC coupling won by a narrow margin! This circuit was also a bit too sensitive for my system so I removed the cathode bypass cap on the first stage. The glare was gone and I got the sensitivity needed.

Nothing is unique about this design; I am merely a "triode chef' mixing a "concoction of ingredients" learned from trying the aforementioned circuits. The first two triodes are direct- coupled in cascade, then, capacitor coupled to the grid of a 3008. 1 prefer the "taste" of 300Bs running at or close to 80 ma. with approximately 425 volts on the plates. This may elicit some controversy in some circles...... it is sufficient to say that I tried and listened both ways and voted with my "earbuds", so no arguments please. Anyway the AN 3K OPTs are rated at 140 ma. If you are worried about burning up NOS WE300Bs, be a cheapskate like me and use Chinese tubes. Believe me, they do not sound 10 times worse considering the insane prices being asked for
NOS WE, that is.... if you can find them. Chinese 300Bs are rugged and take it with a smile while playing the gig.


To the more seasoned and discerning palette, may I suggest, going all the way with Black Gates sprinkled with Rikens and/or Tantalums served through copper foil caps.......

Joseph Esmilla, April 1997

PARTS FOR JE 300B MONOBLOCKS

1. Angela Universal Power Transformer.
2. Hammond 159P, 10H/125mA.
3. Output Transformer, Audio Note 3K 30W SE, with end bells. Also see the Tango and Hammond price lists on this site for alternative choices.
4. Angela Series II SE Triode Monoblock Chassis, aluminum, black Polane T finish with brushed aluminum ends, with ventilated bottom plate, SOLD OUT.
5. 15uF/600VDC Angela Oil Cap.
6. 30uF/600VDC Angela Oil Cap.
7. 50uF/518VDC Angela Oil Cap.
8. Two small cap mounting clamps.
9. One large cap mounting clamp.
10. Angela/Jensen/Audio Note paper in oil, .22uF/630V coupling cap.
11. Black Gate 100uF/100VDC cathode bypass for 300B.
12. Black Gate 47uF/160VDC cathode bypass for 6SN7.
13. Riken 470 Ohm 1W.
14. Riken 100K 1W, two pieces.
15. Riken 220K 1W, two pieces.
16. Riken 47K 1W, four pieces.
17. Riken 1K 1W, two pieces.
18. Angela 880 Ohm non-inductive 50W cathode resistor.
19. 50K 25W Dale power supply bleeder resistor.
20. 3.3K 5W metal oxide power supply dropping resistor. Note previous version specified a 1.5K, we found the 3.3K works better.
21. GZ37/CV378 rectifier tube.
22. 6SN7WGTA JAN Philips '80s N.O.S.
23. Angela 300B, China, latest version with nickel plates, SOLD OUT.
24. Angela ceramic silver octal tube socket, two pieces.
25. China ceramic silver Johnson style wafer socket for 300B.
26. Kimber RCA input jacks by Kimber, chassis mount, Teflon insulation.
27. AC inlet port, IEC type, two screw mount.
28. AC cord, Belden shielded type, heavy duty.
29. On-Off switch, N.O.S. heavy duty type with metal bat.
30. Fuse assembly, vintage Fender type. Use a 2A Slo-Blo fuse you can buy at Radio Shack, etc.
31. Terminal strips, assortment with hardware.
32. Clarostat 75 ohm 2W wirewound pot with locking shaft, approx. 1& 1/16" diameter body.
33. Alps Black Beauty volume control pot, 100K (OPTIONAL-MAY BE USED TO REPLACE ONE OF THE 100K RIKEN INPUT GRID RESISTORS LISTED ABOVE).